# N75 Removal (Boost controler solinoid)



## tony_rigby_uk (Nov 27, 2008)

Ok here is going to be another frowned upon post... :roll: but stay with it :lol: :lol:

N75, as we all know this is the bug bear of most of our lives and constitutes to every under boost or overboost ever occoured in the TT, (maybe an exageration but it's still a pain in the arse).

After speaking to a few people who also run BAM engines in other cars.. there's a nice little trick... clamp the turbo wastegate to N75 hose... this will make your turbo spool it's tit's off to it's maximum... this will be the first time ever you'll have a duty cycle of 100% (although vacom will never see it as your mechanically bypassing the N75 to hit 100%) Now i imagine if you run like this for any length of time the turbo will explode...(although there are people who run like that.... usually about 18 years of age)

Now after some digging and discussing, this principle is the same, when fitting a boost controller... now electronic with solinoid, would be nice, with some program features... (setting A, B, and off) so what you do... well you set the max duty cycle, i belive the max for the stock is about 95% sure thats the figure that bounces back when logging... so with a controller you can adjust it..

A) 85% for all you overboosters.
B) 95% which is the stock duty cycle.
OFF) 100% just like clamping the hose.

just leave the N75 plugged in and hanging, and use a boost controller... no more pesky N75 issues...Belive it's another N249 Delete (so it will be shot down in flames) but more importantly just as a note.... REVO stage 3 software maps out the N75 meaning it's either 100% or you have to get a controller... i would imagine any top end software would do the same... like the emissions light is mapped out on the stage 2's.....

You can also have mannual boost controllers...Very Cheaply..

So Discuss.... :lol: :lol: :lol: :lol:


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## Wak (May 6, 2002)

tony_rigby_uk said:


> Now i imagine if you run like this for any length of time the turbo will explode.


The the best part of the post. :lol:

Let me get my flamethrowing shotgun out!

You like to drop a gun into the kids hands and stand back... Try it yourself and let us know how you are in 6 months! :roll:

This has been done to death by a company a few years ago......

The N75 was replaced with a knob in the the car for owners to twiddle with....... of the 3-4 owners who bought into this crap mod; 3-4 owners blew their turbos and even the company selling the mod sold their development car with a "new turbo" .... Hello.... WTF!

Caused a lot of heartache for the owners and ruined one of them financially as well IMO.

Simple fact is you give the kids a knob to turn it up to 2 bar.... they will turn it up to 2 bar.. not to mention how the ecu will try to adapt, fail to adapt and risk engine damage as well as turbo failure.

So would you do this mod to a stock car or mapped one? 
How would the fueling behave on a narrowband car and a wideband car? 
How would timing advance and corrections behave for the various boost levels and fuel strategy as you increase boost possibly beyond the limits of the fuelling capabilities or the ecu's capabilites to correct.

How does the average owner know whats happenning to their car with mods like this????????
Well 3-4 didnt know and got shafted over it! :?

No one wants to piss on the fire of enthusiasm but if you have unlimited funds, play and learn, if not do a lot of research first.


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## Charlie (Dec 15, 2006)

Wak said:


> tony_rigby_uk said:
> 
> 
> > Now i imagine if you run like this for any length of time the turbo will explode.
> ...


LOL sums it up pretty nicely if you ask me 

Seems like a complete waste of time if you effectively have no real control over what is going on, why anyone would want to risk expensive components of their car is beyond me :?

Charlie


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## antcole (Apr 4, 2009)

.... i thought that hour and a quarter of silence was ominous..... we seem to have lift off....


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## Charlie (Dec 15, 2006)

antcole said:


> .... i thought that hour and a quarter of silence was ominous..... we seem to have lift off....


It's like fishing, Tony was hoping for a bite and got one 

Charlie


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## Rich196 (Mar 31, 2011)

so why cant you fit a maual boost controller to a TT but there are many other brands of cars that people are happy to and successfully fit boost controllers? whats the difference can someone explain?


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## anthony_m (Aug 28, 2008)

hi all,
there are people here who can explain this better than I, however, it dosent take a genius to understand that you cannot simply alter one parameter without somehow having the ability to alter those that also need attention to take advantage of the extra air/boost the turbo will give when being used wide open etc.
Another reason you do not want to use the turbo flat out is because the heat generated by the full exhaust constantly through the hot side would eventualy lead to damage ie/cracking of the turbo body, [yes i have seen this on RS cars where someone thought it a good idea to remove the wastegate piping etc] so, its not as simple as it may first seem, yes you will get a higher initial boost but at what cost ?
Alter one parameter, you have to alter the rest ie; fuel, timing etc to take advantage of the extra boost.
Thats the reason why we have ECU's with set codes that control everything, and why the clever people who re-write those codes are held in such high regard.  
Anthony.


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## alun (Aug 2, 2010)

im not sure exactly what were discusing here. but if its getting shot of the n75 im in.. :lol:

my last car had something similar to the n75, probs exactly the same just called something diff. i binned it and set up an ebc. afterwards i got much more consitant boost and the delivery of the boost was way better. i also tried an mbc which gave great results too.

the key to this is not setting the boost too high. as this pushes the cars fueling etc too much.

when i do it on the tt, ill be setting it to the command pressure. if that makes sence. my car should then produce consistant boost to an acceptable level all the time and not just when my ecu decides it wants to.


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## Wak (May 6, 2002)

Just to throw in the "other side" of this coin...

Sometimes it may be neccesary to use a manual boost controller to manage peak boost. e.g. Big Turbo situations, high boost, or boost control on normally aspirated conversions for example.

But mapping for it is a given!


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## everton5 (Dec 15, 2010)

wak could you use the apexi boost controller instead of the n75? i had 1 set up on my evo with ecutek remap


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## UK225 (May 12, 2002)

everton5 said:


> wak could you use the apexi boost controller instead of the n75? i had 1 set up on my evo with ecutek remap


You could use the Apexi AVCR if the mapping is setup to suit.


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## everton5 (Dec 15, 2010)

I'm still Gettin my head around this bam engine so how many ports are on the n75?


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## alun (Aug 2, 2010)

n75 has 3 ports. one from the turbo pipe. (hot side) one going to the actuator and one goes to the tip.


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## everton5 (Dec 15, 2010)

Is there more than 1 version of the n75?


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## alun (Aug 2, 2010)

yes, but i cant remember what ones. from what ive read there not really recomended.


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## coachvtt (Aug 25, 2009)

My two cents!

I have the Turbo XS MBC with the Race N75 electrically connected not the ports!

I run top 20psi I hold steady around 18-19psi

Been running this way for about a year now with no problems.

I have the n249 delete with the diode and I have deleted the evap pump for the oil catch can.

So is the question being asked is this safe? Well safe so far and more boost! Burning more fuel not really!
Getting 356 miles per full tank! 25mpg to 32mpg hwy! Not bad! for a 10yr old TT Modified. No cat no res!


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## tony_rigby_uk (Nov 27, 2008)

Wak said:


> Just to throw in the "other side" of this coin...
> 
> Sometimes it may be neccesary to use a manual boost controller to manage peak boost. e.g. Big Turbo situations, high boost, or boost control on normally aspirated conversions for example.
> 
> But mapping for it is a given!


I Have high boost so i'm ok :lol: :lol: :lol:

But in all seriousness, as my duty clycle programming suggests, i will be running at less than the N75, personally i the one i've got also has a alarm, which wiull be set at 2bar, (as you know my boost is too high at 30psi) the other amusing factor is the boost is still at 28PSI if you drop the boost level to 4 on the REVO map, (I blame the actuator :lol ALthough les is currently boosting more than me and doesn't have the aftermarket actuator... very odd.

I know matt B doesn't have the N75 and as said the revo stage 3 maps it out... so unless you fit a controller you'd be running with a clamped hose anyway...

I'm just exploring what controllers people are going for, and if they are doing away with the N75 when fitting them... my view would be to bin it... one solinoid replaced with another...

P.S i'll be running the AEM tru Boost syetem :lol:


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## Grahamstt (Jul 22, 2008)

I'm running the modshack boost machine which still uses the N75 as a back up safety feature,
I presume from what's been said that when I get the stage 2 mapping this will be binned for a more appropriate map?


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## tony_rigby_uk (Nov 27, 2008)

To My immense surprise :? :? :-

http://www.wak-tt.com/mods/boostmachine/boostmachine.htm

and i Quote


> Boost is stronger, the car pulling better than ever, I may be reaching torque limits as ESP seems to be kicking in on gentle turns and 1st gear launches in the DRY! boost is being held longer and is higher on reapplying the throttle.
> 
> This is a fantastic mod, I'm really pleased with it.


Is this the same one that blew the turbo's and engines...? 
will let you all know how i get on with the AEM version... but so far so good... (although it's actually set up very tame at the moment)

Would be good to see how yours is wired up grayham... I did think of how to piggy back mine, but it just isn't looking do, able.

Obviously mine has 3 ports..

One to the Wastegate, another to the charge pressure... Now obviously if i put the N75 back in the line, then the inn would be wategate and out to the charge line... with the air out having a filter on and blowing out...


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## Grahamstt (Jul 22, 2008)

Hey tony thats the modshack one I have


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## Wak (May 6, 2002)

tony_rigby_uk said:


> To My immense surprise :? :? :-
> 
> http://www.wak-tt.com/mods/boostmachine/boostmachine.htm
> 
> ...


No, this worked in tandem with the N75 and we are all led on my enthusiasm at some point!
I highlighted an issue with a full blown manual boost controller, no N75, no electronic management control... simple bleed valve mod that killed turbo's.

Why are you suprised Tony? :roll:

I learned my lessons and advise from them, I being selective in quoting you conveniently ignored the "quote" at the top of the page Highlighted in RED on the first paragraph!!!!



> UPDATE:- Right now, as good as the boost machine is, I have removed mine as it was eating into my fuel bills and am currently testing an alternative which I'll report on when ready.


And the alternative is.................. get it mapped properly. :roll: :lol:


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## Grahamstt (Jul 22, 2008)

Yes Wak mine is in tandem before the N75 = apparently it allows a little ECU intervention to keep a little safety factor.

When my car comes to you for it's stage 2 mapping will this boost machine be best taken off?

Graham


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## jamman (May 6, 2002)

Looks like someone is being very selective in their quote grabbing :lol:

Ever thought of going into politics Tony :wink:


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