Jump to content
Sign in to follow this  
NIS-15

S15 doesn't reach full boost till 5000rpm

Recommended Posts

My s15 is playing up boost wise. If I floor the car in any gear I get 0.5 bar (on the stock boost gauge) pretty quick, the boost doesn't move again until 5000 rpm at which point it hits full boost (0.9 bar).

 

Stock turbo

3" exhaust (brand new cat), pod (cleaned recently), intercooler (cleaned)

 

I've checked all intercooler piping for any leaks but not 100% I don't have a vacum hose leaking somewhere. Where should I be looking? Inlet leak, stock boost controller, stock bov? My Vct gear is shot (have a brand new solenoid already and new gear on the way though) if that could have anything to do with it too?

 

Cheers for any help

Edited by NIS-15

Share this post


Link to post
Share on other sites

Yea could be a wastegate thing. Have you looked at your waste arm on the actuator? Make sure the little clip is there.

The BOV shouldnt be leaking boost at that pressure. They are usually good up to 1bar without having mod it.

How old is your cooler and piping? checked for cracks and small holes etc? It doesnt take a very big hole to cause issues.

Share this post


Link to post
Share on other sites

Cheers for the replies. Yeah the circlip's still

On the wastegate actuator but I'll have to make sure it's not opening early or anything. It does appear that its shutting fully but yeah it would make a lot of sense if that's the problem. Might be time to hook my compressor up to my cooler piping and check for leaks under pressure. It's a greddy setup that's about 5 years old now.

Share this post


Link to post
Share on other sites

Well I fitted a brand new actuator and while the car is now more responsive (hits 5psi pretty quick then does nothing again till 5k) I've still got the issue. Stock wastegate pressure is 5psi so I'm looking at the stock boost control again. I did notice that the wastegate flap was a little sticky in its operation but doubt it's related as the wastegate is shutting fully. I might try pulling the vacuum line off the wastegate and see if it boosts quicker then I can work out if it's the stock boost control or not. Don't worry I know I'll have unlimited boost and my engine will go pop pretty quick if I let it over boost.

Share this post


Link to post
Share on other sites

That new cat you put in could be very restrictive. I have had many cars with same problem, collapsed cat cause blockage which makes the problem you describe.

Share this post


Link to post
Share on other sites

It's a catco cat which I know isn't the best but flows 400 odd cfm so should be ok for my setup. If I don't have any luck with the wastegate I might try swapping cats just to rule it out though

Share this post


Link to post
Share on other sites

Ok just did a run without the wastegate hooked up. Boosts normally so I'm pointing my finger at the factory boost controller. What ebc's are people running these days? I hear good things about profec b's - don't want to spend more than about $4-$500. Oh and yes the wastegate is already hooked back up.

Share this post


Link to post
Share on other sites

Ive had my Apexi AVCr for nearly 4 years now. Has performed very well. They do take a little bit of time setting them up, as they have a pile of functions and displays,

RPM-based boost and solenoid duty cycle control, scramble boost, self learning mode2D ghost map trace mode, analog display mode, real time replay and peak hold data modes.

Should be able to pick one of these up for $300-$400 at a guess??

Share this post


Link to post
Share on other sites

HKS EVC-S also looks pretty good. Anyone running these?

 

I've got one in my evo. Good unit in my opinion. Easy to use and has multiple displays on the screen to choose from.

Share this post


Link to post
Share on other sites

Ive had my Apexi AVCr for nearly 4 years now. Has performed very well. They do take a little bit of time setting them up, as they have a pile of functions and displays,

RPM-based boost and solenoid duty cycle control, scramble boost, self learning mode2D ghost map trace mode, analog display mode, real time replay and peak hold data modes.

Should be able to pick one of these up for $300-$400 at a guess??

 

stock car would not bother with the avcr. simple manual bleeder would do the job fine.

Share this post


Link to post
Share on other sites

^^^ yep use a 30 dollar turbo smart..

 

or if you are still bent on fixing the stock system.. unplug the solenoid and place 12 volts on it and ensure that it is opening.. if so check the line going to the solenoid.. it will have a restrictor.. ensure it is not blocked.. if that is ok then the ecu output needs to be checked..

Share this post


Link to post
Share on other sites

Yeah I put 12v across the solenoid and no click so it's stuffed. Also checked that the resrrictor wasn't blocked.

 

Only reason I'm keen to keep the stock solenoid is I was going to try to control it with nistune - I've seen a lot of your info on the nistune forums about this from yourself Chris though it seems you've ended up going stand alone control?

 

Ive got a bleed valve in it for now and it's boosting nicely but I'd still like to go electronic control long term.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

×