Destroking an LS7 for road racing
02-04-2019, 05:44 PM
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Destroking an LS7 for road racing Hey guys,
Looking for a race engine for my track car project. Thinking about going with an oversquare engine setup as the engine will be at high RPM all the time on the track. Torque loss really isnt an issue as my track car only weighs 2200 lbs wet. A more linear curve is better in my case. Target HP would be above 500 but not more than 600. I'm really looking for something that can be spun to 8,000 rpm or more, to provide long, sustained horsepower to suit the characteristics of the car.
If I cut the LS7's stroke from 4.000 to 3.625 inches and maintaining the stock 4.125-inch bores, the displacement would be 388 cubic inches (6.35 liters). It would also make this short-stroke motor carry a 1.14 bore/stroke ratio.
I've already got a 5 stage dailey for the motor and am going to need all forged reciprocating parts for this build. Most engine builders are used to building big boy inch LS engines that make boatloads of torque at low rpm, but I'm looking for a builder with experience with something out of the ordinary. Anyone on the forum have suggestions as to who might be able to tackle this project for me? Trying to make hyperfest by mid May and the right engine recipe is proving the difficult bit...
Looking for a race engine for my track car project. Thinking about going with an oversquare engine setup as the engine will be at high RPM all the time on the track. Torque loss really isnt an issue as my track car only weighs 2200 lbs wet. A more linear curve is better in my case. Target HP would be above 500 but not more than 600. I'm really looking for something that can be spun to 8,000 rpm or more, to provide long, sustained horsepower to suit the characteristics of the car.
If I cut the LS7's stroke from 4.000 to 3.625 inches and maintaining the stock 4.125-inch bores, the displacement would be 388 cubic inches (6.35 liters). It would also make this short-stroke motor carry a 1.14 bore/stroke ratio.
I've already got a 5 stage dailey for the motor and am going to need all forged reciprocating parts for this build. Most engine builders are used to building big boy inch LS engines that make boatloads of torque at low rpm, but I'm looking for a builder with experience with something out of the ordinary. Anyone on the forum have suggestions as to who might be able to tackle this project for me? Trying to make hyperfest by mid May and the right engine recipe is proving the difficult bit...
02-04-2019, 06:01 PM
#2
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With the correct camshaft, intake and valvetrain setup, that would be a high rpm screamer. A shaft rocker system would be mandatory if you want it to live.
This thread should be in Gen4 internal, btw...
This thread should be in Gen4 internal, btw...
02-04-2019, 07:42 PM
#3
I would check out GSpeed if I were you. They are not engine builders, but they could help you choose an engine to help achieve your goals. They do use HPR for their engine builds, but Erik there has been involved in 9000 RPM LS engines since the early 2000’s. A 388ci engine would be a cake walk for them.
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02-05-2019, 02:35 PM
#12
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LS7 block with 4.8 crank and send it lol
02-05-2019, 05:31 PM
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02-05-2019, 07:02 PM
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02-05-2019, 10:23 PM
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Originally Posted by fullofdays
Hey guys,
Looking for a race engine for my track car project. Thinking about going with an oversquare engine setup as the engine will be at high RPM all the time on the track. Torque loss really isnt an issue as my track car only weighs 2200 lbs wet. A more linear curve is better in my case. Target HP would be above 500 but not more than 600. I'm really looking for something that can be spun to 8,000 rpm or more, to provide long, sustained horsepower to suit the characteristics of the car.
If I cut the LS7's stroke from 4.000 to 3.625 inches and maintaining the stock 4.125-inch bores, the displacement would be 388 cubic inches (6.35 liters). It would also make this short-stroke motor carry a 1.14 bore/stroke ratio.
I've already got a 5 stage dailey for the motor and am going to need all forged reciprocating parts for this build. Most engine builders are used to building big boy inch LS engines that make boatloads of torque at low rpm, but I'm looking for a builder with experience with something out of the ordinary. Anyone on the forum have suggestions as to who might be able to tackle this project for me? Trying to make hyperfest by mid May and the right engine recipe is proving the difficult bit...
Looking for a race engine for my track car project. Thinking about going with an oversquare engine setup as the engine will be at high RPM all the time on the track. Torque loss really isnt an issue as my track car only weighs 2200 lbs wet. A more linear curve is better in my case. Target HP would be above 500 but not more than 600. I'm really looking for something that can be spun to 8,000 rpm or more, to provide long, sustained horsepower to suit the characteristics of the car.
If I cut the LS7's stroke from 4.000 to 3.625 inches and maintaining the stock 4.125-inch bores, the displacement would be 388 cubic inches (6.35 liters). It would also make this short-stroke motor carry a 1.14 bore/stroke ratio.
I've already got a 5 stage dailey for the motor and am going to need all forged reciprocating parts for this build. Most engine builders are used to building big boy inch LS engines that make boatloads of torque at low rpm, but I'm looking for a builder with experience with something out of the ordinary. Anyone on the forum have suggestions as to who might be able to tackle this project for me? Trying to make hyperfest by mid May and the right engine recipe is proving the difficult bit...
02-06-2019, 07:43 PM
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I think so. He is in Canadia so I dont remember the last time he drove it.
02-16-2019, 06:45 PM
#19
I had a 2470lb RX-7 with 18x12's at all corners running a 438ci setup(530rwhp/510rwtq) and 4speed Gforce GSR dog box/3.27 gears/8.8" IRS. It ran LS3 heads to limit HP; however it still made 500rwtq+ which is what you want... torque. just change the rear end gear to something that will not multiply the power as much. I didn't build the engine; however IMO it could've use more as it could put the power down pretty much everywhere once in 2nd gear. This is the car with a new paint scheme and some aero mods the new owner did. We couldn't max out the rear wing because there simply wasn't enough downforce from the front end.
If I were to build a track car again it would be a single turbo 3.622" stroke setup that rev'd to 8000rpm with an exhaust that exited the side of the car (under /thru the door). Aero is critical if you want to go fast..... real fast. meaning no dual exhaust under the car.... you need a flat bottom with diffuser out back.... as few openings as possible in the front bumper... big splitter... all the tricks. By going with a 3.27" stroke you are simply giving up torque. There are plenty of 3.622" stroke engines revving to beyond 8000rpm.
I'm selling a road race oriented 441ci motor with a single plane intake manifold which I wanted to actually kill some low end power.... Turn key ready to rock 800hp n/a.
https://ls1tech.com/forums/market/1915086
If you have your heart set on a short stroke combo I have a used Callies Magnum 3.27" stroke crank with more work done to the counterweights, Howards billet rods for $2500 shipped. Plus a Dailey billet 5 stage I believe billet oil pan from a Daytona Prototype also used.
Last edited by gnx7; 02-16-2019 at 06:53 PM.
02-16-2019, 10:57 PM
#20
TECH Senior Member
Now how many people can make the statement- "It ran LS3 heads to LIMIT HP"?? Pretty cool!