Independant Throttle Bodies (ITB's/IRTB's)

Yeah, I hear about the AEM from time to time... I'm still not sure about it. I'll have to get in touch with him, for sure. Even if the AEM is out, I'm sure he can offer SOME ideas.

Excluding EMS, mine (note, this makes a difference =)) is going to cost me around 300-400 dollars. I'm getting the throttle bodies from a friend who owes me a favor or two, though, so I'm getting them pretty cheap. Presumably, you could use the throttle bodies from a '00 - '01 Suzuki GSXR 750 for cheaper, too, so then it would end up costing me, or you, about $200 - 500, depending on what you have laying around, and what you can do on your own.

You don't need high compression to run these, but my compression will probably be sitting around 9.7-10:1, after my head work. (Read a little further down for details) Wagner can make the block using high compression pistons, if I remember properly, too.

2.25" header-back exhaust is what I'm running presently, though some changes will be made to it, the principle is the same. I'm building this car up for all-around power more than peak power, though, so your milage may vary; You might want to go as high as 2.5" on an extreme N/A setup, like Install has in the works.

Tuned, I expect probably 12 - 20 hp... But the 20 would be awfully surprising to me!

In reference to the head work... I need to do this sooner than later. My valves are starting to sound pretty rattly (Not a big surprise; 70k on the engine!), and last night they sounded pretty pissed on the way home. I'm thinking new valve springs, guides, valves and retainers are in order, too, which is going to be freakishly expensive, unfortunatly. This is what's going to be done, by me, as well as a light port job on the intake/exhaust outlets. Then the head is going to a good head welder (If I can find one!), and the quench area is going to be enlarged in a clover leaf design; This should reduce the chance of detonation, while increasing the compression ratio, still.

This is going to turn really expensive, really quickly, but I hopefully won't end up going over 1k for everything before the EMS, since I'm doing all the work myself, but I have a feeling I will be, by a good margin.
 
awesome...I would love to do it if I find time...

As far as gains...I would bet it would come to around 10-12whp alone aside from better tuning...meaning you gain 10-15whp from the good tuning alone with the new controller...then another 10 or so from the ITB's...but realize that is with the puny stock cams...with more aggressive lobes, you could easily get over 15whp from the ITB's alone...obviously the TB diameters used will affect where this power is located in the rev range, but give or take it will definately be decent...
 
I really want some cams, but I'm really, really broke lately. Hehe. The ITB's I can stretch out over time, so I'm not too worried about the cost of that, but the EMS is a big drop in the bucket, and cams would tack a good $400 ANYWAY onto that cost. Uugh.

Anyone know where I can get an FS head for pretty cheap? Heh.
 
Yes, you can go forced induction with ITB's, but that's an impure thought, so we'll just pretend you didn't say that...

No, you just need to make a log that can force the air into the throttle bodies. I've seen a vid of an Integra GS-R with a GT28RS running 12PSI at 11.5:1 compression with ITB's... Talk about weird!
 
There are plenty of 4AGE Corollas with quads and forced induction. You just build a manifold around the velocity stacks.

For anyone who doesn't know about them, individual throttle bodies are a way to get good power gains, and the best sound and throttle response you can find. There's an intake roar that can send chills down your spine, especially with uncovered velocity stacks. Because the distance from the throttle plate and intake valves are so short, and there's equal distance between each cylinder and the throttle plates(wheras each runner is a different length from the TB with an intake manifold), the time it takes from when you hit the go pedal, to when you make power, is very minimal. aka throttle response.

They make more low-end power than people think, as you can have relatively small diameter runners to keep velocity up at lower engine speeds; and the combine volume of all runners allows for a low restriction at high RPM, and it's able to flow quite a bit. Because they can't control resonance events when the intake valves open, a well designed intake manifold might have a slight power advantage. The sound is what got me hooked though.
 
ghetto waggon said:
So if I were to spend a grand on the gsxr ITB setup + accessories, what would install cost typically be?
Whatever it would cost for a custom manifold and machining. The bore spacing of the Gixer TBs would be different, so some custom bits would have to be made. Then it's the cost of stand-alone. Some are better than others. ie the Link unit doesn't control them well apparently. Other than what flat black is doing, I can't picture being able to get IRTBs to work for less than $4000. There's quite a bit of tuning involved too. I'm lucky, as I'm getting my set for only $850CDN, although they need some machine work(larger venturis and new seals).
 
$4k altogether is not all that bad.
You speak highly of this...does that include things like cams and port and polish?

Are MPITuner and AEM the same? Why not haltech ?
 
MPI Tuner isn't the same as the AEM. The MPI tuner is based off of another system, and is not a standalone, but rather a very powerful piggyback. Haltech is an option, but if AEM's EMS ends up being plug and play, more or less, then that's less hacking you have to do to the stock harness and so-on.
 
Hard to say! =) I'd like to think that, but I honestly doubt that, unless I get cams. Who knows! We'll see once I start tuning it and everything, but that's a long-assed way off.
 
Nope, there's no way to do it without an EMS... You won't be able to run a MAP without an EMS.

If you wanted to try, all you could do is make a log-style plenum that plugged in, then attached to your MAF. That's about the only way I could think of.
 
Actually, IRTBs are mostly run off Throttle Position Sensors. Even a MAP sensor needs some sort of manifold/plenum. Most guys have an airbox they put on when they're not at the track. Here's the one TWM makes for their set-up.

airbox_16v_vw.jpg



ghetto waggon, I like individual throttle bodies A LOT. Mostly because of the sound, as I'm yet to drive a car with them. Haltech would be good choice, and it's the one I'm using. Here's a sound clip of a BP Miata with IRTBs.

http://www3.telus.net/terence_chu/coolstuff/irtb.mpeg
 
eddie..i'll sell you my motor, you can put ITB's on that and you'll all the power you'll need..until you get beat by a MSP with a boost controller...sigh...
 

New Threads and Articles

Back