9,000rpm oem rotating assembly, how would you do it?
03-22-2012, 01:35 PM
#41
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to add to this, a longer rod will keep the piston speed down more and help reduce the highs and lows of the velocity and acceleration curves. This should make it live longer. I don't know if a stock 4.8 rod is up for it, but given how cheap they could be had...why not try it with a short skirt custom piston.
I really think the limiting factor will be how well your valvetrain is setup. I don't think you can go the budget route with that. Solid lifters, shaft rockers, titanium retainers/valves and perfect geometry etc.
I've wanted to see somebody do this for awhile, so i say go for it! Basically a modern day dz 302.
I really think the limiting factor will be how well your valvetrain is setup. I don't think you can go the budget route with that. Solid lifters, shaft rockers, titanium retainers/valves and perfect geometry etc.
I've wanted to see somebody do this for awhile, so i say go for it! Basically a modern day dz 302.
03-22-2012, 02:01 PM
#43
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Oh how I LOVE summer
Just did some math
Stock 4.8 rods and crank with 6.0 pistons ends up adding 4.5 mm to tdc dwell and totals to 8.57 compression ratio
Gonna have to boost it or bump that ratio to get enough juice to spin 9,000rpm!
But with 8.57 cr that allows TONS of psi
Just did some math
Stock 4.8 rods and crank with 6.0 pistons ends up adding 4.5 mm to tdc dwell and totals to 8.57 compression ratio
Gonna have to boost it or bump that ratio to get enough juice to spin 9,000rpm!
But with 8.57 cr that allows TONS of psi
03-22-2012, 02:08 PM
#44
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To stay cheap on budget, you could always have the stock rods, shot peened to relieve stress. It works well on old school stuff, so it should do the same for the ls. Interested in seeing how long it will hold up. You plan to use stock valve train( rockers, ect) ?
03-22-2012, 02:12 PM
#45
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I'd like to find a dyno local, pop in the motor and watch for valve float and rocker flex then upgrade as necessary. Get it to run as reliably as economically possible then run the bitch til the heads meet the fender.
03-22-2012, 02:23 PM
#46
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Some things i would consider are staking the mains, removing all the casting flash from the crank, knife edge itand try to polish the entire thing. You want the counter weights as smooth as possible so the oil will just slide off of it. I would also try to cut it down an much as possible to keep it super light. Clean the casting off of the rods as well would be a huge improvement. Id try to find as many rods as possible and pick the lightest out of the bunch to start with. Same with pistons too. They already have a short skirt from the factory compared to the gen 1's.
as far as valve train goes ive spun my old 402 to 8500 with stock rockers, comp lifters, magnum pushrods and pac springs. I'd really focus on making sure your spring hights and everything is in check.
Your gonna need a good head cam intake to go that high. With that sma of cubes i dont see why a set of cnc'd l92's wouldnt work.
as far as valve train goes ive spun my old 402 to 8500 with stock rockers, comp lifters, magnum pushrods and pac springs. I'd really focus on making sure your spring hights and everything is in check.
Your gonna need a good head cam intake to go that high. With that sma of cubes i dont see why a set of cnc'd l92's wouldnt work.
03-22-2012, 02:52 PM
#47
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Speed hole the rotating assembly
Check lol
I was thinking forced induction
A blower may be better than turbo due to back pressure
8500rpm! Damn
Stock rockers saves alot of coin over shaft mounted
How often did you spool it that high?
Check lol
I was thinking forced induction
A blower may be better than turbo due to back pressure
8500rpm! Damn
Stock rockers saves alot of coin over shaft mounted
How often did you spool it that high?
03-22-2012, 03:34 PM
#48
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HPTuners can tune over 8k btw. Go hit up noisy on tech he'll point you in the right direction.
8500 was an accident, but i accidentally did it quite a bit, haha. There are quite a few guys spinning stock rotating assemblies to 8500 or so. Robz with his old set up, noisy with his n20 camaro and Bret Bauer are a few that come to mind.
I think spinning that high and going FI, I'd stick with a turbo. the cylinder pressure comes up and down more linear. With high reving motors a key to keeping them alive is to not have sudden rpm load changes, just keep the engine loaded at the upper rpms.
If you do go the stock rocker route I'd definitely do the trunion upgrade!
8500 was an accident, but i accidentally did it quite a bit, haha. There are quite a few guys spinning stock rotating assemblies to 8500 or so. Robz with his old set up, noisy with his n20 camaro and Bret Bauer are a few that come to mind.
I think spinning that high and going FI, I'd stick with a turbo. the cylinder pressure comes up and down more linear. With high reving motors a key to keeping them alive is to not have sudden rpm load changes, just keep the engine loaded at the upper rpms.
If you do go the stock rocker route I'd definitely do the trunion upgrade!
