Turbo application with carburetor
 

Hi,

I'd like to know if anyone here has used carburetor pressurised?
5-7 psi max boost, 5.7 liter Chevy smallblock ZZ4 crate engine with log manifolds and two small turboes on both sides of the engine. No intercoolers or electronic management. Currently carburetted with 750 cfm Holley I beleive. There is not much room to box the carb into pressure box, like in some systems.

At the moment no interest in Megasquirt, think more like basic greddy kit type application. I'd like to learn how to jet the carb for mild boost.

The bike will rarely see continous boost for more than 10 seconds.

Any carb users here?

hrk

In a blow-through application, you have to box the carb. Otherwise, you'll just blow the fuel out of the carb the wrong way.

One option would be a draw-through setup. Put the carb on the inlet of the turbo Or in your case, one smaller carb on each turbo.



edit Wait a sec... You have a 5.7 liter V8 on a motorcycle, and you want to turbo it?

I'm fairly knowledgable on small 2-stroke carb applications, but 4-stroke not so much.. I take it you want to make a blow-thru setup?

I would not recommend a blow through setup. Draw through is easier to set up. If you want to get some info on the blow through, see how Vortech pulls it off. IIRC, they have supercharger kits for carbs, that allow you too pressurize the the body. They might have a carburetor that you need to buy. I wouldn't know.

The engine my dad and I work on in the Elko is a ZZ4 as well. Only we have a B&M 144 mini blower on. Its designed as a draw through setup, and we have the fuel injection stuff from B&M, but no computer. So carbed it stays for now. To compliment the setup, we have a Comp Cams hydro valve train with a cam profile designed for the B&M blower.

I can't say how much power it makes, but you tell me what its like to hang even with a Z06 in an Elcamino and say it feels weak. ;)

I've only seen it with a hat/pressure box around the carb. And those 2 I saw had constant fueling issues.

Just a little, nothing crazy :)

Attachment 210682

Some thoughts here.
http://www.dune-buggy.com/turbo/carbureted.htm

hrk

holy shit batman

BTDT with an RX-7 and a 600 Holley. Draw Through is the right answer.

Works well even up to 10 PSI of boost in this case. It was pretty amazing to see a bone stock RX-7 with a 12A throw down 210 RWHP with a T3S60.

Mark

I wouldn't want to sit on top of a 350. That's like straddling a death puma with rabies.

Somebody is off their meds!

Autozone sells a book on Holley carburetors. It details the modifications to setup a Holley for a blow through setup.

Hmmm.

A quick Google search revealed some pretty pictures of a Holley being modified for Blow Thru. Looks like a fair bit of custom work, though I'm amazed they've got it working at all. Seen a lot of people fail at doing this with Weber IDFs.

http://www.superchevy.com/technical/...wer/index.html

http://www.hangar18fabrication.com/blowthru.html

Jesus tittyfucking christ... why?

Why 600WHP in a bike, or why using a Chevy V8?

HRK, I'm curious to know a little more about the race class that you campaign that bike in. From the picture, that looks to be a pretty run-of-the-mill streetbike frame, which makes me suspect that this is more of a hobby bike than a pro entry. 500-700 shaft HP is certainly not out of the ordinary these days for a serious drag bike, though usually in the form of an inline-4 being fed by a monster GT42 series turbo.

As much as I like the idea of two sidedraft carbs in a draw-through config, I'm really drawing a blank trying to find one to suggest. I have no idea how something like an 55 DCO would respond to being configured in a 2-1 setup...

Nevermind. Seems the carb isn't as big a deal as the distributor in space management.

Thank you for the encouragement :)

At the moment it is just a mindpuzzle. But entertaining one and if there seems to be viable solution like weber sidedraft in front of each turbos and reasonable chance of success it might turn into winter project.

No race class at all. No real reason. The rated 400 lbs/ft is enough to make rolling burnouts from 75 mph, but the unique aspect and the challenge to make it work in your garage and reasonable budget would be reason enough.

Keep them coming. Here is the moped as it is when it is in one piece.
Attachment 210681

hrk

hrk

I've seen V8s in scooters before, but I've never really seen detail on the clutch / transmission / transfer / final drive setup. Mind sharing?


How crazy would I be if I suggested a pair of 2bbl progressive carbs, each one sitting normally (upright) with a 90° bend feeding into the compressor?


edit: Don't get me wrong, I still think you're insane. :D

Both, I guess. Ive seen those bikes before, is that a boss hog?

Still a cool project though, I agree with Joe- needs more pics.

Unfortunately for me I acan give pretty good impression of the drive line of my -97. Bear in mind that this is old model, and I could ramble about the differences between years as it is relevant.

Boss Hoss started to make these things in 1990 they had vacuum assisted clutch and 1 speed built into 90 degree angle drive to the front sporcket and then belt to rear wheel, which used car tire 225/70/15 Firestone I beleive. One had to slip the clutch below 12 mph speeds. Clutches lasted typically 5000-7000 miles.

Second generation was one speed automatic, which I have. It consist of flexplate, torque converter, electric solenoid activated gear combined into 90 degree angle drive, belt drive and 230/60/15 Avon rounded motorcycle tire.
One flips the gear on, bike creeps forward on idle just like automatic car, can be held with feet or brake. Accelerates with gas. Engine rpm 3500 at 75 mph.

Third and current configuration replaced the one speed transmission with Nesco made tranny consisting two speeds forward and one reverse. second gear is made for cruising 55 mph and higher and should not be stressed.

Frame:
Attachment 210669

Frame split
Attachment 210670

Drive arrangement
Attachment 210671

Broken flexplate and torque converter
Attachment 210672

Tranny from front
Attachment 210673

The bike is getting back together and should start up tonight.

Wow, what a beast. Post up some videos, lol.