Shorter Runners for FAST Intake!!!
Thread Starter
TECH Fanatic
Joined: Aug 2009
Posts: 1,845
Likes: 255
From: Coast of San Mateo County Between Pacifica & HMB
You're piston speed @ 6350 RPM equals mine @ 7500 RPM.
I predict peak HP @ 5800-6000 RPM. It will be a beast!
What car is this going in?
I predict peak HP @ 5800-6000 RPM. It will be a beast!
What car is this going in?
TECH Junkie
Joined: Dec 2005
Posts: 3,092
Likes: 11
KCS.
What is the displacement, heads and cam specs on
you're engine below that LSXRT?
1989GTA,
I posted results with the mid length runners in both this
section (0 replies lol) and the Dyno results section with
few replies/comments.
I can surmise from my results that to take advantage
of the mid length runners a combination should
reach peak HP @ 7000 RPM Minimum up to 7500,
and shifting @ 7500 RPM Minimum up to 8000+
So I would consider LLSR & Top Tier Heads at a
minimum. Have some thoughts on a killer 416"
street/strip combo I will post in the other threads
if there is any interest.
What is the displacement, heads and cam specs on
you're engine below that LSXRT?
1989GTA,
I posted results with the mid length runners in both this
section (0 replies lol) and the Dyno results section with
few replies/comments.
I can surmise from my results that to take advantage
of the mid length runners a combination should
reach peak HP @ 7000 RPM Minimum up to 7500,
and shifting @ 7500 RPM Minimum up to 8000+
So I would consider LLSR & Top Tier Heads at a
minimum. Have some thoughts on a killer 416"
street/strip combo I will post in the other threads
if there is any interest.
Right now my motor is peaking at 6600rpm and holds on to close to 7000rpm. I really do not want to spin the motor any further than that. I am currently at 512rwhp on a Mustang dyno and a 6L80 transmission.
I have the LLSR with 244/252 with .650" lift on both intake and exhaust. I seem to be in the middle power wise with some higher and a few lower than me.
Thread Starter
TECH Fanatic
Joined: Aug 2009
Posts: 1,845
Likes: 255
From: Coast of San Mateo County Between Pacifica & HMB
1989GTA
What heads,compression, Header size, exhaust, and LSA &
Advance do you have,
My cam is LLSR 243*/249* (add 2* for larger diameter lifters)
and I Peak 7100-7300 RPM with a 3.600" Stroke.
Is your engine 4.06"X4.10" stroke or 4.125X4.00" stroke.
What heads,compression, Header size, exhaust, and LSA &
Advance do you have,
My cam is LLSR 243*/249* (add 2* for larger diameter lifters)
and I Peak 7100-7300 RPM with a 3.600" Stroke.
Is your engine 4.06"X4.10" stroke or 4.125X4.00" stroke.
Mid runners have absolutely made more hp on stock displacement ls3's. But they're shorter, large runners. Right away this tells you they'll need more rpm or more CI. If you want to stick around 6500 rpm then long ones are better. If you want to go 7500 or so the mid lenght are better
Got it! (LMMFAO!)
KW
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Like the post but can Never understand why isn't there *Short runners for the other style heads that FAST makes intakes for. There more cathedral style FAST intakes than anything else and what about the poor old Ls7. It would be nice if they had a Universal short runner makes more sense.
Again Nice post!
Again Nice post!
Like the post but can Never understand why isn't there *Short runners for the other style heads that FAST makes intakes for. There more cathedral style FAST intakes than anything else and what about the poor old Ls7. It would be nice if they had a Universal short runner makes more sense.
Again Nice post!
Again Nice post!
TECH Junkie
Joined: Dec 2005
Posts: 3,092
Likes: 11
Headers are stepped 1 3/4" by 1 7/8". Exhaust is dual 3" with an X-pipe. Straight through 3" mufflers. Camshaft is on a 115lsa with 4 degrees advanced.
Meh.
I just think that losing torque at all RPMs and losing HP all way up to and beyond 6K RPMs is a bad trade-off in order to gain HP above 7K RPMs......particularly in a car that's gonna see regular street duty.
But hey.....I'm just silly like that.
KW
I just think that losing torque at all RPMs and losing HP all way up to and beyond 6K RPMs is a bad trade-off in order to gain HP above 7K RPMs......particularly in a car that's gonna see regular street duty.
But hey.....I'm just silly like that.
KW
Perhaps for some the high RPMs is not worth the trade in lower-RPM power. My interest was in the ability to make any power at all at 7500. Longer runners just fall on their face it seems.
