LQ4 in a 1971 Nova
115 is corrected mph. I actually only hit 111.
Iron 370 cid
10.5 scr
L92 heads milled .020"
LG motorsports G6x3 cam (235/245, .645/.610, 111(?))
LS3 intake
Holley 90mm TB
American Racing 1 7/8" headers with 3" Pypes exhaust
4L80e w/ Vig 3600 stall and HD2 shift kit
~3200 lb car w/o me
3.90 gears
255/60-15 MT ET Streets
Iron 370 cid
10.5 scr
L92 heads milled .020"
LG motorsports G6x3 cam (235/245, .645/.610, 111(?))
LS3 intake
Holley 90mm TB
American Racing 1 7/8" headers with 3" Pypes exhaust
4L80e w/ Vig 3600 stall and HD2 shift kit
~3200 lb car w/o me
3.90 gears
255/60-15 MT ET Streets
dyno tune was 414/373. AFR was good. had the best tuner in the valley do the tune. that was about a year and a half (and 1000 miles) ago. I won't really start to worry until I get a few more races on her. Still disappointing though.
That flatline HP at the end of the curve seems pretty common with these engines. It may simply be an airflow limitation (intake? throttle body?). Looking at futureuser's dyno, it does the same thing (link). Texas Speeds VVT2 L99 dyno curve does the same too (link). All three running LS3 intakes, although hookem has a bit bigger cam.
Art Morrison ladder bars w/ chassis works coil-overs. I put the shock/spring down as low as I could go, then adjusted the springs pretty taught with the spanner nuts to reduce deflection on the street. The driver's side tire had less than a finger's width to the outer fender statically, so I'm positive it was rubbing (and scrubbing speed) on launch. The tight springs certainly didn't help either. Next time out (next weekend), I'm going to put the rear up a bit and reduce the effective spring preload. This should help the 60' times. And after watching my videos, longer burnouts will also be practiced to hopefully heat the tires a little more (I actually spun while on the line-lock before one launch)
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Could be valve train related.
Springs, pushrods need to be updated for that cam and rpm with that big intake valve. Need a 155/400 double spring and thick wall (0.100+) pushrods.
And geometry setup correctly.
And your intake doesn't help, but the long runner is why all the LSx motors peak around 6300 or go flat. Stock Fast 102's flow considerably less than those heads will. And not everybody can port them well despite how easy it looks.
Nice build btw, yours along with bandit and fro keep me motivated on mine.
Springs, pushrods need to be updated for that cam and rpm with that big intake valve. Need a 155/400 double spring and thick wall (0.100+) pushrods.
And geometry setup correctly.
And your intake doesn't help, but the long runner is why all the LSx motors peak around 6300 or go flat. Stock Fast 102's flow considerably less than those heads will. And not everybody can port them well despite how easy it looks.
Nice build btw, yours along with bandit and fro keep me motivated on mine.
I've got Comp Hi-Tech pushrods and springs to support the valvetrain. LS3 intake is untouched... no need to mess with it with the cubes I'm at.
I've been reading up on ladder bar suspensions, and I've got a few things to try next time out.
Man, and I can get Garretts for cheap...
I've been reading up on ladder bar suspensions, and I've got a few things to try next time out.
Man, and I can get Garretts for cheap...
Seems like you are low on torque. Perhaps you went a bit too big on the cam. You should be knocking on 400ft-lb somewhere in the curve, but it's just not happening. Looking down low you don't break 300ft-lb until a bit after 3,000rpm. Compare your curve with futureuser's for example and he's already making 350ft-lb by that point. His cam is a 227/239 .614/.624 115. Peak HP is about the same.
trust me, I've looked at Dan's dyno (and timeslips) more than a few times... I'm going back tonight to do some suspension tuning. I'd like to at least hook up before doing anything drastic like a cam swap, but if it comes to that I'll be contacting Pat G for a solid setup.
You know what I find interesting? LG Motorsports's dyno results. Here they put down 493/440 on a 2008 C6 with only a CAI, headers, and G6X3 cam. And here's a cam-only C6 that put down 462/430. Both are 6-speeds, but the discrepancy with my numbers is staggering.
Anyway, I'm uploading videos of my runs as we speak. I'll post them shortly. At least they look good with the gopro.
You know what I find interesting? LG Motorsports's dyno results. Here they put down 493/440 on a 2008 C6 with only a CAI, headers, and G6X3 cam. And here's a cam-only C6 that put down 462/430. Both are 6-speeds, but the discrepancy with my numbers is staggering.
Anyway, I'm uploading videos of my runs as we speak. I'll post them shortly. At least they look good with the gopro.
Here's some videos.
http://www.youtube.com/watch?v=fnQRy1xKMmM
http://www.youtube.com/watch?v=fdIEV...ature=youtu.be
http://www.youtube.com/watch?v=KsKrP...ature=youtu.be
http://www.youtube.com/watch?v=fnQRy1xKMmM
http://www.youtube.com/watch?v=fdIEV...ature=youtu.be
http://www.youtube.com/watch?v=KsKrP...ature=youtu.be
Last edited by hookemdevils22; May 4, 2012 at 03:19 PM.
Thats an awesome angle! Love the part where it gets dark, it seems to make your car disappear. Yeah your losing traction like hell off of the line. How exactly did you mount the camera? I think my next purchase is going to be a GoPro! Trying to hold a regular video camera still is impossible.
What kind of vacuum are you pulling at idle? Are you positive you have 10.5:1 compression? I noticed your intake has quite a bit more lift than the exhaust and given the size difference between the intake vs. exhaust valves/ports you would think it should go the other way. The 111 LSA is killing you too. Look at the new LSR cams Comp is putting out and they are seperating the intake from the exhaust in the neighborhood of 20 degrees heavy on the exhaust for the rectangular ported heads (L92/LS3). Also they are using the 115 LSA to smooth things out on the low end. Just a thought. First things first, traction and then power. Car looks great tearing up the quarter by the way!
What kind of vacuum are you pulling at idle?
Are you positive you have 10.5:1 compression?
Edit: according to this calculator, with Mahle L92/LS3 4cc relief pistons, 66 cc chambers, and a 4.060" bore, .051" gasket on a 4.030" engine bore, I'm at about 10.45:1. Piston deck height was checked on a few slugs during pre-assembly, and they were .005" out of the hole.
How exactly did you mount the camera?
Last edited by hookemdevils22; May 4, 2012 at 03:38 PM.
On the third video your run seemed to be a little more tame coming off of the line. Did you leave at a lower rpm? What did that run yield? Did you have any luck getting this thing to hook?