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Is the garrett GT3788R a good turbo upgrade?


love0126
08-21-2009, 07:54 PM
I'm interested in hearing people having experience with this beautiful turbo from garrett. I know it flows much better than stock, but I am curious if people have noticed a real difference by upgrading the stock LB7 duramax turbo. I haul heavy loads occasionally, and normally in hilly terrain. I'm looking for all aspects: low end torque, upper end snort, turbo response, and experience with fuel economy changes, etc. The truck is currently stock, but I am planning on introducting an upgraded intercooler as well as a methanol injection system. Thanks in advance for any experiences you may wish to relate.

cramer_77
08-24-2009, 06:14 PM
you might look into a EFIlive upgrade first, got a few friends that have had there trucks dyno tuned with this and one had a stock dmax and got 502 at the wheels on stock intake and exhaust with 150k on it.

jyount
09-02-2009, 10:20 PM
I'm interested in hearing people having experience with this beautiful turbo from garrett. I know it flows much better than stock, but I am curious if people have noticed a real difference by upgrading the stock LB7 duramax turbo. I haul heavy loads occasionally, and normally in hilly terrain. I'm looking for all aspects: low end torque, upper end snort, turbo response, and experience with fuel economy changes, etc. The truck is currently stock, but I am planning on introducting an upgraded intercooler as well as a methanol injection system. Thanks in advance for any experiences you may wish to relate.

i bleed 15-40, im a powerstroke man, but diesel is diesel, the gains from a turbo alone will be minmal, bigger turbos are for more air, so you can burn more fuel, if you aren't throwing more fuel in than your stock turbo can handle you really aren't gonna see a whole lot of gain from a turbo alone.
Like said, get a good custom tow burn and you should be able to tow fine a keep the egts down, if you need it the bigger turbo will go a long way to drop the egts, but unless you are pulling heavy with a high fuel rate program you won't overheat the egts anyway.
Before you do ANY mods put some gauges in it so you can see what is going on....
EGT is the important one for the engine, boost is nice to troubleshoot and neat to watch, but not neccessary, if you have an auto put a tranny temp gauge in it too, that one can save your tranny.

love0126
09-02-2009, 11:17 PM
I understand the part about the custom tune. That is a given. Just not sure when I have time to program the EFI live for my evil purposes. HAHA. So as far as EGT's, what can the duramax handle? Furthermore, the Allison transmission does have a temp gauge right on the dash. That's the one thing GM did right. Their electricals suck, but that they didn't skimp on. haha

jyount
09-03-2009, 10:28 PM
I knew they had a tranny guage, I just don't know how accurate it is and how fast it reads, it may be fine.
As far as how much egt you can safely run, a rule of thumb with pretty much any diesel is 1250 to 1300 MAX sustained. In short burst you can handle more, ie 30 seconds or less. Contrary to popular belief, the turbo is not your worry, they fail because of overspeeding, high temps do bad stuff, like melt the tops of pistons and stuff, no joke, not melt turbos. Newbs think heat kills turbos, it don't too much boost does....
But Duramaxes are not know for running out of control egts. You should be fine. As far as efi live yes you can get into a lot of parameters yourself, but WHY? There are tons of very good programmers out there that make good chips with very good burns, no I'm not talking superchips programmers, I'm talking like talk to the programmer, get what you need for your conditions, and get what you need for YOUR truck, not just everyone's that wants a tuner, In the powerstroke world, Dp Tuner is excellent and have great tuners, I don't know what is kickin in the duramax world for sure, but there are tons of chevy diesel enthusiast site on the web that are full of guys that will point you in the right direction.

By the way, a custom program will go along way to making that tranny hold up to 500 and 1000. If you have a good chip burn for shift logic and power it WILL be a whole new truck to you. I promise.

BUT you have been forwarned. I had a SERIOUS case of PMS (powerstroke modification syndrome), you will get err DMS I guess.

Diesels have so much tuning bang for the buck now days it is LUDACRIS.
You spend 800 bucks on a gen iv small block and its still pretty mild, spend 800 on your duramax and it will leave most factory sports cars (ie mustangs and such) in the smoke. AND you weigh ALOT more than they do. I had a 97 powerstroke. That I maybe had a grand in and if you could shift it fast enough you could really suprise quite a few people. Granted being a 97 it only weighed 6700 pounds dry, your truck probably weighs 11 or 12 grand, so I might've had less hp and tq, but same results.

cramer_77
09-07-2009, 10:10 PM
for chevys EFI Live is the way to go, you can talk to a lot of people and they will give you names of people to talk to or you can take you truck to a local diesel performance shop and they can tune it for you and if its the right shop they can dyno tune it. But EFI can be very involved, you name it and you can change it now you can go with another prgrammer company and they will have preset programs already burned into the module(im sure you already knew that) Another perk with EFI Live which i actually have friends that have this they can install a dial and you can have up to 5 different settings. Even though i got a gasser i talked to the local performance shop and they said they would tune it with EFI live for $375 not bad really seeing as how just a programmer would cost around $400 and i still have to tune it. But i can see why you want a turbo but pushing more air means nothing, you need more fuel to go with it.

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