Swiper

I have a somewhat different question. I´m going to use a GM V8 for a application where I'm going to run the engine at 3200 - 3400 rpm. In that rpm range I need 300 hp from the engine. It will never rev higher.

My question is if the LS3, with modifications like a new cam, would be able to deliver 300 hp at 3200 - 3400 rpm? Or would I need to go with the LS7 (at a much much higher cost )?



I may get the question so I think it would be best to answer it right away: I'm building an aircraft .

scatillac

iTrader: (12)

In addition to the HP/Torque advantages, the LS7 also has dry sump oiling that would be probably be beneficial in your application. It's not as sophisticated a system as you would need for extreme aerobatics, but should be adequate for "normal" use.

Granted, the cost is a factor , but it's worth it in the long run.

Swiper

Thanks for your reply. You are very right about the dry sump. It will not work without it. But the LS7 create engine only have the dry sump pan. Tank and the rest would be the same cost as on the LS3. A LS3 with a dry sump oil pan is still a lot less than a LS7. So if it's posible to get 300hp at 3200-3400 rpm with a lower priced LS engine than a LS7 it would be nice .

ringram

Thats about 500ft/lb converting back from BHP to ft/lb
500ft/lb at the crank is a goodly amount.

That was about what my 440 pushes out with a small 227/243 cam.
You need lots of cubes. Take a look at the 454lsx and cam it accordingly.

Or actually as much as I hate to say it, the ideal is probably a PD TVS blower to get you that torque at that rpm.

1989GTA

How about a gear reduction unit? I saw where someone had already did this. Just don't remember where.

Swiper

I guess that the LS3 as it is can't handle the task, then. Why is it that the ceapest way never work .

Would the LS3 work with a PD TVS blower to get that hp or would I need far more cubes/better internals? I will need to check the price for that blower and other modifications that the blower needs.

Swiper

Good call! It is actually my gear reduction unit that needs the 3200-3400 rpm to work well.

Swiper

Was thinking about a blower, but since boost response isn't a factor in my case maybe a turbo would be a good option. Should come at a lower cost (or so I hope).

redtan

iTrader: (5)

By the time you spend all that money on an LS7 crate you can build a 6.0 or 5.3 with a roots supercharger on it that will deliver a whole lot more punch at 3000rpm then even the LS7. That's the direction I would go in if I was looking for the most power at that level.

FoHawk

iTrader: (3)

Almost sounds like your looking for a motor you can use in a homebuilt plane kit.

That would be awesome to use the LS3 like that. People have used LS1's in kit planes, just not sure 300hp@3200 rpms were attained.

LLave

iTrader: (3)

I would ask this guy

FoHawk

iTrader: (3)

LOL I didnt see the fine print at the bottom, but I didnt have to because I knew where you were headed with it

I think your biggest issue will be weight of the block. But these guys are right that displacement is going to be key. My Lycoming 540 is a 6 cylinder.... lol, blows my mind to think it has 200 more CI then an LS1. Mine makes right at 245HP though.

A roots style blower on an ls3 would be sick. You'd climb 2000FPM!

newschool72

iTrader: (12)

To get stellar low end #s from an LS3, go with a camshaft with a tight LSA + a lot of advance. D&A machine built a 409 for the Engine masters challenge using a GMPP dual plane intake and a cam with 226-228 at .050 on a 108+6 LSA with the LS3 heads. That engine made 525 ft lbs at 2500 rpms! The stroke is shorter with the LS3 but I believe the out line will work with it. How do I know? Im running a stock LS3 crate engine with a custom grind 220-230 at .050 108+4 and the GMPP dual plane. It makes fantastic power down low and is very unLS3 like in the way the power come on. The power is instant, with no normal" wind up" like the LS design is known for. Down side is limited upper rpm. Mine is all done at 6200rpms, but has enough beans to run well into the 11s with "grandma to the grocery store" street manners and 3.42 gears w a 2004r trans at 3500lbs.

WKMCD

iTrader: (2)

Just dug up a Superflo engine dyno chart on my build. It is a 427 but makes great power at 3-3500RPM. LS2 block with 4.125 Darton sleeves and L92/LS3 WCCH heads.



Build thread is in my sig.