Need to discuss my Turbo Situation. Step In

[RED LS1]

Here's my deal.

'87 GN. Bottom end will be built shortly with Forged pistons and Roller 212 Comp cam with Morell lifters. I already have Champion CNC Irons and matching Champion CNC intake. I have an Accufab 70mm TB and 70mm Plenum. The fuel system is Aeromotive A-1000 Pump and braided fuel lines with 83lbs injectors. It has the 3 inch down pipe, 4 inch inlet, 3200 stall Billet converter and built 200 trans. It's tuned with an XFI.

I currently have a Turbonetics CPT-66 and the small of the trims (P-trim I think). It's an older turbo maybe '07-09? It's actually the second one I have had. My last car had the same turbo.

Now, I have an idea of what these turbos are good for which I believe high 10's at 20 psi and maybe .60's or so at 25 psi?

I want to know what i'm leaving on the table with this turbo. I know there are so many better options but I just don't know what or really why? I know Precision offers a ton of turbo's for these cars but How do I know what's a better suited turbo for my combo. I wouldn't mind spending some good money to bolt on a replacement turbo that could make it a low 10 car at 25 psi. Can I leave the 60's and go into the 70's with turbo sizing? The car also has an external 46mm T-netics Wastegate as well.

I know goals will be a big factor. I will probably run a conservative tune at 18-20 psi this early spring. Once the car is all back together and in good health and sorted out i'm putting the Alky kit on and going to town. I'll run 25-26 psi or who knows. Maybe i'll turn it up further if everything is staying together well.

So where is the money well spent on a turbo these days?

 

[bison]

With what you have and normal converter coupling you should be mid 10's with the current turbo at 25psi. The one with the large comp cover works a lot better with that crappy compressor wheel though. One thing for sure is you don't need a larger turbo. Just a better match of wheels will do a lot for you. Typically with backpressure to intake pressure at 1.4:1 or better you will need 25psi to run low 10's with the small cam and heads. I was able to run low 10's (best of 10.13) with boost in the mid 20's using that turbo but it struggled to support the demands of the engine with boost spiking to 27-28psi then dropping a lot over 5500rpm down below 25psi. I did have the large compressor cover too. The small cover with 6 bolts really kills that compressor and drives up backpressure and will net less. Low 10's like 10 teens in 93/alky is not typical with what you have without really nailing down the tune and gearing regardless of what turbo is used.


BPE2013@hotmail.com

 

[RED LS1]

That's helpful. What I gather from your post is that i'm leaving efficiency on the table right now with the current compressor wheel. I remember a few years back I called T-netics and was told these turbo's are outdated and now they use an F1 wheel. They seemed like they didn't have any options for this turbo and it was the best it will be.

Cotton's site show a crap load of high dollar modern Turbo's. It's tough to look at that and not think that there's a bigger and better turbo that will contribute to more E.T and MPH over the one I have (even with the better wheel.) I remember in the late 90's the TA or TE 70 was the big turbo to have. Guys were running in the 10's back then. Do I not have enough Bottom end to push a bigger turbo? I have no problem putting race gas in the car either. In fact, there's a good chance it will run on at least 100 most of the time and maybe 112 or 116 with intentions of turning it up. I honestly am not chasing a number. I really would not like to exceed 25-26 psi but i'd like to go as fast as I can with that amount of boost.

 

[Reggie West]

Have a look at Comp Turbo. They can match the right compressor and housing. You can go to a dual or triple ball bearing cartridge as well That will help too. . if it were me I would get the alky system running with it right now in tune with that.
The tuning is way different with pump gas and alcohol as opposed to straight race gas.

A higher stall speed on the converter might be needed to get the car to 60 foot better.
You have the right parts to get it done.

 

[RED LS1]

Funny thing is, I just tightened the converter up a bit. With the current combo it was going 3200 at 1 psi and about 3400 at 5 psi. After releasing the brakes it would push right through it. While the motor is out I cut the converter and put a tighter stator in it.

 

[bison]

F1 is the turbonetics turbine design. If it's 2009 it has the f1. The f1 65 flows slightly more than a standard p trim. The hot side isn't what is restricting. It's the crappy compressor in a too small comp cover that choke flows. I've updated a couple of those antiquated t-netics 66 to either the garrett tv45 or my own MFS 67 compressor. Both work ok in the smaller housing but really want the large t76 style comp cover or the Holset style with the 3" outlet. Here is the cheapest upgraded compressor that will flow the most per $ spent with that turbine.

The 65f1 turbine would be ok with this compressor but it really wants this:

The smaller comp covers will choke flow the compressor wheel over 70lbs/min but it's still possible to achieve almost 80lbs/min with them. In the larger covers this wheel combo will hit 85lbs/min and it will work at higher pressure ratios as well. It's not worth doing an expensive point milled compressor in the small covers because they will choke flow before the compressor is done. This compressor with your turbine will support about another 100hp compared to the old cast 66. Notice I said support. Not make 100hp more. Turbos support mass flow. They don't make power. These have done 900whp on a supra at 7500rpm.


BPE2013@hotmail.com

 

[tonka]

Is this potential flow obtained with the existing exhaust housing?

 

[RED LS1]

I called Precision last night. I was curious to see if they could land me on a nice fit for my car. It's pretty safe to say that the guy I spoke with doesn't even know what a Turbo Regal is and could have possibly just started working there yesterday. I got a bunch of ummms, and eeehhhhhs, and was put on hold about 3 times for 3 minutes a piece. He said they have two options which I forget the number (62/64 & 64/64 or something). I was pretty turned off by that point and the explanations of why one would be better than the other were pretty laughable so I had to abort the call fast as possible.

Maybe upgrading the one I have is a good option which seems to be what i'm being told by Bison. Mine does not have an F1 wheel which I know for a fact. So it must have been pre 2009.

 

[Mr.Spool]

after you get the car back together why not run the compressor out on the 66p?there definatetly is a gain with the billet comp wheels size for size but you would need to raise boost or have a killer set of heads on the car to see more power at lower boost ranges.the 66p when pushed might surprise you and friend of mine runs a 66pbb on a stroker motor car and it goes good.if your goal is 10s its the right turbo if you want 9's there are better options inmo.

 

[REAPER231]

I called Precision last night. I was curious to see if they could land me on a nice fit for my car. It's pretty safe to say that the guy I spoke with doesn't even know what a Turbo Regal is and could have possibly just started working there yesterday. I got a bunch of ummms, and eeehhhhhs, and was put on hold about 3 times for 3 minutes a piece. He said they have two options which I forget the number (62/64 & 64/64 or something). I was pretty turned off by that point and the explanations of why one would be better than the other were pretty laughable so I had to abort the call fast as possible.

Maybe upgrading the one I have is a good option which seems to be what i'm being told by Bison. Mine does not have an F1 wheel which I know for a fact. So it must have been pre 2009.

Bison can set u up with what you need he's top notch . He's finishin my buddy's car up at his shop . Does great work man .