Injection manifold problems

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Twin-turbo-tr7
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Injection manifold problems

Post by Twin-turbo-tr7 »

Hi I'm fitting twin turbos to a 3.5 rover
V8 in a tr7 only running low boost 6 psi ,
I'm cutting up the plenum top
So the throttle body can go on the front
Instead of on the side a bit like an act
One ,I'm going to use a bolt on tb
Either one off A Toyota supra that I have
Kicking around Or a skyline one ,
both have quite a small
Footprint so should be possible,
now my questions

1) I have clearance problems so is it possible
To have some material ground off the bottom
Of the trumpet base aprox 10mm or so where it joins to the
Manifold ( part with the injectors in it )so when it fits on the
The manifold it's lower ? So I can avoid using
Subframe spaces
2) if this is possible will it be detrimental as it will
Shorten ten inlet tract?
3) also if I. Shorten the manifold ,could I still
Pull out the tubes and do a blended base or with the
manifold now being shorter and effectively
Having a shorter inlet tract would this hinder
Performance ,

Thanks



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Eliot
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Post by Eliot »

Google "MGB V8 plenum lowering" under images - quite a few have done it.
Eliot Mansfield
5.7 Dakar 4x4, 4.6 P38 & L322 TDV8
www.mez.co.uk / www.efilive.co.uk

stevieturbo
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Post by stevieturbo »

Dont worry about altering the length, boost will sort anything out.

I did this years ago with mine, think I removed a good amount

Original

Image

Shortened

Image

I think I also had the base manifold shortened a few mm too. Although there are limits there before it starts hitting fuel rails etc

I then just made a crude alloy box to bolt on top. I only used two throttle blades because it seemed easier at the time and I had two lying about.

Image
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

Twin-turbo-tr7
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Post by Twin-turbo-tr7 »

Thanks for the replies chaps ,
do you thinking I could get 10 mm lower ?
Also what would be best to remove the trumpets or not ?

stevieturbo
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Post by stevieturbo »

Get which bit 10mm lower ?

I certainly wouldnt remove the trumpets completely unless there really was no other option
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

Twin-turbo-tr7
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Post by Twin-turbo-tr7 »

I wanted to get the top of the plenum 10 mm lower to
help clear the bonnet a bit better, it does clear but its
very very tight and didn't want it to hit when the
engine rocked as you rev it up as they do , so thought
I could remove 10mm from the bottom of the plenum
base or take say 8mm off the plenum base and say
2mm off the top of the intake manifold, it wont affect
the internal dimensions of the plenum itself , it will
just shorten the inlet tract 10mm

the reason I thought about removing the trumpets
and doing a blended base is because im conveting
the plenum so its a bit like a westfield one, but
with the throttle body on the front not the back
, im going to modify it so I can bolt on a 70mm skyline
one that ive got kicking around, its going to be very
close to the front of the plenum" for bonnet clearances
again" and I thought the air going in might hit the bottom
of the trumpets and cause me some problems ,
just thought it might be a smother air flow with the trumpets
removed and a blended base ,

so my thinking was a smoother airfow with no trumpets
should be better??

but this plus the shorter inlet
tract coupled with no trumpets lose me any hp or torque ?

stevieturbo
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Post by stevieturbo »

Still not clear whether you're trying to retain OEM parts, fabricate parts, etc etc

You can easily lose 20-30mm in trumpet height. So if you make a new custom top for the manifold, you've an easy 20-30mm reduction possible there.

If you're trying to use an OEM plenum top with no modification, then you will need to lose the height elsewhere. That could be a little bit of manifold, trumpet base and manifold top plenum.

And if you're concerned about the engine moving when revved, bolt it in solid then it wont move.
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

SuperV8
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Post by SuperV8 »

I took 25mm out of the plenum base, by machining both top and bottom faces.
I also cut down the trumpets.
Just do some careful measuring!
Some photos here:
http://forum.daxsportingclub.com/phpBB3 ... 5&start=60

Tom.
Dax Rush 4.6 supercharged V8 MSII

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