# Rear Ballast - Facts and Info



## Bikerz (Aug 23, 2008)

Here we go guys. (updating when pics upload)

I have got loads of info off this site over the last 10 months and now im going to gve somthing back on a subject that comes up very oftern!

The QS does NOT have the rear ballast!

Here is my TTC 225. I decided to remove some weight today after removing seats and other bit sa few weeks ago. I used Wak's great guide found here

http://www.wak-tt.com/rearbumper/rearbumper.htm

Was very easy and decided to also remove the towing hook thing (as clearly no need for it on a TT (unless you plan and putting it through a hedge and need to be towed out? :roll: )

I wouldnt recomend doing this, look at my ride height now









:lol: 
Yes I know, only playing

Here we go









This is what we have (dirty)









Ballast

















What are thoose black vents for? I stuck my finger through and it doesnt go anywhere, so cant see what they are for? I was thinking rear brakes but theres a solid lump of metal behind :roll: :lol: 

























Here you can see ballast









I had to remove crash bar to get weight off









Nasty Tow Hook









Tow hook Removed









All off









Cleaning time









Cleaned The Inner Arches









Tow Hook









Bits I removed









When fished I decided to weigh the bits-

Ballast - 15kg
Brakets and tow hook - 3.8kg

these were on my scales so feel free to say its actualy 15.2 or whatever, but this is what I got.

So thats another 18.8kg off my TT today.

Oh and just because im a show off, last sunday I was driving this










2007 Boxster S
3.4


































Intresting that people on here take the boxster calipers and put on TT for better brakes, I however found them realy really poor, I ask Rob (owner) what was wrong and he said they are all really bad he took it bad saying there was somthing wrong with brakes they took it for a drive and said they are all like that  This is the S so had the 4 pot fronts and rears


----------



## Bikerz (Aug 23, 2008)

All there people


----------



## plumb (Jul 10, 2006)

Your TT looks 100% better than that ugly boxster,
Bet he got some rubbish compound brake pads fitted if the brakes are poor, they should be very powerfull and better than the TT brakes.


----------



## conlechi (May 6, 2006)

Nice work pics and write up Sheldon 

did the loss of weight raise the rear suspension height at all ?

My counter weight will be coming off in July with some other planned work etc 

I will probably leave my tow eye bracket in place in case i need it for track days etc , hopefully won't need it to be pulled out of a gravel trap 

Mark


----------



## Bikerz (Aug 23, 2008)

Its under porche warrenty still so will be running porche pads (hes one of those sorts of people if you know what i mean, well he did buy a brand new boxster S for 60k rather than a 1 year old 911 or R8 :roll: )

Cheers Mark


----------



## JNmercury00 (May 22, 2007)

your tt is naked


----------



## plumb (Jul 10, 2006)

Bikerz said:


> Its under porche warrenty still so will be running porche pads (hes one of those sorts of people if you know what i mean, well he did buy a brand new boxster S for 60k rather than a 1 year old 911 or R8 :roll: )
> 
> Cheers Mark


I'd have bought a year old R8 like you said, it's in a different league to a Boxster, he must really be one of theose people. :lol:


----------



## Hark (Aug 23, 2007)

What else have you removed mate? If you had removed rear seats, ballast and towing hook that's all from the back. Doesn't that screw your handling?

What you gonna remove from the front?


----------



## 26ash_tt (Jul 16, 2008)

has the weight saving so far made any noticeable difference?


----------



## JNmercury00 (May 22, 2007)

26ash_tt said:


> has the weight saving so far made any noticeable difference?


good question!


----------



## Alan W (Oct 8, 2007)

Hark said:


> If you had removed rear seats, ballast and towing hook that's all from the back. Doesn't that screw your handling?


It'll move the front to rear weight distribution forward and will change the handling on the limit if the weight reduction is significant. That's the theory but you may not notice a change in practice if the weight reduction is less than 50kg.

However, it would be worth moving the battery to the boot to lessen any change in the weight distribution.

Alan W


----------



## was (Mar 24, 2003)

Bikerz said:


> What are thoose black vents for? I stuck my finger through and it doesnt go anywhere, so cant see what they are for?


they stop your ears popping when you close the boot :wink:


----------



## Bikerz (Aug 23, 2008)

The ride height is actually higher! Yes i know its hard to belive, but charlie came home from work and 1st thng she said was that 

I havent noticed any difference in handleing but I dont drive it hard all the time il have to take it for a rag without "her" :lol: and see what think. The battery will be going to boot ot a lightweight battery, whichever Is cheaper I think. come on Mark pull your finger out :lol: Tho I cant afford anything now after seeing my tyres


----------



## DAZTTC (May 20, 2005)

was said:


> Bikerz said:
> 
> 
> > What are thoose black vents for? I stuck my finger through and it doesnt go anywhere, so cant see what they are for?
> ...


Well done that man Was you are spending far to much time with Wak :lol: :wink:

DAZ


----------



## Bikerz (Aug 23, 2008)

OK. You wont belive this, but thi sis a huge change!!! The back end goes light mid corner and you can get it out, you feel far more in control of the car, I may not be quicker but im happier. I know 19kg isnt alot, but its as far back as you can get. I can see why Audi put the weight on there now. If your bored at a weekend definatly take it out guys and gals


----------



## Hark (Aug 23, 2007)

Bikerz said:


> OK. You wont belive this, but thi sis a huge change!!! The back end goes light mid corner and you can get it out, you feel far more in control of the car, I may not be quicker but im happier. I know 19kg isnt alot, but its as far back as you can get. I can see why Audi put the weight on there now. If your bored at a weekend definatly take it out guys and gals


Mate I'm not sure I follow. How does the backend going light mid corner make you feel more in control?

Surely your therefore more likely to spin it if you induce too much oversteer or under heavy braking approaching a corner?


----------



## Bikerz (Aug 23, 2008)

Nah its just more fun, can really slide the back end round, even as slow speed if I prevoke her.


----------



## Tim G (Feb 16, 2005)

Bikerz said:


> Nah its just more fun, can really slide the back end round, even as slow speed if I prevoke her.


Worlds slowest response to a question? :lol:


----------



## tony_rigby_uk (Nov 27, 2008)

Tim G said:


> Bikerz said:
> 
> 
> > Nah its just more fun, can really slide the back end round, even as slow speed if I prevoke her.
> ...


 :lol: :lol: :lol: :lol: :lol:


----------



## Bikerz (Aug 23, 2008)

Tim G said:


> Bikerz said:
> 
> 
> > Nah its just more fun, can really slide the back end round, even as slow speed if I prevoke her.
> ...


Only just spotted it had been answered.

Now im on coilovers too she really dose slide well, I warned my uncle last night in the pub, I cant see it long before I get too cocky and have to ask him for a tow out of a field (he said as long as it doesnt have to peel me off a tree thats fine)


----------



## Guest (Jan 29, 2010)

Personally, I'd rather keep 19 kg and have a more even weight distribution. I found that both my previous diesel hatches handled so much better with luggage and stuff in the back, the Corolla particularly since the engine is, unbelievably these days, an iron block. I used to do a tasty drive twice a week up the A701 from Moffat to Penicuik in all weathers, all times of the year so used to see a big difference. I wish I had my TT back then :-( I used to drive my wife's 1.0 litre 1994 Micra more 'enthusiastically' than I do my QS now. I could average a 35 mile cross country section with villages in 33.5 minutes. Madness. But that was between 06:30 and 07:30 in the morning when the roads were empty. One day in summer I'll try it again in the TT to see what can be done.

Saving weight is just one part of the equation, keeping it properly distributed is important too. I'd still like to see four wheel balance output for the various Mk1 TT models to get a handle on just what kind of difference the weight saving and battery moving has had from 225 to QS.

Doug


----------



## tony_rigby_uk (Nov 27, 2008)

Doug Short said:


> Personally, I'd rather keep 19 kg and have a more even weight distribution. I found that both my previous diesel hatches handled so much better with luggage and stuff in the back, the Corolla particularly since the engine is, unbelievably these days, an iron block. I used to do a tasty drive twice a week up the A701 from Moffat to Penicuik in all weathers, all times of the year so used to see a big difference. I wish I had my TT back then :-( I used to drive my wife's 1.0 litre 1994 Micra more 'enthusiastically' than I do my QS now. I could average a 35 mile cross country section with villages in 33.5 minutes. Madness. But that was between 06:30 and 07:30 in the morning when the roads were empty. One day in summer I'll try it again in the TT to see what can be done.
> 
> Saving weight is just one part of the equation, keeping it properly distributed is important too. I'd still like to see four wheel balance output for the various Mk1 TT models to get a handle on just what kind of difference the weight saving and battery moving has had from 225 to QS.
> 
> Doug


Thats funny as i don't think you have the 19Kg anyway if your car is a QS :lol: :lol: :lol: :lol: :lol: :lol:

:lol: :lol: :lol: :lol: :lol: So that post about keeping it balenced ect...... would you like my ballast if i take it off???? perhaps you'd like to fit it to Balance your car :lol: :lol: :lol: :lol: :lol:

well i'm sure thats what it says on the first post... unless yours is a QS replica ofcourse... then by all means keep the ballast :lol: :lol: :lol:



Bikerz said:


> Here we go guys. (updating when pics upload)
> 
> I have got loads of info off this site over the last 10 months and now im going to gve somthing back on a subject that comes up very oftern!
> 
> ...


----------



## Bikerz (Aug 23, 2008)

QS does not have teh ballast! I have checked many QS and none have it. Simon QS and Rich car and 2 others certainly dont have it


----------



## tony_rigby_uk (Nov 27, 2008)

Doug Short said:


> Personally, I'd rather keep 19 kg


do you want me to send mine to you when i take it off? since you feel you need it :lol:


----------



## UR_TT (Nov 8, 2008)

Doug Short said:


> the Corolla particularly since the engine is, unbelievably these days, an iron block. Doug


Sadly u will find that the TT also has an Iron Block, not alu. Something to do with what forces it need to handle etc...


----------



## V6RUL (May 28, 2009)

Does the haldex play a part in trying to keep the car balanced by monitoring traction to the wheels and adjusting as nes to balance the drive, if so then by lightening the car the faster it will go and unless you are in mid air the haldex will split or share the power to keep the best traction it can distributed across all four wheels and if youve got the blue one this is even better for the distribution unless your just sraightlining when the majority of the power is sent to the front wheels.
Steve


----------



## Charlie (Dec 15, 2006)

I have about 3 ballasts if anyone wants to put them all in the boot :lol: cost of posting will only be about £100 :lol:

Charlie


----------



## Guest (Jan 29, 2010)

tony_rigby_uk said:


> Doug Short said:
> 
> 
> > Personally, I'd rather keep 19 kg
> ...


For the avoidance of doubt, I simply meant that if I had a 225 PS coupe (which I don't) I wouldn't bother taking it apart to remove 19 kg which will then affect the handling and weight distribution. I don't feel I need it enough in the QS (which I can read doesn't have ballast) to bother taking it apart to put it on. If adding it helps balance up the car nearer to 50:50, then why not fit it, perhaps on the opposite side to the battery? It's not that preposterous a suggestion to merit such sarcasm is it? 

That was the reason why I'd like to see four wheel balance results for all models, including the QS. Maybe there isn't that big a difference with all the weight saving and redistribution that was done in the QS and it wouldn't be worth doing. I don't know though. There was similar discussion on this thread where I posted some US data on Mk1 TT coupe weight distribution:

viewtopic.php?f=2&t=129267&start=30#p1518359

Doug


----------



## tony_rigby_uk (Nov 27, 2008)

Balance of the car is pointless unless you take into consideration driver weight... Thats the biggest thing tha will upset balance... if removing 19kg makes you feel abit better then go for it... but even a car with perfect 50/50 is shagged as soon as the driver sits in...which is something that always confussed me on the QS with relocating the battey... obviously engine is over to the right... gearbox to the left... gearbox is lighter than engine so battery helps balance... then add driver and the left front is still heavier :?


----------



## DAZTTC (May 20, 2005)

tony_rigby_uk said:


> Balance of the car is pointless unless you take into consideration driver weight... Thats the biggest thing tha will upset balance... if removing 19kg makes you feel abit better then go for it... but even a car with perfect 50/50 is shagged as soon as the driver sits in...which is something that always confussed me on the QS with relocating the battey... obviously engine is over to the right... gearbox to the left... gearbox is lighter than engine so battery helps balance... then add driver and the left front is still heavier :?


Very good point Tony. 

DAZ


----------



## tony_rigby_uk (Nov 27, 2008)

DAZTTC said:


> Very good point Tony.
> 
> DAZ


They do happen Occasionally.... Usually when it's a blue moon :lol: :lol: :lol: :lol:


----------



## DAZTTC (May 20, 2005)

tony_rigby_uk said:


> DAZTTC said:
> 
> 
> > Very good point Tony.
> ...


Would it have to be denim :wink:

DAZ


----------



## JNmercury00 (May 22, 2007)

this is all very interesting but how much power does this mod give you? my k&n panel filter gave me an extra 50 bhp so i am guessing this will push it over the 300bhp mark, and i haven't even had a remap yet!!!!!


----------



## DAZTTC (May 20, 2005)

:lol:


----------



## tony_rigby_uk (Nov 27, 2008)

You mean Brek... :wink:

It depens if your cars a "good en" as that 50Brek in it's self :wink: :wink:

But on a more serious note... wouldn't the 19kg weight (being where it is) actually unbalance the car when you consider lowering??? if it is trying to counteract the excessive front wight with rear weight then surly the center of gravity plays a part also and should be lightened acordingly???? All maths and calculations though... but i'm sure someone could work it out... also why do QS have extra welds on the chasis... I can understand it for the roadsters (because if you cut the roof off something you crate more flex) but why dos the QS need it... it's got a roof :roll: or should we 225's start putting more welds on ours ???


----------



## Guest (Jan 29, 2010)

I agree with you on this one Tony and the driver sits offset to one side in all regular cars, so I always wondered about the effect that had.

I have been mulling these kinds of issues over for some time and, I'm afraid, there'll always be pub-style banter over the relative merits of removing weight to give improved acceleration and fuel economy versus the effect on weight distribution and therefore handling unless some hard data and physics is brought into it. If you'll forgive me, I've knocked up some simple calculations to try to illustrate objectively what I was trying to say earlier when I was misunderstood, i.e. that the benefit of slightly increased power-to-weight ratio by saving 19 kg from the rear end on a 225 PS coupe is outweighed by increasing the unbalanced cornering force, front-to-rear.

See next post when I've formatted it from MS Excel to display here. Then the scientists and engineers can really roll their sleeves up and have a barney!

Doug


----------



## Fred (Jan 7, 2010)

This ballast thing interests me.

Firstly, I doubt VERY much you can notice a difference in 19kg on the road - it must be a placebo.

Anybody know why its officially there? (any Audi technical docs for dealers etc)

Its not like it gives you more rear end grip becasue that weight pushing down is also balanced out by the fact the weight is there.

A heavy car is not as fast as a light car - I.e. Weight does not give you more grip.


----------



## JNmercury00 (May 22, 2007)

Fred said:


> This ballast thing interests me.
> 
> A heavy car is not as fast as a light car - I.e. Weight does not give you more grip.


you are opening a can of worms here mate!


----------



## Fred (Jan 7, 2010)

JNmercury00 said:


> Fred said:
> 
> 
> > This ballast thing interests me.
> ...


Its true though 

Its like people who go go-karting and say the fat bloke is faster around corners. Its total crap.

Sure the car is pushes down more but the forces the tyres have to contain goes up.


----------



## Fred (Jan 7, 2010)

I tell you what would be interesting as well.....

Was this weight here befre they revised it to have a spoiler?

It may be even befor ethe spoiler they tried to fix any issues with weight at the back. They could have then fitted a spoiler but left the ballast just as a carry over and never put much thought into it??

Also am I correct in thinking this is only on the nearside??

if so maybe on LHD cars its on the other side and is to aid balance with a driver in.

I know my Integra is setup in such a way that the weight distribution side to side is only perfeect when you have a driver in.


----------



## JNmercury00 (May 22, 2007)

Fred said:


> I tell you what would be interesting as well.....
> 
> Was this weight here befre they revised it to have a spoiler?
> 
> ...


IIRC they added it along with the spoiler, think it's also on the same side for lhd countries. correct me if i am wrong


----------



## Super Josh (May 29, 2009)

tony_rigby_uk said:


> Balance of the car is pointless unless you take into consideration driver weight... Thats the biggest thing tha will upset balance... if removing 19kg makes you feel abit better then go for it... but even a car with perfect 50/50 is shagged as soon as the driver sits in...which is something that always confussed me on the QS with relocating the battey... obviously engine is over to the right... gearbox to the left... gearbox is lighter than engine so battery helps balance... then add driver and the left front is still heavier :?


LHD FTW


----------



## Guest (Jan 29, 2010)

O.k., here goes with the geeky stuff then. Publish and be damned...

Unladen mass 225 PS coupe: 1465 kg (accepted figure but April 2005 brochure ref 533/1102.87.25 quotes 1515 kg).

Mass distribution (from http://www.audiworld.com/model/tt/01/coupe_specs.shtml)
60.0% (879 kg) front
40.0% (586 kg) rear

[N.b. No manufacturer's data or empirical information from four wheel balance measurements available on UK vehicles to substantiate this information.]

Q1. How would the mass distribution of a 225 PS coupe change if a 27.4 kg battery was moved from the front to the rear (i.e. most significant effect on mass distribution change from 225 PS coupe to 240 PS coupe)? 68 Ah sealed lead acid battery mass interpolated from data at http://www.powerstream.com/Size_SLA.htm)

*58.1% (851.6 kg) front
41.9% (613.4 kg) rear*
[This is assumed to approximate to the mass distribution of the 240 PS coupe given that the weight difference between standard heated and bucket seats is approximately on the axle centreline. Rear seat delete kit is aft of axle centreline but difficult to estimate effect on mass distribution/no mass data available.]

Q2. What effect does removing a 19 kg counterbalance weight have on the power to weight ratio (PWR) of a 225 PS coupe?

225 PS (221.9 BHP)
1.465 tonne standard unladen, 1.446 tonne unladen with 19 kg counterbalance removed

151.5 BHP/tonne standard unladen
153.5 BHP/tonne unladen with 19 kg counterbalance removed
*Difference: +2.0 BHP/tonne*

Q3. What effect would adding a 19 kg counterbalance weight have on the power to weight ratio (PWR) of a 240 PS coupe? (Doug Short vs Tony Rigby argument)

240 PS (236.7 BHP)
1.438 tonne standard unladen, 1.457 tonne unladen with 19 kg counterbalance added.

164.6 BHP/tonne standard unladen
162.5 BHP/tonne unladen with 19 kg counterbalance added

*Difference: -2.1 BHP/tonne*

Cannot estimate effect on 0-60 mph acceleration until a correlation between PWR and 0-60 mph times is done (work in progress). Basic assumptions for this would be that variations in Cd, tyre rolling resistance and power & torque delivery are second order compared to power-to-weight ratio (PWR) from model to model.

Q4. What is the mass of a full tank of premium unleaded petrol and what difference would this make to the mass distribution of a 225 PS coupe?

Density of Shell V-Power = 754 kg/m^3 (http://www-static.shell.com/static/aus/ ... ds_new.pdf)
Capacity of 180 PS, 225 PS & 250 PS coupe fuel tanks = 62 litres (0.062 m^3)	
Mass of a full tank = 46.75 kg

*879 kg front (58.1%)
632.75 kg rear (41.9%)*

Cornering Force Estimates

Input data and assumptions: 
0.5 g (4.91 m/s2) estimated cornering acceleration. Anyone with data from Liquid TT on a track day, please post up measured data.

Calculated parameters (GCSE physics, F = ma) for 225 PS coupe assuming 60:40 weight distribution and treating the vehicle as a simple two-point mass model:

4.31 kN cornering force front
2.87 kN cornering force rear
1.44 kN unbalanced cornering force front to rear. BASELINE. Tendency to understeer?

Q5. How does the cornering force distribution on a 225 PS coupe change when a 27.4 kg battery is moved from the front to the rear?

4.18 kN cornering force front (from F = ma)
3.01 kN cornering force rear (from F = ma)
1.17 kN (18.7% less) unbalanced cornering force front to rear than 1.44 kN baseline.

[Would be grateful if someone could interpret this in layman's terms of oversteer & understeer.]

Q6. How would the cornering force distribution of a 225 PS coupe change if a 19 kg counterweight was removed from 
the rear?

4.31 kN	Cornering force front (from F = ma)
2.78 kN	Cornering force rear (from F = ma)
1.53 kN	(6.5% more) unbalanced cornering force front to rear than 1.44 kN baseline.

Q7. How would the cornering force distribution of a 240 PS coupe change if a 19 kg counterweight was added to the 
rear?

835.4 kg front (estimated from battery move but on 1438 kg car instead of 1465 kg car)
621.6 kg rear (estimated from battery move but on 1438 kg car instead of 1465 kg car)

4.10 kN	Cornering force front
3.05 kN	Cornering force rear
1.05 kN	(8.0% less) Unbalanced cornering force than standard 240 PS coupe with 2.1 less BHP/tonne.

I'm not interested in getting into a debate about the actual masses of different cars. Suffice to say there is variation in data out there.


----------



## Fred (Jan 7, 2010)

Anybody weighed a TT 225?

There are seemingly mixed figures. EVO quote 1395kg which to be fair seems about right given its performance relative to that used in a bhp/ton.

Also, relative to spring, damper, roll bar, alignemt, etc etc weight distribution at this level (20kg) is pretty much insignificant in terms of balance.

Indeed 2PSI front or rear in the tyres will do more to change the balance IMO.


----------



## Bikerz (Aug 23, 2008)

Doug as much as I can see you have put some effort in there, figures dont mean everthing, its how the car feels, after all thats why we brought our TT :roll:


----------



## Guest (Jan 29, 2010)

Bikerz said:


> Doug as much as I can see you have put some effort in there, figures dont mean everthing, its how the car feels, after all thats why we brought our TT :roll:


I agree wholeheartedly and how the car feels has already been covered in the thread. I wanted to add some objectivity to the discussion. At least we have some calculations to argue about now. :wink: There are folks on here who will pore over data and analyse things to the nth degree and those who just enjoy the car. I fall into both camps! I'm caring less and less as the effect of half a bottle of Jacob's Creek Shiraz Cabernet 2006 kick in... 

Doug


----------



## Bikerz (Aug 23, 2008)

:lol: Id like to think im one for figures too being an engineer, but after all week at work and a friday evening drawing in, I just cant be arseed :lol:


----------



## Guest (Jan 29, 2010)

Bikerz said:


> :lol: Id like to think im one for figures too being an engineer, but after all week at work and a friday evening drawing in, I just cant be arseed :lol:


Ah, come come now. I work night shifts on my shift pattern as Homer Simpson at the Springfield power plant and if I had been on them just now, I'd have been working this through in the wee small hours :wink:

Doug


----------



## Guest (Jan 29, 2010)

Fred said:


> ...I doubt VERY much you can notice a difference in 19kg on the road - it must be a placebo.
> Anybody know why its officially there? (any Audi technical docs for dealers etc).


Me too Fred. I don't know, but I reckon Hans or Fritz that designed the motor in the first place knows more about cars than all the TT Forum members put together, which is another reason why I'd just leave it in place (if I had a 225 PS coupe, which I don't, nor a replica QS).

Doug


----------



## Fred (Jan 7, 2010)

Doug Short said:


> Fred said:
> 
> 
> > ...I doubt VERY much you can notice a difference in 19kg on the road - it must be a placebo.
> ...


Yep, they will know more than us all put together times 1000.

But.... It depends the reasons behind it. If something is there to cater for the masses (i.e. people who cant drive) then it could be that with it not there, the car would suit the 1% of drivers who can drive.

So for them them removing the ballast is an advantage.

The truth is we will never know the exact reasons. One thing we can be sure of though is you average driver on here sure as hell wont notice a difference removing it!

Another thing we can be sure of is - its a total bodge! :x


----------



## Gone (May 5, 2009)

This was covered in detail by some chap who wanted to lighten the car to gain PWR on the track and mpg on the road. The consensus view as I remember it was that the car would be destabilised (possibly dangerously so to the inexperienced/unwary) by removing 15 kg, if it was standard, but if lowered the weight loss was tolerable.

Perhaps this explains why the QS (lowered relative to 225, IIRC) can do without the counterweight.

If I can find the post I'll edit.

Edit: Ta-da! viewtopic.php?f=2&t=125044&start=15

Not as much info on effect of lowering as I remembered though!

But at the end of the day it's your car and you can do what you like with it.

PS Doug good effort on the calculations, that's dedication.


----------



## Grahamstt (Jul 22, 2008)

How heavy do you think 60litres of V power is. [smiley=bigcry.gif]

Does that mean it's best to put a fiver at a time in

On the balance note - M Sport lighten the Focus WRC so much they then add ballast by way of a 75Kg REAR sump guard, they can shift this weight around the car accordingly depending on driving style and type of roads to be attacked.

You could try the "lighter" route by removing spare wheel and tools and virtually no fuel then try again with full tank and spare back in and see if you notice any difference. I tried it at a sprint (not in a TT tho) and went slower in the lighter set up :?

Very interesting and complex topic handling [smiley=gossip.gif]

Graham


----------



## Hark (Aug 23, 2007)

I did a few runs at santapod last Sunday. The difference with and without a passnger (so I guess removing less than 80kg) made about 0.5 sec difference, which is quite alot on a 1/4 mile tbh.

My best time of 14.27 was when I removed the spare wheel as well. This beat my previous time of 14.45.


----------



## liffy99 (Feb 28, 2007)

Doug Short said:


> O.k., here goes with the geeky stuff then. Publish and be damned...
> 
> Unladen mass 225 PS coupe: 1465 kg (accepted figure but April 2005 brochure ref 533/1102.87.25 quotes 1515 kg).
> 
> ...


Hmmmm, now let me think . . . .

I know - is the answer 42 ? :wink:


----------



## tony_rigby_uk (Nov 27, 2008)

Completely agree with what your saying with your figures... bu that is on a rear axel vs a front axel... with the assumption the force is distributed evenly through the axel...

just my initial thoughs with regard to the ballast....

if you examin under your car the haldex system is offset:- 









This is to the opposite side to where the ballast is... so maybe the ballast equals up the rear corners... perhaps the QS with the battery doesn't need this Ballast... but then why does it need the Roadster chasis runners (double) also what fills the gap in the engine bay to even out the variation between gearbox being on the left.....

In my personal opinion the car was designed as LHD (from germany and most of the market) meaning the driver weight would counter the engine being over on the right handside (as the driver is on the left) then the counter balance in the 225 is the attatched 19kg... in the QS it's the battery.. as steering column rack, mastr cylinder.. ect ect ect.. would probably even up the balance at the front....Therefore i think the best balance to the TT is infact how it was origionally designed LHD.. and not how it was adapted to RHD... Think about it.... compared to a LHD have audi done anything to balance the car for RHD..... answer in short is... NO..... so best balance would be LHD !!!


----------



## Grahamstt (Jul 22, 2008)

Some good pointers there Tony - You could get a fat passenger to even out the rhd balance prob :lol: :lol: 
Graham


----------



## HighTT (Feb 14, 2004)

I'm very surprised that nobody has had their TT 'corner weighted'.
With say half a tank of fuel and both with, and without the driver, and maybe with a passenger too.

Ring round a few companies that prepare cars for track use, to find one in your area.
It cost me a tenner to put my track car on a set of scales (a local Porsche tuning company wanted £85!)

That would put a stop to all the guessing.


----------



## Guest (Jan 30, 2010)

Tony,

Good call again on the reasons for corner-weighting. I thought that one through and came to roughly the same conclusions regarding offset of heavy components like Haldex gear. I'm not sure whether there's any offset in the fuel tank. Agree that the QS has a battery there so that's probably why there's no need for the counterweight. I reckon you're spot on with the LHD origins of the car shaping the design. I hadn't realised the QS had bigger chassis members. I suppose that's part of creating a stiffer monocoque than standard?

Calcs (back-of-***-packet estimates) were knocked up in 20 mins on Excel using a simplistic approach over a glass of wine and are only intended to put some rough figures on what was being discussed earlier in the thread, so don't read too much into them guys, just use as a guide for discussion. I wanted to save my earlier comments from further ridicule too :lol: I think the nail has been hit on the head since I posted by other commentors, including your good self. I'll try to find some time this evening and some more wine to do a correlation on PWR and 0-60 mph time. Think I'll need to pore over the Evo magazine web site for that.

Conclusion: If I had a 225PS coupe, I'd prefer to pass on the 2 bhp/tonne improvement on PWR (+1.3%) and not risk the -6.5% extra unbalanced cornering force. Thankfully, I've got a QS which is a bit more sorted. Nice to know if I ever manage to drive the car on nice twisty A roads again. 

Thanks for another quality discussion guys. I don't think we'd get this on the Citroen Saxo owners club, ahem. :wink:

Doug

Doug


----------



## Guest (Jan 30, 2010)

HighTT said:


> I'm very surprised that nobody has had their TT 'corner weighted'.
> With say half a tank of fuel and both with, and without the driver, and maybe with a passenger too.
> 
> Ring round a few companies that prepare cars for track use, to find one in your area.
> ...


Me too. I posted on another thread asking this very thing and was astonished that there was no response. I'm going to go on the internet and see if there is anywhere around the central belt/Fife. Maybe there would be somewhere near Knockhill given the racing that goes on up there.

Doug


----------



## Grahamstt (Jul 22, 2008)

Does any one know whether the 180 2wd has ballast. If not the rear must be alot lighter than just removing ballast off a quattro.

If Bikerz got more oversteer without ballast does 2wd get more oversteer as well :?: 
[smiley=idea.gif] [smiley=idea.gif] Or does it get ballast on left and right to compensate for no haldex
[smiley=gossip.gif] Graham


----------



## SAJ77 (Nov 16, 2008)

Doug Short said:


> Agree that the QS has a battery there so that's probably why there's no need for the counterweight.


Does the V6 have the ballast fitted? As they also have the battery in the boot :?

Saj


----------



## Guest (Jan 31, 2010)

Grahamstt said:


> How heavy do you think 60litres of V power is. [smiley=bigcry.gif]
> Does that mean it's best to put a fiver at a time in


Edit added to the calculations this morning Graham. Answer is it adds 46 kg over the rear axle and low down so improves the weight distribution by approximately the same percentage as moving the battery fore to aft. It's the same argument as I was making about adding weight rather than removing it, but I think the only sensible conclusion is that weights & PWRs should be quoted with a full tank of fuel because as soon as you fill up the car and put a driver in to use it you've instantly added about 125 kg and thus the unladen weight quoted in manufacturers' data is meaningless.

We'll get no peace on this one until we get some four wheel balance data. I still haven't looked on the internet for anywhere nearby.

Doug


----------



## peter-ss (Sep 3, 2008)

was said:


> Bikerz said:
> 
> 
> > What are thoose black vents for? I stuck my finger through and it doesnt go anywhere, so cant see what they are for?
> ...


They're also there to give the air that blows through your heater somewhere to go!


----------



## Guest (Jan 31, 2010)

O.k. guys, the numbers have been crunched to find see how good the correlation is between PWR and 0-60 mph acceleration times to follow up on previous discussions about the effect of weight saving measures, specifically removing a 19 kg counterbalance from a 225 PS coupe. The data obtained from http://www.evo.co.uk on 30 Jan 2010 (682 vehicle variants have available data).

Post edited 04 Feb to remove superfluous detail.

Conclusions:

1. The expression A = 210xPWR^-0.7 gives a good correlation between 0-60 mph acceleration time (A) and power-to-weight ratio (PWR) over the range 150 to 350 bhp/Te.

2. Applying the expression gives the following rule-of-thumb results:

150 bhp/Te; 0-60 mph in 6.5 s
200 bhp/Te; 0-60 mph in 5.0 s
250 bhp/Te; 0-60 mph in 4.5 s
300 bhp/Te; 0-60 mph in 4.0 s
350 bhp/Te+; 0-60 mph in 3.5 s

3. You need about 3.6 more BHP/Te (a saving of 32 kg) to get your 0-60 mph time down by 0.1 s in a 225 PS coupe.

Doug


----------



## Hark (Aug 23, 2007)

What? :?


----------



## JNmercury00 (May 22, 2007)

Hark said:


> What? :?


+1


----------



## pinotattt (Oct 5, 2007)

:?  :?

So in Layman's terms for a TT Quattro 225, remove ballast & replace with battery for a rhd car :?:

What are the physical differences between the Quattro & QS :?: Does the QS have the rear ballast or not :?: We know that the battery is in the boot and it has wider rear wheels, bigger chassis members which apparently transforms/improves the handling :!:

Bottom line :roll: to remove rear ballast & relocate battery for better handling or leave as is for fear of upsetting the handling [smiley=argue.gif] [smiley=book2.gif] [smiley=gossip.gif]


----------



## lego man (Nov 9, 2008)

Is it worth it?

The only reason I had to have my battery moved is because the of lack of space within the engine bay. 
But I guess the less weight you have hanging over the front wheels the better !

Also you can go for a lighter battery for the rear !

I havent removed by ballast yet, although its on the cards to be removed when I can get round to it!

I guess its worth it ! every little helps.


----------



## Hark (Aug 23, 2007)

lego man said:


> Is it worth it?
> 
> I guess its worth it ! every little helps.


I think that's the point that is missing. Removing ballast on it's own prob isn't. but if you fit lighter wheels, remove rear seats, spare wheel and ballast your now making quite a difference.


----------



## lego man (Nov 9, 2008)

Hark said:


> lego man said:
> 
> 
> > Is it worth it?
> ...


Topic is rear ballast ? :lol:

I like to keep my back seats in ! Cant see removing them will make anymore difference than me having 2 Big Mac, a tin of rice pudding followed by a cadburys cream egg. !

ie a nats fart !

LEGO


----------



## Guest (Jan 31, 2010)

lego man said:


> Is it worth it?


If you mean the ballast removal, then no. That's the point I was hoping to prove.



Hark said:


> What? :?


Sorry for the blinding with science approach. I just wanted to see if there were simple relationships between weight saved/effect on PWR and hence 0-60 times to positively contribute something objective to the discussion.

When I did maths, if you showed your working out, you usually got some credit even if the answer was wrong! :wink:

Doug


----------



## Bikerz (Aug 23, 2008)

Still totaly dissagre Doug! Removing weight is less weight 

I wish I didnt bother trying to help people now with a guide :?

Removed Sams Ballet last night in his


----------



## V6RUL (May 28, 2009)

Bikerz said:


> Still totaly dissagre Doug! Removing weight is less weight
> 
> I wish I didnt bother trying to help people now with a guide :?
> 
> Removed Sams Ballet last night in his


I think if you have traction then less weight is good but if you loose traction then more weight might help improve the traction.
Steve


----------



## Bikerz (Aug 23, 2008)

So a 4wd TT struggles with traction? :lol: Hence my comment stands less weight = GOOD!


----------



## lego man (Nov 9, 2008)

This is getting daft, but funny !

People and there egos ! We all know that audi but it there to cover there arse ! same with the front bushes !

I don't know if I will tell any difference with our without it, and for traction ! hummmmm
Unless my near side rear is wheel spinning more that to other, I might leave it on. :roll:

Best thing is to have your vehicle corner weighted ! little bit extreme when half the cars on here are just road cars.

LEGO

PS I think people are abusing the rear ballast just to try and gain a few bhp per ton. It will give you a gain, but I could visit the toilet before and make more of a difference ! ( whats the weight of the ballast again ) :lol:


----------



## Bikerz (Aug 23, 2008)

Your right lego. But it is 18.8kg which is actually more than a large dump :lol: Well for me, I cant speak for your rear end :lol: 
Every little helps if you ask me. Mines totaly striped in the rear tho, trim panels and all.


----------



## lego man (Nov 9, 2008)

Bikerz said:


> Your right lego. But it is 18.8kg which is actually more than a large dump :lol: Well for me, I cant speak for your rear end :lol:
> Every little helps if you ask me. Mines totaly striped in the rear tho, trim panels and all.


Upps, 18.8kg. My dumps are big, but not that big. Yes my car is stripped at the rear apart from the "Rear Ballast".

I will remove it on my car due to the battery is in the boot, plus 18.8 kg hanging on the back end....

How much Brek will that get me !? muhahahahah

LEGO

PS Common boys, 2 x 10mm spanners a kitchen knife and 20 minutes of your time. Get it removed !!


----------



## waTTford (Jan 19, 2009)

Bikerz said:


> Tim G said:
> 
> 
> > Bikerz said:
> ...


I love these technical threads. Just one point, haven't you removed the tow hook :lol:


----------



## Bikerz (Aug 23, 2008)

Yep :lol: 
Took Sams off too even tho he said maybe I should leave it on incase I need towing out of teh kitty litter, but he decided to remove it after i said it was heavy :lol:


----------



## V6RUL (May 28, 2009)

Bikerz said:


> So a 4wd TT struggles with traction? :lol: Hence my comment stands less weight = GOOD!


At the Pod the other week i was spinning the wheels in first and second and the DSG changed gear as the red line was reached due to the spinning wheels, hence i was going nowhere fast. If i had better traction i would have pulled off a lot better without spinning. Laying rubber down helps this but im not going to burn my tyres up. Adding some more weight to the car in this instance across all four corners should have improved things but i will look at feeding the power next time instead of going for the max asap.
Steve


----------



## lego man (Nov 9, 2008)

stevecollier said:


> Bikerz said:
> 
> 
> > So a 4wd TT struggles with traction? :lol: Hence my comment stands less weight = GOOD!
> ...


Steve,

1/4 runners never try and add weight, the try and loose it! Its a little inefficient to do this. How much power are you running?

Next time, check out your tyre size compound and pressure against the track conditions.

I really dont think adding more weight is the way _forward_ for you and your pap pap !

LEGO


----------



## Guest (Feb 4, 2010)

Bikerz said:


> Still totaly dissagre Doug! Removing weight is less weight
> 
> I wish I didnt bother trying to help people now with a guide :?


Bikerz: Firstly, I haven't provided much in the way of an opinion for anyone to agree or disagree with, only the results of some simple calculations from which people can draw their own conclusions. The topic title was, after all, "Facts and Info". I've tried to interpret the facts for people. I got my efforts resoundingly trashed too, so perhaps people aren't that interested in facts, just their own mostly unsubstantiated opinions?

However, I'm personally pleased you did bother with the guide. It was useful and interesting. I think people have generally concluded that removing the rear ballast *alone* isn't worth much but when done as part of a weight-saving exercise, it's useful. I recall the disclaimer on the packet... "Can help you lose weight as part of a calorie-controlled diet" :lol:

Thanks.

Doug


----------



## HighTT (Feb 14, 2004)

I took off my ballast but it completely ruined my handling and traction :wink:

:idea: so I replaced it with some carefully arranged ballast :idea: ...........

.........








:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :roll:


----------



## Fred (Jan 7, 2010)

stevecollier said:


> Bikerz said:
> 
> 
> > So a 4wd TT struggles with traction? :lol: Hence my comment stands less weight = GOOD!
> ...


You were spinning your wheels in a standard 3.2 DSG?

I can hardly spin the wheels in a more powerful manual in the wet, let alone dry.

Wet I can easily do 4000 RPM (which will be more torque than yours even at peak) dumps with only a couple of turns of spin.

EDIT...

The more I think about it the more silly it is (if your standard). You are either running some really bad remould tyres or your haldex is not working an your in 2wd mode.


----------



## V6RUL (May 28, 2009)

lego man said:


> stevecollier said:
> 
> 
> > Bikerz said:
> ...


Hi Leg, as a general rule i agree that a light vehicle and good traction will see the best results all day long.
Altering tyres pressures a little would have a benefit, if im running 30psi should i let some out or put more in.
Im running 18" Toyos on a medium compound. My car is a DD so i dont plan to deviate to different wheels or tyres.
Im going to be running Eibach coilies soon so hopefully the rebound rate will hopefully keep the nose lower instead of lifting and spinning the fronts which then changes gear sooner. Im running not far of 300 brake.
Steve


----------



## V6RUL (May 28, 2009)

Fred said:


> stevecollier said:
> 
> 
> > Bikerz said:
> ...


Hi Fred, im not running a standard 3.2 and i was using launch control at 4250 Rpm hence the wheels spinning, but maybe only the fronts.
Steve


----------



## Fred (Jan 7, 2010)

What sort of power are you running Steve?


----------



## V6RUL (May 28, 2009)

Fred said:


> What sort of power are you running Steve?


292BHP


----------



## TR4 (Jan 31, 2010)

Snap oversteer is not something you want to encourage IMHO, if your car is going rear end light mid-corner you are half way there. Could be difficult to recover from given you have no control over how much drive is being distributed to the rear.

I used to drive a Mk1 GT6 with the notorious swing axle rear suspension. If you lifted off mid-corner you could induce a pendulum effect at the rear which was extremely difficult to recover from, not dissimilar to an early 911.

I can tell you from experience that spinning a car on a busy road is not fun.

In real world conditions from A to B between two same spec cars, the one that corners most effectively and can brake latest will be quicker. On any car I rebuild I start my modifications with the brakes and suspension before I do anything to the engine.

Andy


----------



## pcrepairmandan (Jul 6, 2013)

Is it in the v6 ???


----------



## BaueruTc (Aug 21, 2011)

Bikerz said:


> Here we go guys. (updating when pics upload)
> 
> I have got loads of info off this site over the last 10 months and now im going to gve somthing back on a subject that comes up very oftern!
> 
> ...


Is it just me or does that pic look R8 like?


----------



## roddy (Dec 25, 2008)

if all this is true about weight distribution then what effect does fitting bigger ( heavier ) brakes to the front of a 225q have on the handling ?


----------



## brooksesi (May 8, 2012)

Does a 3.2 have more ballast at the rear, given the heavier engine?


----------



## roddy (Dec 25, 2008)

brooksesi said:


> Does a 3.2 have more ballast at the rear, given the heavier engine?


and heavier brakes


----------



## V6RUL (May 28, 2009)

roddy said:


> brooksesi said:
> 
> 
> > Does a 3.2 have more ballast at the rear, given the heavier engine?
> ...


I have a lighter engine than a 225 and lighter brakes too..  amazing what you can do with a hack saw.
Steve


----------

