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I joined this page in 2011 shortly after getting my cobalt in January of 2010. I decided to finally make a build thread since a lot of new things are happening to the car. Most of you know I ended up putting an m62 on it back in 2015. Turned out pretty decent for the setup. Put down 264/266 on a mustang dyno at tx2k16 and managed to break 12s in the 1/4. Not bad for an auto. Then put the tvs on it this past may. Ran it once and got low 12s. Didn’t get to enjoy it much because we ran into a few problems. My crank pulley broke off while I was driving it. Not sure how it happened. Hurricane Harvey flooded it so it was down for about a month. Gutted the car and cleaned it really good and replaced the carpet. Added a few extra goods while it was down. Got it all fixed up and shortly after ended up melting a piston and cylinder sleeve while racing an lnf. Car went lean and we weren’t watching. Oops. That was beginning of October. Instead of replacing the piston and sleeve it’s getting a built gen 3 and a built auto trans. Might as well build it now. Almost got all the parts for the bottom end. Car should be running sometime in January. Most will laugh but it’s being set up for the 1/4 mile. A trans brake and wot box will go in also. After everything is complete the goal is to run low to mid 11s. Not really too concerned about a dyno number but it should be around 400whp. Here’s my setup and some pictures. I’ll update this post as the build continues.
ENGINE
2.4 GEN 3 LEA block
11:1 forged diamond pistons
Total seal piston rings
Molnar rods
ARP Head studs
Balance rotating assembly
Cloyes timing kit
Balance shaft delete
Supercharged ATI dampener
TTR motor mount
Lsj 6 rib conversion
Ported head
Custom cams
Supertech 75# valve springs
PERFORMANCE
TVS 1320
2.6 pulley
Zzp midlength header(1.75primaries)
Zzp 2.5 catless downpipe
Zzp 2.5 catback w/resonator&muffler
3.5 OTTP intake
LS4 Throttle body
WOT box
Mpx catch can
Hp tuned by Mad Scientist Performance
I know he made 420ish but I’m not 100% sure what his build is. But I doubt I will. I’m aiming for 1/4 mile times, not a power number. We will see though. It will get dynod at tx2k18.
I considered the turbo ATI damper or the Under drive damper when I was doing my rebuild. I thought it would be nice to under drive the accessories a bit since the build was going to be high rpm and there wasn't any need to drive everything that much faster. I would have went with a stock pulley diameter ATI if it was available. However I got to figuring what that would do to my pulley ratio and the Under Drive pulley is about 1" smaller in diameter. This makes you need a significantly smaller supercharger pulley to maintain the same ratio. For example if you were running a 2.6" SC pulley with the stock diameter harmonic balancer then you would have to run a 2.2" pulley with the underdrive ATI. I didn't think running that small of supercharger pulley would be a good idea as I don't think that small of pulley would grip the belt very well and would probably slip. It will also increase side load on your snout bearings. Also I don't know if you would be able to find a short enough belt.
Running the turbo ati doesn’t it increase pulley size by one size? Like if I put a 2.6 on it wouldn’t it be a 2.7? Basically opposite of the supercharged ati? If that’s not true then I’m not going to use it. Only reason I was going to use the turbo one is because we already have one laying around. Would save like $400. I was going to put a 2.5 pulley on thinking it would actually be a 2.6. Am I wrong?
OD ATI is oversized by 5%. UD ATI is undersized by 12%
Edit because I didn't have time to respond proper earlier had to get to a meeting. But what Mike says directly below me is true. To compare ratios just do like 2.6/6.5=??/6.78 for OD and 2.6/6.5=??/5.5 for UD. ?? is your SC pulley size to maintain pulley ratio.
12-07-2017, 10:48 AM
