Twin TB on 2X4 tall plenum LS Carb intake with MPI
01-13-2012, 11:24 AM
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Twin TB on 2X4 tall plenum LS Carb intake with MPI I'm trying to pull the trigger on something to get this thing running before spring so I'll be ready to disassemble truck and paint it.
I have some fuel injection experience. I put this in here instead of the carb forum because I figured I"d get flamed for wanting to put fuel injection back on. LOL's. I wanted the old school look with fuel injection.
I'm trying to wrap my mind around something.
1rst scenario:
Holley 2X4 tall plenum carb only for LS1. As I recall, the reasons the tunnel ram isn't usually considered street friendly is a motors torque suffers down low. Typically used for high cu in motors wound tight. If fuel isn't pulled through the intake fast enough the vapor becomes liquid? Same situation with too large of a carb?
Which leads me to the 2nd scenario:
Holley tall plenum 2X4 carb intake with MPI ports using air only throttle bodies. Since the fuel/air mixture is at the intake runners using injectors why would it matter how tall the intake is? Same air in either way? Or does it simply have to do with volume and density?
The reason I ask. I'm told that Holley is now making the 2X4 tall plenum for the cathedral port LS's. I'd like to continue to use the MPI with this and a pair of FAST air only TB's. I'm trying to fill up the engine bay on the 36. I have plenty of room.
Any thoughts?
Dave
I have some fuel injection experience. I put this in here instead of the carb forum because I figured I"d get flamed for wanting to put fuel injection back on. LOL's. I wanted the old school look with fuel injection.
I'm trying to wrap my mind around something.
1rst scenario:
Holley 2X4 tall plenum carb only for LS1. As I recall, the reasons the tunnel ram isn't usually considered street friendly is a motors torque suffers down low. Typically used for high cu in motors wound tight. If fuel isn't pulled through the intake fast enough the vapor becomes liquid? Same situation with too large of a carb?
Which leads me to the 2nd scenario:
Holley tall plenum 2X4 carb intake with MPI ports using air only throttle bodies. Since the fuel/air mixture is at the intake runners using injectors why would it matter how tall the intake is? Same air in either way? Or does it simply have to do with volume and density?
The reason I ask. I'm told that Holley is now making the 2X4 tall plenum for the cathedral port LS's. I'd like to continue to use the MPI with this and a pair of FAST air only TB's. I'm trying to fill up the engine bay on the 36. I have plenty of room.
Any thoughts?
Dave
01-13-2012, 03:04 PM
#2
Yeah..I've need interested in the same thing.. I have read a few magazine articals in the past that in some case, street Tunnel Ram setup have had great results on the street and gave up no lost of Torque and did produce great numbers in lower range of the RPM. (these were of course Carbs).
No reason you couldn't get a tuners to do the same.
BC
No reason you couldn't get a tuners to do the same.
BC
01-13-2012, 03:21 PM
#3
On The Tree
That set-up would flow a massive amount of air. I bet you would have less issues getting it to run right if you went big on the displacement, like 454ci or so
That should help fill up your engine bay....
That should help fill up your engine bay....
01-13-2012, 10:18 PM
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A fella from Holley just told me the tall plenum for cathedral ports may be available late this quarter or early 2nd quarter. Looks like I'll have plenty of time to decide. But he did say this would not be very street friendly.
I'm leaning toward the mid-rise 2X4 wi MPI, a pair of FAST air only TB's if they have the 4160 bolt pattern, and FAST EZ-EFI. Add to that a TCU for the tranny. Going to get more details from FAST when I can call.
I did some more searching on the reason the taller plenum isn't as streetable on small cu in motor. I forgot about air speed. With the longer runners I would lose air speed over the short runners. Correct? If so, that makes sense now.
Roughly $2800 to go the above route. Now the Jenevy ITB's aren't looking quite so bad.
David
I'm leaning toward the mid-rise 2X4 wi MPI, a pair of FAST air only TB's if they have the 4160 bolt pattern, and FAST EZ-EFI. Add to that a TCU for the tranny. Going to get more details from FAST when I can call.
I did some more searching on the reason the taller plenum isn't as streetable on small cu in motor. I forgot about air speed. With the longer runners I would lose air speed over the short runners. Correct? If so, that makes sense now.
Roughly $2800 to go the above route. Now the Jenevy ITB's aren't looking quite so bad.
David
