5 Liter Eater

Good call Ben, but no they don't have that typical port you're talking about. The boss is there but it's not drilled. I could drill and tap the boss though.

schpenxel

tap dat boss

Dude_man

Your IAT's seemed normal so I dont really see that as much as a restriction. Typically if it is the IAT's will go up pretty high.

Turbo-Geist

boss is synonymous with

Turbo-Geist

Here's the overlay of a typical T3 flange on a T4 flange. The T4 is red and the T3 is represented in blue. I wish someone would provide the dimensions of the opening for the adapter flange that is welded directly to the up - pipe.

5 Liter Eater

Hmm, I don't see a problem there. At least when running a T3 frame.

inspector12

Yeah I know I've been on you to move to the T4 flange. But this is the prime time to do it, before I welded on a T3 flange.

Dude_man

I'm team inspector on this

Turbo-Geist

Yeah, unless the adapter plate is somewhat smaller than a T3 to account for bolt hole placement and universal sizes.

I just don't see the point of a T3 housing or .6x A/R at this power goal. Is there a T4 turbine housing available? Also, it would be nice to know the turbine wheel size to see if it is capable of driving the compressor wheel to where it needs to go.

SBCGENII

Prescion 65mm t3 .68 Ar vs 65mm t4 .96 flow difference got to be huge if you are having a BP problem.

Louis Gigliotti

Bill doesn't like facts. Or PTE parts. Or going fast. Lol. He probably has a t25 .49 housing on the way cause it's in the head flow waste gate routing.

SBCGENII

I hope some facts do come out in this thread. There will be no guessing as far as the turbos go now that he is getting some gauges setup.

C6 Curtis

Lmfao...... Haha I ran a T6 1.58 S480 on my LS7 BP was def in check.

-Curtis

Dude_man

You're my new favorite person haha

5 Liter Eater

Anyhoo, tried the other bung tonight. For the record, five year old Harbor Freight epoxy isn't cut out for this duty. Melted as well. Still, I think I got some decent data. Did three pulls on SP3 (18.5#). Two with the cutouts open and one with them closed. Didn't seem to make a difference. Whats weird, well to me it's weird but I haven't measured backpressure before, is that on second gear pulls it would spike to 50#. On 3rd gear pulls it was pretty steady at ~42#. I think this is where the 30# VS: 37# difference came from last night. So I think it's more like 2.2-2.3:1. Moving to post turbo testing next. Then IC backpressure.

harveyjl

2.2:1 on 18lbs is pretty bad IMO..... Change the cam that will help with your back pressure issue. I run t3's and my back pressure isn't that bad. I could be wrong but that just what I think

Louis Gigliotti

Camshaft has little effect on Backpressure. The turbine has all to do with Backpressure.



I'm breaking your *****, because you're trying so hard, but stuck with so many unknowns. Probably doing more testing than UPP.

Your 2nd gear spike is likely due to the waste gate vs engine accel relationship. The gate doesn't open much in 2nd gear, but the engine is still moving the volume.

This is a simple turbine/turbine wheel/turbo mismatch. Opening and closing the cutouts not affecting the Backpressure tells you the banana in the tail pipe is the turbo itself. Not the mufflers or midsection.

inspector12

Yeah a Cam change could help manage it, but that seems to be masking the problem, when he could just put a housing on that will flow more and be better suited to the setup with 422CI etc...

C6 Curtis

That is still awful, you really need to run a bigger turbine housing and let her breathe. You're punishing your motor. Go run a lap around the track and breathe through a straw once your done. It won't be very fun. Get new housings or strap a real turbo on there. PTE, Borg or Garrett with the correct a/r and foot print and be done.

-Curtis

Jason913

Where's CK? Turbo defense.