The short version: The SR20DET at stock boost couldn't handle a hot day on the California freeway, when running the piss poor "91" octane that we have here.
I was close to the top of fourth gear when the car had what felt almost like a flameout. It was building boost just fine, then suddenly it shifted over to this sputtering tone and I then let off. Ever since then, it hasn't been as quick to boost. I don't have the A/F or EGT gauges in yet, but I thought the engine was supposed to be good at 7psi with an upgraded fuel pump. It feels kind of like it leaned out, so there was probably some detonation. Grrrrrrrr!!!!!!
I guess I gotta put compression test on the list of things to do next week. What a pain in the ***, eh?
Edit: Oh yeah, the piece o-junk, driven by a drifter transmission that I got from Japan does not seem like it will continue to hold up much longer. I wonder how much torque those KA transmissions take before they start to break...
Blew some compression out of the motor today
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SpeedRacer1
- Posts: 3144
- Joined: Fri Jul 26, 2002 7:44 pm
- Car: 1990 240SX, G35
Random stuff like this story makes me think that one should check everything before jumping to conclusions.
I have had many instances where this type of thing has occurred and im sure many of you would think "oh crap there goes the engine." (Warning, stories about my experience, nothing all that technical so if you dont care then you might want to stop reading my post now)
One time I was driving down the street and barely hit any boost then "bam" and the car wouldnt idle worth crap, so in order to keep the car from dying I had to rev the crap out of it while I found a parking lot to coast into. There I found out it was just that my hotpipe had been completely blow out of the clamp, mainly because I let someone else touch my car and they did not even have the technical skill to tighten it up.
Another time I was boosting on the freeway when the engine would simply stop going faster than about 65mph, anything above that and it would sputter. So I pulled off the freeway and realized that the engine wasnt getting stuck at 65 mph, it was not boosting past about 0 bar, yet was completely driveable under less than 0 bar conditions. I finally parked and found that to my amazement everything looked fine. Then I realized that when I hit 0 bar, the hotpipe slipped out of the clamp and released metered air, and when boost levels dropped, the hotpipe went back into place. So I tightened the clamp on the hotpipe and off I went.
Another time I was driving my car when I noticed that it felt a little boggy. I thought it was the BOV i installed leaking boost, however boost was fine, but I was not going anywhere. Turns out that my throttle body hose had worked its way loose because of some spilled coolant and was popping off the throttle body during acceleration thus letting in unmetered air. Again this happened another time and was diagnosed alot faster since I knew the symptoms.
Another time (hahaha this is getting old) I was driving along when I heard a loud pop from the engine bay and my car lost all power. I pulled over to the side of the road and looked under the hood to find my #4 coil and spark plug had blown straight through my wire cover. Appearantly the plug had been somewhat stripped, and was not torqued tight enough. This resulted in my car misfiring before the accident occured. So three problems, misfiring, bad emissions and bad performance were solved with one fell swoop.
Bottom line, check most of the obvious stuff before thinking you have detonated. I have an SR that detonated on two cylinders and was still driveable. So that could be your problem Phax but check everything as well as doing compression (since compression tests are easy to do).
As for crap trannies, you should get another SR transmission from one of the local SR places. I have a local supplier so you being in Cali should definately have a few, you should check around for price quotes.
I have had many instances where this type of thing has occurred and im sure many of you would think "oh crap there goes the engine." (Warning, stories about my experience, nothing all that technical so if you dont care then you might want to stop reading my post now)
One time I was driving down the street and barely hit any boost then "bam" and the car wouldnt idle worth crap, so in order to keep the car from dying I had to rev the crap out of it while I found a parking lot to coast into. There I found out it was just that my hotpipe had been completely blow out of the clamp, mainly because I let someone else touch my car and they did not even have the technical skill to tighten it up.
Another time I was boosting on the freeway when the engine would simply stop going faster than about 65mph, anything above that and it would sputter. So I pulled off the freeway and realized that the engine wasnt getting stuck at 65 mph, it was not boosting past about 0 bar, yet was completely driveable under less than 0 bar conditions. I finally parked and found that to my amazement everything looked fine. Then I realized that when I hit 0 bar, the hotpipe slipped out of the clamp and released metered air, and when boost levels dropped, the hotpipe went back into place. So I tightened the clamp on the hotpipe and off I went.
Another time I was driving my car when I noticed that it felt a little boggy. I thought it was the BOV i installed leaking boost, however boost was fine, but I was not going anywhere. Turns out that my throttle body hose had worked its way loose because of some spilled coolant and was popping off the throttle body during acceleration thus letting in unmetered air. Again this happened another time and was diagnosed alot faster since I knew the symptoms.
Another time (hahaha this is getting old) I was driving along when I heard a loud pop from the engine bay and my car lost all power. I pulled over to the side of the road and looked under the hood to find my #4 coil and spark plug had blown straight through my wire cover. Appearantly the plug had been somewhat stripped, and was not torqued tight enough. This resulted in my car misfiring before the accident occured. So three problems, misfiring, bad emissions and bad performance were solved with one fell swoop.
Bottom line, check most of the obvious stuff before thinking you have detonated. I have an SR that detonated on two cylinders and was still driveable. So that could be your problem Phax but check everything as well as doing compression (since compression tests are easy to do).
As for crap trannies, you should get another SR transmission from one of the local SR places. I have a local supplier so you being in Cali should definately have a few, you should check around for price quotes.
SpeedRacer1 wrote:...As for crap trannies, you should get another SR transmission from one of the local SR places. I have a local supplier so you being in Cali should definately have a few, you should check around for price quotes.
First off, thanks for pointing out the various things it could have been. It could have just been that the temps were so hot that the pipes expanded to a point where they usually don't, and I'll get into the car tomorrow morning and it will run fine. Turbos are kind of funny like that. I was up around ~7000RPM, and common belief seems to be that the T25 is only good to around 6500. That might have been some of what happened as well.
Do you have any idea at what point the spark starts to scatter with the stock ignition system?
Oh, and not that I'd know anything about running into weird engine conditions while driving alongside a Civic hatch, but those things rev like mf'ers. I saw this guy today who even had a chassis brace going across the inside of his car, visible about mid-height in the rear window. Those FWD guys do some weird things with handling dynamics..
To answer the question about the KA transmission's breaking, I just broke mine yesterday (sunday 9/21) while leaving the strating line at the dragstrip. Slicks, and 2step launch control set at 5krpm making 7psi and dropping the clutch too hard. My car has dynod 331tq at 5krpm at 16psi, its turned up to 22. Its not the power or torque that breaks it, its the shock of hard engagement. I ended up breaking the main shaft off at the driveline.
So if you have a stock KA 5spd trans from a 91-96 email me at [email protected].
Rick
So if you have a stock KA 5spd trans from a 91-96 email me at [email protected].
Rick
It turns out that the compression on the engine is fine. 175, 175, 170, 175. There is something wrong with the way the O2 sensor is wired though. So it'll be a day or so of tracking everything down and getting it properly wired up. The ECU has been running in open loop this whole time. I can't wait until it's actually wired up correctly!