Velocity Stacks

azopelnut · 08-11-2009

I have a pair of Weber DCOM 40's on a GT that has had the heater box removed so I have ample room for velocity stacks and a CAI.
1) What is the max length for velocity stacks one can go...longer is more low end ...correct?
2) Are there any recommended air boxes or am I best to build one from scratch?

wrench459 · 08-12-2009

Originally Posted by azopelnut

1) What is the max length for velocity stacks one can go...longer is more low end ...correct?

Even with knowing every detail of your motor.
It would be just a guess.
It's up to you now to max. out what ever numbers you want.

CDN OpelNut · 08-12-2009

Originally Posted by azopelnut

2) Are there any recommended air boxes or am I best to build one from scratch?

This is a pic of Otto's set-up that I am basing mine on. There is a thread on this somewhere but I couldn't find it. The airbox is from a 300zx. I will probably buy some Scepter intake tube when it comes time to fashion that portion.

RallyBob · 08-12-2009

Originally Posted by azopelnut

I have a pair of Weber DCOM 40's on a GT that has had the heater box removed so I have ample room for velocity stacks and a CAI.
1) What is the max length for velocity stacks one can go...longer is more low end ...correct?
2) Are there any recommended air boxes or am I best to build one from scratch?

You're probably better off erring with a 'too long' intake tract over a 'too short' intake tract, whenever feasible. You'd probably never feel a loss of 5 hp, but you'd certainly feel a loss of 5 lb ft of torque.

I'd built the air box from scratch. One of the weakest areas of a GT in the power-making department is the lack of room for good airflow and the high underhood heat.

neuropel · 08-12-2009

Originally Posted by RallyBob

I'd built the air box from scratch. One of the weakest areas of a GT in the power-making department is the lack of room for good airflow and the high underhood heat.

Any pics of your GT air box Bob?

RallyBob · 08-12-2009

Originally Posted by neuropel

Any pics of your GT air box Bob?

I don't personally have one. When I do my Bonneville engine for the GT, the airbox will be a huge priority for me. I'll cut out as much of the body's sheetmetal as needed to build an airbox to feed the engine's requirements. My dad's car will be turbo'd, so the air feed will be near the grill opening, and the intake manifold will be fully custom (similar to what Audi runs for better air distribution under boost)

It's interesting to note that even in the early 1970's Conrero found the GT underhood had severe airflow limitations and subsequently lower power than a comparable Manta/Ascona chassis. All due to the tight confines and high underhood heat.

neuropel · 08-12-2009

Originally Posted by RallyBob

I don't personally have one. When I do my Bonneville engine for the GT, the airbox will be a huge priority for me. I'll cut out as much of the body's sheetmetal as needed to build an airbox to feed the engine's requirements. My dad's car will be turbo's, so the air feed will be near the grill opening, and the intake manifold will be fully custom (similar to what Audi runs for better air distribution under boost)

It's interesting to note that even in the early 1970's Conrero found the GT underhood had severe airflow limitations and subsequently lower power than a comparable Manta/Ascona chassis. All due to the tight confines and high underhood heat.

I see...inferior in every aspect.