gt35/t4 for m106 ?

[marc79euro645]

I want more from my m106. My current 745 setup runs good, and seems to be solid.
I'm using MS2,
60# injectors from TCD
manual boost controller with m102(early) waste gate (cranked shut)
3" exhaust
I could do the kkk27 upgrade, but I'm tempted by the prices of the cheap ebay turbos.
I'm looking at this one
https://www.ebay.com/itm/Universal-Perf ... Sw92RbH3zo
My goal would be 400 hp/400tq at wheels.
I would be notching the t4 bolt holes to bolt to the 745 manifold. I also will do some porting on the manifold.

What do you think of the t4 a/r of .82 for street driving?

[marc79euro645]

Well, I ordered an .68 t4, gt35 ebay turbo. This one has a 66mm inducer on the compressor, so it's a little big. I hope the .68 turbine housing will get it spooling. Turbine wheel is 74/64mm, which is close to my kkk27 at 76/64, so hopefully the turbine won't be a choke point. I'll report back once I get it installed.

[euroshark90]

That should be a great fit. Im running a 6262 turbo with a .82 t3 exhaust housing. Boost comes in around 2400, I kinda wanted the 66 wheel Anyway. I think you made the right choice

[marc79euro645]

thanks for the feedback! I'll report back once it's installed.

[Tiit]

Following

[marc79euro645]

I'm making progress. I mounted the turbo and manifold today. It looks like it's going to work. I'm going to need a longer drain hose, so that stopped me from final mounting. I had to remove the top rear motor mount bolt to clear the larger compressor housing. That still leaves 3 bolts to block.
I hope to get the exhaust done this week.
I can't wait to see how it works!

[marc79euro645]

I'm so disappointed! I got the exhaust hooked up today, couldn't wait to try it. I'm only getting 5# of boost, and that didn't happen until I wound it out.
I've double checked all charge piping and everything is tight. Recirc BOV is working properly. I'm wondering if wastegate might be stuck open (unlikely).
Is the t4 .68a/r to big? I expected a little more lag possibly, but this is extreme.

[demetk]

Bummer. I was so interested. Is there any way to test a turbo before installing it? Like maybe using a shop vac's blower?

[marc79euro645]

good idea! I did actually use a leaf blower to spin up the t4, just to feel for vibration. It spins nicely, just not fast enough apparently. I'm not giving up. I just pissed away $255.00 on the wrong turbo, lesson learned. I've now ordered an ebay gt35 with 63mm compressor,t3 @.63. I'll report back when I get it installed.

[demetk]

Did you test the wastegate theory by blocking the port?

[marc79euro645]

I'm not able to block the port easily, but I did check it ,and I don't think that's the issue. I think it's just too big. I'm really surprised at just how bad the lag is, but hopefully the t3 will spool, we'll see.

[marc79euro645]

I got the new turbo. I'm going to have to rework the oil feed line, that's a minor delay. I decided to start disassembling the charge pipes and found a loose clamp. I thought I had checked, and rechecked the connections, but, I missed one. So, out for a test ride. Wow, big difference! It's still too laggy, not boosting until 4k, but, it pulls all the way to 6.5k like a big block. Before, it would only pull to 5.5k , no farther. I saw 12# boost.
I'm glad I already bought the t3/ .63 turbo, I can tell just looking at the difference in turbine housing size, this is going to spool. I not sure what was choking the upper rpm before, the 48mm inducer, or the small manifold outlet (now ported larger). I'm loving, hearing the motor go to 6.5k. I'm hoping the t3 will clamp up well. The t4 seems to clamp with no exhaust leak. I'll report back when the t3 is on.

[demetk]

Cool. Link to the t3?

[marc79euro645]

I don't see it listed on ebay right now. It was from jackspania, cost $400, has a 63mm billet compressor, t3 .63 a/r, v band.

[marc79euro645]

Well, I've got the t3 installed and I'm happy with the results! It was a pita to rework the oil lines, and I must have reclocked it a dozen times. The car now builds boost from 2400rpm, 2000 if I'm on a hill. I'm going to have to revisit my tune. With the t4, I was amazed at the topend power, and reving to 6500. The t3 goes pig rich on top which may have been the problem with the kkk. Overall I'm happy, and I picked up power, but in truth I'm a little disappointed. I was hoping for more. Next project is rebuilding my unlimited slip sideloader diff. Any advice is welcome on the diff. I'm thinking I'd like to add a shim to get better lockup.