Drag Racing Results - New track times, car has problems

New best 60ft of 1.73
New best 1/8th of 7.77

But only 12.27 1/4 mile

Also MPH was down even though the weather was awesome. Down 2 mph in both 1/8th and 1/4, some shift point tweaking got me back to 90mph in the 1/8th but the 1/4 mile was only 108mph all night. Cars previous was a 111mph 12.24 pass.

Changing shift points on the 2-3 made no difference anywhere between 5600rpm and 6400 rpm.



Roll raced a friends stock 2011 5.0 (we always run door to door from rolls) and he pulled 2 cars on me and said my car sounded rough like it was breaking up in the upper RPM.

I'm thinking its likely worn out valve springs and getting float. Any other good ideas?

how old are the plugs and wires. clean maf also, is the tranny slippin?

MAF was just cleaned, plugs and wires are about a year old.

No indicators or reason to believe the trans is slipping. It's also fairly new and was built with some good parts.

Any other ideas? Leaning towards worn out springs causing valve float.

Put it on the dyno and see how the graph looks. Only other thing I can think of is it could be coils, how many miles on them.

Put it on the dyno and see how the graph looks. Only other thing I can think of is it could be coils, how many miles on them.


X2 Put it on the rollers. Any idea how much rwhp the car has?

http://img.photobucket.com/albums/v477/thunderstruck507/20110915081713_00001.jpg

After that the car was trapping 110-111mph in worse DA. I'm down 2 mph in better air and a friend said he could hear it breaking up in the upper rpm.

I've got a new cam on the way and some 799 heads in the corner along with fresh patriot gold duals. Guess I'm going to just tear it down and swap all that on and work the tune back out.

How much does the car weigh and what valve springs?



I'm not an expert but IMO it sounds like the car needs to be tuned again. I have a set of PRC243's, TR224 cam, and stock LS6 intake and it made 378rwhp and putdown an 11.83 on drag radials

Race weight is 3700 or just over. PAC 1218 springs but I just tossed them on and didn't check them or shim them, didn't realize I was supposed to.

My previous dyno run was way worse (partially due to a ls1 intake) and had very obvious issues after 6k rpm and the ls1 intake choked it off down around 5400rpm.

All runs were with the converter unlocked and the cutouts closed (2.25" tailpipes after the muffler were choking it a little).

Springs now have close to 40k miles on them I believe. Since I already have the other heads, gaskets, arp bolts, and a weeks vacation I think my time is better spent doing the swap I wanted to do anyway. Got a used cam for a good price so the cam swap is basically free after I sell mine (if it's not damaged for some reason).

On a different run the car put down 368rwhp (this is on stock 806 heads mind you), it was just a little lean. Trans grenaded so it was a couple months into summer when I got back to finish.