CID and HP

[shady milkman]

why is it that on alot of hi-performance engines that their CID match their hp output alot of the time. like ls1's 345.69 CID and they put out around 345hp ?? i've realized it on alot of the older engines like the 426s and such.

[Mr. Luos]

My 402 makes 531 at the wheels.

[shady milkman]

My 402 makes 531 at the wheels.

with no bolt ons it pulls those numbers at the crank?

[Mr. Luos]

The 364ci (my motor with stock stroke) makes 400 in the LS2 form and 345 in LQ9 form.

I have no idea what mine would make at the wheels with stock cam/heads/exhaust. Probably 390-400 RWHP.

[shady milkman]

hmm i'm talking flywheel hp..but you've never realized that? alot of engines CID is close to if not the same as their HP rating.

[BlackLT1Z28]

why is it that on alot of hi-performance engines that their CID match their hp output alot of the time. like ls1's 345.69 CID and they put out around 345hp ?? i've realized it on alot of the older engines like the 426s and such.

It really just depends on the setup. I was looking at an ad on my magazine, and a company had 4 long blocks, 350ci-350hp, 350ci-400hp, 383ci-400hp, and a 383ci-440hp. It just varies, but yes, some outputs match the displacement. I guess its 1hp per 1ci.

[Mr. Luos]

It is true.
A lot of motors look for one HP per cube.

In my second post I was talking about flywheel numbers...sorta. The 400 and 345 ratings were factory ratings.

[shady milkman]

yea i guess its just a factory thing were they like 1hp per CI.

[BlackLT1Z28]

I'd say more often than not in aftermarket, that hp is greater than the ci of the motor, but yes, some are equal.

[shady milkman]

It is true.
A lot of motors look for one HP per cube.

In my second post I was talking about flywheel numbers...sorta. The 400 and 345 ratings were factory ratings.

i like your numbers your running now.

[Mr. Luos]

600+ at the crank.

[BlackLT1Z28]

600+ at the crank.

Is that corrected or straight up in that high Colorado altitude? I think you would be running 10's at least in a decent altitude.

[Mr. Luos]

445 RWHP not corrected. So probably be about 530 crank not corrected.

[Fedge]

roughly 408hp for my 383.25 CID

[BlackLT1Z28]

That's still a lot in that thin air. Get a turbo to help it breathe in that altitude. That would be nasty. But there's nothing better than a high powered N/A motor.

[Mr. Luos]

I really like it how it is.

I uncapped the cutouts today to get some short dumps installed.
Makes such a difference. Above 4200 this thing SCREAMS.

[Fedge]

That's still a lot in that thin air. Get a turbo to help it breathe in that altitude. That would be nasty. But there's nothing better than a high powered N/A motor.

+1

wish i had one, lol...this middle-tier stuff is for the birds

[shady milkman]

I really like it how it is.

I uncapped the cutouts today to get some short dumps installed.
Makes such a difference. Above 4200 this thing SCREAMS.

why dont you just dump them after the headers ..no muff no exhuast i bet your neighboors(sp) would

[Mr. Luos]

why dont you just dump them after the headers ..no muff no exhuast i bet your neighboors(sp) would

[BlackLT1Z28]

He wants it somewhat tame on the streets and wild at the strip.