Quote:
Originally Posted by Tom Meyer
My sons and I have raced dirt track IMCA with a eco powered cavilers since 2012 and have done a lot of wheel dyno work. We must run stock exhaust manifold so I am sure a good header would make more power. With this being a VVT engine it should make more power than non VVT engine than we run. We also did a lot of testing on the air intake system and a open TB makes about 4.5 hp more than a cold air system. The intake manifold is the biggest restrictions on these motors, early on till outlawed you could just bolt on a later model 2.4 intake and pickup over 25 hp. Baseline hp at the wheel was 135 hp with limited mods, tuned stock ecm, stock cams, injectors stock exhaust manifold with a bigger pipe with some other small mods brought the power to around 150 at the wheel. Camshaft lift is 419 a the valve. Changing the valve angle helped flow on the flow bench but did not do any back to back dyno testing. I am sure a good stocker valve job would help. Eliminating the balance shafts with a kit gets rid of rotating weight. We run manual trans so never did much with the autos. Saturn VUES run the same basic set up but are geared lower because of the heaver vehicle. With the stick It goes from a 3.94 final chevy to a 4.45 Saturn, HHRs have 4.19. Checking out these cars with an auto could find something. The stock valve train will turn 7000 all day long, stronger valve springs would collapse the lifters and lose lift in long lap races. The rear of the cam gear can be ground to change cam timing or aftermarket adjustable gears are available. If you could find someone to regrind the cams mite help also. I always thought someday this would be a fun combo to do but, hell I cain't even get my SS car going. Tom.
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Thanks for all that info on the transmissions and all the other engine intel I'll keep that all in mind if this gets underway and gets serious down the road. There are a lot of "ifs" involved since this is really to hold me over while my dragster is waiting to go into the shop. (4 month waiting list to get in the door, season starts in March and goes to July).
A far as wheels go, are you using 13 inch or 15 inch rims on your dirt track cars?
That's the first big hump with the Cobalt, is being able to use 13 inch rims with a 20 inch tall slick. I don't want to have to change transmissions or swap to a Geo Metro brake set-up (which may not work for me anyway since the Geo Metro bolt pattern may different than the Cobalt from what I read).