Seriously looking into compounds... Need help tho

Powerstroke Cowboy · Mar 4, 2013

silverpsd_06 said:
There are guys that have done that its all in how you gate it to make the HP turbo live. I know there was a guy back on psn who built a set out of a stocker and a s480 made like 450ish horsepower. So it can be done but your backpressure had better be in check. Depends on what you're wanting to do. Daily drive and tow you may be able to get away for a long time. David lott built a set for someone with a s480 atmosphere.

I think what David lott built used a GT45.. I Remember it was a little atmosphere charger.

907DAVE · Mar 4, 2013

I'll make you a hell of a deal on my old atmo.

TyCorr · Mar 4, 2013

Watcha got?

bad12jr · Mar 4, 2013

Think I'm gonna give it a shot. The worst it will do is die but a 38r is an easy swap.

Sent from my x2 chillin in the middle of no where

907DAVE · Mar 4, 2013

Mid frame Turbonetics 88mm.

Chvyrkr · Mar 4, 2013

What's the exhaust on it?

907DAVE · Mar 4, 2013

That's the thing, its a 75mm turbine. Turbo worked great with my 238/100's and 300/200's. It would run a 1:1 up to 25psi which is hard as I would push it. This turbo worked good for DD, towing and street. If you are looking for all out power this is not the turbo for you.

Since my big motor got swapped into the little truck along with 450/400's this turbo was not what I needed anymore.

Dzchey21 · Mar 4, 2013

Yeah allot of TN turbines are too small. Like you said works done under 30 psi but over that not enough.

I like 95+ turbines for compounds. The low pressure turbine isn't nearly as particular about spool up

907DAVE · Mar 4, 2013

Yup.

In all reality you can make a lot of boost with the atmo pushing 25psi though.

DocBar · Mar 4, 2013

What are y'alls thoughts on working the crap out of the LP and keeping the HP at ~15-20 psi? If understand it properly, isn't the cfm the HP can flow more important than the lbs of boost it's actually providing in a compound set up? If I'm completely off base, you'll immediately realize why I didn't choose to size the turbo's myself. LOL

907DAVE · Mar 4, 2013

I can do the math in a bit, but if the HP is pushing 20 psi and the lp is around there...your making a sh!t ton of boost.

Powerstroke Cowboy · Mar 4, 2013

that imho would be the way to go.. hp to get you boost and more power down low then let the hp go as high as it can safely go. With the right supporting mods of course.. That is what i plan to do. 15 to 20 on the high pressure to get me going good (or just gate the High pressure to stop building boost as soon as a or a little after the low pressure takes over) then let the low pressure take over from there, and run it up to it is in the center of it "meat" in the comp map then gate it to keep it there..

But then again i am going to have fire rings to. i plan on both the head and engine block grooved for the rings to get the best seal possible...

i might be all wet there to.. Just how i would do it.. unless i did not need it. and it just made more heat then need be. otherwise that is the way i am going to run it..

DocBar · Mar 4, 2013

907DAVE said:
I can do the math in a bit, but if the HP is pushing 20 psi and the lp is around there...your making a sh!t ton of boost.

Powerstroke Cowboy said:
that imho would be the way to go.. hp to get you boost and more power down low then let the hp go as high as it can safely go. With the right supporting mods of course.. That is what i plan to do. 15 to 20 on the high pressure to get me going good (or just gate the High pressure to stop building boost as soon as a or a little after the low pressure takes over) then let the low pressure take over from there, and run it up to it is in the center of it "meat" in the comp map then gate it to keep it there..
But then again i am going to have fire rings to. i plan on both the head and engine block grooved for the rings to get the best seal possible...

i might be all wet there to.. Just how i would do it.. unless i did not need it. and it just made more heat then need be. otherwise that is the way i am going to run it..

I'll be gating both stages, and I'm trying to talk one of the best to do the install and get it dialed in.
Cowboy, this is kind of how I was looking at it. About the only engine mods I'm missing are hardblok and a Swamps bedplate. I have an old Gen3 hpop I plan on trying to use. If that doesn't work, I'll use BTS's set up with dual IPR's.

Powerstroke Cowboy · Mar 4, 2013

Sounds like you have a goal!! Are you going to do about half the block with hardblock??
I have heard that when you do this it is a good thing to have the block line honed to make sure the cylinders are still strait and true. i have had guys tell me the cylinders moved as the hardblock got hard..

DocBar · Mar 5, 2013

Powerstroke Cowboy said:
Sounds like you have a goal!! Are you going to do about half the block with hardblock??
I have heard that when you do this it is a good thing to have the block line honed to make sure the cylinders are still strait and true. i have had guys tell me the cylinders moved as the hardblock got hard..

I'm not planning on doing the hardblok unless something lets loose and I have to tear into it. The motor might be pulled to install the drain line for the atmo in the oil pan, but I don't really want to pull the crank or heads unless it's needed. If the motor does come out, I'll be very interested to see if I had any walk with the girdle installed.

silverpsd_06 · Mar 5, 2013

You will be pushing around 67-68psi of boost.. I have found that at what pressure you gate the HP turbo at is going to be very dependent on when your atmosphere actually comes online. Gate it at ten in my setup the atmo would never get into the game. Knock her up to fifteen and I was seeing five from the atmo... 17psi seemed to be the sweet spot. Also word to the wise v band everything! That's is why mine is coming back out. No boot on this planet will hold the heat and pressure of 65psi and its a hell of a racket when it let's go kinda makes you chit your pants. Also if you are going to run boots from turbo to turbo do yourself a favor and weld a little ridge on them to help hold them

Chvyrkr · Mar 5, 2013

So... If a guy had an S476 with a 2.6 cover, 88mm turbine 1.15ar, and he was dead set on puttin a bigger S400 in front of it... Should he drop ar size on the turbine?

Obviously this guy wouldn't be street driving the truck.

Vader's Fury · Mar 5, 2013

I would say it depends on how that turbo spools now. If it lights off well now, then it should still work just as well as the hp in a compounds setup or even better.

Didn't Brian Jelich use a 75 as a hp when he had the p101?