Custom intake question

[seq4x4]

Are the injectors for the buick mounted off the plenum like the ecotec cause i cant see them in the photo

I'm just wondering if it isnt possible to leave to stock heads on there and go itb from there... would be a much easier system to make and install then

The "injectors" are there. Look at the 6 hose lines..

If you want 6 ITBS in a line then use the stock manifold. If not, start shortening the manifold, But what lengeth you take off has to be made up for in trumpet length i think it is.

 

[Dr HaxZaw]

The "injectors" are there. Look at the 6 hose lines..

If you want 6 ITBS in a line then use the stock manifold. If not, start shortening the manifold, But what lengeth you take off has to be made up for in trumpet length i think it is.

Yeah i wasnt to sure if they were mounted in the throttlebody like some or those lines were for the IAC

 

[seq4x4]

If i get the time ill do some research on the ITBs and how to make it plenum less. Only issiues i see are: Map sensor, IAC and TPS.
Iv thought about this idea for a long time and never went ahead with it due to being bloody terible for a street driven car for the following reasons:
Tuning issues
You would need a bonnet scoop
If it rains good luck going for a drive.
The throttle response would be way to responsive infront of cops or city driving

Just a few points i thought of that turned me off the idea.
We all of use we can come up with how to fix those problems with the sensors, but street driven cars might be a bad idea. With my pretty cheap and basic intake system i chirp at the lights at times (with light throttle) and light them up (with full throttle), imagine with properly tuned ITBs?

 

[seq4x4]

Just took my manifold off and had a quick looky. You would want to cut straight (so when its mounted the cut is level) roughly where the line is in the picture. You would want to cut out and weld up the injector holes. You want a ITB with injector holes. The TBs about 35mm to 40mm (havnt cut mine so i cant tell you how big the runners are). Then you have to work out how big your flutes need to be. At a quick guess without math, about 60mm tall. Then all you have to do is make up the linkage, figure out how your going to mount your injectors, your fuel lines, IAC and TPS.. Job done....

But, to come up with that flute length thats just how much runner length your taking out from a stock manifold. Thats not taking into account of how big the TB is going to be. So thats my theory, do with it what you will.

 

[LETZRIDE]

my thoughts on this...I think 2 tbs on each side without seperating the manifold is going to cause crazy amounts of turbulence.

Now I had a few thoughts for making an ITB setup, I think the best way with the holden manifolds would be to split the tbs into 3 per side...like this



Just the pic on the bottom, I would rather run the fuel through the stock lower manifold.

^^ this is MY ideal setup, the problem being the expensve of me having source out CNC and welding of a piece like that. I have a buddy who is willing and capable of doing it (tool and die, and very good) but I can't ask him to work for free.

As far as running a MAP, I believe that is easy...run a vacuum nipple off each TB to a vacuum canister, and run your MAP in there.

Then comes the unknown tuning headaches, and unforseen issues (while I'm already $$$ in)

So, in an attempt to redesign my ideas (which I based off the above picture) I have been chewing on a few new ideas...maybe some of you might see flaws with it though?

I was thinking of utilizing the stock upper manifold. Weld in a breaker wall isolating each cylinder (so now you have 6 compartments inside the Upper manifold...run a TB to each compartment. Now, to make life easy I was thinking about leaving something small like a .25"-.5" gap between your compartment walls and the lid of the manifold, this I was hoping would allow you to still utilize the vacuum line on the upper plenum that is provided from stock. It also allows the PVC valve to still be used as well.

I was hoping by leaving a small gap at the top it would allow the vacuum to be present, but eliminate turbulence from being created in the manifold that you would otherwise have if you did not put those walls in place.

what are your thoughts on that?

Do you think that small gap will still cause turbulence?

 

[delcowizzid]

theres a thread on here where greenfoam split a 3800 manifold in half with alloy plate but the pulses were so strong in the manifold that the plate made a horrible harmonic vibration and was going to tear itself unwelded in a short time LOL

 

[LETZRIDE]

they ever find out what caused it? the turbulence? thats why I was thinking 6 compartments.

 

[ephect]

With the six compartments, u will lose a heap of air speed and create turbulence within them. U really want a straight air path. Leaving a gap won't be good, the six throtts won't be true to each breath of air as it can suck from the gaps. In this instance ur better of using the stock manifold and thrott setup.

 

[Dr HaxZaw]

Inlet manifold - Wikipedia, the free encyclopedia

Thought that was a pretty interesting read especially about the Helmholtz resonance

The main problem really is that you could get it to work but you need to be able to change the tune at will and have the car off the road till you get it running. Unless you have a second car you cant really do it over a weekend

 

[ajvx01]

my thoughts on this...I think 2 tbs on each side without seperating the manifold is going to cause crazy amounts of turbulence.

Now I had a few thoughts for making an ITB setup, I think the best way with the holden manifolds would be to split the tbs into 3 per side...like this

View attachment 134640

Just the pic on the bottom, I would rather run the fuel through the stock lower manifold.

^^ this is MY ideal setup, the problem being the expensve of me having source out CNC and welding of a piece like that. I have a buddy who is willing and capable of doing it (tool and die, and very good) but I can't ask him to work for free.

As far as running a MAP, I believe that is easy...run a vacuum nipple off each TB to a vacuum canister, and run your MAP in there.

Then comes the unknown tuning headaches, and unforseen issues (while I'm already $$$ in)

So, in an attempt to redesign my ideas (which I based off the above picture) I have been chewing on a few new ideas...maybe some of you might see flaws with it though?

I was thinking of utilizing the stock upper manifold. Weld in a breaker wall isolating each cylinder (so now you have 6 compartments inside the Upper manifold...run a TB to each compartment. Now, to make life easy I was thinking about leaving something small like a .25"-.5" gap between your compartment walls and the lid of the manifold, this I was hoping would allow you to still utilize the vacuum line on the upper plenum that is provided from stock. It also allows the PVC valve to still be used as well.

I was hoping by leaving a small gap at the top it would allow the vacuum to be present, but eliminate turbulence from being created in the manifold that you would otherwise have if you did not put those walls in place.

what are your thoughts on that?

Do you think that small gap will still cause turbulence?

This...... WHEN REFINED could work nicely..

My input= make a symmetrical ecotec (Aus style) plenum with no tbs on either side.. run & weld mandrel pipe bends from each internal factory runner to the side of plenum, 1st cylinder drivers side 2nd passengers and so on.. Then inside the plenum below the lid tap a vac line In each pipe to the factory vac port at rear of plenum then run vac line to behind fire wall where u mount vac canister and map sensor.

This idea I say could work as

A) trumpets will be horizontal and then can be lengthened/shortened as needed.

B) no scoop required

C) vac lines are ran but hidden

D) injectors are not needed to be moved thus you needn't be concerned with spray angle and nozzle ports etc.

E) Air speed if the tbs and pipes are done will increase if anything

OK DISCUSS

Also if any one decides to make this I hereby legally require one be made for me too! Yes I'd pay...