Project: Mavro Gato - 99 Turbo'd 3L

[warmonger]

Originally Posted by FastCougar

I really don't have a target date set in stone since it's going to be a one-off system (no A/C). I figure about roughly 4-6 weeks.

My driver's side half-shaft is shot and needs replacing ... I tore the boot on install and it's click and snapping like crazy at low speed turns and stops. Once I replace that, I will begin finishing up the turbo kit.

Well I guess I was wrong about the HP an torque, overoptimistic. lol
I was right last night when I talked about your airflow numbers due to those monster-cut heads though! Low compression and low restriction ought to work pretty good as long as you can spool that turbo reasonably quick. I can imagine this thing putting down 450-475wHP on the dyno with 15psi boost.

[FastCougar]

Here are the plots. The runs where done in 4th gear from about 30 MPH all the way through 135 MPH. It's painfully obvious that the cams can't do their job due to the turbo cut in the heads being too open. Once we retest with the turbo on, expect that torque curve to raise all the way through redline

Run 1



Run 2



Run 3



AFR from Run 3 ... note it's running along fine until about 4K RPM and then the sensor went haywire. The sensor errored out on the previous 2 runs. Looks like they need to replace it.

[FastCougar]

Tom was asking about what turbo I plan on running. About 6 months ago, I picked up this Precision Turbo SC61 ... good for 650+ HP and relatively quick spooling. It has a .60 intake A/R and a .63 exhaust A/R.

[warmonger]

Well that ought to work pretty darn good, a .68 exh ought to be pretty good for midrange spool but it is still a big turbo so it won't work miracles.
So you ought to be more or less limited by your exhaust flow through the turbine rather than the compressor side. Make sure to use at least a 38mm wastegate if not a larger race-gate.

[FastCougar]

I have a Tial 38mm wastegate and Tial 50mm BOV ... like I said, I have EVERYTHING I need to complete the system, I just need to find the time to do so

Originally Posted by warmonger

Well that ought to work pretty darn good, a .68 exh ought to be pretty good for midrange spool but it is still a big turbo so it won't work miracles.
So you ought to be more or less limited by your exhaust flow through the turbine rather than the compressor side. Make sure to use at least a 38mm wastegate if not a larger race-gate.

[warmonger]

Well I bet I could round up a set of hot pipes and high flow FMIC........
lol

[FastCougar]

Well, I didn't get to work on the turbo kit as much as I would have liked this weekend, but I will keep at it this week in the evenings ... I should be able to finish it next weekend ... two weeks from now for sure. Here is today's progress:

tacked up the Y-pipe/Up-pipe assembly and ensured fitment



A closeup of how I marked the pipes for fitment and then tacked them in 4 spots



The finished product fully seem welded



I'm going to have to get creative with the downpipe routing and/or rebend my up-pipe.

[FastCougar]

I just realized that I never posted my Y-Pipe/turbine inlet flange fabrication pictures in this thread ... at least I don't think that I did. Let's start with the turbine inlet flange:



With some help from the bench vise and a 5 lbs. sledge hammer, I managed to get the "rough" shape below. BTW, this is 2.5" 304ss 16 gauge tubing



Close, but barely not large enough.



So, you need to massage the metal into place, like this.



Since I don't have an Oxy/Accet. setup to heat the tubing for swedging, I used MAPP gas.



What you do is center the tubing on the flange and then tack weld it into place REALLY good on both the inside and outside on the "long" edges. You then heat the crap out of it with the MAPP gas until it's cherry red. Then you beat the crap out of it with the 5 lbs. sledge and in my case, a 3/8 ratched extension.







When it all done (like above), you start to weld the outside of the flange.

[FastCougar]

Now the Y-Pipe fabrication. These are 2" pipes at a 15 degree bend. They are cut to fit, then welded and then the end is roughly 2.5", but not quite. So, you have to do some more swedging. I ended up using the ball end of the stock exhaust manifold to swedge the shape out that I desired.

[FastCougar]

Originally Posted by warmonger

Well that ought to work pretty darn good, a .68 exh ought to be pretty good for midrange spool but it is still a big turbo so it won't work miracles.
So you ought to be more or less limited by your exhaust flow through the turbine rather than the compressor side. Make sure to use at least a 38mm wastegate if not a larger race-gate.

I double checked today ... I was wrong ... the exhaust A/R is .63, NOT .68