45 replies to this topic

[xFactor]

I wanted a small fab project to cut my teeth on welding aluminum, and we had a small collection of motorcycle throttle bodies, so this is what transpired...









I know the itb's are from a cbr 650 or 750, I forget which one. I wanted 4 separate vs. 2 and 2 so I could match up the spacing to the ew fuel rail. I had to stretch the outers 10mm with a spacer and grind the inner two a bit, and found metric threaded rod to tie them back together.

The total length is 10" for a real power band, no 11k rpm crap...

So far the only thing that needed to be modded was the mc reservior with a heat gun to clear the thottle position sensor.

We fired it off the first time the other night, and it started without hesitation. Like fired off instantly...I was expecting the total opposite. Due to a faulty oil pressure sender I shut it down after 20-30 seconds. I had to pull the manifold off to fix a little leak on the coolant flange, and will be back at it Tuesday night. I will say this, it sounded ANGRY!

Later, Matt

Edited by xFactor, 25 November 2012 - 03:44 PM.

[Buford]

Ya got it wrong..short runners shift the power band to higher RPMs, longer runners shift power band to lower RPMs. This is also Cam duration and profile dependent. There are some decent intake length calculators on the internet, the good ones also ask about the cam as well. Also read about Helmholz resonance to understand intake and exhaust tuning.

[cbstdscott]

Oh My God! That is my wet dream come true. (I apologize for the TMI)

DO WANT!!!!!!

The long runners will make it much more tractable for street driving. Not much room for velocity stacks or air cleaners, but wow that looks good.

It looks like you are using the stock fuel rail. Are those the stock injectors?

The ports on the head are kind of egg shaped to accept the injectors at the port entrance. Are your manifold ports round or shaped like the head ports?

Where do you get vacuum for the brake booster?

Does the Suzuki TPS have the same range as the Honda TPS?

Details about the plates it appears you have fabbed to attach the fuel rail.

Please, more detailed pictures when you have the manifold/throttle bodies off the car.

Mad props to you sir.

Scott

[xFactor]

The whole project is for a track only Lemons and Chumpcar build.

The runners are that length for a useable powerband, and the extra injector distance is part of that equation. There are still a couple of inches to the firewall, but I'm having trouble finding cheap velocity stacks. I do have some elastic filter hats.

Stock fuel rail. People will laugh because I don't know if it's a crx or integra injector. They were inherited from the Obamanation/Killer Whale car.

I ovalized the runner with a vice to get a closer match. It's ok but still a little off. If the whole thing works out I'll probably port match the head.

We don't have the booster connected, but the tb's have nipples that go to an equal length mini-manifold for the pressure regulator and the map sensor.

I was incorrect with my motorcycle lingo, they are from a cbr.

The plates are jigsawed from aluminum. Its adaptor-on-adaptor technology. They bolt to bosses on the tb's, and you can see the rest in the top pic.

Thankfully my aluminum welding skills match the whole theme of the races, amatuer and crappy, but it will work...

We have a Hong Norr Racing facebook page that has some pics of stuff, but a lot got changed.

Later, Matt

[xFactor]

Obligitory crappy video...










We got everything back together again last night, and now need to sync up the throttle plates so they pull the same amount of vacuum at idle. Right now there are only 2 cylinders doing all of the idle work, and the other two not so much - obviously idles stoopid rich...it sounds more like my wrx. But with the throttle cracked at a 1200rpm "idle", 14's on the wideband, and it sounds nice and clean.

The adjustment screws are under the whole fuel rail mounting assembly...so I'm hoping to drill some access holes through the adaptor plates, because I don't see anyway to sync them if the car isn't running.

later, matt

Edited by xFactor, 28 November 2012 - 08:39 PM.

[cbstdscott]

Iirc you said you used CBR tbs for this project. Did they come as separate units or did you saw them apart?

Scott

[cbstdscott]

Iirc you said you used CBR tbs for this project. Did they come as separate units or did you saw them apart?

Scott

[xFactor]

They were four separate ones. Definately the way to go if you are looking for some because the injector spacing isn't identical. The two center tb's (cyl's 2 and 3) are closer together than cyl's 1, 2 and cyl's 3, 4.

later, matt

[gtpilot]

We got everything back together again last night, and now need to sync up the throttle plates so they pull the same amount of vacuum at idle. Right now there are only 2 cylinders doing all of the idle work, and the other two not so much - obviously idles stoopid rich...it sounds more like my wrx. But with the throttle cracked at a 1200rpm "idle", 14's on the wideband, and it sounds nice and clean.

The adjustment screws are under the whole fuel rail mounting assembly...so I'm hoping to drill some access holes through the adaptor plates, because I don't see anyway to sync them if the car isn't running.

later, matt

You don't care about the position of the butterflies at idle on a race car - you want them all parallel at wide open throttle. Sync them with the motor off loking donw the ITBs so you can see that they are all open the same amount.

Kirk

[xFactor]

Another one of the nice things about these particular throttle bodies- they have springs on both sides of each actuator arm. At WOT, each throttle plate will bottom out at its own internal stop, and the upper spring on the actuator arm absorbs and negates any differences that are dialed in for the throttle body's idle settings.

Yes, it's a "race car". but I know I can tune it to idle better than 9's on the wideband with some simple tweaking on the throttle plates...

later, matt

[xFactor]

Ok, I know it seems obvious, but you need to wait for the ecu to get through start/after start/ warm-up sequence before you go and mess with it.

I found a cheat for my set-up. I can cycle the throttle bodies to almost wide open to find the correct angle for a long screwdriver on the throttle plate adjusters. No drilling through the adaptors...

By the hand over inlet method, (and the car warmed up)I have them tweaked even enough now it idles in the 14's around 1k rpm's. Now each throttle body seems to pull a similar amount of vacuum. With a vacuum gauge hooked up to the manifold, it bounces as deep as 20" when it idles the cleanest.

It is an angry little bastard on the street so far. We made a few pulls, and it melts the new 205r15 star specs rolling through first and most of second gear...

more to follow, matt

[xFactor]

From the other night...


















Dyno time should be next, but with the holidays, I'm not sure how soon...

later, matt

Edited by xFactor, 08 December 2012 - 09:26 AM.

[NWClassicHonda]

I love the paint and wheels!

[CRXfanatic]

General Ree! hahahhaha!!!! Great stuff!

[Blue87Crxsi]

Wow man this is a great project that thing smashes hard want to itb mine out soon also