Garrett 3582 - GT vs GTX?

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commtrd

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I was visiting with Pat at Big Twin Diesel today about getting a twin turbo setup built for my truck told him I had a GT3782R currently but that I was kind of thinking about going with the GT3582R as my secondary instead thinking the slightly smaller turbine wheel may help it spool faster? The turbine on the 3782R is actually out of the GT3788R and is 72.5 X 64. The turbine wheel on the 3582R is listed on V5 of the Garrett catalog as being 68mm (inducer right?) which is actually 4.5mm smaller than the turbine wheel in my GT3782R.

So will the GTX3582R work better or worse in a DD/tow vehicle than the GT3582R? It looks like the GTX compressor wheel has 11 blades and the GT wheel has six. I was telling Pat I was thinking about going with the GT compressor and he seemed to think the GTX would work better. I want very fast spoolup thru midrange more than top end as I will not be using this truck for racing but all DD and towing up to 20k+. 2006 dodge 5.9 with EFI Live and will be going with some bigger injectors up to 100 hp or smaller. I wanted to use a GT4202R for the primary. Would the GT3582R work better than my current GT3782R and is the GTX preferable to both of these selections? Looking for around 600+ hp / 1200 tq. These turbos listed should help do that easily with cool EGTs I think.

This will be my first set of twins so that's why the 20 questions... Thanks for any help and pointers.
 
My two bits, a 600hp Dmax will spin the living crap out of a GT3788. My gut tells me that the GT35 turbine is just too small and may become a bottleneck. You may end up needing to wastegate the heck out of it.
 
Prolly why Garrett made the GT3782R with the turbine wheel out of the 3788. I would prefer to be able to not even need to gate it at all. If the turbos are sized properly should need very minimal to no gating from what I have been reading on compd.
 
If you are dissatisfied with how the spool up is now, you better knock down the turbine a size. Whatever turbo you have on now will spool slightly slower when you compound it. The no gate theory implies that exhaust flow through the turbine is ideal at all RPM's and loads, this is not the case. By using a wastegate on a smaller housing, response (spool up) is improved greatly, yet the exhaust system will flow adequately at full power.
 
i have looked at the GTX3582 GT3788 and the GT4088 all as option to run as a the small charger.. "on papper" the GTX3582 would spool faster and make comparable HP as the GT4088.
two things that i would consider going to the GTX3582...
do you need better 0-part throttle cruising response?
do you need better off line response? which to use the lower spooling capabilities you would need ~1500 rpm stall tc to load the engine sooner

stall really makes a difference on the driving of a truck... the OEM on my 99 was a ~1500 it would take much to slip the tires on a 1-2 shift as part throttle nose would come up off the line.... now it has a 2000 and you dont get the kick in the but 1-2 shift no nose raise off line.. with nothing done to the tune between the two TCs..

that said what TC you got behind the cummins
 
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Well I am not sure what stall TC I have it is the Garmon triple-lock he puts in front of the Stage 2 tranny. I don't remember Jeff telling me what the stall was on the TC. I use this truck for towing a 10k fifth wheel and DD so I wanted the build to be more suited to that and when I got the GT3782R intended to use it as the secondary in a small twin setup. It has the turbine wheel out of the 3788 and reading about the 362FMW in T4/.83 I believe those guys claimed to be at 10psi boost by 1500 rpm. Well I am not near that boost at 1500 I am actually over 1700 starting to get to around 8 psi. But then it takes off and runs on up quickly to the gate at 37 psi if I stay in it at all.

So that is not really laggy but seems like it should be better to me. I don't have a DP gauge yet but another guy has on his 04.5 and says his drive pressures pretty much stay at or under 1:1. I may have issues if using this turbo for secondary and it spools even slower. Pat said he needed the turbo for about a month to fab up the piping and I thought about a better spool any way so now trying to size a set of Garretts for tow and DD mostly. I had not thought about the stall but I think it is a lower stall TC than stock but I could be wrong.

So any suggestions for extremely quick spool say a 4508 over a 3788? Smaller on the primary? GTX3582R secondary? I kind of wanted to stick with the 6 blade wheels if possible. There is much to learn about sizing turbos for a compound setup! Those pressure ratio equations have helped a bunch.
 
i'd lean toward a 4202 more than a 4508 both with tight AR and gated
is the 3782 currently on the truck?
 
Yes I installed the GT3782R on a 3rd gen manifold some time back. It's a good little charger and really wanted to utilize it as the secondary. It just seems to me that with some 100hp injectors with a 4202 or 4508 under it would be a really nice setup. And twin dilemma's are fun! I spend hours on here studying these threads to learn all I can about compounding turbos and diagnosing problems. Compd is awesome!
 
commtrd said:
Yes I installed the GT3782R on a 3rd gen manifold some time back. It's a good little charger and really wanted to utilize it as the secondary. It just seems to me that with some 100hp injectors with a 4202 or 4508 under it would be a really nice setup. And twin dilemma's are fun! I spend hours on here studying these threads to learn all I can about compounding turbos and diagnosing problems. Compd is awesome!
Click to expand...

i know for fact that nathan at MPI used 4202 with the LB7 (58mm) IHI turbos and that they worked very well together on the dmax

did garret drop the GT3782R? i can only find the GT3788R

GT3788R with a .89 a/r housing
GT4204R with a 1.01 a/r housing

the other option i'd run is a
GTX3582R with a .63 T4 ( i read it as a GT4088R that spools better)
GT4508R with a 1.01 T4
dual 40mm wg on both setups
 
Few things:
When looking at garrett turbos, the first two letters and numbers denote frame size and turbine size. IE: GT37__ will always have a certain frame and turbine wheel no matter what the last two numbers are or what compressor wheel is on it. The last two number denote the exducer size of the compressor wheel.

IMO, a GTX wheel is not really needed as a secondary. You could drop down to a GT35 frame, or maybe try some better tuning.

My $0.02
 
The GT3782R is a "kit" turbo designed to be a drop in replacement for the stocker. Called a Powermax kit. Scroll down nearer the end of the Garrett catalog and will find these turbos there. Stage 1, 2, and 3 just have different size compressor wheels, with bigger turbine wheel from the GT3788. I am thinking about just going with a 3788 as the secondary and leaning more towards the GT4202R as primary as the GTX wheel probably not so important on the primary? Actually I wanted to just use GT wheels on both. Also the primary should have a T6 ported inlet? A little tighter turbine A/R on the secondary will help encourage the good spoolup on sec that makes it work hard enough to keep pressure ratios in line?
 
commtrd said:
The GT3782R is a "kit" turbo designed to be a drop in replacement for the stocker. Called a Powermax kit. Scroll down nearer the end of the Garrett catalog and will find these turbos there. Stage 1, 2, and 3 just have different size compressor wheels, with bigger turbine wheel from the GT3788. I am thinking about just going with a 3788 as the secondary and leaning more towards the GT4202R as primary as the GTX wheel probably not so important on the primary? Actually I wanted to just use GT wheels on both. Also the primary should have a T6 ported inlet? A little tighter turbine A/R on the secondary will help encourage the good spoolup on sec that makes it work hard enough to keep pressure ratios in line?
Click to expand...

ahh the powermax kits im tracking now
 
malibu795 said:
i know for fact that nathan at MPI used 4202 with the LB7 (58mm) IHI turbos and that they worked very well together on the dmax

did garret drop the GT3782R? i can only find the GT3788R

GT3788R with a .89 a/r housing
GT4204R with a 1.01 a/r housing

the other option i'd run is a
GTX3582R with a .63 T4 ( i read it as a GT4088R that spools better)
GT4508R with a 1.01 T4
dual 40mm wg on both setups
Click to expand...

Both these setups look good. I think leaning towards the 3788 with 4202. I looked at Pat's work on their facebook page (can do that even without a fb account) and sure looks good. Price he gave me as a rough estimate (depending on turbos) wasn't a whole lot more than a custom setup with BW turbos and FMW billet both turbos. I had also considered a S362 FMW/.83 T3 divided/internal gate over a 475 or 480 FMW/1.32 T6.

Thinking I will stick with the Garretts though...
 
I've seen a GT35xx compounded with a GT55xx on a street driven 12 valve Cummins that put down over 900 HP fuel only and had the low rpm spool-up characteristics of a stock turbo'd truck with a massive increase in power on the mid range and top end as the GT55 came to life.

If you want spool-up, go with the GT35 class charger and add an external gate if you want to hang a monster turbo under it.
 
Big Blue24 said:
I've seen a GT35xx compounded with a GT55xx on a street driven 12 valve Cummins that put down over 900 HP fuel only and had the low rpm spool-up characteristics of a stock turbo'd truck with a massive increase in power on the mid range and top end as the GT55 came to life.

If you want spool-up, go with the GT35 class charger and add an external gate if you want to hang a monster turbo under it.
Click to expand...

Now this sounds like the ticket here! Just in case I got the urge to fuel harder in the future ya know... This setup moderately fueled would still tow well? Don't see why not...
 
commtrd said:
The GT3782R is a "kit" turbo designed to be a drop in replacement for the stocker. Called a Powermax kit. Scroll down nearer the end of the Garrett catalog and will find these turbos there. Stage 1, 2, and 3 just have different size compressor wheels, with bigger turbine wheel from the GT3788. I am thinking about just going with a 3788 as the secondary and leaning more towards the GT4202R as primary as the GTX wheel probably not so important on the primary? Actually I wanted to just use GT wheels on both. Also the primary should have a T6 ported inlet? A little tighter turbine A/R on the secondary will help encourage the good spoolup on sec that makes it work hard enough to keep pressure ratios in line?
Click to expand...

Just to help out your lingo, like I was saying the GT37 ALL have the same turbine wheel and frame.

Big Blue24 said:
I've seen a GT35xx compounded with a GT55xx on a street driven 12 valve Cummins that put down over 900 HP fuel only and had the low rpm spool-up characteristics of a stock turbo'd truck with a massive increase in power on the mid range and top end as the GT55 came to life.

If you want spool-up, go with the GT35 class charger and add an external gate if you want to hang a monster turbo under it.
Click to expand...

Your probably talking about a ~$2500 + turbo new, correct?
 
AHall said:
There is a couple gt37 hotwheels.
Click to expand...

Well, I noticed the trim is slightly different on one...:stab:

Difference is only 2 mm on the exducer(66 or 64)

But, I guess that means they are different.

I'm wrong. My bad.
 
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