Tuning Questions

[87GN&98VET]

Hi all, need some advice here. When I go WOT from a stop, I begin lighting up my Caspers knock gauge (the middle yellow light) as the boost climbs in first gear. Ironically, the lights seem to occur as the tires are breaking loose. Has anyone ever had poor traction cause the knock gauge to light up? The boost peaks at about 18# in 1st, but when I jump on it while I'm moving (either downshifting into 2nd or staying in 3rd), the boost spikes to almost 20# then settles back to 17# but I get no lights on the knock gauge. That's why I'm asking if the poor traction is causing knock (or false knock) in first because I'm not getting anything in 2nd or 3rd.

Also, I'm already up to 47 psi with my stock injectors. If I am truly running lean, is it time to upgrade the injectors? The car is basically a 13k mile stocker (stock intercooler, turbo, etc.) with the usual beginner upgrades. I also have a 62mm Hemco intake plenum I'm going to put on and I'm not sure if that will eleviate my problem or make it worse. I appreciate any advice!

 

[87GN&98VET]

Oh yeah, I forgot to mention that I do have a scan tool - Turbolink. But I've only seen about 2-3 degrees of retard and the O2's are in the high 700's / low 800's. I figured since the sampling rate is less than 1 Hz, the Caspers gauge is probably a truer indication of what's going on.

 

[87GN&98VET]

One more comment I forgot to add. I'm running a Thrasher 92 street chip. I figured that's probably one of the more milder chips since I've never heard of anyone having a detonation problem with them.

 

[ES1]

I have seen post that wheel spin can cause knock. One of the fixes was to go to a Translator and a Ls1 MAF.
I get knock from wheel hop.

 

[azgn]

you are on the edge, octane wise, running 18+ lbs of boost with pump gas....additional fuel probably won't help.....additional octane will help

 

[87GN&98VET]

So it probably wouldn't be worth going with a bigger injector? I also have a 62mm Hemco intake plenum I was going to install. The theory behind the design is to distribute air more evenly to the cylinders, so detonation should be less frequent, altough with a 62mm opening I'm allowing more air into the plenum. Would injectors help here, or just lower boost. Also, what are your thoughts on just feeding on 100 octane and getting a 100 octane chip for a car that is 99% street driven?

 

[Whistle Pig]

Get SMC Alcohol Injection

Best 350.00 dollars I have spent yet. Stock intercooler t44 turbo 24 psi boost today no knock! Sombody may chime in and be correct in saying that 21 psi is about the limit a stock turbo is efficiant at! You may also try H&R parts and stuff motor mounts advertised here to help with false knock as it keeps the motor from moving as much alowing thing like the downpipe to hit and set off the knock guage. good luck Kevin

 

[TRENT THOMPSON]

when my car had a stock setup on it I used too experience wheel spin knock all of the time

 

[kenmosher]

The statement about the knock gauge being more accurate than TurboLink is comparing apples to pistachios

The RETARD shown on TurboLink is the reaction to the signal that the knock gauge is hooked up to. It's what the ECM DOES with the signal... while the gauge is showing you the unfiltered input.

Look at the ESC in TurboLink and that will give you a pretty good idea of how severe the event was (by the change in counts) and what the ECM did with it (degrees of retard).

 

[V6POWER]

Ken--Is there a correlation between ESC counts and RETARD? For instance, do 10 ESC counts = 1* retard? Thanks.

 

[azgn]

I would think the costs/recovery rate would be very good on an
alcohol set up if you want to run high boost on the street vs buying truck loads of 100 octane unleaded

 

[c&cgn]

Originally posted by 87GN&98VET
So it probably wouldn't be worth going with a bigger injector? I also have a 62mm Hemco intake plenum I was going to install. The theory behind the design is to distribute air more evenly to the cylinders, so detonation should be less frequent, altough with a 62mm opening I'm allowing more air into the plenum. Would injectors help here, or just lower boost. Also, what are your thoughts on just feeding on 100 octane and getting a 100 octane chip for a car that is 99% street driven?

I would try the 100 octane unleaded with you current chip just to see if the knock disappears. If it does then your knock is octane related and you can start narrowing it down from there exactly when and why it is happening.

 

[kenmosher]

There's a really good description in the Gn/TType traffic archives about the particulars on ESC counts.

Basically, the counts shown are only part of the story and the ECM does different things with the counts than what shows on a scan tool.

There's logic in the ECM to react to spark knock and recorver/attack rates burned into the chips and they all differ.

Basically, there's no direct correlation ... but you can definately see severity (lots of ESC means there were multiple knock events).

 

[V6POWER]

Thanks Ken.