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06-04-2011
Here's where I am perplexed... The GenV outlet temps are lower. Our cars knock because of the excessive heat generated by the blower. So why are people being advised to pulley up with the GenV vs GenIII when their outlet temps are going down? Wouldn't this mean they are less likely to knock?Originally Posted by Bio248
06-04-2011
And the GenV is generating less of that heat...boost is heat.
The GenV simply takes less power to run at boost, and post-blower air is colder.
So I can't understand why people are being advised to get bigger pullies with the GenV.
Has anyone ever looked at how much more aggressive the 04+ timing tables are than the 97-03? Same pulley size... Why didn't GM keep the same timing tables and go to a 4.0'' pulley?
Last edited by SnowFlake; 06-09-2011 at 07:46 PM.
06-04-2011
I'm still very confused... after extensive analysis of my genIII scans vs my GenV scans I still cannot understand why people are advised to pulley up when switching to the GenV. The engine was able to handle more timing vs boost 100% of the time with the GenV.
I'm wondering if anyone else has ever done any testing on the subject? I'm thinking that people have just been reading and passing along information that was at one time skewed from the original theory.
My theory is that the GenV will roughly produce the same power as a GenIII with a pulley .1-.2'' bigger, with other factors weighing in, such as timing. This is a rough estimate and is surely not linear, especially as pulley sizes get smaller. However this has nothing to do with what pulley you should chose when modding your car.
I have concluded that anyone who says you "Should run a bigger pulley on the GenV than GenIII" has simply only heard this from someone else, and has no real understanding of the actual differences regarding knock between the two blowers.
Like I said before, take a look at the 04+ timing tables vs the 97-03 timing tables, they are WAY more aggressive.
So to tie this into the OP... you most likely don't have a chipped piston because of running a 3.4 pulley... with headers and exhaust that's not really overkilling it at all. Of course other factors could come into play such as bad gas, poor tune, or if you were relentlessly beating the piss out of your car for an extended period of time, among other possible causes.
If anyone else has clear and well thought out opinions on this topic I'd love to hear it.
06-04-2011
so your theory is.
If im running a 3.4 on a gen 3 now, i should be able to run a 3.4 on gen V no problem
06-04-2011
I was able to run more timing on a GenV with a 3.4 pulley than I was able to run on a GenIII with a 3.5 pulley.
06-04-2011
look at the inlets.
Thats all I have to add to this discussion.
06-04-2011
Yes the physical differences are obvious. The affects they have on timing vs boost vs pulley size have been widely skewed.
06-07-2011
once i had the 3.4 put on i had the car tuned, there was no knock, i just installed a port and polished LIM, supercharger and TB, plus 39lbs injectors
06-07-2011
And I had colder plus in there i think they were 105's
06-08-2011
GP Kid..if your motor runs there's almost no chance that you jumped timing. Similar to a SBC350, our chains and gears are extremely beefy. Timing jumping is something that doesn't happen. If you broke the chain and replaced it, lost the dampener and replaced it etc then it might be possible.
Now to diagnose your problem. See those pretty red MSD coils on your car, those are known to break down and cause high rpm misfires in as little as 6-12 months from time of install. Maybe sooner. Add those to the 3.4 pulley that's technically a little small for your mods and this can cause some kr and power problems.
What I'm saying is..if your tuner isn't a die hard 3800 guy with years of knowledge, he's misdiagnosing based on what most other motors tend to do. Kinda like someone that knows DSM's saying they think a 3800 has crank walk. ... something that happens to the other motor and doesn't happen to our.s
07-25-2011
Oh it can happen to ours.
I had nasty crank walk when i bought a supercharged regal.
flexplate chewed the rear cover, thrust bearings were worn out, had a quarter inch of play.
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