Twin throttle bodies

[Super_Low 91]

Search nicefrog on Ebay. Thats Green foam. $70 and a change over memcal for a custom tune.

yea tried him on ebay,, i sent him a few msgs an he sent a few back but when it actually came to doing it an giving him the go ahead cause i had the money ready he stopped replying

 

[soop]

Hmm, that a bit sad.
I could only suggest you keep trying. I seen him advertising a couple of days ago, so perhaps he personal issues at the time?

The effort to get through to him would surely be better then spending the $800 else where?

 

[chevy_big_block_bro]

You payed $300 for that? Seems a little steep for some ally tube and flanges that are cut off $10 wrecker parts. But im only saying that because I could build it myself. If you cant then you have to pay for the time and materials etc.

Its a bloody good idea though. You have the throttle bodies way back off the manifold now so maybe open it up and build a bigger plenum for it. Just a suggestion.

I built a twin TB manifold for my VT and the induction noise is fairly noticeable and your exhaust note should go a little chunkier too.

 

[soop]

It wouldn't be real hard to modify that intake manifold to make it work better. The heads will be the limiting factor.

 

[chevy_big_block_bro]

you'd cut it down to a point where you still keep the integrity of the manifold. Probably just inline with the top of the fuel rails. Have it come out at an angle and then up into a larger box so you can still fit the injectors in place. Seen it done a few times.

 

[soop]

Personally I'd keep the runners as long as possible.
Can't see how a big plenum will help an NA car much. Wouldn't it just slow the intake airspeed down and cause turbulence above the runners?

 

[delcowizzid]

bigger slows airspeed so the air is moving slower and gets a chance to be sucked down the runners .a biggeer plenum should open up the upper rev area a lot

 

[soop]

That works on FI engines. where the plenum is pressurized.
Trick with an NA engine is to keep the airspeed up into each runner. Basically make it easier for the engine to get the air. Otherwise intake manifolds would be just a big square box on top of the motor.

 

[delcowizzid]

there is a lot to designing one the commodore one is very small around 1.5 liters

 

[chevy_big_block_bro]

Hence the reason the Grp A manifolds have the trumpets inside. They're just a box

I was able the achieve a result on my VT because I didn't modify the runner length that much except for a mace plenum spacer. I just increased the plenum volume and added twin throttle bodies. I still think to this day that I fluked it coz it went alright with a Dr Bob tune.

The runners on the buick motors don't start until the plenum starts to fan out at the bottom which is below the fuel rail so if you keep above this the you'll be fine. Addition of a few trumpets might be an option too if they'll fit