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3.69's As a KR reducing mod?

A

Ace

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The more load there is on an engine, the less aggressive the ignition timing curve can be before spark knock occurs. With that being said gp's are very heavy and have very low final gear ratios. Id imagine this puts a lot of load on the engine, limiting timing advance. With 3.69's engine load would be reduced,in theory allowing more timing advance before spark knock. Can anyone with 3.69's support or disprove my theory? I'm not trying to justify 3.69's over headers or anything just want some info.
 


That sure is a new one.

Swapping gear ratio and changing it in the PCM will really do nothing but reduce gas mileage and make it a better drag car.

These car will see a good amount of load in 4th gear but its not harming the car, we can see upwards of 35-40+* timing while crusing to get the good mpgs. Once the car is moving its not really working at all to stay at that speed.

Adding a set of headers is the one of the best things to do to reduce KR when going WOT and during modding.
 
Agreed that headers are one of the best anti-KR mods,but if you already have headers,pulleys,etc. and can run xx amount of safe ignition timing at WOT. Will a higher gear ratio allow you to run more timing at WOT?
 
There's also an optimum amount of timing to run, if you run to much then you can loose power. People running everything don't really have a problem running timing AFAIK.
 
The trans really shouldnt have anything to do with what kind of timing the car is going to run.

Thats all going to come down to what kinda mods your have on the motor and how well it can flow it and run it safely.
 
Gears are a nice addition...but probably at your mod level I wouldn't worry about it at all.

A set of headers, a solid WB tune, and a pulley drop will net better gains than a gear swap in an attempt to beat physics and crank the timing.
 


You won't gain enough to notice it. I've worked with 3.29 and 3.69 gear ratios and the end result timing ends up being about the same. Keep in mind that these were highly modded cars by the time they went to the higher ratios.
 
Sandman said:
There's also an optimum amount of timing to run, if you run to much then you can loose power. People running everything don't really have a problem running timing AFAIK.
Click to expand...

Much more likely to see kr before that point.

However i would like someone to find mbt on a dyno.
 
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