LOL! Yeah it was suprising yet hilarious when the calipers opened that far.

I've pressure checked all IC tubing from the outlet of the turbo to the TB with no leaks anywhere.

No exhaust leaks

WG opens when I put another pressure source to it (air compressor)

Went through two boost controllers hooked up any way you can hook em up with no boost increase....just hits 9psi and stays there.

Now I really cant wait to see what you dyno or anyone else dynos gives me something to look foward to when I get it sorted out. Right now i'll have to focus getting us moved into our new home.

J

 

Now I can't wait to get mine

Glad to hear you got ths matter resolved

 

Hey Doc, I never doubted you a bit OK OK maybe I did a lil.

And I had a post about the 9psi problem about 4 months ago...nothing worked. Spent a lot of $$ trying to figure it out too

 

Nice to resolve part of the matter the other part is still unsolved

 

Well something is going on for sure. We have customers due to this post that have been calling to order these units making sure they get a 76mm....lol. Also we are working on something for these units to improve them even a little more and make more power.

As for your 9psi, don't know what the heck it could be. Somewhere their is a leak. Pressure test the turbo next....

 

Have you checked your BOV/bypass valve to make sure its holding closed at above 9 PSI applied pressure? Also you could connect a boost gauge directly to the compressor outlet fitting and check pressure leaving the compressor to find it for sure if its a leak post compressor outlet... Might also try disconnecting the exhaust at the downpipe.... If none of these nets you above 9 PSI something is not kosher somewhere in the unit or one of the valves. What BOV are you running?

 

Don't think the filter is choking it, short and direct with plenty of filter


And my crossover is pretty standard when it comes to truck manifolds


As for the customers, tell em to look on the edge of the compressor housing, they'll see the stamp "HP76" save em some worry and trouble.

I'll be able to dig into the engine next week. I'll go over the valve train, intake manifold etc as well as replace the cam to a more turbo friendly ZO6 cam.

 

Its a TiAL 50mm BOV. And it we checked it more than twice I still don't like the clamps they use to attach em though. I'm trying to locate some V bands that'll fit em.

We'll hook the boost gauge up to the compressor housing, easy enough to do, and frankly I don't know why we haven't tried it.

 

Good to hear you have to right turbo J. Now go find that missing boost and make some killer numbers.

 

Looking at that wastegate I probably would have mounted it differently but then again I can't see the exact placement from the one pic... Although to be honest I sincerely doubt thats the issue. In that position I would expect you to overboost. Certainly not have an issue with only making 9 PSI. Unless everything is welded you should be able to easily drop the exhaust after the downpipe to check for backpressure issues. And as for check the BOV, I don't know what your setup looks like but as a quick test to see if thats the issue you could replace the pipe with the BOV with one that has no opening. Basically run no BOV. I would only do this once though as you will surge the compressor extremely bad running like that but it would tell you if there is an issue with the BOV or mounting of it. I seem to remember saying you tried with the boost controller disconnected. Did you? If so what pressure rating spring is in the wategate? 9 PSI? It would be interesting if you want to lets say a 12 PSI and the boost went to 12 PSI. That tells you your boost controller is not working for sure...

 

Me too, just for the fact that I don't have to send it anywhere LOL.

Get yours dyno'ed yet?

 

Speaking of which what is your wastegate boost signal settings? I never saw what controller you were running. You should have one boost signal line going from the compressor outlet to the lower wastegate port. There should be another line going from the boost controller solenoid or valve outlet to the upper wastegate port. As for the boost controller going off experience from most boost controller assuming its an electronic unit there should be a source signal for the controller going from the charge pipe just before the throttle body to the in port on the solenoid. The output signal I already discussed. The signal for the main control unit usually comes from the intake manifold... This is all dependent on the type of controller used of course. Just something to check if you haven't already..

 

My filter is smaller than yours and your truck kit looks just like mine.I make 14psi fine and the wastegate is def stopping it from some high boost.Do you still have the big cam in there??My friend just swapped out his big split cam with a 224 cam I have in mine and he had to turn his boost down because the new cam raised it about 3psi.That was my initial guess back when I saw your old GT-42 like mine was making boost alot later than mine.Im sure youve checked this as long as youve had the prolem.

 

Right now its a Hallman Pro MBC. The compressor boost ref goes to the side lower port on my TiAL 44mm WG with the top port vented. Hooked it up the way Hallmans instructions said too. Also hooked it up to the top port to with the side port vented.

I've also ran a boost ref from behind the TB, no difference...


Super, yeah the ol STG 3 blower grind is still in there. But the GT42 had no problem making 12-15psi at all and the WG was always loud and clear at WOT It just spooled a tad slow...especially compared to this turbo
The ZO6 cam will be going in very soon.

 

No. I keep changing my mind on the shop cars setup . I am going to stick with the 6.0L manifolds and a T4 flange for now but thats about all I have set in stone. I will more than likley do a 100% stainless setup with the turbo located where I can swap out differnt units easily. The production kit should fit a PT88 which I am going to try . I am still Jonesing for a 91.5mm... Maybe later down the road.

One thing is for sure. I am going to run the TC76MPS turbo on the car first to get some verfiable dyno numbers for everyone. I hope to have the car done soon. Probably be a few weeks. Work at the plant has been killing me with OT latley. I still have to get everything esle finished on the car and then cut the core support out and box it to make room for the BIG ONE.

It never ends with me.

 

Block the gate and see what happens with boost. Just monitor the boost pressure and let off when boost goes beyond the dreaded 9psi. That will rule out the exhaust side.

 

but i'm skeered to do that LOL... Guess i'll have to Anyone have block off plates made or do I have to fab it up?

 

you can get them from atp.

 

It never ends for any of us that are infected with Forced Inductionitis....its a disease worse than any drug addiction.

Me on this one car, i've been through 2 blower set ups, 2 turbo kits, and 3 different turbo's...with the 3 turbo's all in one year. GT42, MPT70, TC76MPS



Abeasst, huh?? Jer clicks on his ATP bookmark

 

I'm not too familiar with manual boost controllers. I never used them as the electronic boost controllers always exhibited better boost threshold and better response overall from the turbocharger. Something you said sounds fishy though...the lower port on the wastegate basically forces the valve to open using the pressure source from the compressor to act against the spring in the wastegate. With a 9 PSI spring installed the pressure from the compressor outlet going into the lower port would eventually overcome the spring tension and open the gate to keep 9 PSI compressor outlet. The top port is the one that holds the gate closed. Since I'm not too familiar with the manual setup I'll say that with an electronic controller the boost pressure reference from the charge pipe is fed into the top port. This has the function of increasing the spring rate in the wastegate to make the valve stay closed past 9 PSI. Once the boost controller main control unit sees the boost pressure you set it immediately removes the added pressure to the top port of the wastegate and the valve slams open to vent exhaust gas. Because the electronic units has processors and typically (for good ones) dual solenoids or stepper motors they control boost better then any MBC or wastegate alone can. My apologies if you already know all this. I looked at Hallmans instructions online and it does say to run compressor outlet to Hallman to the lower wastegate port. I'm not sure exactly how that is going to increase boost but I suppose it works for someone. Do you know what pressure rating spring is in the wastgate? Just wondering if the controller is doing anything.