bman22

So, I've talked to the guy at VSRacing, and sent him a video of the shaft play, which he says seems normal. Gotta say, they're going way above and beyond trying to help. I've sent him my tune and logs, pictures of the setup, and run a few checks for him, and he's right there trying to figure it out. Says if we cannot find anything else, he's willing to check out the turbo for me.

I did not run an oil restrictor. Has a -4AN from the oil cooler port, and a -12AN drain back to the pan.

I did run a pressure test on the cold side as part of the checks for the guy at VS, and it took 20psi without leaking. Popped the ghetto rig I made to put pressure into the front of the turbo off at 20, but nothing else was leaking before it did. I still think I'm gonna try running the turbo straight to the intake and bypass the intercooler, see what happens.

Here are the wheels.



Sorry the exhaust side is a crappy photo. Didn't have much room to get the exhaust away from the turbo.

truckdoug

iTrader: (25)

yeah nothing weird there. side to side is p normal for journal bearing turbos...its when you get the ol in n out you know youve fucked up

viren is a stand up dude. if its bad he'll sort it out.

I guess yeah my next step would be bypassing the IC, maybe checking the gate opens with shop air and doesnt hang open or anything

Game ova

Money is on the bearing. Hard to imagine that the tune is so bad that it won't rev past 4k.

truckdoug

iTrader: (25)

where are you feeding oil from? pull the hose off the turbo and route it into the valve cover filler hole and fire it up just for a sec.


my experience with box stock big turbine s475 is they really don't start spooling until 3000 and theres a good engine load. YMMV of course...cam, converter etc..

JoeNova

The fact that it loses power when you hook the charge pipes up is your main clue.

Add the charge pipes in one piece at a time.
Throttle body coupler plus first piece of piping, check MAP sensor readings during a pull. If everything is okay, add more pieces in.
I suspect you'll find the issue when you hook up the intercooler to the end of the intake piping.
If you don't notice the loss in power until you make it all of the way to the turbo, make sure its getting oil through the feed line and that its spinning at idle.
Don't run a filter on it the compressor inlet.

Oh, and shove that intercooler pipe much farther up into the throttle body elbow if its sucking shut. There's a good change that collapsed coupler is your problem as well.
Don't use the cheap ebay plain silicone ones. Try to find a good 4 or 5 ply that isn't so flexible. You'll need to REALLY get a good clamp onto the throttle body though with a thicker coupler.

lower_the_dynamite

iTrader: (22)

I had a similar issue with my 68 Rambler 4.8/s475/80e and it ended up being too small/cheap inter-cooler. This is a copy/paste from the SM Public page late last year." PSA on SMALL e-bay intercoolers, Bought the smallest intercooler & piping kit I could fit in a 68 rambler. Its a 28"x7"x3" with 2.5" inlet/outlet. 4.8/80e/BWs475 with 2.5" piping. Ever since we built the car, it never made boost in 1st gear even with all 3 springs in the 44mm gate. Once it shifted into 2nd gear, it would jump to 4lbs. We did multiple boost checks with air and smoke and could not find anything wrong. I changed everything around the cold side and couldn't fix the issue. Finally took the front end apart and swapped the intercooler with a piece of 2.5" pipe and it makes boost everywhere. Never though a intercooler this size would completely choke out a combo like this. Trying a 28"x9"3" next and hope it will fix the issue"

bman22

I was going to try it because I was beginning to get suspicious of the intercooler, but this kinda reassured me that it might actually be the issue. I swapped a straight 2.5" tube in place of the intercooler and this thing is running like a bat outta hell. Only on about 4-6psi is all I'm seeing from the log, but it's a complete monster as is.

I really appreciate all the suggestions guys. Learned a few things from it.

lower_the_dynamite

iTrader: (22)

Good deal! It took me 2 months to finally do that mainly cause it was a PITA to swap. If you are limited for space, try searching Ebay for the following. I used this and it worked well. If not, get the biggest intercooler you can ad go from there.

"28x9x2.5 2.5" Inlet & Outlet Universal Bar&Plate Front Mount Turbo Intercooler"

truckdoug

iTrader: (25)

damn that is crazy that intercool was that much of a restriction!

3 window

iTrader: (1)