Hey Guys,

I was wondering if anyone had any data comparing an open scroll T3 to and open scroll T4. I have seen data with the Twin scroll t4 to open scroll t3, but cant find anything on the open scroll T4..

I know back in the day RNR made a the same looking Ram Horn manifold for T4 and T3 open. I am assuming data then said to step up to T4 when you step up from like a 35r to a 40r...

I am particularly looking for 35r data going from t3 to t4 if anyone has any info. But any would be helpful...

Thanks,
Freddy

 

T3 and T4 is just the inlet flange for the exhaust hosuing it doesnt mean **** except if it will work with X manifold. Its the A/R that changes everything.

 

I don't see why you would want a t4 open scroll. Go with a t3 open or a t4 twin scroll, simple as that. This is a thread that could easily get out of hand. A t4 ts 1.06a/r is about the same size as a t3 .63a/r.

I would love to see the data you are referring to between the ts t4 and the open t3. I am not saying ts t4 doesn't work but I just want to see the same vehicle with both, which will probably never happen...

 

Different people have different opinions , mine is that the only justification for using a single entry T4 International flanged exhaust manifold is to merge large diameter runners . Large runners that can communicate with each other into a common collector will accentuate any reversion issues which your four cycle air pump (engine) won't thank you for .

To each their own , cheers A .

 

Found this thread on a different form.. very interesting..

http://www.dsmtuners.com/forums/turb...ivided-t3.html

"According to some information that I have read, and hearsay from the folks at PTE, a .68 t4 will flow a little more and spool a little better than a .82 t3 (both undivided). Other than that i'm sure your not going to get any great information out of this...."

"One of the guys from AMS said something pretty similar to that. I don't remember the exact details but I think they swapped a .82 T3 with a .68 T4 on a GT35R and picked up quite a bit of power and had a similar spool."

 

https://www.evolutionm.net/forums/ev...k-results.html

 

if you want to stop reversion you need twin scroll. end of story

 

That's awesome and it is from an unbiased shop. I can't believe I have never seen that thread and it is about a year old. Thanks, I am 80% sure that I want a TS set up for a hta86 when I finally get around to it. Thanks

 

freddy - in my experience i only run undivided T4 turbos on twinturbo V8s. I have yet to see an advantage of the T4 singlescroll vs T3 singlescroll.

here is a t4 singlescroll vs t4 twinscroll comparison on a subaru of T4 singlescroll vs T4 twinscroll spoolup/midrange -- at 5800ft elevation. This test was performed using the identical turbo, identical manifold, identical downpipe, wastegates, charge pipes, etc. The ONLY difference was the turbine housing was swapped from singlescroll to twinscroll, and the singlescroll was at 25PSI due to knock showing up on the singlescroll that was not on the twinscrolls

.88 a/r singlescroll housing
.91 a/r twinscroll housing
1.00 a/r twinscroll housing



the twinscroll .91 and 1.00 spool very similarly, with the .88 losing huge midrange power and much later spool. the top end power is very similar

agree

 

wow Geoff, 800rpm gain in spool is impressive. Let alone the jump in usable torque.
I've seen a couple of T3 TS housings, and they look very restrictive at the turbine entry (where the exhaust passage comes to an end).
Do you ever port these out?