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At different times I suspected the headers hitting the sway bar or something similar.... but the trans dipstick is well away from the headers and there's a lot of clearance between the headers and swaybar. I have new mounts all around and poly's up top, the motor barely moves at all.
The torque converter I also suspected (and it does act squirrely sometimes) But it happens whether the torque converter is unlocked or not... If I'm at 15 MPH in 2nd gear and goose the gas, I get a big spike of knock too. Only thing that bought me some relief was lowering the PE threshold by about 20% across the board which allows me to roll into it... once PE is commanding an 11.2 and it's been there for a half second or so, I can mash the gas the rest of the way and there's no knock all the way through 2nd and 3rd.
Is part of that false knock? I'm totally stock now (besides poly motor mounts) and just cruising today on the interstate at 70-75 mph I will get knock readings of 2-3 when I'm going up a small incline still in 4th gear. My vacuum gets close to -1 or 0, so to me it seems like the engine is lugging and won't shift to 3rd. Is that what is causing that knock? Brandon, you might want to get some solid motor mounts to stop you engine from moving around so much. I could see you driving at 40mph, flooring it and going into 2nd WOT, could cause a lot of engine movement.
Your KR is likely real. If you get into the throttle a little more, you'll actually build some boost before the car will downshift, especially if you don't have the performance shift option/it's turned off. It's the engine being loaded up. Lugging is not a bad way to put it. You aren't likely to be in PE, so 14.7:1 while having even a small amount of boost is not good.
That all said, a degree or two of KR on a stock car usually isn't the end of the world... these cars almost all have knock from the factory.
I finally have an answer, because I just figured it out myself. At higher power levels the torque converter if stock will act strange sometimes. On a stock trans tune, the TCC does not unlock the converter until almost 50% throttle. That's an enormous amount of load placed on the converter that's suddenly broken free. This effect is amplified if you have a larger throttle body (I have a Northstar), as 50% throttle position on a N* is way more than the same TPS on an L67 TB... The result being the TCC stays locked far longer than it should.
For some reason when it releases under load it generates a noise that reads as a massive amount of KR.
I first suspected my 42# injectors were too small for the job so I put 60's on, only to have the same problem.
So, we lowered the TCC unlock threshold with the tuner to a more reasonable 25%... And voila, the KR was 1-2 degrees.
In other words, I just need a beefier torque converter.
AFAIK tcc doesnt apply in 2nd gear from factory unless you make it to.
with the revised table (2nd one) the tcc will unlock when you go over 18% instead of the 25%.
only if he is flooring it going up (pending mods ) but if only just to unlock the tc and maintain or increase his speed gradually with flow of traffic, at 25% is fine imo
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