L92 DynoJet Numbers Plus Plan B, C, D, E and F...
03-07-2007, 11:02 AM
#222
Originally Posted by cybernco
I've been waiting for someone to try one. Any idea how much CFM it will flow over stock? Any idea how much $$$ they are? Did you see their selection of throttle bodies?
Here's their catalog link:
http://www.wilsonmanifolds.com/shop/...on_catalog.pdf
Here's their catalog link:
http://www.wilsonmanifolds.com/shop/...on_catalog.pdf
Just thinking out loud here. The sheet metal intakes out there now have runners that are too short for my usage. The Billet is really a cross ram setup and the runners look to be about 7 inches long.
Last edited by WKMCD; 03-07-2007 at 11:15 AM.
03-07-2007, 12:26 PM
#223
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Originally Posted by WKMCD
I think they are about 3k. I'd throw my ported LS2 by-wire on it.
Just thinking out loud here. The sheet metal intakes out there now have runners that are too short for my usage. The Billet is really a cross ram setup and the runners look to be about 7 inches long.
Just thinking out loud here. The sheet metal intakes out there now have runners that are too short for my usage. The Billet is really a cross ram setup and the runners look to be about 7 inches long.
03-07-2007, 12:38 PM
#224
Originally Posted by sprayjunkie
Have you looked at the sheetmetal intake being offered by Mizfit motorsports? They were letting it go for $1800...
03-07-2007, 08:54 PM
#225
Originally Posted by StingrayCrazy
I plan to Dyno my 9.0:1 pig NA just to baseline before I put the boost to it. I bet the numbers will be higher than expected...
Frank
Frank
The billet bak intake is 8 inches long on the ls7 version, 6 on the cathedral port
03-07-2007, 10:51 PM
#226
Originally Posted by Brian Tooley
That is when I dicided that most of the LS heads probably suffer from intake port reversion at the end of the intake cycle. The clues were everywhere, people where making dissappointing power with the LS7 heads and big cams, I knew the L92's would follow suit.
Don't forget, an intake port has no velocity all until the valve seat says so.
03-07-2007, 11:40 PM
#227
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Originally Posted by Greg Good
Are you kidding me? To push air back out of the cylinder at the end of the intake stroke at peak power you would need astronomical V.E., which you don't have with a small hydraulic roller cam and no boost. I don't really understand why you are promoting small intake valve sizes. It doesn't appear that you've ever delved much into short track racing, where power out of a turn (torque) is key. Tsk..Tsk....Big intake valves and small runners (high average port velocity) are king there.
Don't forget, an intake port has no velocity all until the valve seat says so.
Don't forget, an intake port has no velocity all until the valve seat says so.
I'm wondering why Brian has a sudden boner for the LS7/L92 stuff? It's kind of embarassing really.
03-08-2007, 05:35 AM
#228
Originally Posted by Greg Good
Are you kidding me? To push air back out of the cylinder at the end of the intake stroke at peak power you would need astronomical V.E., which you don't have with a small hydraulic roller cam and no boost. I don't really understand why you are promoting small intake valve sizes. It doesn't appear that you've ever delved much into short track racing, where power out of a turn (torque) is key. Tsk..Tsk....Big intake valves and small runners (high average port velocity) are king there.
Don't forget, an intake port has no velocity all until the valve seat says so.
Don't forget, an intake port has no velocity all until the valve seat says so.
03-08-2007, 07:43 AM
#229
Originally Posted by Greg Good
Are you kidding me? To push air back out of the cylinder at the end of the intake stroke at peak power you would need astronomical V.E., ...
Depending on your cam events, the intake valve closes after BDC. Which as you know means the piston has already started back up the cylinder. If during that moment in time (which is critical) the piston coming up defeats the inertia of the air charge coming in, you end up with reversion... the charge is basically slowed, stalled, or (worse case) pushed back out the intake valve... Once again all of this is dependent upon runner length, IVC point, rpm, etc....
I think that is where Brian was going (not sure)... but I will not speak for him...
Last edited by SideStep; 03-08-2007 at 08:12 AM.
03-08-2007, 09:44 AM
#230
Not going to happen after peak torque where V.E. falls off.
The problem with a bigger intake valve is not where you shut it but where you open it. a larger intake valve has a higher rate of backflow and the engine will be more sensitive to exhaust reversion.
The problem with a bigger intake valve is not where you shut it but where you open it. a larger intake valve has a higher rate of backflow and the engine will be more sensitive to exhaust reversion.
03-08-2007, 10:28 AM
#231
Originally Posted by Greg Good
Not going to happen after peak torque where V.E. falls off.
The problem with a bigger intake valve is not where you shut it but where you open it. a larger intake valve has a higher rate of backflow and the engine will be more sensitive to exhaust reversion.
The problem with a bigger intake valve is not where you shut it but where you open it. a larger intake valve has a higher rate of backflow and the engine will be more sensitive to exhaust reversion.
Originally Posted by Greg Good
...To push air back out of the cylinder at the end of the intake stroke at peak power you would need astronomical V.E.,
03-08-2007, 11:57 AM
#232
I didn't say anything about port velocity (charge speed). What we're dealing with here is a simple situation where air flows from a high pressure area (the intake port) towards a low pressure area (the incompletlely filled cylinder). What I was saying is that the cylinder would have to be completely full some time before the intake valve closes for mixture to be pushed back up into the head before the intake valve closes. That's not happening past peak torque wiith a smallish hydraulic roller cam. It only happens in daydreams and on laptops. Backflow before peak torque is not the real problem with big intake valves. It's at the beginning of the intake stroke where the intake valve just opens (while the engine is still on the exhaust stroke) that causes the problem. A bigger higher flowing intake valve will allow more exhaust into the intake port. Bad Ju-Ju. keep in mind that during the first phase of overlap (the part before TDC) BOTH valves are in effect exhaust valves. Engines with big intake valves are more sensitive to the intake opening point (cam can't be advanced as much) than an engine with smaller less back flowing intake valves.
03-08-2007, 12:15 PM
#234
Originally Posted by Greg Good
I didn't say anything about port velocity (charge speed). What we're dealing with here is a simple situation where air flows from a high pressure area (the intake port) towards a low pressure area (the incompletlely filled cylinder). What I was saying is that the cylinder would have to be completely full some time before the intake valve closes for mixture to be pushed back up into the head before the intake valve closes. That's not happening past peak torque wiith a smallish hydraulic roller cam. It only happens in daydreams and on laptops. Backflow before peak torque is not the real problem with big intake valves. It's at the beginning of the intake stroke where the intake valve just opens (while the engine is still on the exhaust stroke) that causes the problem. A bigger higher flowing intake valve will allow more exhaust into the intake port. Bad Ju-Ju. keep in mind that during the first phase of overlap (the part before TDC) BOTH valves are in effect exhaust valves. Engines with big intake valves are more sensitive to the intake opening point (cam can't be advanced as much) than an engine with smaller less back flowing intake valves.
Cool, I am with you now....
03-08-2007, 12:49 PM
#236
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Originally Posted by SVT THIS
Joey, that is the right head. However, for a tad bit more you can get them with a dual spring upgrade from SDPC. I think Livernois has a CNC'd set and TSP is working on a set too.
Call West Coast Cylinder Heads.....supporting vendor here =====>
