Cam spec for 450 LS
04-25-2018, 11:20 AM
#21
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LS-7369cc EAP Model Hi D, I made the EAP model with many of your specifications.
My first concern is Piston Speed with 4125@6K RPM, 4813@7K RPM AND 5156@7.5K RPM, your stated MAX REVS.
YOUR choice of the RHS "short" deck block ONLY allows a VERY low C/D with Pin Boss Area problems.
THUS a M-350 DCL pin requirement. AND a special design for the pin boss.
The next concern is the TFS 260 inlet port area (all LS-7) is too small for a 450cid@7500 RPM, the air speed is too fast. (.5 Mach).
The first question is about cams, sure as the "Jake" cam spec with a 116C/L will make 750 HP@6K RPM (Bench) AND the "all out" style will add 20 HP above that@7500 RPM with MAJOR Torque Loss across the complete lower RPM Range. (average loss of 30 ft.lbs)
The best solution is a custom intake OR ITBs as is Jake's direction ?
I would ALSO like to see a "spec" of a 12:1 CR as your crankcase has Oil Jets AND the engine's R/L of 1.48
Please state your Exhaust pipe length ?
MY suggestion is a Max RPM of 6500 engine design ?
Lance, BTW thanks for the phone call, you know a great deal about engines.
My first concern is Piston Speed with 4125@6K RPM, 4813@7K RPM AND 5156@7.5K RPM, your stated MAX REVS.
YOUR choice of the RHS "short" deck block ONLY allows a VERY low C/D with Pin Boss Area problems.
THUS a M-350 DCL pin requirement. AND a special design for the pin boss.
The next concern is the TFS 260 inlet port area (all LS-7) is too small for a 450cid@7500 RPM, the air speed is too fast. (.5 Mach).
The first question is about cams, sure as the "Jake" cam spec with a 116C/L will make 750 HP@6K RPM (Bench) AND the "all out" style will add 20 HP above that@7500 RPM with MAJOR Torque Loss across the complete lower RPM Range. (average loss of 30 ft.lbs)
The best solution is a custom intake OR ITBs as is Jake's direction ?
I would ALSO like to see a "spec" of a 12:1 CR as your crankcase has Oil Jets AND the engine's R/L of 1.48
Please state your Exhaust pipe length ?
MY suggestion is a Max RPM of 6500 engine design ?
Lance, BTW thanks for the phone call, you know a great deal about engines.
04-25-2018, 05:28 PM
#22
Lance,
Here's some food for thought. I'm not saying you are wrong, don't take it that way. But if he wants a "Max effort" engine, I don't think a 6500 RPM limit is going to get him there. I understand having to build desert engines that NEED to be reliable for the given task, but I don't think handicaping him to an RPM limit based on piston speed is the best solution.
Street/Drag cars are much different than desert where there is a lot of sustained WOT and on/off throttle situations. For the most part a street/drag car is only short bursts of acceleration, unless you are in Mexico setting a speed record on a daily/weekly basis.
My 406 SBC runs 5187 feet per minute Piston Speed (4.155" bore x 3.750" stroke @ 8300 RPM) and has the same Callies Dragslayer crank and Chinese "Oliver" copy rods for 300+ 1/4 mile passes and a few thousand street miles. It made 765 HP @ 7900 RPM and 590 LbFt @ 6300 RPM with the "small" cam.
It had standard JE pistons and pins (200 passes) and now has standard Wiseco pistons and pins. No coatings, no thick wall pins, etc. Just off the shelf parts.
Hell, my stock crank and rods LS3 with standard SRP pistons and pins is at 4286 feet per minute at the 7100 RPM rev limiter. I'm not worried.
As far as cams go, the "smaller" of the two cams I've had in my SBC is 274 @ .050" on the exhaust. It's also on a 113+3 LSA.
Here's some food for thought. I'm not saying you are wrong, don't take it that way. But if he wants a "Max effort" engine, I don't think a 6500 RPM limit is going to get him there. I understand having to build desert engines that NEED to be reliable for the given task, but I don't think handicaping him to an RPM limit based on piston speed is the best solution.
Street/Drag cars are much different than desert where there is a lot of sustained WOT and on/off throttle situations. For the most part a street/drag car is only short bursts of acceleration, unless you are in Mexico setting a speed record on a daily/weekly basis.
My 406 SBC runs 5187 feet per minute Piston Speed (4.155" bore x 3.750" stroke @ 8300 RPM) and has the same Callies Dragslayer crank and Chinese "Oliver" copy rods for 300+ 1/4 mile passes and a few thousand street miles. It made 765 HP @ 7900 RPM and 590 LbFt @ 6300 RPM with the "small" cam.
It had standard JE pistons and pins (200 passes) and now has standard Wiseco pistons and pins. No coatings, no thick wall pins, etc. Just off the shelf parts.
Hell, my stock crank and rods LS3 with standard SRP pistons and pins is at 4286 feet per minute at the 7100 RPM rev limiter. I'm not worried.
As far as cams go, the "smaller" of the two cams I've had in my SBC is 274 @ .050" on the exhaust. It's also on a 113+3 LSA.
04-26-2018, 10:41 AM
#23
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Dailey Driver Corvette Hi Cole, I too agree with YOUR remarks.
My report is based on his 66 year age, the "driven each day" and the requested need for low end power wide torque band.
HE ALSO told me in the phone conversation, "my car spins the tires NOW, why do I want more power".
I would ADD YOUR R/L is much higher 3.75"/6.125 VS 4.125"/6.125" as is his 450.
The "pull" on the rod (acceleration) is VERY DIFFERENT.
There is ONLY one person, the owner, who chooses the best advice for his needs.
I did own a Cristal Ball, it was broken by the man would cleaned my office floor.
I do respect your tech.
Lance
My report is based on his 66 year age, the "driven each day" and the requested need for low end power wide torque band.
HE ALSO told me in the phone conversation, "my car spins the tires NOW, why do I want more power".
I would ADD YOUR R/L is much higher 3.75"/6.125 VS 4.125"/6.125" as is his 450.
The "pull" on the rod (acceleration) is VERY DIFFERENT.
There is ONLY one person, the owner, who chooses the best advice for his needs.
I did own a Cristal Ball, it was broken by the man would cleaned my office floor.
I do respect your tech.
Lance
04-27-2018, 07:00 PM
#24
I would like to thank Lance and Cole for your input. I’m going keep doing my research but I’m thinking nothing over 680 lift for the street?95%street and 5% strip probably will be using short travel Hyd lifter and cam. And Lance I hate to toot my own horn but @ 66 i,m still 1 tuff old SOB but u way above my head with this ls engine thanks for help everybody PS what do you no about Mike Jones cam design?
04-27-2018, 09:37 PM
#25
I would like to thank Lance and Cole for your input. I’m going keep doing my research but I’m thinking nothing over 680 lift for the street?95%street and 5% strip probably will be using short travel Hyd lifter and cam. And Lance I hate to toot my own horn but @ 66 i,m still 1 tuff old SOB but u way above my head with this ls engine thanks for help everybody PS what do you no about Mike Jones cam design?
I ended up with a cam that does exactly what he said it would and makes the same amount of power with 11 degrees less on the intake and 18 less on the exhaust (274/274 vs. 285/296). It makes 580+ LbFt from 5300 to 6800. Not bad for 22 year old NASCAR parts in a street/drag car.
It's best to call and speak with him if you can and see if he has the cam cores in stock. Depending on the market, some cam cores can be hard to get if one of the 3 manufacturers that make them don't have any in stock or a production run coming up soon.