Individual throttle body setup

posted Sep 16th 2005 9:30am by Eliot Phillips
filed under: transportation hacks

itb

Homemadeturbo.com is dedicated to scratch building turbo systems using salvaged parts. That’s pretty cool, but this project really caught my eye: building an individual throttle body manifold for a Honda engine. Jeff picked up a set of throttle bodies from a 2001 gixxer on eBay for $50. He then cut down the stock manifold and added extensions to attach the throttle bodies using silicon couplers. The velocity stacks also came from eBay for $35. The only really difficult part seems to be attaching the throttle position sensor. It is definitely a great looking set up and much cheaper than it would ever be off the shelf.

[thanks bodiby]

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Comments [17]

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I like their main page, where it shows the picture and says “HMT… where safety is always our first concern ;)” I would feel real good doing this. *wink*

Posted at 10:07 am on Sep 16th, 2005 by bird603568

The biggest hurdle with these ITB setups is tuning them correctly. Theres a few folks over at http://www.pgmfi.org working on these, and they seem to be quite the power making mod. Require MUCH tuning though…

Posted at 11:08 am on Sep 16th, 2005 by Kabuki

He doesn’t mention what power gains it gives him. Also, it looks like it is still taking the air from under the hood.

Why would you want to make your Honda look like a Gasser?

Posted at 12:00 pm on Sep 16th, 2005 by Old Number 7

#2 Thats my friend Dave (from pgmfi.org) When I saw this hack, I though, hey, Dave already did that!

I have not had a chance to see the setup yet, but sure its done right.

I did also hear that it is hard to tune..

Posted at 4:58 pm on Sep 16th, 2005 by Andy

Good question… Anybody care to take a guess about the performance gains that can be had converting to individual throttle bodies, assuming the best available tune?

Posted at 5:06 pm on Sep 16th, 2005 by andrew

I was wondering about this for a Triumph spitfire I was working on, where the dual and single carbs were replaced with a rack of 4 Mikuni sidedrafts from a motorcycle. Unfortunately, running EFI on an engine that’s never had EFI gets to be a real pain in the butt.

I’m wondering if the MAF will be getting the correct info, since it will sort of get an average based on draw at all 4 intakes. And since it’s effectively drawing the equivalent of a much larger TB, is the management system getting optimum data?

Hope he left the ports open that you use to sync the individual throttle valves:)

If it starts and runs, it’s still a cool deal for non-streetable applications. You definitely don’t wanna be sucking street crud right into your engine’s heart unfiltered…tho he could always mount a K&N pod kit from the Gixxer.

Only other thing would be to have the manifold welded up so the TB’s were vertical. Run the velocity stacks/pods thru the hood in a scoop and get a little extra airflow. If the MAF is getting the right info, it should have no trouble dealing with the varying air pressures.

Posted at 6:51 pm on Sep 16th, 2005 by Phugedaboudet

Pardon my possible ignorance, but what about an air filter, where does that fit in?

Posted at 7:52 pm on Sep 16th, 2005 by Sleighboy

in racing situations, air filters usually arent used because the engine is gonna be rebuilt frequently.

Posted at 1:54 am on Sep 17th, 2005 by fucter

I seen that website and it left me a bit baffled as to what was being done?, now i admit i am a king noob when it comes to car engines, so if anyone can recomend a good place to start learning about all this (what kinda books, websites etc i should be reading), i would really appreciate it, thanks.

Posted at 4:53 pm on Sep 17th, 2005 by Saf

a lot of people do this, combined with the homemade megasquirt fuel injection computer. check out msefi.com.

Posted at 12:41 am on Sep 18th, 2005 by chris r

I doubt you’d use MAP or MAF with this sort of setup. Actually you see him mucking around with the TPS, which is probably what they are using. I think this is referred to as Alpha N tuning, and opposed to speed density, where how much fuel used is determined only be throttle position. It seems like a bit of a kludge, but can be made to work. If you’re an engine newbie, I’d recommend picking up a copy of “Four Stroke Performance Tuning” by A. Graham Bell. Brilliant book, and will teach you just about everything an amateur racer needs.

Posted at 11:23 pm on Sep 18th, 2005 by Mike

Cheers guys, seems to be a lot to learn, but im up for the challenge.

Again ta for helping me to start learning this stuff.

Posted at 11:31 am on Sep 19th, 2005 by Saf

Honda’s do not use a mass air flow sensor so it is not nessceary on a ITB setup. There are also many filters avaible for this setup from individual filters to a custom airbox that can be built. With dyno tuning and a decent ECU program such as hondata s300 or uberdata, I think neptune supports ITBs as well, you can see gains of 20 h.p. depending on cam timing and cam profile. Huge cams can bring even better gains but you sacrifice drivability. I have also seen turbo set-ups on hondas with ITBs systems as well.

Posted at 4:28 pm on Sep 19th, 2005 by Zac Carter

man o man u guys need to read. “hey dave did that already”… thats jus like seeing a turbo car n saying “hey my uncle’s came with one of those”. unnecessary… tuning aint that much different then tuning other N/A cars if u kno how to tune. if u use honda cbr itb’s the tps sensor plugs right in. n older honda’s use map sensors that jus run off vacuum source so that’s a sinch… read up more on the site, it has lots n lots of useful info. dont be afraid to ask questions there cuz im sure you’ll get more questions answered and answered properly over there then here.

Posted at 12:15 am on Sep 20th, 2005 by turboda6

Hi!
I got this idea from some people of the swedish lancia-delta-forum and decided after som research that the gsxr-1000-bodies looked easy to adapt to a car. I have now built a intake manifold based on these although at the moment running stock ECU cannot run open runners. When my project is done i will translate the forum-thread to english for those who are interested in reading my notes about it. The project is a Mazda Miata (Mx5) ‘90 with a Mazda 626 2.0 16v engine (FE3) and stock ECU+tranny.

Posted at 10:37 am on Feb 26th, 2008 by egonn

I am not sure about the honda cars, but honda bikes open/close their throttle the opposite from the Suzuki GSXR throttle bodies. Did you have to setup some sort of gear to reverse the action of the TPS, so low voltage was closed?

Posted at 8:18 am on Mar 17th, 2008 by Leo

Leo, The TPS is just a potentiometer.. reverse the supply polarity to the pot and hey presto the output is transposed.

Posted at 3:50 pm on Apr 20th, 2009 by Martin_K