Rickj350RS

iTrader: (1)

my latest plan is to mount twin remote mounted turbos. i'm wondering if anyone had some suggestions of what types/sizes of turbos i should be looking for. thanks a lot.

89JYturbo

I have always been interested in trying a RMTT system. Probably won't ever do it though, since I already have TT's on my IROC. I did try the RMT system on my Z24 with good results, but with a single T3/T4 hybrid turbo.

As far as sizing, keep the turbine sides slightly smaller than you would normally for standard turbo systems. Off the top of my head, I would be suggesting something like a T3/T4 Hyrbrid, possibly TO4E 57 trim compressors mated to T3 turbines with .48 a/r turbine housings. This should give you decent response along with a power capability of 500 or so HP.

KiLLJ0Y

iTrader: (1)

you need to talk to the guys at www.STSTurbo.com


Rick's car is now a Twin Turbo 4thgen T/A making 730hp..

Dustin Mustangs

iTrader: (1)

"Jammer" from LS1tech.com has a twin rear mount...not sure if it's done yet tho. Hear is a link:

http://www.ls1tech.com/forums/search...archid=2088776

Rickj350RS

iTrader: (1)

cool thanks guys. i'm not looking for loads of boost, prob. about 10 to 12. this is going on a built 383 so i'm shooting for about 600 crank horse. do you think i should maybe go for something alittle bigger?

JoBy

The only major reson to use twins is to keep the exhaust manifolds short ... or if you have trouble finding a single unit that is big enough.

Building a twin remote is just making things more complicated without gaining anything.

Rickj350RS

iTrader: (1)

i already have true dual exhaust, so i figured that two smaller turbos would be easier. this way i wouldn't have to modify the exhaust. i've also been reading about sequential turbos (one big one small). plus, with two smaller turbos, i was thinking that they would spool up faster than just one big turbo.

89JYturbo

Would have a direct link to pics or info, for those of us who are not a member of LS1tech?

I agree. The only advantage I can see is that twin turbos would have a little more awe effect, if that is important.

For that power goal, I would just switch to a larger turbine housing, like a T3 .63 A/R and use better flowing turbine wheels (stage II or III). This turbine combo would easily be good for 300hp of airflow each. The TO4E 57 trim compressors I mentioned earlier support over 35lb/min (at your desired boost levels), so a pair would be capable of your goals and then some. With remote systems, the compressor is sized juat as with standard turbo systems. Adjustments are only required to the turbine section sizing for remote mounting.

Dustin Mustangs

iTrader: (1)

Whoops, sorry for the dead link...here is some of what that was supposed to show:

http://www.ls1tech.com/forums/showthread.php?t=249883
http://www.ls1tech.com/forums/showthread.php?t=256445
http://www.ls1tech.com/forums/showthread.php?t=258611
http://www.ls1tech.com/forums/showthread.php?t=261098
http://www.ls1tech.com/forums/showthread.php?t=267964
http://www.ls1tech.com/forums/showthread.php?t=268798
http://www.ls1tech.com/forums/showthread.php?t=272929
http://www.ls1tech.com/forums/showthread.php?t=274413
http://www.ls1tech.com/forums/showthread.php?t=315802
http://www.ls1tech.com/forums/showthread.php?t=319463

You should register JY, thier forced induction board alone is worth it.

Rickj350RS

iTrader: (1)

do you guys think i would be better off just running a blower? i have dual 3'' exhaust and i don't know if that is too big as far as maintaining exhaust pressure. plus, i'm thinking that two turbos, plumbing, and fuel system upgrades might be a lot more expensive than just a blower and fuel system upgrades. the awe factor definitely plays a part in all of this, but i want to make sure that the boost is there when i want it. which is basically when i stomp on it. the absolute max lag i would want would be 2000 rpm, but i don't know if that is possible. i have along time to decide what i would like to do b/c the motor isn't even built yet. i'm just planning ahead and looking at my options. i've heard that the remote turbo systems are "dyno queens", meaning that they make good power, but don't perform like a supercharger. i've seen sts's videos of their twin turbo setups. they are quite impressive, but the cars don't launch hard b/c they are making no boost. if i could somehow make boost much sooner, i would definitely go with the turbos. i basically want low 11's to high 10's. my experience is telling me that with my car that would translate to about 600-650 crank hp. so that's my goal. with a highly moded 383, i'm guessing that 10 psi of boost should for sure get me there. i don't care where the boost comes from as long as it's there when i stick it to the floor. i'm just wondering what route you guys think would be the best.

JoBy

With a centrifugal supercharger the boost is a function of engine RPM. More RPM will give you more boost. When you WOT the boost is instant for the RPM the engine is at.

Turbo is a bit different. You set the boost with a wastegate and it is the same regardless of engine RPM if the turbo is not too small or too big.
It is not a problem at all to have full boost at 2000 RPM.
Lag is another issue. If you have a manual in high gear and WOT at 2000 RPM, then you will start at atmostheric pressure in the intake manifold. The exhaust pressure will build and start to spool the turbo. A small turbo will spool quicker than a big. Now the boost will start to rise and you will eventually get full boost while still at about 2000 RPM. The differance is that the boost is not instant, but you get full boost at a much wider RPM range.

All turbos have lag and it depends on the turbo and engine RPM. At higher RPM you have less lag.


Boost

rocluvr0013

turbo + full boost is possible @ 2000 rpm
-Lag is possible but with correctly sized turbos almost nonexistant
+ Roughly twice as efficient as cen. supercharger = more power!
+ TuRbos Are Way Cooler!

Supercharger + No lag
+ simpler install
-Full boost is ONLY available @ redline

89JYturbo

We should clear up the difference between tradition roots style SC's and later centrifugal SC's.

The older, less efficient Roots superchargers are possitive displacement devices, that give roughly the same boost pressure throughout the RPM range.

sleepybu

don't forget about the twin-screw superchargers that are about as efficient as a turbo

slickrock55

There is some misconception here that i want to try and clear up between lag and boost threshold. They are VERY different.

Lag:
This is what happens when you are cruising at higher rpms and go WOT. The time between when you mash the throttle and when full boost is delivered to the intake. The turbo(s) need time to accelerate from the rpm they were at during cruise to the rpm at boost (often 100k+ rpm). This is going to be a function of the physical size and mass of the rotating components, and the configuration of your setup, including pipe sizes and length, etc.

Boost threshold:
This is the minimum rpm your setup can make maximum boost. It takes a certain amount of exhaust flow to make full boost, and under the rpm where this amount of exhaust is created, you will not get max boost. This is mostly a function of the hot side setup, specifically your turbine A/R.

For example, i can be cruising in 6th gear in my car at 1800 rpm and hit WOT. Manifold pressure will go instantly to atmospheric (0 boost), maybe a few psi boost, and then slowly start to climb as rpms climb. I can not make the full 14psi until I hit 2300rpm. (boost threshold)

However, If i downshift to 3rd or 4th, i could be at something like 3500rpm. WELL above boost threshold. When i nail WOT here, the boost will almost instantly hit 14psi. Maybe a tenth of a second or two. (boost lag)