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Dragging not Bragging
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Discussion Starter · #1 ·
Who wants a head ache ????

If you had a tunnel ram (with no plenum) with the injectors at the bottom of the runners (MPI), so the bodies are there only to measure the air flow/throttle position, would it be possible to mount the bodies to the tunnel ram WITHOUT the bolt on plenum ............

http://vicperformanceparts.com.au/images/detailed/0/1000cfm-4-vic-peformance-parts.jpg

http://images.oreillyauto.com/parts/img/large/hol/7540.jpg

Or would you still need to space each TB up off the tunnel ram :beuj:

Remember there only there for air not fuel

CoNfUsEd .......... i know i am :tup:
 

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Heavy Oiler
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Think it would be possible, but why would you? You would need to make adapters for the TB's to fit the the top of the tunnel ram bit and as they're "D" shaped ports, gas flow would be compromised.
Why not use a conventional tunnel ram with Holley bolt pattern or use the complete TBI with an aftermarket large bore TB?
Holley Performance Products 1985-88 5.7L TPI Camaro/Firebird 112-503
 

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Dragging not Bragging
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Discussion Starter · #4 ·
Got the tunnel ram but not the bolt on bit to go on top .......... so big bro (Chris-461) was contemplating using 1" carb spacers to go under the TBI's as they would be cheaper than buying just the plenum .... he already has the 750 TBI's and the billet fuel rails and is already running a WOLF 3d mappable whatjamacallit but his main concern is that the front 4 will be running totally separate to the rear 4
 

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Supercharged 461 cu in
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1,407 Posts
Sounds like a job for someone with plenty of patience and a laptop with the exact program for mapping on it. Any ideas who might have these things??????

Chances are he prob did the original install lol.
 

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Premium Member
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don't you know anyone who can tig up a new plenum bit to bolt your 'bodies to? you could fab the ally plate and just get it welded together.
 

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Looking at the pics the system you have is a Holley Stealth Ram. I am fitting this to Mrs BGP's truck, and have the same electronics on the race car engine with a Converted Dart manifold. and they are excelent. you will have a fit when you price 2 4bbl throttle bodies they are more expensive than a carb (cos the contain less????) and you will really compromise the flow going from the relatively wide spaced T/bodies to the close packed ports at the top of the manifold, as well as the sudden change in section.
Also the plenum is the sensing point for the inlet air temp (IAT), and manifold absolute pressure (MAP) for the system. IAT is not so critical, but the MAP is. It is the measure of "load" on the engine and is used in the fuel map matrix against RPM look up table. A quick look at my fuel map for the race car shows that at 7000rpm withl wide open throttle hence low vacuum (Top Right on matrix) my injectors are open for 120m/sec when the throttle is close at this RPM high vacuum (bottom right of matrix) they open for 45m/sec. This is the essence of a speed /density system. The sytem uses rpm and MAP to find the appropriate cell in the user defined look up table (fuel map) and the applies correction factors for coolant temp, air temp and lamba (exhaust O2 info). It all sounds very complicated but I new but I knew bugger all about it 6 years ago when I fitted it to BGP, I would now never go back to a carburetor.
I would be inclined to get or fabricate the upper plenum and use the 2 barrel T/body as the holley set up
If you need pics/ info /dimensions of the plenum contact me
 

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with some systems like Emerald, you can run a really basic control system, all the inputs are, Air Temp, Water Temp and throttle position, it does run rather well, you can also run it with a lambda sensor which enables the system to self teach, when set up to do so, Dave Walker (Mr Emerald) will put any car on his rollers and set it up for a fixed price, and he is good too, I took my car up there for its initial setup, and found 40 hp and 44 ftlbs all in 3 hours, best £250 I have spent on a tune up ever,
 

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Dragging not Bragging
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5,718 Posts
Discussion Starter · #9 · (Edited)
Sounds like a job for someone with plenty of patience and a laptop with the exact program for mapping on it. Any ideas who might have these things??????

Chances are he prob did the original install lol.


don't you know anyone who can tig up a new plenum bit to bolt your 'bodies to? you could fab the ally plate and just get it welded together.
The plan was to get the spacers welded to the manifold and save around 4" in height :tup:

Looking at the pics the system you have is a Holley Stealth Ram. I am fitting this to Mrs BGP's truck, and have the same electronics on the race car engine with a Converted Dart manifold. and they are excelent. you will have a fit when you price 2 4bbl throttle bodies they are more expensive than a carb (cos the contain less????) and you will really compromise the flow going from the relatively wide spaced T/bodies to the close packed ports at the top of the manifold, as well as the sudden change in section.
Also the plenum is the sensing point for the inlet air temp (IAT), and manifold absolute pressure (MAP) for the system. IAT is not so critical, but the MAP is. It is the measure of "load" on the engine and is used in the fuel map matrix against RPM look up table. A quick look at my fuel map for the race car shows that at 7000rpm withl wide open throttle hence low vacuum (Top Right on matrix) my injectors are open for 120m/sec when the throttle is close at this RPM high vacuum (bottom right of matrix) they open for 45m/sec. This is the essence of a speed /density system. The sytem uses rpm and MAP to find the appropriate cell in the user defined look up table (fuel map) and the applies correction factors for coolant temp, air temp and lamba (exhaust O2 info). It all sounds very complicated but I new but I knew bugger all about it 6 years ago when I fitted it to BGP, I would now never go back to a carburetor.
I would be inclined to get or fabricate the upper plenum and use the 2 barrel T/body as the holley set up
If you need pics/ info /dimensions of the plenum contact me
I should of stated the pics were just for reference (not what he has) it was the only pic of a tunnel ram with no plenum attached and he has two 4bl TBIs and is running one as we speak ..............and the Wold3d Advanced Engine Management Systems - Wolf EFI Electronic Fuel Injection and Performance Ignition Control Systems

with some systems like Emerald, you can run a really basic control system, all the inputs are, Air Temp, Water Temp and throttle position, it does run rather well, you can also run it with a lambda sensor which enables the system to self teach, when set up to do so, Dave Walker (Mr Emerald) will put any car on his rollers and set it up for a fixed price, and he is good too, I took my car up there for its initial setup, and found 40 hp and 44 ftlbs all in 3 hours, best £250 I have spent on a tune up ever,
He was looking at a rolling road Dyno session last year but managed to get it pretty damn close with the aid of Si (1970 prostreet gto .......... I know Chris REALLY appreciates all the help m8 :tup:) With the laptop programming software and ALL that spare time you have :lol:

These are the TBIs

 

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Premium Member
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if height is an issue cut 2-3" off the tunnel ram base then fab' your plenum and get it welded on.
 

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Supercharged 461 cu in
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1,407 Posts
Thats pretty, 461BBC Weiand tunnel ram, Multi port Wolf3D EFI, Edelbrock runners, 44LB injectors, dual Accel 1000cfm throttle bodies, Fully onboard remapping etc very nice

sure i have seen one like that somewhere?????? cant quite think where tho:beuj:

Thats gonna go like hell!!!!!!
 

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prostreet enthusiast
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195 Posts
Thats pretty, 461BBC Weiand tunnel ram, Multi port Wolf3D EFI, Edelbrock runners, 44LB injectors, dual Accel 1000cfm throttle bodies, Fully onboard remapping etc very nice

sure i have seen one like that somewhere?????? cant quite think where tho:beuj:

Thats gonna go like hell!!!!!!
could the one you have seen be the same one considering you spent all afternoon filling it out (& a great job you did to):D
 
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