Turbo application with carburetor
10-07-2008, 03:26 PM
#1
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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
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
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10-07-2008, 03:48 PM
#2
Boost Pope
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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?
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?
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10-07-2008, 03:57 PM
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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.
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.
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10-07-2008, 04:48 PM
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10-07-2008, 06:27 PM
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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
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
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
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10-07-2008, 09:54 PM
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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
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
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10-08-2008, 12:25 AM
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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...
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...
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10-08-2008, 01:12 AM
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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.
hrk
hrk
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.
hrk
hrk
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10-08-2008, 01:35 AM
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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.
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.
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10-08-2008, 10:25 AM
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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.
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.
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:
Frame split
Drive arrangement
Broken flexplate and torque converter
Tranny from front
The bike is getting back together and should start up tonight.
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