HomemadeTurbo - DIY Turbo Forum - The HM-ITB Write up...

-- added this writeup to tech projects. :)

https://www.homemadeturbo.com/tech_projects/itb/

-random-strike

Lots of you have been asking me to do a write up for the homemade individual throttle body setup. Well, I finally took some pics and got the thing installed on my car.. so here we go!

https://www.homemadeturbo.com/itb/itb1.jpg

Starting off with a set of 2001 Suzuki GSX-R Throttle bodies. I picked up this set on ebay for very cheap! 50 bucks. The spacing looked about right, I think it was about 80mm, perfect for alignment on the B-series head.

Measureing at 42mm @ the butterflys and tapers to a 45mm (which also had secondary butterflys that were taken out).

https://www.homemadeturbo.com/itb/itb2.jpg

The stock manifold was chopped off slightly after the fuel rail mounts, I then had 1 1/2 inch long aluminum runners welded on (1.75od) After the welded I had the manifold surfaced on both sides, and threw a chanfer on the lips of each runner. (75 dollars weld/machine work)

https://www.homemadeturbo.com/itb/itb3.jpg

Here are the cheap ass velocity stacks I got on ebay, they were 35 bucks. used some small machine screws to fasten them down. Looks kinda cheezy, but they do the job.

https://www.homemadeturbo.com/itb/itb4.jpg

These are the silicone couplers that attach the Throttle bodies to the intake manifold. Sounds kinda half ass huh? well the factory Suzuki ITB's are this way, and most other bikes too! And after attaching them they were very sturdy. I used Napa bulk Silicone hose, with some hose clamps.
(20 bucks from Napa)

https://www.homemadeturbo.com/itb/itb5.jpg

The Cover shield that hides the linkage and other stuff, just cosmetic.

https://www.homemadeturbo.com/itb/welded.jpg

The factory ITB Fuel injector bungs were JB welded shut, except for the last one which has my brake booster port coming out. You can also see the map sensor signal lines, each port all T's into one and goes to the map sensor.

https://www.homemadeturbo.com/itb/b16itb2.jpg
https://www.homemadeturbo.com/itb/b16itb.jpg

Thought it looked long? so did I, but after measureing up with the stock manifold, I felt a bit better, I thought for sure the stacks would be touching the firewall, but its actually just a bit shorter than the stock manifold.

https://www.homemadeturbo.com/itb/tps1.jpg

The TPS situation, well the Suzuki tps had a way differant range than the stock honda one, I tried to make it work, but it just wasnt happening, So the stock honda one had to be modified to fit somehow.

First I made a baseplate with a hole saw and some scrap aluminum. This is on the backside of the shaft (driverside)

The Brass fitting, was bored out to be a custom bushing for the shaft.

https://www.homemadeturbo.com/itb/tps2.jpg

The Shaft is actually a honda throttle body shaft cut down about 1/4

https://www.homemadeturbo.com/itb/tps3.jpg

Now for mounting, I used a piece of PVC pipe to space out the tps, so it could mount solid.

https://www.homemadeturbo.com/itb/tps4.jpg

Hoggered out the holes on the base plate a bit, so I could get a good amount of adjustment.

https://www.homemadeturbo.com/itb/tps5.jpg

Used some extra long machine screws to mount it down

https://www.homemadeturbo.com/itb/tps6.jpg

All mounted down, Its very secure and pretty easy to adjust.

https://www.homemadeturbo.com/itb/volt1.jpg

Now setting the TPS up in the correct range. Stock TPS setting @ closed .4 - .5v

https://www.homemadeturbo.com/itb/volt2.jpg

Stock setting WOT about 4.5v

https://www.homemadeturbo.com/itb/volt3.jpg

Best I could get the ITB TPS was .6 @ closed

https://www.homemadeturbo.com/itb/volt4.jpg

and 4.4 @ WOT

https://www.homemadeturbo.com/itb/linkage.jpg

The throttle linkage was alot easier than I thought! I used an extra throttle bracket from a D16a6 intake manifold, and it fit right off the backside perfect!

https://www.homemadeturbo.com/itb/tps7.jpg

This kinda pissed me off, I mounted the TPS upside down, it was hitting the master cylinder. So I had to rotate it, and re-adjust it.

https://www.homemadeturbo.com/itb/itbinstalled.jpg

Overall, for a couple hundred bucks it was well worth it, it took a little bit to get running, the idle was pretty easy, a nice 1100-1200rpms. It sounds pretty interesting too, especially when vtec kicks in. I'll try to post some sound/video clips soon.

https://www.homemadeturbo.com/itb/jdm31.jpg

The "high flow" JDM 3-1 (yes 3) header, got banged pretty hard the other day. lol, ebay 90 bucks baby! haha

https://www.homemadeturbo.com/itb/exhaust.jpg

Sporting my old greddy exhaust, (thanks again turbohf) dustin.. You cant even hear the exhaust over the intake, lol.

https://www.homemadeturbo.com/itb/redrex.jpg

Quick shot of my new front end, new bumper, new hood and new windshield.. Also sporting JDM Civic Single Housing head lamps.

JEff