JAvenger007

iTrader: (9)

well I'm pretty stumped.

car is 99 and set up with .4bar spring. stock heads and 228/228 cam. turbo is a T60. we were picking up knock at part throttle 20% and then maxing the sensors out around 20-40% but seemed to go away during WOT. the 02 sensors are also reading off of each other during start up and idle sometimes but then stabilize after few minutes.

it builds boost to 5psi but after couple street runs it overheated and spewed coolant out of the resevoir.
IATs were in 120s after the hot runs. it was about 90s outside here in texas. engine temps were normal but them shot up to 250 once coolant shot out.

the car is driving fine out of boost and cruised for hours with no issues but again I never went into boost during that.

do 99 have cheaper gaskets? trying to figure out how coolant system is getting boosted. do I need to pull the heads and swap gaskets/arp bolts. I didn't think 5psi would be an issue. leak down showed everything is sealing good.

thanks for any help.

BLKWS6

If i remember correctly the 99s have/had the graphite gaskets. the GM MLS are supposed to be much better.

JAvenger007

iTrader: (9)

afr is at 14.5-14.8

SonofaBish

iTrader: (5)

please tell me its not that high under boost....????

even an n/a car wouldnt want afr's near that high at wot

Josh@MASPORT

iTrader: (3)

im hoping thats at idle


also if ur having 02 sensor missreading, it could be an exhaust leak

JAvenger007

iTrader: (9)

that's while cruising and idle. sorry I was typing while driving
ill check at wot

we were thinking my cats were going bad and could be contributing to knock. they've been removed now.

for 02s, leak would likely need to be close to the sensors for them to be off, right?

I have no hptuners or anyway to monitor unfortunately. also, I think my wg line might have a hole. that's only going to contribute to vac leak correct? only issue would be if I'm boosting and wg isn't getting proper reference

Josh@MASPORT

iTrader: (3)

for a leak it would have to be anywhere before the 02 sensor or close after

cablebandit

iTrader: (37)

couple of things.....you need to be tuning off a wideband and watching knock like a hawk. Your heads lifted due to detonation. KP had good luck with the graphite gaskets when he ran them. I'm not saying they will hold 20psi/1000rwhp but are not the prob in your case. TwnTrboCE Ran 9s with the stock headbolts if i recall correctly on his incon'd CE. You are having probs with tune and or octane. That liile turbo should have killer midrange and high cylinder pressures at mid rpms.....you gotta have timing low there and extra fat tune. I hope you are watching your fuel pressure as well......a lot to get right to make the motor survive.

99Z28LS1

iTrader: (4)

wow, that sux. i was hoping to see you get some good power..... thats a bummer man

JAvenger007

iTrader: (9)

yea I was interested to see what this little T60 could do. before overheating it would spool at 2400 rpm. .70 comp and .70 exhaust. it spools up real fast. I'm wondering if its negatively restricting the motor.

475 rwhp and instant spool would be fun.

anyway back to the problem. it was street tuned off wideband. timing was around 12 I believe. I'm not sure if he thought to pull some down low.
gas is 93 shell (i never use anyone else) and I added octane booster to the empty tank before tuning.
needs a fuel pressure guage which is going in this weekend.

it needs more time with hptuners/efi ect I just didn't want to cause problems 14 hours away from home

imo 5psi should not be causing this big of a problem considering my motor is in pretty good shape (never seen a track, rarely driven hard, and well maintained). shes a virgin when it comes to abuse

any other advice?

cablebandit

iTrader: (37)

it is restricting the motor..causing high backpressure and lifting the heads....5psi should be ok though so i am still gonna say its going lean at some point

trtturbo

iTrader: (25)

car is set up a little on the rich side with very conservative timing. It was picking up knock out of boost. Car at times had a little bit of a sulfer smell is why we were concerned about the cats.
Also, we did a pressure check on the cooling system and it did great.
Also, a leakdown test before the cam install and the engine is very tight.

cablebandit

iTrader: (37)

TRT...dunno then...something is detonating to lift the heads at that low of a power level...

RealQuick

iTrader: (14)

Problem is that you didnt use that perfectly good T67 you got I kid... I kid. Goodluck!

Jon

JAvenger007

iTrader: (9)

Shoot i shoulda known better
well I still have it on standby...with the .96 or .70 housing

Like billy said, there wasn't anything out of the ordinary during the install or after other than the overheating and knock registering at part throttle. Car has 80k on it.

Cats are off now. Not sure if that was contributing to knock. Its driving good right now (staying out of boost), but its hard to say without being able to monitor anything like knock. I haven't noticed any overheating issues since driving it home and around town last night. Is there a free version of EFIlive or something similar that I can hook up to my laptop?

Also, would leaks lead to knock and where should I check? Car seemed to build boost properly when initial tuning was taking place but still felt low on power.

JAvenger007

iTrader: (9)

back up top.

Just an update, im in the process of getting some LQ9s on the car. I think the gaskets have to be the culprit because TRT did a great job on the car and tune . I don't have my OBD stuff in yet to monitor knock just in case, and this car has yet to see more than 1psi on the road so hopefully things haven't gone bad.

Any other advice concerning the swap or the compression problem?
Im also considering a meth kit to help. With my IC we were seeing IATs in the 115-120s mostly and 140 while stopped for awhile idling.

JAvenger007

iTrader: (9)

Update:

I took the car out and did some scanning. Ive read some guys having a knock issue during shifting (2-3 shift) and it setting off the sensor due to the clutch, a rare case possibly I guess. Here is what I found:

-Car randomly picked up 1.7* of KR while cruising. Possibly went into a little boost, but its hard to say, ill have to take another look at TP and other things to tell what was happening.
-The only other time was 3.3* of KR when I went WOT and hit 3-4psi and shifted to 3rd and hit another 2-3psi until letting off.

Is 3.3* significant? I know that no knock is better but I'm wondering if dangerous knock is more like in the 20* range?

Heres some other info for the run:
-shell 93 octane with octane booster added
-IAT was in the 90's
-ECT was 189
-I swapped to a .96 exhaust housing. It spools slower but feels noticeably stronger when it hits boost. I think its running rich though due to spool coming later.

What do you guys think of a T67 with a .81 housing? Im currently running my 60-1 turbo.

phildo

iTrader: (7)

Any knock retard is bad. The tune needs to be double checked. If you are overly lean or rich it could cause knock retard. Too much timing causes it also.
If everything checks out and you feel it is false you could adjust the knock tables at your own risk. I have seen this in a couple of cars. Careful adjustment of the knock tables and it is gone.

RealQuick

iTrader: (14)

Use the T67 already

JAvenger007

iTrader: (9)

is 1-3* a significant amount of KR though? The car doesn't seem to be overheating, so I am wondering if there's a way to start narrowing down reason for the KR. The tune is very conservative.

I still have to drive the car back home before putting the 317s and meth on, which will hopefully help with this issue. This log session was the first time the car had hit more than 2psi (or really any significant boost for that matter). Does it still sound safe to drive (out of boost obviously)?
Thats going on with the new heads and meth