View Full Version : More 346" ET 240cc 11 degree progress - 10.7 @ 131 N/A 2500'

09-17-2006, 08:44 PM
Today we went to do alittle test and tune in the heat. Our only swap this time was the American Racing Long tubes. The new long tubes are much closer to equal length which yeilds more consistent A/F from cylinder to cylinder. One thing to note is we're not launching the car yet so the 60's are slow but consistent.

Old Long tubes -> American Racing Long tubes

1850' DA
10.9 @ 129
Shift 7400
A/F avg: 12.5
Timing: 24 deg

After Header Swap ONLY
2500' DA
10.7 @ 131(calculated 2.2MPH gain in worse weather)
Shift 7400
A/F avg: 12.5
Timing 24 degrees

The run was pretty smooth, we left very easy the car 60' was 1.69 and terminated the run with a very pleasing 10.7 @ 131 in the middle of the heat today.

09-17-2006, 08:57 PM
With the DA it looks like you gained 3mph. Good gain from a header swap. What size are the headers?
where both headers the same size?

09-17-2006, 09:03 PM
Yeah, about 3mph with the DA figured in. The headers went from a 1 3/4" to a 1 7/8" but the ID changed pretty drastically @ points. Do you think 137-138mph is out of the question with -2000' air? We see that in the later parts of october here.

09-17-2006, 09:35 PM
Are you saying that the old headers were 1 3/4 and the new are 1 7/8?
Or are both step header from 1 3/4 to 1 7/8?

I think from a + 2,500DA with 131 MPH to -2,000DA you could see 137mph.

09-18-2006, 04:57 AM
wow!!!! impressive!

09-18-2006, 11:27 AM
real nice NA times. Is the bottom end stock? Are the pistons fly cut? What cam? Your making me want to sell my H&C !

09-18-2006, 12:35 PM
real nice NA times. Is the bottom end stock? Are the pistons fly cut? What cam? Your making me want to sell my H&C !

Its a forged bottom end with heavier beefed up parts for nitrous, -2cc reliefs, 254/260 cam.

09-18-2006, 08:53 PM
Looks like we broke another MAP sensor sunday. We either need to move the MAP sensor or cut the top of the firewall. Any suggestions?

09-19-2006, 12:39 AM
I'd relocate the MAP. Seen a thread on it somewhere...


09-19-2006, 11:50 PM
Map is fixed, cowl is fiberglassed and the car is going to be back in action this week with 2 more degrees of timing and 5% less fuel(12.5 - 13.0). We'd love to see 133 before the cold air sets. :eek2:

09-21-2006, 08:57 PM
Congrats on the great times.

What is the compression ratio and weight with driver?

I went nearly 128mph n/a with 10.7:1 compression, milled .024" AFR 205's, TSP 233/239 .600 112LSA cam, LS6 intake, ported TB, MAF tune, UD pulley, 1 7/8" headers thru dual 3" cats/Xpipe/muffs. I was 2950lbs with driver. That was in January with 50* temps and great DA I imagine. In 90* heat it runs 125-126 mphish.

With nitrous that Vette will fly.

09-21-2006, 10:09 PM
The compression is 9.4:1 DCR and the car is about 3300lbs maybe more.

09-21-2006, 10:10 PM
you havn't had the car on a dyno? would really like to know what kind of power it is making...