Draw-through turbos

I know this has been hashed out on the interwebs for years already, so this isn't a question about the merits of draw through. Does anyone in the collective know where I can buy a turbo with graphite seals?

Everyone talks about it but no one advertises one for sale... it's weird...

I'm re-building my girl-friends mustang motor, straight six. She won't go V8 and I'm not shelling out two grand for an aluminum head or aussie head. I'm thinking a draw through would be easy to plumb with a side draft SU carb. Will post pictures of the finished product for your enjoyment if you can help me find a turbo...

Mopar 2.2 Turbo I?

At least, they were drawthrough, so the turbos were known to work under vacuum. And it's probably about the right size!

Turbo regal or trans am.

Yep, get yoself a t3 turbo from an 84-87 non-intercooled dodge 2.2, or use some kind of T3 center section and buy the rebuild kit for said dodge to get the proper seals.

If you do decide to use the whole dodge turbo, port the wastegate orifice in the turbine housing as much as the puck will allow to mitigate the possibility of boost creep on the larger motor.

What would I find the dodge ones on? Omni, Charger, is it a Shadow or the spirit also?

I dont know if they all had the same turbo, but dodge put it on pretty the turbo motors in pretty much everything. Daytona, Omni, sundance, spirit, shadow, caravan, charger etc.

This is a useful link You can scroll to the green lines that say "engines using turbo 2,2 or whatever and click show and it will list them all for you. http://en.wikipedia.org/wiki/Chrysler_K_engine#2.2_Turbo_IV

any 87 and down 2.2 turbo non-intercooled car. omni and charger are your best bet, shadow, daytona, lebaron, and the rare k-car had it also

Forget about it. Megasquirt it!

I've looked into this myself. The graphite seal rebuild kits for a T3 are out there and not too $$$.

One of these days I'm going to get off my ass and build a draw through turbo. From what I've heard, while it does limit boost somewhat and intercooling's out the window, throttle response is pretty good and it actually improves fuel economy (assuming you don't just stomp the go pedal everywhere you go) by better mixing of the intake charge.

Go for it. And post pictures. My D-T setup would involve an SU carb, too...or possibly gheto-jection.

Find a carbed 2.3 Ford. They were draw through.

moparman76_69 wrote: any 87 and down 2.2 turbo non-intercooled car. omni and charger are your best bet, shadow, daytona, lebaron, and the rare k-car had it also

Is there a difference in the seals required for a carbed (wet) draw through vs. a fuel injected (dry) draw through?

Why would you do a dry draw through?

Pat wrote:

moparman76_69 wrote: any 87 and down 2.2 turbo non-intercooled car. omni and charger are your best bet, shadow, daytona, lebaron, and the rare k-car had it also

Is there a difference in the seals required for a carbed (wet) draw through vs. a fuel injected (dry) draw through?

Yep. You have to seal the bearings from the gasoline in the airstream.

original Ford... think it was Garret...??? The 79 - 81 2.3 Turbo Capri and Mustangs were draw through

oldopelguy wrote: Why would you do a dry draw through?

Rally car? Make all the spools.

oldopelguy wrote: Why would you do a dry draw through?

I have yet to figure that out, but that's what Chrysler did with the pre '88 turbo I cars that were mentioned earlier.

Yep. You have to seal the bearings from the gasoline in the airstream.

I dont see why. The bearings are already sealed against letting the oil lubricating them INTO the airstream. Unless that seal breaks down from gasoline but not oil, i dont see why it would need to change.

Having been inside a blow-through and suck-through Garrett turbo, I don't see any differences in the seals.

Compressor seals need to be able to withstand the vacuum at the compressor inlet that happens in part throttle situations.

Pat wrote:

oldopelguy wrote: Why would you do a dry draw through?

I have yet to figure that out, but that's what Chrysler did with the pre '88 turbo I cars that were mentioned earlier.

If I had to guess, I'd think that it had something to do with part throttle efficiency. The turbo can spin happily in a vacuum, decreasing the load on the turbine, reducing pumping losses. That or it makes plumbing a lot simpler on a non-crossflow cylinder head.

On the flip side, it makes intercooling a bitch. A blown intercooler hose turns into a runaway engine. IIRC Chrysler came up with a few lines of code that checked for rationality between engine RPM (or was it manifold pressure?) and throttle position.

Now, if I didn't want to guess, there are some neat tech docs/engineer interviews out there online. At least, there were ten-odd years ago.

Whoa, information overload. You guys are freakin awesome. I emailed atpturbo and they flat out said no to graphite seals. Said it's an almost extinct way of doing things.

oldopelguy wrote: Why would you do a dry draw through?

The intake is integral, I can have it machined down to mount a dgv weber carb with an adaptor plate, buy a crossflow head from somebody in Australia (not that I know where I would even begin to do this), or buy an aluminum head (one place makes them and they run about $1500 bare so not worth it for this particular project). I figure it would be easy enough to weld up a flange for boost and fuel and mount an SU carb to the front of a turbo. Run 5-6psi and maybe get myself in the 150-175hp range and have some cool factor without spending a lot of money.

But that would not be a dry draw through, now would it? A dry draw through would have the throttle upstream of the turbo but inject fuel downstream, meaning clearly not a carburetor. If you are going to run injection might as well do it conventionally.

how hard are those integrated intake heads to get? Drill 6 holes, braze in some steel injector bungs, and add megasquirt.

For carb plus turbo I think pressurizing a box around a carb with a turbo is the way to go.

I agree with OP on the simplicity of the draw-through approach.

If you could get the turbo put up right beside the intake manifold and basically discharing right into it through a short 90 degree turn, it would be a really tidy setup and you wouldnt have to do any vac/boost related mods to the carb, just fuel tuning.

I'm on board with the whole idea.

Vigo wrote: I agree with OP on the simplicity of the draw-through approach. If you could get the turbo put up right beside the intake manifold and basically discharing right into it through a short 90 degree turn, it would be a really tidy setup and you wouldnt have to do any vac/boost related mods to the carb, just fuel tuning. I'm on board with the whole idea.

That's essentially what I'm thinking.