Compound air ratio and gate questions

[HobbyStock62]

So I am pretty set on a fmw 62 and s475 or 8. How do you decide what air ratios will work good together? And what turbines, flanges...things like that. Divided up pipes or not? Looking for quick spool and street manors.
What external gate is everyone using and where would the best place be to stick it? And how the heck do you set up a gate?

 

[NRHX2009]

To start, turbine flow is key. I would do a 62/68/91 or 62/73/91 with an S475/88/1.10 or 1.32 depending on injector size.

I would put a single 46-50mm gate in your up pipes as well. That way you can get quick spool with a smaller turbine wheel/housing, and bypass the excess bp once the LP charger is lit.

 

[windrunner408]

Turbine flow and both chargers operating at similar pressure ratios is what is key to getting the most "efficient" operation out of a given setup...

 

[Redneck6.0L]

Have u ever driven a 63 73 .91 thats a nasty laggy turbo. The whole point if twins is so u can have really fast spool up and gate around it and let the big one take over in the top end

 

[O2ShootTheJ]

all this compound talk is making me want compounds...

 

[ODAWG714]

all this compound talk is making me want compounds...

Do it!!!!:toast:

 

[onebadcoastie]

So I am pretty set on a fmw 62 and s475 or 8. How do you decide what air ratios will work good together? And what turbines, flanges...things like that. Divided up pipes or not? Looking for quick spool and street manors.
What external gate is everyone using and where would the best place be to stick it? And how the heck do you set up a gate?

I'm in for this as well. Kubik has my 62fmw and is currently working on the pipes and I went with the same turbine that James mentioned earlier. I'm also considering the 75 or 78 for the lp when the time comes. I'm looking at 225/100's but I also want to tow heavy so I'm interested in what folks think. I emailed shawn and he said the same thing he mentioned in here about the laggy turbo but I'm curious as to how bad that las will be. Guess I'll find out soon enough. my 62fmw will be utilized as a single until next summer sometime when I can get to the build.

 

[HobbyStock62]

I plan to go with a little less fuel so I can maintain stock oil relatively easy like 190/100s or 205/75...somewhere along those lines.

 

[O2ShootTheJ]

Do it!!!!:toast:

when dental school is over and I have a play truck or another vehicle to make this a play truck a probably will. Adds up quick when you factor in all the supporting mods for compounds though....

 

[HobbyStock62]

Adds up quick when you factor in all the supporting mods for compounds though....

This ^
All the flanges and stainless tubing adds up real fast too. And those AN fittings and braided line for fuel and oil...

 

[onebadcoastie]

I plan to go with a little less fuel so I can maintain stock oil relatively easy like 190/100s or 205/75...somewhere along those lines.

I've got plans for a second oil pump.

 

[kdogg85]

Good lord, why so big on the secondary turbine? I ran a 364/.76 divided t3 over a s475/1.32 with 205/100's. I had my gate open around 53psi and would hold 1:1 till around 60psi. The big one for awhile was the .83 t4, get the 1.32 on the primary, you'll be glad you did.

 

[NRHX2009]

Good lord, why so big on the secondary turbine?

I would do a 62/68/91 or 62/73/91

Notice the OR in there... OP never posted hp goals. Things can vary greatly depending hp goals and wastegate setup.

 

[HobbyStock62]

I would do a 62/68/91 or 62/73/91

Notice the OR in there... OP never posted hp goals. Things can vary greatly depending hp goals and wastegate setup.

Would like to see 650-700 at the wheels.

 

[NRHX2009]

the 73mm turbine will keep backpressure lower and wastegate wont work as hard to maintain a proper backpressure. 68mm turbine wheel will spool faster for sure(150-200rpm), I would still stick with the .91 A/R for overall flow.

Do a 46-50mm wg and take your pick of turbines. A 62fmw/68/.91 can easily be assembled at a lower cost than making a "hybrid" of a turbo with a fmw62/73/91.

S475 or 80 with a t6 1.32 should do just fine. A 1.25 would be the ticket probably, housings just get expensive for the 96x88 turbine other than the 1.32 A/R

 

[onebadcoastie]

Even with the 62fmw/68.91 and the 475 or 480 with the 1.25/96x88, is it absolutely necessary to gate it?

 

[NRHX2009]

Cant say for sure. All depends on how the bp readings are.

 

[Cutting-Edge Diesel]

FMW62 68mm .83 with s483 96mm 1.32 psi:bp is 60:75 with out a gate. going to try the .91 on it soon.

 

[FaSSt9602]

If it we me, I'd rather do the .83 with the 68 wheel and add a gate over the .91. Then again, I would be building to use the truck for towing and would want the quickest spool-up possible...

 

[Pizza pig]

The difference between the .83 and .91 with the same turbine wont be much if at all different.


Hellen Keller sent this?