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intake manifold/ plenum for v6

VRV6BT1

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G'day,
I am looking at making a custom intake manifold/plenum after seeing an american v6 with twin plenums.

I am having problems getting a used manifold from any wreckers..... they just wanna sell the whole motor.

By any chance would anyone have one sitting around that they would like to sell? I am after one for a vr with the thermo housing at the front.

I will pay cash and postage.

Also during and after information with pictures will be posted, from all digital flow testing I will be hoping for about 40hp increase.

I can only hope.
 

ephect

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do you have any pics on your design? how are you testing the flow? have you any other engine mods?

looking forward to seeing this thing take shape
 

VRV6BT1

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A mate of mine is into cad, and works at an engineering firm.
I gave him a rough idea of what I was after and he made it in cad or whatever and used the same software they use at work.
He said the best flow would be a semisemi circular shape made out of tubing welded onto the standard(ported) manifold base with large alloy plenums with a throttle body on each plenum.

I've never welded alloy before, so I'm thinkin if I draw up the designs( my mate can't export to anything but the machinery at work(spewin))
Im thinkin I could have the ends of the plenums screw in and out to change the length and volume of the plenums, I may have to experiment with runner lengths though.
 

Andrew426

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Just came across this on trademe, it may be good for a few ideas.

67430930_full.jpg
 

KhaosInc

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Twin plenum and twin throttle?

ive seen 2 made for 3800 engines

first is hogans from america

second is from walker made for ecotec i think? needs some things moved to accomodate.

looking at my g/f's dads nubira (GM 2L 4 cyl engine) today looks like it uses the same IAC and TPS as commodore throttle body. didnt measure how bi the throttle opening was but im quite sure 2 smaller throttles that are a little more surface area than stock would flow better then 2 stock size throttle on NA smaller hole means faster air rate.

stock manifold can handle 360ish hp look at formula holden engines (rules state they must use stock engine manifold) they are big key to buick performance ;)

This is what ive found as im looking at going down the same route. Im looking at going stock plenum top cut off then making it split down the middle with a plenum extending a little over the rocker and throttle towards the back. i'll make some 3d pics of it soon.
 

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VRV6BT1

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Sweet, that's almost what im looking at...
Basically ill be cutting off the top 3/4 of the plenum give or take, and welding in tubing mandrel bent to form a semi circle( maybe 15-20 cms) into large ( like 4 inch or bigger) pipe with one end welded to accept throttle body, and the other end will have a screw in alloy cap so I can screw in different lengths of pipe to tune the volume uf the plenums, I had not considered the size of the throttle bodies it is something else to think about.

Do you know of any technical information on the web that I can study to find out about the effect that throttle bodies will make?

Very interesting though.
 

DaCoffee

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Read this is quite old but has someone made one for the alloytec. I pulled mine off the other day and was interesting how it looks like the old carb intake and sucks you can't put a 90 deg bends and run a different throttle there instead of the crappy look std has
 
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