turbo idea

[curious]

i was talking to a friend of mine about twin turboing a 360. he is on a strict diet (his walllet is). he wanted to use twin 4 cyl turbos (2.2 or 2.5 something like that) i told him that would be a restriction on a 360 causing higher rpm breathing problems.
was i wrong in saying that?
how high will the turbos work until breathing is a issue?
then i was hit by a lightening bolt. it must have really fried my brain becuase the thought of multiple turbos on each bank hit me. i thought just because 2 4cylinder turbos dont flow enough doesnt mean 4 wont.
can he do this?
he has access to a junk yard of parts so i told him to watch for buick gns as they have pretty big turbos. but if he can get by with 4 smaller 2.2s that ll be great because they are more accessible.
what are the pros/cons of such a setup?

[TT440]

easy now... Don't overthink the setup.
Two of the 2.2 turbos will be just fine if you swap the turbine housings for .63 A/R pieces.
OR
You can get the turbos off 85-87 T-Brid Turbo coupes with A 5 SPEED TRANNY. The automatics use the same 2.2 turbo.
OR
You could use the 2.2 turbos as is and reduce your RPM to 5000. 5500 RPM will still be achievable but the turbos will be a little restrictive.

It's not that hard. Stick with the stock cam. It will perform better than most hot rod sticks unless you have one custom ground.
Do your homework and study as much as you can. It will make the engine much easier to build and enjoy.

It's all a balance of pressure. Pressure in vs pressure out on the engine, turbo, fuel, everything. Get something out of whack and it can be a real pain to figure out. Keep it simple and stick to the non-trick parts. In most cases, you simply don't need 'em.

[Thunderstruck]

Interesting as I am gathering parts for a turbo 273 in my 65 Cuda. I am using a garret from early 2.2 TI. This particular turbo fed my 2.5L TI 22 psi and hammered a rod bearing out. Since the wife has determined I will not spend more money on the Turbovan I will turbo the Cuda. The way I figure it is this, if this turbo can feed 22 psi to a 2.5L (153 CID) engine at 6000 rpm it ought to feed 10 psi to a 273 engine at 5000. Even if it's just 5 psi it's better than no psi. Unfortunately, I have not figured out how to stuff an intercooler in the Cuda, it's tight.

Steve

[TT440]

You're not gonna like that itty bitty single on the 273. You'll choke that engine and it won't rev over 4000 RPM. It'll be dog-city!
Get another one and use two of those things. They'll be a good match but don't expect boost as soon as you get on it. You'll probably have good boost by 3000 RPM.
I can get 'em from the local salvage yard for $35 each. We stopped by on Saturday and there's plenty around. I'm sure you can find 'em down there.
If not, come on up to the Mopar Mini-Nats in Garland. That way you can check out the TT440 and stop at Pick-n-Pull on Sunday before you go home.

[curious]

ok so ill tell him not to mess with 4 but he can make 2 work. what kinda power can he expect with stock type parts? can he make at least 350hp<or more?
any ideas on a 318 build?

[TT440]

You're going to be limited by the heat in the intake charge, the heads, and the 318 crank.
Those turbos can be pushed to nearly 300 hp each but that 318 isn't going to see 600 hp.
Grab some 360 heads and drop the compression into the basement. Those wastegates are set for 14 psi unless you play with them. That should easily net 450 hp.
What kind of power can the rest of the car take?

[curious]

well it can take as much as necessary. its going in a 80s long bed pick up. tf727 (not sure how much ill build it) and dana 60 full floater. im working on a 4 link that lll work in conjunction with the leaf springs or maybe air springs in the future.

[Thunderstruck]

Originally posted by TT440
You're not gonna like that itty bitty single on the 273. You'll choke that engine and it won't rev over 4000 RPM. It'll be dog-city!
Get another one and use two of those things. They'll be a good match but don't expect boost as soon as you get on it. You'll probably have good boost by 3000 RPM.

Well, I doubt the turbo will choke it more than the tiny 2bbl that's on the 273 right now. I'd like to run two but I doubt I can squeeze one in on the pass side without cutting sheet metal, something I don't want to do to a 65 Cuda. The one I have room for is on the drivers side, but only if I relocate the battery. I do not want one big turbo.

My experience with this turbo tells me the boost will be on as soon as I give it gas. That is exactly how it operated on the 2.5L it was on, no lag. Helps that the Cuda has a 3.55 SG in it's 8 3/4. I'll let you know.

Steve

[TT440]

I'm tellin ya that it's a bad idea.
First, you must have both sides of the engine fed into that turbo. Have you ever driven around with a big restriction in one side and an open header on the other? It makes for an unhappy engine. Life expectancy drops dramatically too.
Second, that turbine can't flow enough exhaust to let that engine rev. That thing was designed to flow exhaust from 150 cubic inch engine. Now you're going to cram 273 inches of exhaust through it? At 3200 RPM, you're exceeding the exhaust flow of the 2.5 at 6000 RPM. At 5500 RPM, you're pushing nearly twice the amount of exhaust it was designed for. Try running a marathon while breathing through a soda straw. I bet you're not going to like the results. Neither will your engine. It will overheat the air, push boost into uncontrollable levels, send the compressor into surge, and destroy your engine through detonation. That's assuming that the engine will be able prevent exhaust reversion from all that pressure stacking up in the turbine.

Running a restriction in the intake limits power. Running a restriction in the exhaust limits reliability, economy, and performance. Take a quick jog around the block. Breathe in through the nose and out through the mouth. Kinda easy. Do it the other way around and you're not going to be happy.

If you want to run a single turbo, then you'll need to route all the exhaust to one side and then stuff it into a larger turbo. A Buick V6 turbo would probably get you by. Again, it would be a wee bit on the small side, but you would be much better off.
A quick-n-easy way to mount it would be relocating the battery to the trunk and placing the turbo where it used to be. Then, have some headers made or modify the driver's side exhaust manifold to run upwards. The passenger's side exhaust can run under the engine and back up on the driver's side. Both manifolds could dump into one large pipe running to the turbo.
Without seeing the car, I can't really come up with much else. I have no idea how it's packaged.
Please don't take offense to what I've said. I'm just trying to keep you from making the same mistake I made. My turbos are too small and it's killing power production. The tight turbines are too big of a restriction for my engine to breathe easily. A twin turbo 440 should make more than 359 RWHP at 6 psi. That's small block territory. Bigger turbines and better exhaust should push me much closer to 500 RWHP. I should be able to swap 'em out this week, so check the Moparts board for a TT440 update.