Giving birth to twins

GNVenom

Well-Known Member
Joined
Jan 6, 2002
Got a question for you guys out there that are running twin turbos. My latest VENOM project involves a pair of Schwitzer ball bearing turbos with a stock block steel main engine, Champion iron heads, and a lightweight vehicle. Here is what I have now: GN Spyder. I have the plumbing ready to tig, two massive waste gates, and a custom made front mount intercooler. Now my question:
What do I need to know about twin turbos, anything in particular about trying to balance them, control the boost, etc.?
Comments?
Suggentions?
<ear to the rail>

Regards,
John Spina
 
Man what an incredible machine that is...
I'm sure that will be in several magazines, way to go man :)

(sorry, don't know anything about running twins)
 
You're definitely twisted John,but I like it.
You're going to have to refrence the two wategates together with a "T" line connecting the two.
You'll also have to be sure that both W/G's are set the same for default.
Flowing the turbos to be the same is possible,but doesn't seem to be totally necessary.
I would feed both ends of the fuel rail under boost.
Who's intake is on the engine?
E-mail me if you like.
 
I've got the wastegates figured out, one regulator and identical spring pressure on 'em. I had to put the turbos up high because of the oil return...need to drain properly otherwise I figured I would need a siphon pump or something. Anyway, they're slightly differently located from the engine, one is further away than the other for steering and plumbing room. The throttle body is a Supercharged 3800 TB, 75mm with a MAF IAC and TPS built on to the unit. I realize the throttle body is a suck-thru design and I'm using it as a blow-thru but I don't see a problem there...yet.
The intake is the stock unit, with a 68mm dog house by RJC. The oil supply lines will also be tee'd as well as the return line. Sooooo, if it can go together without too much hassle, it'll be ready to start within a week or two. Mm mmmm can't wait.

Spyder Project

-John Spina
 
Get in touch with Steve Kaminski he's building a few twin turbo cars now, he knows what you have to do. Tons of knowledge.


e-mail- skturbo@aol.com

phone- 856-881-3235
 
Originally posted by GNVenom
I have the plumbing ready to tig, two massive waste gates, and a custom made front mount intercooler. Now my question:
What do I need to know about twin turbos, anything in particular about trying to balance them, control the boost, etc.?
Comments?
Suggentions?
<ear to the rail>

Regards,
John Spina

Looks like a cool project, engine and wiring work look extra clean and body looks good in the works, reminds me of painting several cobra kit cars ( Contemporary mfg. and West coast mfg.), do you know if Contemporary ever made a Shelby Daytona coupe ( they were talking about it)? and has Shelby or whoever owns the name, no longer allows the kit industry to use the Cobra name? I am going down a similar path with a twin turbo Buick into a scratch built custom, don't want to use the name ( have to come up with my own) but looks very similar to the Ferrari F50. Though my car and set up are different, mid engine using TH325-4L transmission, but general twin turbo set up similar to yours at least in plumbing configuration, that is L/R heads have a header to turbo each, turbos Y into intercooler( the best I can tell from your pictures), and intercooler to TB.

As long as both turbos are working the same, in this configuration balance is already handled, unlike plumbing one turbo to opposite bank and visa versa with a crossover tube. The exhaust/ downpipes would be just getting to fit chassis, I am not sure of primarily the electronics part of things. First the MAF , seems that connecting to one common MAF would be easiest electronically but adds to the plumbing clutter as opposed to two separate air cleaners. Second would be hook up of O2 sensor or sensors, not sure about that one. Third is how each turbo is performing in lag, boost, etc. vs. a larger single. Because we are building cars that will also see corners, that for me at least seems to be the big advantage of twins, the driving conditions need fast spool , up and down shifting, etc. My set up is a lot easier to put together only because I have the room and wierd trans to do so, using stock passenger header,turbo, bracket on left bank as in the GN, and just duplicating on the right bank, re clock rear turbo as needed for plumbing etc. looks stock beacause it kind of is!

Looks like your project is going to move along alot faster than mine though I hope to complete in a year, the engine will not be ready to fire up till early spring, I can watch your posts and see your solutions, though I plan to keep looking also, the o2 thing is my biggest concern and would like to clean up the air cleaner MAF plumbing a bit. If anyone has any experience/ working twin turbo combo advice (electronic hookup, cam used, etc.)let us know

:D
 
I had the intercooler built with two inlets on either side of the top tank, and a single outlet which goes to the intake. The way I solved the MAF (so far) is to use a supercharged 3800 throttle body, 75mm, which is a cast aluminum part that can take the inlet pressure, and has the MAF, TPS and IAC built in to the unit. The O2 sensor - a single sensor - can be positioned on either side although I am putting two in, one on each side. I'll use one, then the other, and see if there's any difference between them. I'll probably use the side that's best suited if there is a difference. Also, up the road, I'll probably install a WBO2 sensor on one side figuring I'd be using a FAST system. The turbos are small ball bearing turbos made by Schwitzer, used on some John Deere application, not sure which one. We will soon see if the combo works like I hope it will. Engine will be running in the body in January. Latest images at
-John Spina

Visit Casper's Website GN Spyder Build
 
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