750hp ls1 combo? Critique
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Joined: Mar 2017
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750hp ls1 combo? Critique Hey guys just wanting ideas on an engine built to make hopefully 750 at the crank.
5.7ls1
232/238 114lsa cam with springs upgraded
90mm tb
Arp head bolts and rod bolts
75/75mm bullet turbonetics turbo
Powerglide
E85 system for way more than needed flow rates.
Exhaust
With this combo should I expect to see 750 at the crank or pushing it?
Prior to this bottom end on a previous stock one incl standard bolts it turned 540whp which I guess is around 650crank that was on 20inch wheels and 3.07 rear gears.
5.7ls1
232/238 114lsa cam with springs upgraded
90mm tb
Arp head bolts and rod bolts
75/75mm bullet turbonetics turbo
Powerglide
E85 system for way more than needed flow rates.
Exhaust
With this combo should I expect to see 750 at the crank or pushing it?
Prior to this bottom end on a previous stock one incl standard bolts it turned 540whp which I guess is around 650crank that was on 20inch wheels and 3.07 rear gears.
I would not run head bolts at that power level, I would put in head studs. Cheap insurance and they provide superior clamping force. Pair them with LS9 gaskets and it should be good to go.
My opinion - you will reach your goal with the combo easily. But how long the factory bottom end holds up is another question. My buddy cracked cylinder liners in a 710whp stock LS1 bottom end...liners cracked before the pistons did...Cylinder pressures were too high, but tune was good so pistons survived.
I agree with regapping the piston rings as well.
I agree with regapping the piston rings as well.
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With running e85 you dont need the meth. If you plan on pump gas, then you either need meth or need to drop the boost to stay alive.
With higher boost, you create higher cylinder pressures and temperatures. Materials (including the steel alloys used in piston rings) have a coefficient of thermal expansion, meaning they expand a certain amount with an increase in temperature. If this didn't happen then piston rings would have no end gap, or we would run no piston rings and set the piston to wall clearance at close to 0.
You should increase the end gap to allow more growth with increase temperatures. If you do not, then the ends of the ring will contact each other and continue to expand, causing an increase in mechanical friction on the cylinder liner, ultimately welding the rings to the cylinder liner. Your connecting rods will buckle and your engine is TOAST.
My recommendations for piston ring end gap on your engine would be:
TOP RING = ~0.024 to 0.026 inch
2ND RING = ~0.026 to 0.028 inch
For reference, I run a bit more to be safe but am make more power (more pressure and heat)
With higher boost, you create higher cylinder pressures and temperatures. Materials (including the steel alloys used in piston rings) have a coefficient of thermal expansion, meaning they expand a certain amount with an increase in temperature. If this didn't happen then piston rings would have no end gap, or we would run no piston rings and set the piston to wall clearance at close to 0.
You should increase the end gap to allow more growth with increase temperatures. If you do not, then the ends of the ring will contact each other and continue to expand, causing an increase in mechanical friction on the cylinder liner, ultimately welding the rings to the cylinder liner. Your connecting rods will buckle and your engine is TOAST.
My recommendations for piston ring end gap on your engine would be:
TOP RING = ~0.024 to 0.026 inch
2ND RING = ~0.026 to 0.028 inch
For reference, I run a bit more to be safe but am make more power (more pressure and heat)
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Verdad Gallardo Thread Starter
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Awesome. Thanks for the explanation.
Last thing. Are the arp chromoly studs fine or should I get the aged 625+?
And lastly with the e85 and front mount and the bolts upgraded ect what boost should I ask it to be tuned on?
Or should the tuner always aim for no knock and good afrs as opposed to a max boost setting?
Just curious as I see some people saying max psi should be 10 some people say it doesn't matter its a max hp rating some people say no knock and stable afrs.
Last thing. Are the arp chromoly studs fine or should I get the aged 625+?
And lastly with the e85 and front mount and the bolts upgraded ect what boost should I ask it to be tuned on?
Or should the tuner always aim for no knock and good afrs as opposed to a max boost setting?
Just curious as I see some people saying max psi should be 10 some people say it doesn't matter its a max hp rating some people say no knock and stable afrs.
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Joined: Jun 2013
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From: Avon, Ohio
The issue is not the clamp strength here- its the AL block. You are 400% more likely to pull threads sending bolts back into those holes as opposed to a stud
TECH Apprentice
Joined: Aug 2015
Posts: 397
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I'm running a ls1 with a tsp228r 112lsa cam, head studs, ls9 gaskets, high mileage . Last week I went and got tuned, on 12-13 psi I was making 609rwhp, with a turbonetics 7868. since then I've upgraded fuel pumps and I've been running around 16-17 which I'm sure is close to your goals. Although on a real hard run you can tell the drivetrain is extremely pissed off at me 😂. The t56 starts to throw heat , the rear end feels like it's dragging slightly and the motor well, smells like i just hit it with a 300 shot. Do I expect it to live at this power ? Not for very long . But is it fun ? Oh hell yeah !