Turbo application with carburetor - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Insert BS here A place to discuss anything you want

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 10-07-2008, 04:26 PM   #1
hrk
Junior Member
Thread Starter
iTrader: (6)
 
Join Date: Oct 2005
Location: Atlanta GA
Posts: 335
Total Cats: 2
Default 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
hrk is offline   Reply With Quote
Old 10-07-2008, 04:48 PM   #2
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

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?
Joe Perez is online now   Reply With Quote
Old 10-07-2008, 04:48 PM   #3
I haz no trubo
iTrader: (2)
 
Oscar's Avatar
 
Join Date: Jan 2007
Location: Bolton, UK
Posts: 3,021
Total Cats: 114
Default

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?
Oscar is offline   Reply With Quote
Old 10-07-2008, 04:57 PM   #4
Junior Member
 
Join Date: Sep 2008
Location: Tulsa, Oklahoma
Posts: 350
Total Cats: -1
Default

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.
944obscene is offline   Reply With Quote
Old 10-07-2008, 05:26 PM   #5
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

I've only seen it with a hat/pressure box around the carb. And those 2 I saw had constant fueling issues.
Ben is offline   Reply With Quote
Old 10-07-2008, 05:48 PM   #6
hrk
Junior Member
Thread Starter
iTrader: (6)
 
Join Date: Oct 2005
Location: Atlanta GA
Posts: 335
Total Cats: 2
Default

Quote:
Originally Posted by Joe Perez View Post

edit Wait a sec... You have a 5.7 liter V8 on a motorcycle, and you want to turbo it?
Just a little, nothing crazy

Name:  PA060209.jpg
Views: 1
Size:  127.9 KB

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

hrk
hrk is offline   Reply With Quote
Old 10-07-2008, 07:20 PM   #7
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,198
Total Cats: 2,584
Default

holy **** batman
18psi is offline   Reply With Quote
Old 10-07-2008, 07:27 PM   #8
Senior Member
 
Join Date: Mar 2006
Posts: 1,379
Total Cats: 1
Default

Quote:
Originally Posted by hrk View Post
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
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
Markp is offline   Reply With Quote
Old 10-07-2008, 07:58 PM   #9
Junior Member
 
Join Date: Sep 2008
Location: Tulsa, Oklahoma
Posts: 350
Total Cats: -1
Default

I wouldn't want to sit on top of a 350. That's like straddling a death puma with rabies.
944obscene is offline   Reply With Quote
Old 10-07-2008, 08:03 PM   #10
Senior Member
iTrader: (14)
 
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0
Default

Somebody is off their meds!
lordrigamus is offline   Reply With Quote
Old 10-07-2008, 08:38 PM   #11
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,797
Total Cats: 248
Default

Autozone sells a book on Holley carburetors. It details the modifications to setup a Holley for a blow through setup.
patsmx5 is offline   Reply With Quote
Old 10-07-2008, 10:54 PM   #12
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

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
Joe Perez is online now   Reply With Quote
Old 10-08-2008, 12:59 AM   #13
Elite Member
iTrader: (13)
 
Join Date: Dec 2006
Location: Taos, New mexico
Posts: 5,703
Total Cats: 237
Default

Jesus tittyfucking christ... why?
Fireindc is offline   Reply With Quote
Old 10-08-2008, 01:25 AM   #14
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Quote:
Originally Posted by Fireindc View Post
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...
Joe Perez is online now   Reply With Quote
Old 10-08-2008, 01:38 AM   #15
Junior Member
 
Join Date: Sep 2008
Location: Tulsa, Oklahoma
Posts: 350
Total Cats: -1
Default

Nevermind. Seems the carb isn't as big a deal as the distributor in space management.
944obscene is offline   Reply With Quote
Old 10-08-2008, 02:12 AM   #16
hrk
Junior Member
Thread Starter
iTrader: (6)
 
Join Date: Oct 2005
Location: Atlanta GA
Posts: 335
Total Cats: 2
Default

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.
Name:  DSC_4086.jpg
Views: 1
Size:  182.8 KB

hrk

hrk
hrk is offline   Reply With Quote
Old 10-08-2008, 02:35 AM   #17
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

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.
Joe Perez is online now   Reply With Quote
Old 10-08-2008, 04:38 AM   #18
Elite Member
iTrader: (13)
 
Join Date: Dec 2006
Location: Taos, New mexico
Posts: 5,703
Total Cats: 237
Default

Quote:
Originally Posted by Joe Perez View Post
Why 600WHP in a bike, or why using a Chevy V8?
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.
Fireindc is offline   Reply With Quote
Old 10-08-2008, 11:25 AM   #19
hrk
Junior Member
Thread Starter
iTrader: (6)
 
Join Date: Oct 2005
Location: Atlanta GA
Posts: 335
Total Cats: 2
Default

Quote:
Originally Posted by Joe Perez View Post
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.
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:
Name:  PA050182.jpg
Views: 1
Size:  130.9 KB

Frame split
Name:  PA050186.jpg
Views: 2
Size:  137.5 KB

Drive arrangement
Name:  PA050187.jpg
Views: 1
Size:  147.1 KB

Broken flexplate and torque converter
Name:  PA050195.jpg
Views: 1
Size:  112.2 KB

Tranny from front
Name:  PA050196.jpg
Views: 1
Size:  113.9 KB

The bike is getting back together and should start up tonight.
hrk is offline   Reply With Quote
Old 10-08-2008, 03:59 PM   #20
Elite Member
iTrader: (13)
 
Join Date: Dec 2006
Location: Taos, New mexico
Posts: 5,703
Total Cats: 237
Default

Wow, what a beast. Post up some videos, lol.
Fireindc is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 12-15-2017 09:00 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
ISO 1.6 turbo cast iron manifold cale saurage DIY Turbo Discussion 16 10-01-2015 12:25 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:07 AM.