Opps...KR problem...

[Orion231]

Well last night I went otu to the local street race scene, and well I decided to run my car once with a bud, and I launched ok, mind you this is in total street trim. I had turbolink up and I recorded the run, I got a little knock up till 70 MPH or so, maybe 3 degrees, then WHAM it went to 17.4 in 4th gear at 98 MPH...I saw this on my caspers knock detector and I let out immediatley I didn't win the race I lost by a car and a half, but it was a just for fun race between me and a low 12 second GS 455 Stage I, I took him until the very end of the run. But I felt really awful and I was worried I may have damaged soemthing, the car has no idle problem, no boost problem, nothing out of the ordinary coudl it have possibly been fasle knock? I am freakin gout cause I was running O2s in the 792 ish range at WOT top of 3rd gear...This was one pump gas also. I am going to change the oil soon, but should I worry? Or if a problem would have happen, head gasket, woudl it show immediatley. I have never blown a HG and I don't want too!


Cory

 

[Orion231]

Paranoid

I know I'm paranoid, but I am still learning how to tune the car, and I don't want to hurt it. Can someone explain to me what "types" if any ok KR there are? True KR detonation occurs in a constant rise correct? And flase is generally a spike, or a blip or knock? What else?


Cory

 

[Turbo__Tim]

17 PSI is bad, but hitting that once isn't going to hurt.

Since you were shifting into fourth gear, the piston has a longer time to heat the gas prematurely (lower rpm's). Combine that with the fact that the combustion chamber, and all it's components were super hot during a WOT run, and you are just asking for it!

Most HG's are blown in third gear, and at the 3rd shift, for that very reason.

Yes you had real KR!

Remember now that we have modded these cars they make a lot more power, and heat. Stock cars won't have as much of a problem with that situation, unless they are running lots of timing.

The usual remedies would apply here, alchy injection, higher octane, or scaleing the timing back 3 degrees on the shift. I'm not sure that pulling timing on fourth shift will work, however.

Personally, I never go into fourth with a full pedal.....

Glad nothing bad happened. I would get the car (and oil) hot, and see what, if any change there is to the oil pressure now, just to be sure. It's a good thing to know what your 'normal' oil pressure is at say 3,000 rpm. Use that figure as a benchmark for future reference. Lots of continous knock will loosen the crank bearings (as you know) and cause oil pressure to drop...

 

[tim87tr]

Looking at your sig, didn't see a fuel pump and hotwire upgrade, but I'm sure you have it seeing the other upgrades. 17 psi is borderline to get kr on pump gas.

Be sure you have adequate fp at WOT. A fp guage on the end of the fuel rail that you can place under the wiper blade to check fp at WOT will show if your pump is ok. If your static fp, line off, is set at 43, then you would need the 43+17 = 60 lb at WOT to keep the car from leaning out. Lean out will show up most at WOT in high gears when the engine is under load most. Stock pumps only put out low 50's fp.

Knock on shift is not as bad as runaway knock that keeps spiraling in high gears. If you see a big number on the kr, let up right away. I had never thought about what Turbo_Tim said, but I will use that rule to not hit 3rd and 4th at full pedal.

Some chips seem to do better with kr. I have tried a few and since I had to replace my MAF and went with the LT1 and translator, I used the extender chip. It has been the best chip for eliminating kr that I have used. You either need more octane or less boost to eliminate kr.

 

[Orion231]

Real KR....

I pulled over and checked everything over last night, I have VDO guages and I noticed nothing new in the oil pressure all wa sin the green, no new noises, car ran fine, and I do have a Walbro GS 340 pump with hotwire kit, I did realize that in 3rd gear my engien has the most strain, and that it is very possible that I could have damaged something, and if I haven't then I am very lucky. SMC alky will be here Monday hopefully, I ordered the dual nozzle setup. I hope it gets here. I was just gald I was hanging with that Blue GS because his car is WICKED. Well I appreciate it guys. I guess if I would have blown a head gasket then I would notice all the normal symptoms immiediatley.... oil in water, rough idle, boost needle shaking, car hesitation, etc. Anyting else guys?

 

[Steve Wood]

With luck, you did not. If it runs okay, it should be fine. But, when the car shifts into 4th gear, the load increases greatly.

I don't know how much boost you were running but it sounds like too much if you had 3 degs down lower.

I find most of these cars run better on 93 octane up around .820 or so on the useless O2s. Give it some more fuel and see if you can juggle boost and fuel to get no knock down thru the gears.

Stay out of fourth gear if you can. The 9/11 has a fair bit of slip in it so lock the converter up in third gear with a manual switch and stay in third.

 

[Orion231]

911 Lock Up...

Another question, is it best to lock this converter on th eline or at top of 2nd or what? What is the difference? I saw 17 almost 18 PSI in 3rd and I am running tuner for the wastegate. It still surges a little at part throttle but at WOt there is no hint of surge and it pulls hard...I really like this PT51. One more question, when I get alky, will I need to lean out my fuel? How does that work? With the MSD 50s I am wondering what to do next.