Am I crazy for wanting to downsize?

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
38
Berthoud, CO
Specifically downsizing my high pressure charger to a GT3788r? I've come to the conclusion that my old age is setting in and I am tired of a smokey, laggy truck for the street. I've done some searching but cant seem to find much on compounds with a 3788. I feel like the GT4094 would be just as laggy as what I have now, and the 4088 shares the same compressor wheel and flow map as the 3788. So my understanding would be to go with the smaller turbine of the 3788 and just utilize my external gate a lot more? I plan on getting Garrets speed sensor as well.

Like I said this truck sees 95% street use and I hate leaving even a haze of smoke on traffic behind me. I'll be keeping my 88 for now but will probably swap brands in the future. For comparison here at 5300ft I can't make over roughly 8lbs of boost until about 2200rpm and frankly never gets any cleaner than a haze.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
1,868
113
Mid Michigan
Nothing wrong with re-evaluating and making a change. You're not the only one. Thats where a lot of people who used to be here went.
 

Stancedlb7

Cummin Stroke this Duramax
Feb 9, 2015
649
0
0
SLC, UTAH
My buddy had a "powermax" 3788 it only smoked on his race tune when punching it. It spoolled quick like a stocker. I think it would be great to compound with :woott:
 

delong_1

<< my work
Dec 5, 2008
1,282
0
0
38
Arvada, CO
My buddy had a "powermax" 3788 it only smoked on his race tune when punching it. It spoolled quick like a stocker. I think it would be great to compound with :woott:


Ya uh that's a vgt so not really an accurate comparison...

You already know some of my thoughts on this. I didn't ask before are you wanting to stay ball bearing?
 

minisub

6-5/6-6;Whatever It Takes
Sep 11, 2006
474
0
16
Cleveland, OH
Nope. Not crazy. I put a tune on the Jeep to smoke/haze less than the stock programming. The couple score HP increase and 4 mpg increase was a nice bonus.
 

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
38
Berthoud, CO
The most I can find in regards to running the GT3788 is for a VGT replacement. Seems a lot of people say don't use it as it's not much of an upgrade from stock in regards to a single charger application. But having this larger atmo feeding it and with an external gate I feel like it would be a different animal. My knowledge of sizing compounds is definitely minimal. I'm just curious on the downsides of running a somewhat smaller high pressure charger in relation to the large size of my atmo charger. Haven't heard much 63/88 or larger setups before.

You already know some of my thoughts on this. I didn't ask before are you wanting to stay ball bearing?

I definitely appreciate all the info you've given me so far! This is still a learning experience with me. I'm willing to stay with a BB charger and am really wanting to stay with Garret due to having the hookup at work.
 
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malibu795

misspeelleerr
Apr 28, 2007
8,239
550
113
42
in the buckeye state
I have a GT4088R with the powerax GT3788R T3 internal gated exhaust housing...
Only difference between 3788 and 4088 is bigger turbine 72.5 vs 77mm. Mika did 4088/4518 gate couple years back
4088 T4.85 housing with an external gate. How I'd set that up.. Could go 3582 gtx with larger housing couple Cummins boys doing that on compd
Only time I see any haze is I lug the turbo under 1600 all while loaded.. Haven't had a chance to play with it on the street with no trailer. I have yet to be able to get under the charger and cause it to surge even at 14-1500 rpm

Nate is thinking of the 3794 which is VGT.
 

Stancedlb7

Cummin Stroke this Duramax
Feb 9, 2015
649
0
0
SLC, UTAH
Yah my buddy got his from Danville. I just talked with mark, he said they discontinued the turbo. I guess they had a bearing issue for the lb7. It did do better than a stocker tho.
 

mike diesel

I'm alright.
Sep 6, 2012
4,005
0
36
SLC, Utah
The most I can find in regards to running the GT3788 is for a VGT replacement. Seems a lot of people say don't use it as it's not much of an upgrade from stock in regards to a single charger application. But having this larger atmo feeding it and with an external gate I feel like it would be a different animal. My knowledge of sizing compounds is definitely minimal. I'm just curious on the downsides of running a somewhat smaller high pressure charger in relation to the large size of my atmo charger. Haven't heard much 63/88 or larger setups before.

There is a guy here somewhere with a 64/s510 95mm compounds who just went 10.85 in a full weigh crew cab.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,681
5,835
113
Phoenix Az
Just go stock over s480 Dustin. Truck ran awesome up there this weekend and spooled really fast even at 10,000ft.
 

malibu795

misspeelleerr
Apr 28, 2007
8,239
550
113
42
in the buckeye state
Yah my buddy got his from Danville. I just talked with mark, he said they discontinued the turbo. I guess they had a bearing issue for the lb7. It did do better than a stocker tho.

Yep. I bought a use 4088 with a 1.06 t4 housing way too big for what I do.. Mark offered to machine a housing for little less than what it would cost me for a new T4 pedestal and .85 t4 housing.

This is in my LMM BTW. Runs a lot better than. Stock charger
 

Verlon at ATP

New member
Mar 19, 2015
165
0
0
The gtx3582r would make a screaming little high pressure charger for getting things going at your elevation. Do you have an overall horsepower range you still want to maintain? That with a gtx5018r would make a killer combo....