LE 383 LT4 Dyno Results
08-19-2008, 11:02 PM
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LE 383 LT4 Dyno Results I just finished my LE 383 LT4 build. I blew up the engine in my 96 LT4 C4 back in December at Texas World Speedway, and just now got it back running. More details on the car: http://www.mowhineracing.com
I had it dyno tuned at Henderson Performance in New Bruanfels. Final numbers:
According to the print out, the correction factor is 1.06, which is a bit high IMO. I didn't see this until after I had left. It was raining that day, with humidity right at 90% according to the National Weather Service, but it seems like 1.03 is more reasonable. Either way, I was only really hoping for 420 at the wheels, and it beat that uncorrected and it's not even broken in yet. While this isn't a drag car, I do plan to take it to the strip at some point, and trap speed should tell what it is really making.
Local machine shop did the machine work and installed the rotating assembly, but I finished the rest myself. I would imagine a pro builder could squeeze a bit more power out of it, but it was nice to do the work myself (first engine).
Big thanks to Lloyd for good work on the heads and specing the cam to make it work, and for providing the best customer service after the sale.
- Scat 9000 Crank
- Childs & Albert 6.0" Rods
- Mahle Power Pack Pistons
- LE3 Cam 23x 24x .60x .60x 10x
- LE2 GM LT4 heads
- Mr Gasket .029 Head gasket
- 12.5 : 1 compression
- Exotic Muscle 1 3/4" Long tubes
- 3" True Duals, Spintechs
- Stock ZF6, Fidanza flywheel
I had it dyno tuned at Henderson Performance in New Bruanfels. Final numbers:
According to the print out, the correction factor is 1.06, which is a bit high IMO. I didn't see this until after I had left. It was raining that day, with humidity right at 90% according to the National Weather Service, but it seems like 1.03 is more reasonable. Either way, I was only really hoping for 420 at the wheels, and it beat that uncorrected and it's not even broken in yet. While this isn't a drag car, I do plan to take it to the strip at some point, and trap speed should tell what it is really making.
Local machine shop did the machine work and installed the rotating assembly, but I finished the rest myself. I would imagine a pro builder could squeeze a bit more power out of it, but it was nice to do the work myself (first engine).
Big thanks to Lloyd for good work on the heads and specing the cam to make it work, and for providing the best customer service after the sale.
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08-20-2008, 07:14 AM
#10
Very nice numbers! I'll bet that motor throws that Vette around like nothing 
Can't weight to see the track numbers! What were your mods/track numbers before this build?
Can't weight to see the track numbers! What were your mods/track numbers before this build?
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08-20-2008, 11:11 PM
#17
Looking at the graph again it looks like something is happening around 5900rpm. The hp line looks like it is heading for the moon and then just keals over.
I wonder if valve float is setting in?
I wonder if valve float is setting in?
08-21-2008, 12:11 AM
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I've had several requests for vids, and I'm working on it. There is an auto-x practice this weekend, so hopefully I'll get some action shots as well as video.
Part throttle is good above 1800 rpms; below 1800 is a bit iffy. Currently, it is running in open loop due to my right O2 flipping out and giving crap data. Hopefully it will clear up once I fix the issue (might be O2, might be wiring).
I've only been to the drag strip twice; that is not the main goal of the car. But, my best run to date is a 12.85 @ 111. At that point, it had cheap 1 5/8" headers and a HotCam. My 60' was a 2.07, so I think there was a 12.5 in there if I could have gotten a good launch. The clutch was a bit iffy and I don't have much practice launch the car.
I just have 2 Spintech 3" mufflers. I made my own header back using some mandrel bent pieces and a Magnaflow X pipe.
Thanks! Hopefully my site will actually have some action shots now instead of just "soon this, ordered that."
The dip at 5900 has been the subject of several theories. The tuner played with the timing and claims the electronics (spark, injector pulse, etc) are all constant yet there is a dip. I do know my spark plug gap is too big (.055), and I need to make sure my valves aren't adjusted a bit too tight.
I'm certainly not an expert, but I wouldn't think valve float would be a problem. Lloyd speced the cam, valves, and valve springs knowing the max RPM as well as the peak power RPMs, so valve float is not something I'd seriously considered.
I just have 2 Spintech 3" mufflers. I made my own header back using some mandrel bent pieces and a Magnaflow X pipe.
I'm certainly not an expert, but I wouldn't think valve float would be a problem. Lloyd speced the cam, valves, and valve springs knowing the max RPM as well as the peak power RPMs, so valve float is not something I'd seriously considered.
