Depape

hey guys,
im getting my hands on a hybrid t3/t4 turbo for pretty much free! (The exhaust housing is a .67 and the compressor is a .50, not sure if that'll fit... so my dreams might be crushed right there, could i make it work?? ) would it be worth the money to switch? i have a k26/8 now, what will be the major differences.

I have been looking at old post's and couldnt really find a direct comparison between the k26/8 and a t3/t4 hybrid turbo.
(I Know that I am going to have to invest in a MAF and piggyback system)

so question: is it worth it? (street DD, and some track days)
-Pieter


-Current engine mods: LR 4in graduated exhaust w/ cat delete. Tial 38mm wg, 3 bar fpr, Welt. chips, mbc, boost gauge, a/f gauge, new vac. lines.... and some more that I cant think of off the top of my head...

I appreciate the help!

Depape

anyone?

NZ951

A few points... firstly, I doubt its turbine housing is .67, more likely .63. There are hundreds of different T3/T4 configurations, literally. Saying T3/T4 isnt enough to make a fair comparison. Personally, I think the full garrett turbo is a lot better, I achieved a MUCH better torque curve just by changing from a #8 Turbonetics replica housing to a full garrett .63.

Jfrahm

Does anyone know the cost of converting a T04/T3 to a T4/Replica #8? I have a T04b/T3 I was thinking of converting. At one point I thought about changing the downpipe flange to use the T3 hotside, but the up pipe would need to be converted also and this turbo has a divided housing so it's probably not a good fit. I think there are also some issues with the center section, oil pressure (which some solve with a restrictor) but I think there might be issues with the support for the gasket as the ports on the turbo mount do not match perfectly?
-Joel.

Driftomagnifico

You'd need to change the header collector to a T3 flange, and the downpipe would have to be re-fabricated to whatever your T3/T4 turbo has (they come in a billion different styles of bolt patterns).

I would advise going with a Precision SC50, or the Garrett GT Series if you can pony up the funds. The wheel design on the Garrett T3's and T4's are a bit outdated. Besides a GT3071R would take names on a 951.

Forgot to add, the T3/T4's are oil cooled only so you'd have to figure out what to do with the lines as well. It's oil return more than likely won't fit the OEM stuff so you'd have to fabricate something that works with the engine mount mounted drain.

Cory9584

how about a t4 hotside? would a t4 sit on the mount at the same height? In other words would the pipes have to be shortened or just the flanges changed? I have a spare x-over and im thinking of doing this and buying a full t4

Rob

The replica #8 hotsides run ~190ish IIRC and I'm fairly certain it will just bolt on in place of the T3 hotside.

Depape

no i just double checked and it is a .67. (at least that is what the current owner is telling me, it is off of a xr4ti Merkur )

soo, i could do a T4/#8 conversion??? less work? how much of an improvment will it be?

thanks,
-Pieter

special tool

You need to do a LOT of investgation on this before you even think about buying anything.
The turbocharger will determine the basic characteristic of the whole engine - its the most important thing.
Do a search of the archives, just for starters.

Driftomagnifico

T4 has so much volume that it isn't suited very well for 4-cyl engines; it's generally a drag race application or dyno queen application. It would probably work decently on a 3.0+L engine.

You also need to match the specific housing to the wheel. This is in terms of flow design but also actual physical fitment. If there is too much of a gap between the turbine and the housing you will have horrible boost response.

If you have a spare X-over then just make a twin scroll T3 setup. It will boost the midrange which is where the 951 makes it's power anyways. You'd probably see little benefit in the T4 on a stock-ish or even built 2.5L engine being that it's exhaust volume is relatively small.

Depape

ok, its a no go ... just not worth the time and dosnt look to be to practical.
thanks alot guys

Porschefile

Excellent advise! Things like a turbocharger and cam(s) are some of the most important parts of a setup, and really need to be well matched for your intended purpose. Plenty of off the shelf stuff will work, however if you don't fully understand how to determine what off the shelf components will work well together to meet your goals, you can end up with an inefficient setup that isn't much fun. It doesn't take rocket science to figure this stuff out but, I wouldn't just buy random turbos or something like an off the shelf cam without understanding how your car will react to those components. You might save a few bucks but, you could end up with a poorly matched setup like a cam intended for a 4-7k powerband, but a turbo that makes full boost at 2.8k rpm and is running out of steam by 5k rpm.

IMO, personally I feel that the first question to ask yourself is what your intended power level is. Be realistic with yourself in answering that question. Lots of people talk about wanting much more power than they truly want or have the patience, financial capability, or driving ability to support. Second, determine what budget you have to work with. Then, go from there and check out other's dyno charts and start to get a feel for what it's going to take to meet those goals. There are plenty of "bolt-on" turbos for these cars and dynos that have been posted in the past.


I agree with Drifto. A T4 hotside is pretty ridiculous on a 4 cylinder for anything except high horsepower stuff (like 600+whp). It's just too big for what most people are looking for, and would cause a lot of unnecessary lag.