High compression on 98 gst

[my dreamt dsm]

I did tons of search and coming up with weird mix answers.
I'm ready to drop a new evo3 16g in and don't want to worry bout the motor handling the stress.
I got high compression 180-185-190-185.
From my results I read that it maybe due to carbon build up. I did seafom twice in 3 months and a bottle of injector cleaner.
I know service limit numbers and that a perfect motor is close to 178... I never heard/sure if higher is okay???
This was done on a dry test with four seconds of cranking, car fully warmed to operating temp where the rad fans came on already.

 

[Delta2Echo]

Well the car does run so it is getting spark.

My car ran without any spark to one of the wires. Didn't run well...but it ran.

 

[mattasi]

Fuel filter? When did you last replace it?

 

[my dreamt dsm]

My car ran without any spark to one of the wires. Didn't run well...but it ran.

I am curious on that. I'll pull a test in a day or two since I am off.

Fuel filter? When did you last replace it?

There are no service records of that being change. It's important because the previous owners have service records FOR EVERYTHING, even changing a loose wiper hose at a 76 gas station the day I bought the car.

 

[TSI_93]

Shaft play on the t-25? My 2g was slow as shit on a t-25 with shaft play. It never got so bad the turbo was squealing but it definently chipped some fins. If I really thrashed it it would get up and move, but 2-5k it was just barely hanging with a n/t. '

Swapped it to a T-28 and it ran great after that. I had similar compression on a 180k mile 7 bolt in the first 2g I owned. 180-185 on all cylinders, my bet is that the head had been cut down once or twice due to warping/blowing head-gaskets.

 

[CanMan]

Fuel filter? When did you last replace it?

This or poor flow through the injectors(dirty, clogged, weak) is a possibility. Have you tried cleaning the MAF?

 

[my dreamt dsm]

Shaft play on the t-25? My 2g was slow as shit on a t-25 with shaft play. It never got so bad the turbo was squealing but it definently chipped some fins. If I really thrashed it it would get up and move, but 2-5k it was just barely hanging with a n/t. '

Swapped it to a T-28 and it ran great after that. I had similar compression on a 180k mile 7 bolt in the first 2g I owned. 180-185 on all cylinders, my bet is that the head had been cut down once or twice due to warping/blowing head-gaskets.

I already switch the t25 out to the evo16g. The car seems to pull better but that's a bigger turbo so not sure.
On a side note the car feels sluggish still. Maybe it's my head now!
It won't be conclusive until I have hard facts to back up my claim. More testing to come so hopefully I'll be ready for the track.

 

[DSM1G90]

With being sluggish and high compression (in which Justin mentions the numbers are good...), I would say you got a mixture issue .. just running a tad rich..esp if you're going crazy with that Sea-Foam nonsense where a good hard bump on the gas pedal in 3rd gear to almost red line does the same-blowing out the carbon...for free.

Pull a plug after a good drive and look at them: clean porcelain - mixture is good. Sooty is a rich mixture.

Another trick is to stick the finger in the exhaust pipe and wipe the inside of the pipe. Finger should come out lightly sooty if normal, but tons of soot shows a rich mixture ... and slimy is a worn motor that's letting oil go by.

Timing off a couple degrees can have some effect to this as well...

Good luck - DSM

 

[Beast5500]

im honestly going to go with what the other guy had said... im thinking it may be in your head... turn the boost up some and see if the sluggishness goes away..

 

[mattasi]

That would of been one of the first things to change. I would change that now! They are like $10 bucks. Your somewere around 120k so its time to give it a new one. Treat it good and it will do the same for you.

Edit: I was talking about the fuel filter.

 

[romeen]

Do a boost leak test.

 

[my dreamt dsm]

With being sluggish and high compression (in which Justin mentions the numbers are good...), I would say you got a mixture issue .. just running a tad rich..esp if you're going crazy with that Sea-Foam nonsense where a good hard bump on the gas pedal in 3rd gear to almost red line does the same-blowing out the carbon...for free.

Pull a plug after a good drive and look at them: clean porcelain - mixture is good. Sooty is a rich mixture.

Another trick is to stick the finger in the exhaust pipe and wipe the inside of the pipe. Finger should come out lightly sooty if normal, but tons of soot shows a rich mixture ... and slimy is a worn motor that's letting oil go by.

Timing off a couple degrees can have some effect to this as well...

Good luck - DSM

I'll keep that in mind.

Do a boost leak test.

Got a little leak by biss screw. Teflon tape. It's fine now!

 

[johnmel]

Well what is the idle compression supposed to be on a 7bolt 2g?

 

[my dreamt dsm]

Idle compression??? What? I haven't heard of that yet.
But idle should be around 750 rpms. Or unless you meant within specs of a compression which is 178psi!