Over boosting LCR

[Pyro]

Think 5mm is ok I can't remember how far mine droped but think it was the same

 

[8bit]

I took the DV apart this morning after testing and their wasn't much grease around the piston. Anyway when doing the test the piston dropped around 5mm, it stayed open but thought this was quite a big drop?

Put it all back together after abit of a clean up and went for a drive and as soon as i hit about 23 psi the car went into limp. Came home and VAGCOM and same 2 codes are back.

Sounds like the DV has been ruled out then, looks like Robbie may be right about the map.

When you said "after a bit of a clean up", did you disassemble the DV at all? How many times did you do the test?

 

[NottsLCR]

Yes did the test quite a few times before I disassembled the DV then put it back together. Since then I have disconnected the N75 electronically and the car appears to drive as it should (Boosting normally) and hasnt gone into limp mode. I have the MBC in place to ensure peak boost is kept in check so now i am thinking it could be the N75.

Other than a fault code registering for the N75 not being connected what are the other risk? Like I say I have the MBC in place to keep boost in check

 

[Pyro]

If MBC fails then boom lol

 

[NottsLCR]

hmmm....not sure I want that after the pennies spent recently. I'll see how it goes tomorrow then if the codes do not appear think I have found my problem so will get a new N75.

 

[Pyro]

If you were near me I have a spare you could try lol if there's nothing to keep peak boost in check MBC/N75 then the ECU won't stop it and kaaabooooom lol

 

[NottsLCR]

Cheers Pyro - Might turn the MBC down abit as I just want to test that it is the N75 before shelling out for a new one. Normally the codes come back within minutes and anything over about 10 psi so shouldnt take many miles of driving to confrim this!

 

[Pyro]

If you pm tezzer he knows a company that do N75's for about £25-£30 there second hand I think but hes always used them and there good altho I think that there's a new part number for the J valves and there cheeper now

 

[NottsLCR]

I'll send him one tomorrow if we have a 'successful' days driving - fingers crossed its this simple as I just want to finally drive it properly!

 

[t32er]

no need for the PM im here lol
if the car goes over the boost set on the MAP sensor it will hit limp any way, but yea if the mbc fails and the map sensor is having a bad day BOOM
VRS Northampton is where i get them from, yes there used but there tested and iv not had one fail on me from them, also makes it a cheaper rule out as if the N75 is not at fault you have only spen 30 and not 65...
vrs can take payment on the phone or paypal, and then post it out, the packing is spot on too, iv had 3 off them now i think, 2 J and a H, my LCR hated the J but it seems to get on with the H a lot better

 

[Pyro]

Would ya look at that forgot the map sencor but still wouldn't wanna risk the hybrid lol

 

[NottsLCR]

Cheers mate I'll look them up and give them a call

 

[8bit]

If that MAP sensor was dodgy you wouldn't have gotten limp mode when you hit 23psi so that's not a worry. I know some folks have bypassed the N75 altogether and used an MBC so it can be done, not sure I'd do it myself but I wouldn't think anything would go boom. Too many failsafes built into the system.

 

[Pyro]

I beg to differ you have N75 map sencor and in this case MBC and I think that's all that will kill the boost once it gets to hi so if they don't do there job and you've got your foot down unless you realise your still building boost then you won't be a happy chapy I seem to remember someone having problems with N75 failed before and pop the turbo at 27 psi I thi k that was it

 

[NottsLCR]

Just want to say thanks for all the help so far guys its so frustrating after having the rods fitted and hybrid mapped still haven't had a realiable car

 

[8bit]

I beg to differ you have N75 map sencor and in this case MBC and I think that's all that will kill the boost once it gets to hi so if they don't do there job and you've got your foot down unless you realise your still building boost then you won't be a happy chapy I seem to remember someone having problems with N75 failed before and pop the turbo at 27 psi I thi k that was it

Alright alright, I was forgetting that the N75 controlled the wastegate. No need to be a nob about it.

 

[Pyro]

not being a nob!!!!! you cant say you've never corrected me before

 

[t32er]

handbags down guys....i will bang your heads together one day
bypassing the N75 works but you have to have ya eye on the boost gauge all the time, you will be putting all the trust on the map sensor but the map senser will let you over boost a bit its more when it holds boost for to long, also there will be a good chance of popping intercooler pipes off, i had issue like this on my old LC, id done a risistor mod to the map sensor so it neve told the car if it was over 20 or so psi a mbc and it would boost to about 24-27 depending on the teps out side, but if i hit 27 i blew intercooler pipes off, not a good look on the bypass, sounds good though lol

 

[8bit]

not being a nob!!!!! you cant say you've never corrected me before

True but it was the tone of your post I didn't like, anyway I stand corrected, having only the MBC might not be a good idea.

Just want to say thanks for all the help so far guys its so frustrating after having the rods fitted and hybrid mapped still haven't had a realiable car

Might be worth starting a thread in the Turbo Tuning or Big Turbo Discussion sections. There seems to be a fair few folks that post/read in there who never appear in the mk1 Leon section (some with things like TTs, S3s etc).

 

[Pyro]

How can you tell the tone by reading it? I didn't mean it in any nasty way at all And wasn't trying to sound belittling or anything and if you took it that way then sorry