going from 11:1 comp to 13:1 with same cam.
09-24-2008, 10:55 AM
#21
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I guess out here in California racing circles we do things different. We can agree to disagree. Maybe fuel injected ls engines like the wider lobe separation due to the cam overlap and the computer not being able to keep up. Not to mention both engine shops I have worked at( both run Super Stock) run their engines in the 16:1 compression range and their cams are in the 103-106 grinds and have been known to be installed at 99-100. Every single naturally aspirated carb engine I have built like 106 - 108 lobes. They have made substantial more power naturally aspirated.
Granted, with nitrous, these same engines with a 114 cam made more power with the same amount of nitrous, but when we had them setup up strictly n/a, it was a 8-22hp gain, depending on the cam.
The 22hp gain was on a 14:1 402 with TFS heads and a Super Victor ( the cam was 270/280 690/710 on a 106. Once it was degreed in, it was at 101 and it picked up 22hp over the same grind cam at 112
Like I said, I would never put that type of cam in a fuel injected car, unless it had a BS3 or a FAST...
Granted, with nitrous, these same engines with a 114 cam made more power with the same amount of nitrous, but when we had them setup up strictly n/a, it was a 8-22hp gain, depending on the cam.
The 22hp gain was on a 14:1 402 with TFS heads and a Super Victor ( the cam was 270/280 690/710 on a 106. Once it was degreed in, it was at 101 and it picked up 22hp over the same grind cam at 112
Like I said, I would never put that type of cam in a fuel injected car, unless it had a BS3 or a FAST...
Think of the miller cycle as an extreme example. Those engines usually run two full points higher compression (the late intake closure pushes air back out the cylinder before it can be fully compressed)
09-24-2008, 11:13 AM
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It has to do with everything.. duration, lobe separation, intake centerline, all those will build overlap to bleed the compression off. That's why with 11:1, you can get away with pump gas with a cam that has more than 112 ls.
My engine has a cam in it currently that has 114 ls and we ran it on 91 octane and 11:1 and no signs of detonation and it pulled 14 inches of vaccum at idle. The new cam will probably be in the 280/290 duration with a 106 ls and I'll be lucky to get 4 inches of vacuum, which is why I am running the vacuum pump.
My engine has a cam in it currently that has 114 ls and we ran it on 91 octane and 11:1 and no signs of detonation and it pulled 14 inches of vaccum at idle. The new cam will probably be in the 280/290 duration with a 106 ls and I'll be lucky to get 4 inches of vacuum, which is why I am running the vacuum pump.
09-24-2008, 11:31 AM
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09-24-2008, 12:40 PM
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Car was 3100lbs for those passes, the motor has N20 rings and such in it. Always ment to spray it but it's just so damn much fun N/A. Car weighs less now and makes more power, first time out the trans ate itself up and I puked a head gaskit putting me into the wall. Off a foot brake I went 1.38 60ft, and went through the 1/8 sideways at 6.34@109.
09-24-2008, 12:51 PM
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Holy F* that was awesome. 
Okay basically if you are crazy enough to argue with this guy you need some help pulling your head out of your ***. 
Total beast of an F-body!
09-24-2008, 08:28 PM
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I hope it didn't tear the car up too badly. She looked good on that run.
I have to weigh 3200lbs in one of the series I am running and 2650lbs in the other. I am hoping to get this thing to run 9.50's @3200 and then take all the weight out and try to run 9.teens
I have to weigh 3200lbs in one of the series I am running and 2650lbs in the other. I am hoping to get this thing to run 9.50's @3200 and then take all the weight out and try to run 9.teens
09-26-2008, 11:03 PM
#32
We didnt pick up much at all with a mid 250s hyd cam NA setup we did raising about that much compression. I know it was intake restricted, which would normally like compression?
It went a best of 9.69/139 mph with that setup. We are back down to 11:something to 1 with a different cylinder head/OEM intake setup - and up @ 30 hp when all is said and done.
It went a best of 9.69/139 mph with that setup. We are back down to 11:something to 1 with a different cylinder head/OEM intake setup - and up @ 30 hp when all is said and done.
