Given the same overall cfm, the smaller T04B should be producing more torque sooner than the T04E, correct? Or does the increased efficiency of the T04E counteract the heavier mass? Both being used on a P-Trim turbine wheel open tang .84 AR turbine.

Let's compare a T04B V-trim and T04E 50 trim. Does a compressor map give any hints to how responsive a turbo is?

 

i believe the response has more to do with the exhaust side. the main difference i see in those two plots is the surge line is better on the T04E.

 

I noticed a pretty significant change in turbo spool characteristics just going from a V-Trim to an H-Trim T04B.

 

More thinking out loud.

Larger compressor wheels move more air at the same shaft speed as a smaller one, would this make sense to be producing more torque sooner? (as long as it doesn't surge, that is)

 

Larger compressor wheels move more air at the same shaft speed as a smaller one, would this make sense to be producing more torque sooner? (as long as it doesn't surge, that is)

Yes, it can if there is enough exhaust energy to get the larger diameter compressor up to the same shaft speed. Which is definitely possible.

In an OEM like application where you have to have catalytic converters and mufflers decreasing exhaust flow and exhaust wheel pressure differential the lower drag smaller compressor will produce more torque as it will achieve a higher shaft speed sooner.

I would definitely go with the broader map of the T04E as it does have this surge line further to the Left and it is proven to be a great spooling 350rwhp turbo for the 13B.

To get the shaft speed up quickly go with the largest, most free flowing post turbo exhaust you can and short straight inlet with velocity stack and the largest diesel filter you can find/fit- while isolating the intake from heat.

My data logging showed there are real gains in boost response going over the common 3" exhaust size and the same with going with a 3" to 6" velocity stack/filter over the common 3" pipe to filter.

One of the most incredible highest torque single turbo dyno chart I have seen was a 60-1 S4 TII based stock hybrid turbo (stock exhaust side) with custom divided exhaust manifold/external wastegate and 4" exhaust. Around 400rwhp. I wish I would have saved the pictures and dyno chart.

You can also do pre turbo high pressure water injection to help spool the turbo through denser air charge.

Keep the exhaust manifold runners small for good velocity. Avoid non divided log manifolds even if you must go with undivided turbo.

I would rather have a S5 TII based stock hybrid turbo/manifold than non divided full T04 turbo/manifold if great spool and ~350rwhp was my goal.

If you want full T04, you could use the FD HKS divided manifold (~$500 new), though you might have to space it away from the lower intake manifold with the larger T04E on an FC- not sure on this.

 

I tried the stock hotside thing. One of the issues being shaft speed/compressor surge. Clipping has to be done to skirt under the surge line when running the T04B wheels, which pushes the further band further to the right.

The T04B V-trim was a decent combination with the stock turbine wheel and a mild clip(similar to a BNR Stage 2), H-trim coming into boost much later(still not sure exactly why...)

Then moved onto the same H-trim compressor with a "clipped" P-trim turbine and full T4 which actually brought the spool back down to a more manageable level, now i'm looking for just a little more...This turbo was put together with spare parts I had laying around just to see how they would work together, so it wasn't the most ideal setup.

I would love to run a full divided setup, however cost is the limiting factor here. I do have a full 3" exhaust, and will be using an unclipped p-trim turbine in the future.

So I will be looking at moving up to the T04E, the parts are pretty cheap...just wanted to justify the change and hope it works in my favor.

 

Has anyone here used a TA34 turbine wheel matched to a V or H trim wheel? A member here on this board swore by its potential but I ran out of money building my hybrid before I got to attempt it.

 

i had a t04b v-trim on a .81 collected turbine housing (p-trim turbine wheel) and it was a great little turbo.

it made 360whp@16psi when i had a bigger turbine housing on it, and the owner after i sold it made 350whp at the same boost with great response

these turbos are cheap too. i got mine for 400$ used and spent 160 on a housing and had a great little turbo (this was on an s5 TII btw).

if i did it all over again today on a budget i'd go with a t04e 60 trim .84 divided with a big wastegate (if you're on stock ports). with ported exhaust i'd go with a .96 and possibly dual wastegates.

 

i run this with U trim ( U= 54.15 mm..V = 55.4 mm ) in a knighty cover .. have a couple out there built into standard covers too

it is intended to be a RF320 knighty equiv
( also a similar compressor and changed turbine wheel with less backpressure to stock and reverse thread nut )

as such will never be a 350 rwhp hiflow .. those highflows that get there do so on dodgy dynos and require 360 bearing mods to stop from thrusting out the thrust bearing .. and undoing the nut ( if not reverse threaded )

the ta34 turbine wheel is a much better balanced choice in terms of flow potential of compressor vs that in the turbine
the turbine wheel is also less shrouded, less mass = wins back in spool what it lost in turbine blade profile down low

the result is a much more balanced turbo .. it is still t3/t4 hybrid,, not t4/t4 ( the O and P trim turbine options )
so spools much earlier than these two heavy turbines

expect 300- 320 rwhp.. total backpressure depending .. but with stock like spool and meaty midrange