Turbo + ITB's on a miata.
 

been thinking about this for awhile, and have been reluctant to post the idea/thought of it because of fear of getting a new asswhole ripped but whatever, its just a talk/discussion.

so to start off with what got me thinking!

i was working on a friends Celica and looked at his motor and noticed it is has ITB's from the factory with a plenum on it, and i know that people turbo the 20v engine.

http://www.4age.net/gallery/engines/031.jpg

4AGE 20v turbo

http://www.padandwheels.com/mr2/blac...oject/4age.jpg

http://img696.imageshack.us/img696/6105/jamie164.jpg

with all the chat about intake manifolds, using the 99-00 heads and retrofitting honda intake manifold to our cars. maybe there might be some advantages to this, maybe not.

what are some of yalls opinions?

There would be advantages, question is would it be worth the lots of time and cost it would need?

There are a lot of unorthodox things I would do to my turbo setup before ITBs

If my car had a hamburger logo and a 6 cylinder and twin turbos. Then I'd fux with the ITB Turbo combo.

i know there are plenty of other things that can be done to a car before ITB's. i.e. meth injection, custom intake mani and :hustler:

question is, would a ITB setup with a plenum be more effective than just a custom intake manifold or than the ones that are already out there.....

as far as the cost. im pretty sure if the right parts were sourced and deals were to be had it could be done for rather inexpensive. still may be more than a custom manifold or the ones that are already available for purchase, but what if that cost could be justified with a higher yield of efficiency and what not.

People mention advantages, I'd like to know what they are. More importantly I want to see HOW MUCH of an advantage this would be over a custom sheet metal or retrofitted honda manifold. I'm willing to bet said "advantages" would be so insignificant that they wouldn't even come close to justifying the time/money that would go into something like this.

For the time/money you'd spend on this you could just go bigger turbo and more supporting mods:D

Just my .02 tho

i fully understand your point and logic. in my head i think about this subject in the same way as you. i have just been tossing the idea around in my head for a while and just got tired of keeping it bouncing around in my cranium.

i may see if i can get ahold of a ITB setup off one of these 4AGE 20v's and see where things go, there are a shit ton of them at the local junk yards and i have a friend that runs the celicatech forum so there is a possible place as well for me to get what i need.

i may or i may not do it so we will see.

Short answer:

Do ITB's for feel, not for power. They're good for throttle modulation, as in corners rather than straight lines.

lol @ people who "need ITB's" for modulation.

According to Sav it cost him around $400 to convert to a Honda manifold... for that much an IRTB setup could be built using GSXR throttle bodies. It would take the same or less time than making a sheet metal manifold.

Sometimes MT.net is as bad as M.net when it comes to new ideas...

here are a few that i found. looks kinda cool.


http://www.haywardperformance.com/im...prototype1.jpg

http://www.clockwisemotion.co.uk/ima...bre-airbox.jpg

http://i380.photobucket.com/albums/o...c/IMGP1287.jpg

How do you get a good MAP/vacuum signal from independent throttle bodies?

lol @ people that don't want a more controllable turbo Miata mid corner, it's not a need.

Usually ITB people go Alpha-N, avoiding that problem. BMW got around it in 1989 by putting a VAF in front of the ITB's. There are ways to get vacuum, involving four hoses and a block, but the best way is to put a MAF before the ITB's.

Great, another fix for a problem that does not exist.

Uh, what part of not a need are you not getting here? It's not a problem, just an incremental improvement over the standard system. This is like 9" 6UL's vs 8" 6UL's. Yeah, it's not a need, but it can get you a bit more speed. Control counts, that's why Savington was so fast on the Rotrex car. i'm not saying you or anyone else should buy this, just that there is a reason to do this if you have the infinite money cheat.

That's what I figured, a barbed fitting in each runner to a fuel rail looking tube above each fitting, making a little plenum for a vacuum signal, for things like brakes (or a map sensor). Thanks for the reply :)

1) Sav has access to parts and services at bigger discounts than the typical enthusiast afaik
2) Your average joe can't cut/weld/fabricate so that 400 price tag would be more like 600. most itb setups I've seen are being sold for 1000 or so.
3) Everyone here has a "guilty until proven innocent" attitude. At least most of us. Sure we're skeptical of new ideas because its much better/easier to use a tried/true method and not fuck up our cars.

But hey, when someone shows us proof/results we're more than happy to become believers. At least I am:)

Sav spent 400 bucks putting on having a BP flange welded on a honda manifold...

Man, it sounds like you want to do it so go for it. If the spacing is right on the runners maybe you can graft it onto a Miata flange pretty easily. Be sure to do some before-after dyno tests, on the same dyno, no other changes, etc and see how it compares to stock. The throttle modulation report will be more subjective.

i didnt intend for this to turn into a argument/debate/fight.....


i just wanted it to be a friendly discussion on theoretical pros and cons of doing this. im not telling anybody they should do this or that it is gonna make uber amounts of power gains, this thread was more of a what if.......