PDA

View Full Version : sr20 shudders at 7psi



Impakt
16-07-02, 07:21 PM
Hi all,

My sr20det seems to shudder once it hits around 7-8psi, and from them on (to around 15psi max) it feels as if the brake is on a little. It certainly doesnt accelerate as much as it should even though the boost guage still says up to 15psi.

It has been happening since i removed and re-installed the stock turbo.

I checked the intercooler piping 3 times already, first time replaced one clamp which was threaded, second time replaced another one that was suspect, 3rd time replaced the other 2. After each time it felt normal until i boost it around 5-6 times, then starts shuddering again. I thought i must have done something wrong when i put the turbo back on...

It used to shudder and feel flat after 11psi, now does it all at 7psi. I thought there might a leak somewhere else in the plumbing and hit it around the block a few times to see exactly when the problem starts and after a while the exhaust temp light turned on..

Pulled into the driveway and low and behold its red hot just after the cat. After this im thinking it could be lack of fuel, or blockage somewhere. Tomorrow i will reset ecu, clean afm, replace fuel filter, and maybe spark plugs. I will also remove the intercooler and maybe put the stock one back on.

A friend in a skyline has said he has had similar things happen to his car but goes away after a while.

I dont think its fuel (unless i have had bad luck lately). I use optimax all the time, and i just filled it (still had the problem on the old tank). I also filled it at the space station at lane cove which goes through alot of fuel.

Anyone else had a similar problem or that could give me some pointers as to where i should look?

Any help is greatly appreciated...


Impakt

Impakt
16-07-02, 10:30 PM
i drove the car home from gfs house (very gently) and noticed that the idle has a slight and sporadic miss in it (can hear it when you are next to the muffler)..

Also its very flat on half throttle at around 800rpm and also around 1250 rpm.


apart from all that its just the way it used to be just has these niggling issues at the moment..
hopefully there is enough information for someone out there to have a good idea of what it is!

Impakt

THE ASH
17-07-02, 12:44 PM
I would check the plugs & also the plug leads. My car did this a while back & it was the leads, turbo engine bays are bloody hot & the leads don't last as long as regular cars.

nismoracing
17-07-02, 02:22 PM
SR's dont have leads, they have coil packs.

Impact have you checked your oil and water lines? Also have you checked your wastegate?

Impakt
17-07-02, 02:27 PM
replaced platimun plugs with new ones. Miss mostly went, idled perfectly, and performance on stock boost was perfect. Over 11psi it felt a little flat.

While i was at the mechanics i did a compression test, all pistons reporting 175psi, no more than around 5psi variation. Dizzy cap and rotor button are also perfect nick...

Got some new leads, car is like new again, boost peaks on 16psi and the car goes the way it should..

Just a warning to turbo owners, a faulty lead or plug can make the car feel like something alot worse has happened.

nismoracing: the car is a bluebird atessa, east-west sr20. has leads but coil is inside the dizzy.

Impakt

NOT24L
17-07-02, 02:46 PM
Yo Impakt

Is this happening when you are at low revs in say second gear and then apply throddle? And the boost reads like normal but the car feels like it not boosting at all? Mine used to do this when i got it. Especially on really hot days. The car would shudder a little and feel like its not boosting at all and then come on full boost at like 5000rpm. and it only happened when i applyed throddle at low revs and waiting for it to spool up. if i was already over 3000rpm and applied throddle it would be fine.
It doesn't do it now and i'm not sure what fixed it. Only time the turbo has been touched it when the exhaust shop was looking at the dump section and didn't put the shield back over the exhaust manifold and left one bolt missing. (which i still haven't replaced)

Impakt
17-07-02, 02:48 PM
NOT24L, i edited my last post prolly while you were replying. problem fixed, car is back to normal..

Impakt

NOT24L
17-07-02, 02:55 PM
Impakt

HAHA yeah i think thats what happend. Glad you got it sorted