RPMs bitches

[Danger731]

Agree with 02z28ls1

[smokin_ls1]

Also the life expectancy of a car sized internal combustion engine drops off sharply the more it is pushed past 6000 rpm. This is a proven fact. No matter how good or expensive the parts you use, the more times it goes beyond 6000 revs the quicker it will die.

[newguy WS6]

Quote form Days of Thunder..." UHHH Cole when that tachometer gets past 9000 RPM's.. thats bad...

Same with the LS-1.. Anything over 6200 on stock internals....tick tick tick tick......BOOOOOOM!! Eventually.

Have fun!!

[hammertime]

If you build the engine to stand 10000 RPMs and you can get it to breath up there then why not do it. What do you mean there is no reason to turn 7000 RPMs. I ride an inline four cylinder sport bike. You would be surprizeed what you can do with high RPMs and low torque. High RPMs=more air=more gas burned=more power. Revy engines have been kicking ass for years. I only wish Arao Engineering would make four valve heads for the ls1 so I could rev like a ferrari. It is simple physics. Energy=Mass x Velocity^2

Dude there is so much different between a sport bike engine and a 5.7 Liter LS1 engine that you'll spend tons of money to get anywhere near there.

LS1's swing a pretty long 3.62 in stroke, and therefore make great low end power in a package that is breathing just good enough to make good power up to 6000 or so. To reliably get to 9000 rpm, you'll probably find you'll need to destroke the engine.

So after you get aftermarket crank, rods and pistons; you'll need some good breathing heads and valvetrain to make it all happen. Don't forget that the stock intake isn't going to flow well at those rpms, so you'll either have a major reinvention of the fuel injection or a carbureted conversion on your hands.

In short, while there's technically nothing wrong with your idea, there is a good reason no one else is doing it that way. As stated above, you're gonna spend a ton of money to attempt it, and it's not a very pleasant setup for any kind of driving. Strictly a racing only setup.

That said, if you decide to tackle it - good luck to you!

[MrMiracle]

Launching the sheer mass of a Trans Am, Camaro or other 3000+ lb automobile takes more low end torque than high end horses. Heavier vehicles respond better to long strokes and relatively moderate bores. Some drag racers will actually under-bore their engines by inserting a narrower sleeve into the bore.

I've actually seen a full 32 valve over-head cam mod for Gen III/IV engines, the cost was in the realm of Arm+Leg (guess you'd have to use an automatic) and you'd have probably gotten better performance by actually buying a real Ferrari. Plus you'd get that neat flappy-paddle transmission.

Bikes and lighter cars respond better to large bores and relatively short strokes. An engine with a 4" stroke at 6000 rpms has pistons running up and down at the same speed as one with a 3" stroke running at 8000 rpms. A shorter stoke also means a lower reciprocating mass, making the engine much easier to balance. Shorter strokes also mean the engine can be much smaller overall, and manufacturers will sometimes compensate by using a very large number of cylinders. Why do you think Ferrari was so fond of V12s for the longest time?

[5letr]

As most of the folks here have stated the valvetrain is the weak link and the factory 6200 rpm limit is there for good reason. Drop in some 918s or double springs and you COULD rev it on up to 7000ish. If you get a nice sized cam having the extra several hundred RPMs will make a big difference especially on the drag strip. THose bigger cams love the high rpms and that is where they tend to make the big HP. Remember even if the power drops off a little from 5500 to 6200 by shifting at a higher RPM you will stay right in the sweet spot of your engine for the next gear.

Just my two cents.

[johuckabee]

Thanks for all of the advice guys. Also, who makes the best aggresive cams for the ls1(lots of overlap/duration). And, with a good set of long tubes to take advantage of that overlap and good valve train and good breathing on the intake side, what kind of power can i look to make? (stock head and ports)

[5letr]

I would do some searching on the different LS1 sites, here or at ls2.com or ls1tech for example. You can find a lot of good information ready for you. www.ls1sounds.com is a great site if you want a particular sounding LS1.

[smokin_ls1]

Thanks for all of the advice guys. Also, who makes the best aggresive cams for the ls1(lots of overlap/duration). And, with a good set of long tubes to take advantage of that overlap and good valve train and good breathing on the intake side, what kind of power can i look to make? (stock head and ports)

If you are gonna do all of this don't forget a new rearend and clutch. Also leaving your stock ported heads on is like building a dam in the middle of your river. Tons of air trying to pass through it but the heads won't let it by. Stock heads ain't bad but if you are gonna spend the big money on a new cam, 90mm t-body, 90mm intake, QTPs, a new rear, new clutch, etc. why not get a good set of heads too?

[hammertime]

Thanks for all of the advice guys. Also, who makes the best aggresive cams for the ls1(lots of overlap/duration). And, with a good set of long tubes to take advantage of that overlap and good valve train and good breathing on the intake side, what kind of power can i look to make? (stock head and ports)

Thunder Racing T-Rex is a good starting point. This should give ya an idea anyway. Scroll all the way to the bottom of the page.

The dyno above is of a 99 TransAm with stock unported cylinder heads, Thunder Racing's T-ReX v.2 camshaft, and a full package of bolt-on parts, including long tube headers, pulley, LS6 intake manifold, Whisper lid, ported throttle body. Dyno runs were on 93 octane gasoline and a factory steel flyweel.