Simple 5.3 build, which turbo
Simple 5.3 build, which turbo So my winter project is to swap the N/A LS1 out and put together a single turbo 5.3 combo. As of now I have a LM4 aluminum 5.3 from a 2003 trailblazer, a set of seimens 60 LB injectors, an LS6 intake, and an LS6 5308 cam. Obviously I'll need to pick up a set of valvesprings at some point.
The big unknown at this point is ..... Which turbo? I plan on buying the Denmah kit from VS and upgrading from the typical GT45. So, am I better off with the 76/65 or the 78/75?
A couple of factors that should be considered are the fuel system (60 lb injectors) and the compression ratio of the 5.3. This one has 862 heads on it so according to google I have 9.5:1 compression. I'm assuming this compression ratio will help spool the larger 78/75 but I'm not sure that the 60 lb injectors will support its potential. The only other option I'm considering is uncapping a set of stock injectors to take the place of the 60's.
Last consideration is the physical size of the 76/65 compared to the 78/75. Is there much difference dimensionally? If there's a significant difference than it will likely influence my decision. This is one of the reasons I'm planning to upgrade from the bulky GT45.
The big unknown at this point is ..... Which turbo? I plan on buying the Denmah kit from VS and upgrading from the typical GT45. So, am I better off with the 76/65 or the 78/75?
A couple of factors that should be considered are the fuel system (60 lb injectors) and the compression ratio of the 5.3. This one has 862 heads on it so according to google I have 9.5:1 compression. I'm assuming this compression ratio will help spool the larger 78/75 but I'm not sure that the 60 lb injectors will support its potential. The only other option I'm considering is uncapping a set of stock injectors to take the place of the 60's.
Last consideration is the physical size of the 76/65 compared to the 78/75. Is there much difference dimensionally? If there's a significant difference than it will likely influence my decision. This is one of the reasons I'm planning to upgrade from the bulky GT45.
Personally just go right to a 78/75. I have the GT45 on my 5.3L ls6 cam. Works great but it is larger. Has worked flawless for 2 seasons now. I recently went from 4l80e to T56 and it does spool a bit slower. Worked great on the 4l80e though. I plan on swapping to a much smaller 7875 this winter, mostly due to wanting to change my downpipe and make a bit more room to potentially add AC back into the car.
Jay
Jay
TECH Junkie
Joined: Jul 2015
Posts: 3,012
Likes: 48
Personally just go right to a 78/75. I have the GT45 on my 5.3L ls6 cam. Works great but it is larger. Has worked flawless for 2 seasons now. I recently went from 4l80e to T56 and it does spool a bit slower. Worked great on the 4l80e though. I plan on swapping to a much smaller 7875 this winter, mostly due to wanting to change my downpipe and make a bit more room to potentially add AC back into the car.
Jay
Jay
I think I seen you on another thread explaining the question I'm about to ask, but I cant remember your answer. Why did you ditch the auto over the t56? And to answer ops question, I would think you would be happier with the bigger turbine (7875). Other turbo would be fairly limiting imo.
Jay
I'd be satisfied with 600 rwhp. Did you have both on the same setup? If so, was there a noticeable difference in how quickly they spool?
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Go with the 7875. I had on ON3 7665 on my car long ago and made the switch to a Turbonetics 7875. Spool was similar and the 7875 made great power. You won't stop at 600 rwhp anyway. I didn't and that's the reason I have a Billet S480 now, ha.
I never ran the 7665 because I decided I didnt even want to bother. I knew I would want more right off the bat. the 7875 is going to limit me at some point as well and I wish I just did what he did ^^^^ first go around and went T6 Borg Warner and never be limited.
bring this back from the dead..... im in a similar situation, putting in a 5.3, baby cam, M6.... goal is 600whp...deciding between a TC78 Benita because it can make the power and is good in tight spaces.... or save some money and have more potential and go with a ON3 7875.... any suggestion?
bring this back from the dead..... im in a similar situation, putting in a 5.3, baby cam, M6.... goal is 600whp...deciding between a TC78 Benita because it can make the power and is good in tight spaces.... or save some money and have more potential and go with a ON3 7875.... any suggestion?
I've had friends who have had the same issues with other companies. My On3 worked flawlessly for me and a buddy. I would go with a VS Racing over On3 because the customer support is far better. If you have an issue Viren of VS Racing will take care of you.