Plenum Volume?
Thread Starter
Staging Lane
Joined: Sep 2004
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Plenum Volume? What do you guys think the effects of plenum volume would be with forced induction? I am rebuilding my turbo motor now (not an LS1) and have a choice between two castings for my intake manifold. One has a larger plenum than the other. I think that in a naturally aspirated application, a larger plenum is beneficial, but is this different for a FI engine? I would think that it would add a little lag because the turbo would have to pressurize more volume, but would there be a power increase with a larger plenum? If nobody knows, I may put it together the same way as I had it before, dyno it, and then change only the intake manifold and dyno it again to see the difference. Let me know your opinions, because I am also building a FI manifold from scratch for our Formula SAE car at school. Thanks!
--Bryson
--Bryson
Thread Starter
Staging Lane
Joined: Sep 2004
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meh...I suppose all I can do is build a few different manifolds and see how each one acts on the dyno, but I didn't want to go into this blind because we get graded on design -- they grade hard on the engineering behind the car. Thanks!
--Bryson
--Bryson
12 Second Truck Club
Joined: Feb 2002
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From: Sacramento, CA
On a lot of the FI manifolds for Mustangs back in the day (93-99) were very short runner styles. The long runners were mainly used by N/A guys to aid in TQ production while the short runner intakes helped with high rpm power which is what most drag racers with FI needed since almost every one of em used centrifugal blowers. This was also before alot of the refinments in impeller design to help spool up time.
Not sure how this stacks up now but that's how it worked on Mustangs back when I raced mine. Ford also used 2 intakes back then though, an upper and a lower so that may skew things.
Not sure how this stacks up now but that's how it worked on Mustangs back when I raced mine. Ford also used 2 intakes back then though, an upper and a lower so that may skew things.
In my opinion, the ability to flow the needed air and not sheer off aroudn sharp edges, goo entry into the chamber, would be most important. i dotn think you need a long runner because liek F8L said, your not trying to use inertia to tune for a specific torque band
TECH Addict
Joined: Oct 2002
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From: Mefis
This may be waaay off since it was done in 1954, but:
Bruce Crower's hudson had a blown chrysler hemi in it and had a plunum volume of 105 cubic inches. This was on a 331 cubic inch engine with 14 pounds of boost via a GMC 6071 blower. That car eventually went 157mph at boneville. And that car certainly didn't have the aerodynamics of todays cars.
FWIW
Bruce Crower's hudson had a blown chrysler hemi in it and had a plunum volume of 105 cubic inches. This was on a 331 cubic inch engine with 14 pounds of boost via a GMC 6071 blower. That car eventually went 157mph at boneville. And that car certainly didn't have the aerodynamics of todays cars.
FWIW
