F22a ITB's (pics)

[F22Turbo702]

Thats the thing though, in boosted applications, having it small will choke it. You want a high velocity in an naturally aspirated application(this high velocity actually helps scavenging; this doesnt really exist in boosted applications because the turbine is constantly pushing the air in). In a EFI, the injector nozzles help do the atomization.

I don't consider 40 or 42mm small...however, we'll just have to wait and see. As for boosting on this setup, I don't think these are going to choke the motor what-so-ever, this will be far better than any stock a1/a4 manifold will ever be...and even in EFI engines (N/A or boosted), port size and velocity are the key to fuel atomization, the injector doesn't do all the work.

i have always had to switch 2 wires on the cbr TPS in order to get good tps signal. I also suspect that drivability will be extremely poor with the safc...

I'm going to try and use the CBR tps without modification, however if I need to switch a few wires, so be it. As for the S-AFC, I don't expect great drivability (although I have heard of people having good relusts), just safe A/F ratios until the 5spd swap is done and I install my Hondata S300.

But, please keep in mind, this is mostly a trial and error setup, just something I've wanted to try and now can. I'm sure it won't run perfect, but that can all be sorted out through dyno time and more expiermentation.

-Kyle

[SoySauceCb7]

you want to rune a ITB setup with a SAFC HAHAHAHA best of luck my friend.

[HondaB18]

Wiccanvampier - do you mean flow velocity (speed of which air flows) or the flow capacity (volume of air)

imo its too early in the build to say if the itb are too large in diameter or too small considering it will be turbo'ed later on with a plenum. if a smaller turbo is used then it should be adequate. i think the final result with the turbo with the itb will be more important then squeezing every hp he can NA with just the itb. as you said it yourself, it will be trial and error

but...

resonance frequency would be negated because the frequency would be reflected (into the engine bay). since itb do not use a manifold (or have a plenum or some sort of chamber) its not pushing air back into the engine. so itb do not used the ram air theory

good luck on your build and document and share your journey

[K2e2vin]

port size and velocity are the key to fuel atomization, the injector doesn't do all the work.

That's true if the injectors are moved back or you use the CBR's stock location, but on the Hondas and how I think you're running it, all of the atomization happens in the combustion chamber(the Injector sprays at the back of the valve),

[F22Turbo702]

Here are some more pics I took today, I finished removing the EGR port and Coolant passage and mocked up the ITB's using 1.75 O.D. aluminum tubing. I don't know if you will be able to tell by the pics but the 1.75 is too small, I will be picking up a few feet of 2.00 O.D. tubing tomorrow hopefully and will finish mocking up the runners and possibly welding them, but we'll have to wait and see.

You can see how much larger the far left runner is compared to the others. It's 2.25" and the other three vary between 2.00" and 1.75", I'm not too worried about the size difference, I think I may weld up the runners and port them all to the same size...we'll see how it goes...


Bye-bye EGR



Turns out that the itb's throttle plates are actually slightly larger than the intake runners, so I have a feeling that these will be a good match.






Haven't yet decided on run length, I used 2.50" as a start, but I think 1.50-2.00" is going to be a better length.


I still need to build a vacuum log and get the silicone hose and hose clamps.

-Kyle

[wed3k]

i was gonna go with 2" otherwise with the stacks, you might exceed 13.5" (thats what i measured with my GSX1000 throttle bodies

[F22Turbo702]

all of the atomization happens in the combustion chamber(the Injector sprays at the back of the valve),

Just FYI, that statement is false. Atomization begins the moment the fuel leaves the injector, and Air Flow Velocity has everything to due with atomization, granted more power can be had by moving the injectors further from the head, but in this setup, as it stands, with the injectors in the stock location, in order to maintain good airflow velocity a smaller throttle opening is better than a larger one. The lack of air volume is not a concern with a totally stock head, it can only flow so much as it is right now, I'm more concerned with keeping port velocity as high as posibble to get what air I can into the cylinders as fast as I can.

There is a fine line between "too big" and "just right", I'd rather start smaller and work my way up.

i was gonna go with 2" otherwise with the stacks, you might exceed 13.5" (thats what i measured with my GSX1000 throttle bodies

Yeah, I still need to take a measurement of the overall length as it stands right now and then figure out what I'm going to do.

-Kyle

[wed3k]

keep us updated foo, mine kinda went down the drain due to other priorities but i still have everything. the ONLY thing i need to do is to pay someone to weld aluminum tubes to the manifold.

but yea, from what ive read, its kinda best to keep it just as long as the stock manifold because we non-vtec guys dont rev high enough

[gloryaccordy]

I thought ITBs had to be shorter for low end?

Anyways keep us posted on this. From what I understand, the major hurdles are the MAP sensor, getting the vacuum lines together and the TPS sensor. I have a spare H23 lying in my garage...hmmm....

[K2e2vin]

So you're building it for N/A? In the first post you're talking about building it for boost.

[mondojackal]

So you're building it for N/A? In the first post you're talking about building it for boost.

he already said that he's building it for N/A now, then turboing later, when he gets the manual tranny.

[cp[mike]]

one hint, look into angling them upward a bit! one of the dudes on HT spent tons of time welding and preparing a beautiful straight-runner ITB setup only to find that once he put it on the back of the head, it was hitting the rear motor mount. the motor is tipped back, take this into consideration!

[K2e2vin]

he already said that he's building it for N/A now, then turboing later, when he gets the manual tranny.

I ask that because he keeps bringing up velocity, etc., which does indeed make huge differences in N/A engines, but for turbo; you want it to flow(which is what Im saying).

[wed3k]

one hint, look into angling them upward a bit! one of the dudes on HT spent tons of time welding and preparing a beautiful straight-runner ITB setup only to find that once he put it on the back of the head, it was hitting the rear motor mount. the motor is tipped back, take this into consideration!

i remmeber that thread
im pretty sure longer will retain torque...same applies for exhaust

a cut-out is going to be good for the top end but gonna kill the low end.

but of course, it depends on how built the motor is.

[F22Turbo702]

Thanks for your opinions everyone.

I'm building this as a low compression N/A motor right now, I want to have a good flowing engine combo (i.e- itbs, header, exhaust, cam, mild p&p head, tuned on 91) before boosting on it. Plus, I need this car to perform decently as a daily driver until the 5spd swap, and Hondata tune. I know that I will lose a bit of low end torque, but through trial and dyno time I hope to find a runner length that will bring the torque curve back up with a good tune...

Even on a turbo setup, you can go too big, I'd rather have a decent N/A setup then add boost to the equation, than go way over the top and have an engine that isn't even drivable. Cam choice will be the deciding factor in how well this steup transforms from N/A to F/I, not throttle body size.

I still haven't gotten to the store to get the 2.00 O.D. tubing yet...maybe tomorrow.

-Kyle