Turbo Advice T3 vs T4

I am going to run a T04E compressor on my 200 alum head engine. I WAS going to use a T4 turbine as well. But lately, I have noticed a lot of people using the smaller "hybrid" T3 turbine/T4 compressor units. My Falcon is going to be an 80% street/20% strip car.

I am sure I would like the quick spooling of the smaller turbine, but my concern is that I don't want to be driving around all thime in boost, and also, I don't want the smaller turbine to run out of steam before the end of the 1/4 mile.

What do you guys think? Is the T3 turbine better for our 200 inch street/strip engines, or should we stick with the T4 units?

Also, on a separate note, what is the turbine exhaust outlet diameter on the T3 and the T4?

Thanks.
-Jim

I would definitely stick to the T3 on the turbine side. what kind of power were you trying to make?

According to the engine analyzer program, I'll see just over 300 at 7 psi on the street, and just over 400 at 15 psi with race gas at the track.
That is with the T04E compressor with a 50 trim and .63 A/R.

Quick 8":3251wawk said:

According to the engine analyzer program, I'll see just over 300 at 7 psi on the street, and just over 400 at 15 psi with race gas at the track.
That is with the T04E compressor with a 50 trim and .63 A/R.

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I'm not so up with the power number with aluminum heads but that turbo sounds like a pretty good start. I know with my log headed 200 I only managed 15 second passes as 7psi. But that was with a 1 wheel wonder job. I would say maybe 150hp or so lol

As far as the exhaust size question in your first post it really all depends on the turbo you buy they usually have different sizes and types of outlets.

.63 or .82 turbine housing would be fine for your setup.

Smaller one for more instant boost, or the bigger one to raise the boost RPM up a little.

I also think that your dyno program is showing some higher than expected numbers. View some of the dyno posts from Does10s, he's running 20lbs on an aluminum headed 250 and only seeing mid 300's to the wheels.

That's 375 at the crank, give or take.

Once again I ask the question: Is there a means of sizing the turbine other than experience/trial and error? Charts, nomographs, maps, equations, anything? Any fool who can read a turbo map can size the compressor but what about the turbine?

Here's a list of poeple that are using the TO4 turine:
Linc's 200 - TO4 O trim 13.58 - .68AR housing. He stated lag was not a problem on a stock engine.

Turbo Chick - TO4 P trim (I'm pretty sure) - 10.86 - 250 engine with cam

Fast64 Ranchero - TO4 P trim - 12.33 - even though I think he went faster, couldn't find it - 270 CI - mod log with cam

drag-200stang - TO4 P trim - .96 AR housing - log head, cam.

I follow the turbo Buick site because that engine is similar in nature to ours. Originally they started out using the T3 exhaust wheels. With every new hot trick turbo that came out they kept uping the exhaust side and now they're pushing for TO4 P trim and larger.

The turbo manufacturers didn't design the TO4 turbo with a T3 wheel. It was the Ricer's trick - or is it really?

Our engines aren't Rice.

StrangeRanger":1x34uj2f said:

Once again I ask the question: Is there a means of sizing the turbine other than experience/trial and error? Charts, nomographs, maps, equations, anything? Any fool who can read a turbo map can size the compressor but what about the turbine?

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I've looked in vain for equations and formulas. I think that the nature of how the hot side works, due to the vagaries of load, exhaust gas temp and volume, and the way they interact make it difficult to quantify in a simple way.

I was using a 1.00 hot side and it was too big (on a 200). I was more of it being too small like my previous turbo setup so I went too big. It only took to the top of 1st gear for it to spool. So until 40 or so mph I was driving an almost 18 second car lol

I was originally leaning towards the T04 - P trim - .69 A/R for the turbie side. I'll probably stick with that.
Hopefully it will work well. It is a shame there isn't a way to calculate an actual selection beyond a "best guess" situation.

Quick 8,

I don't want to sound flip-floppy and I'm not a turbo expert, but I do have Ford 6 turbo experience. It is very hard to recommend things because your idea of street-strip may be different than mine. My thoughts are if you're spending the money to get the aluminum head, you want a little more. I looked at the specs on the TO4 E. Originally because of the air flow I thought the wheel was larger but it appears smaller than a V trim and larger than an S trim. It does look like the T3 turbine would work OK but the problem is you've limited yourself at that performance level. No room to grow. With the T4 it gives you the ability to max out the physical strength of these engines. The P trim would be too large for a stock engine but, you're not stock with the aluminum head and with the right cam things should be fine with room to grow. Keep in mind I think the .69 is an on center turbine housing, if it is you want the tangential. They make a lot different sizes, just because your supplier doesn't show them, doesn't mean they're not available. They are more efficient - quicker spool, less back pressure. To help spool out with a larger turbine, run as large and efficient exhaust as you can. If you've been following Will and Kelly's progress, he picked up considerably after going to the V8 timing chain and a larger exhaust system. I'm sure the V8 chain didn't add a lot of horsepower, just made a lot of horsepower longer. What I'm trying to say is your application seems to be borderline, but with the T3 you have no room to grow.

I hope this makes sense.

I didn't know the .69 was an on center housing. I heard the tangential housings are about 5% more efficient. Do you know which housing A/R are tangential?

wallaka":4rxn6iru said:

I've looked in vain for equations and formulas. I think that the nature of how the hot side works, due to the vagaries of load, exhaust gas temp and volume, and the way they interact make it difficult to quantify in a simple way.

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It just amazes me that we have the tools to size the compressors down to the gnat's eyelash for any given application and we cannot seem to quantify the turbine selection process at all. The guys who do this stuff for a living have to have a procedure they go through, it cannot all be trial and error. If there's a procedure, then someone somewhere has committed it to paper and the expert system exists. We simply have to find it.

I think alot of it has to do with all the air moves through the compressor where the turbine is bleeding off excess massflow. combine that with the varying energy that can be in the exhaust and it makes it harder to pair.

XFlow_Fairlane":2vwkyeke said:

I think alot of it has to do with all the air moves through the compressor where the turbine is bleeding off excess massflow. combine that with the varying energy that can be in the exhaust and it makes it harder to pair.

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Only if the wastegate opens.
Presumably, the professional turbo shops size the turbine to not need the wastegate 99% of the time (except for the riceboys who like the sound of all that HP going to waste out their tailpipes :roll: ) so that all the mass flow is available to do useful work