home made over head twin throttle body advice

[danbotten]

hows it going guys just looking to see if anyone can point me in the right direction i have a heap of intakes thottle bodys etc etc
im looking to build a custom twin overhead throttle body for my 3.8 ecotec im not looking for crazy power gains because from what ive heard it dosent make alot of diffrence i heard throttle response is improved alot though witch is more what im after plus i dont see many guys running this kind of set up iim sure theres a reason but if anyone nos of any threads taking you frew building this kind of manifold please feel free to send them would help me out alot the main things im looking for are:

list of all parts and matierials needed for this project
advantages and dis advantages of this set up
guide on building this manifold
and any other tips and advice you think would help me out

also i no this will not clear my bonnet ill be running compact pods frew my bonnet if this all gos well
cheers guys look forward to hearing you advice and ideas and please if you have nuthing nice to say kiindly keep it to your self

[Dr HaxZaw]

Your going to need it tuned as you wont be able to run a maf with that setup up

Also having a pod sticking through your bonnet is a huge target in NSW and defectable so not sure how that would go

A good place to start might be with taking the lid of the plenum and modify that to take 2 throttlebodies and then once you've got all that figured out you can perfect the design a little

[ephect]

I have a pic of the Buick with twins on top to the plenum. I'll throw some pics up later today.

[ajvx01]

Just run a set up like this..

Reson most don't do it as they think there is few gains and it's expensive.

Both statements are wrong, I bought mine from Mrc performance and got a real good tune and it felt like a new car after! And that was coming from a bigger tb and cai already.

[seq4x4]

hows it going guys just looking to see if anyone can point me in the right direction i have a heap of intakes thottle bodys etc etc
im looking to build a custom twin overhead throttle body for my 3.8 ecotec im not looking for crazy power gains because from what ive heard it dosent make alot of diffrence i heard throttle response is improved alot though witch is more what im after plus i dont see many guys running this kind of set up iim sure theres a reason but if anyone nos of any threads taking you frew building this kind of manifold please feel free to send them would help me out alot the main things im looking for are:

list of all parts and matierials needed for this project
advantages and dis advantages of this set up
guide on building this manifold
and any other tips and advice you think would help me out

also i no this will not clear my bonnet ill be running compact pods frew my bonnet if this all gos well
cheers guys look forward to hearing you advice and ideas and please if you have nuthing nice to say kiindly keep it to your self

Hey mate, how many plenums and tbs do you have?

As stated the 2 on the lid need a mafless tune, but also having TBs out the bonnet without a scoop is illegal. Id suggest like Aj is posting up everywhere.. A MRC twin tb. I can write you up a guide on how to make one if you really like. Even then you will need a tune done as well. Send me a PM if you want some instructions and such, and if you have enough to make 2 ill take one lol (dont own a welder anymore)

[wraith]

Hey mate, how many plenums and tbs do you have?

As stated the 2 on the lid need a mafless tune, but also having TBs out the bonnet without a scoop is illegal. Id suggest like Aj is posting up everywhere.. A MRC twin tb. I can write you up a guide on how to make one if you really like. Even then you will need a tune done as well. Send me a PM if you want some instructions and such, and if you have enough to make 2 ill take one lol (dont own a welder anymore)

Lol you live close enough to him you could probably just go round his place and help :P

[seq4x4]

Lol you live close enough to him you could probably just go round his place and help :P

And im pretty sure you live in Caloundra west/Belvista.

[ajvx01]

Hey mate, how many plenums and tbs do you have?

As stated the 2 on the lid need a mafless tune, but also having TBs out the bonnet without a scoop is illegal. Id suggest like Aj is posting up everywhere.. A MRC twin tb. I can write you up a guide on how to make one if you really like. Even then you will need a tune done as well. Send me a PM if you want some instructions and such, and if you have enough to make 2 ill take one lol (dont own a welder anymore)

Ha ha it's funny I ran that set up for ages and now the big influx of threads relating to it!
What's with that? Was squat when I was researching..

Must look like I'm spamming-oops..

[ajvx01]

Also the most common issue with DIY twin tbs is if the linkages aren't PERFECT u can't tune the mongrels to make any good power.
Other than that why not try I guess

[wraith]

And im pretty sure you live in Caloundra west/Belvista.

Nope. But what's that got to do with it? Keen on an epic weekend with OP and myself :P?

[seq4x4]

Nope. But what's that got to do with it? Keen on an epic weekend with OP and myself :P?

Mistaken identity lol. Sorry.

[mr calais 5.0]

If you make it can you do some step by step pics..

[seq4x4]

Give me some time and ill do something up for yall.

[seq4x4]

And here is the how to with pictures:
How to build: Ecotec twin throttle bodies. - Motordrenaline

[danbotten]

If you make it can you do some step by step pics..

ye ill be getting lots fo pics etc when making it as theres nothing realy on here about making them for the ecotec motor (overhead) anyways

[seq4x4]

Its pretty much the same as the link above your comment, except yours are on the lid, so you need i think i worked it out to be 20mm spacers on the lid to fit the TB so the linkages to work. You would also want to have the first TB centred over runner 2 and the second TB centred over runner 5. Then all you do is cut out the TB neck from the side and weld it up so its nice a flush, then on the inside curve the corners on the passenger side like it is on the drivers side.

[mr calais 5.0]

Thats grate find that link.. Is there a how to for a v8?

[wraith]

Thats grate find that link.. Is there a how to for a v8?

Buy one from COME or don't bother at all. A lot of R&D went into making it and it is without a doubt one of the best manifolds for the 5 litre.

[mr calais 5.0]

Buy one from COME or don't bother at all. A lot of R&D went into making it and it is without a doubt one of the best manifolds for the 5 litre.

Who has a truck load of $$ for 1 of them? I dont.. Just wanna see inside of it and see how they made it with the workings. Thats all

[seq4x4]

Thats grate find that link.. Is there a how to for a v8?

Im pretty sure you should join that site and contribute. Lol.

I have never owned or really worked on a V8. The V8 world has so many aftermarket options already. You could prob find second hand ones pretty cheap around or buy another manifold and/or plenum (do that have one?!) and just look at it, and plan something. The questions you should ask are, whats the best way for the air to get down there, can i remove these restrictions, can i take the time to give it some ITBs with some trumpets (velocity stacks). Or even have a look at some photos of others and have a good guess how it works. It may not be as good as the professionals or it could be better. Its all about trial and error.

You also better off trying the V8 development section as they might have a bit better idea then the V6 guys.

[immortality]

If your keen on a twin TB manifold for a ecotec, consider getting yourself a nice thick bit of alloy plate and shape it the same as the plenum lid from the ecotec. That way your starting with a nice flat surface which will make the linkages line up a lot easier. When your finished you can always round the edges off nicely so the lid looks almost stock except for the TB's sticking out the top

Buy one from COME or don't bother at all. A lot of R&D went into making it and it is without a doubt one of the best manifolds for the 5 litre.

If you have a big cube, high rpm motor or using forced induction, even then the COME manifold has issues. It's certainly no bloody good at all on a standard stroke/stockish 5litre engine.

I'd take a Grp A manifold any day

[wraith]

If you have a big cube, high rpm motor or using forced induction, even then the COME manifold has issues. It's certainly no bloody good at all on a standard stroke/stockish 5litre engine.

I'd take a Grp A manifold any day

Oh definitely. Rarity being the issue though.

[ajvx01]

Trick shift make knock offs..

Also star do an exchange banana manifold from memory?? They hone it, upgrade tb to front facing, bigger tb inlet etc etc.

As said this is v6 section, I own a v8 and check the v6 area as I like the little screamers but alot in this area never have or will own a v8.

[Dr HaxZaw]

alot in this area never have or will own a v8.

just rub it in some more why dont you lol

[ephect]

heres the pic , and one with a bug catcher for fun