Choosing twins for 5.3L?
Thread Starter
Teching In
Joined: Jun 2010
Posts: 27
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From: West Fargo, ND
Choosing twins for 5.3L? Ok, i see there's a similar thread up but i didn't think i should jack it with my questions.
Well this is my first time dealing with a v8 so bare with me on this guys. I have done quite a bit of searching and haven't found a thread that gave me a definitive answer to my questions.
I'm going to be running a relatively stock 5.3L with pistons and rods only. I have decided i want a pump gas only set up so all my goals/use will be on straight 91 octane. so with that in mind i think 8:0-8.5:1 comp will be safe enough to allow some good power on 91. I will be running a manual trans but have not narrowed it down yet to which one.
goals:
- street car with occasional track days. (4-5/yr)
- 600whp (reasonable?)
- fast spool (not instant, but minimal lag)
- NOT a drag set up
Now I'm going for a bottom mount setup in a c4 corvette so fitment is tight. and with me on a modest budget BB/GT series turbo's are out of the budget. so with that said I'm thinking t3/to4e or maybe with a to4b cover.
I'm thinking a t3/t04e 50 trim stg3 .63a/r might work but I'm clueless on v8's and there turbine needs. (used to Honda's don't kill me
) I haven't seen much talk on turbine sizing with twins. So??
So do you guys think the 50 trims will let me reach my goal?
Do you think i would lose to much flow if i had to run a to4b cover vs. the to4e?
Do i need to run a larger turbine housing?
Well this is my first time dealing with a v8 so bare with me on this guys. I have done quite a bit of searching and haven't found a thread that gave me a definitive answer to my questions.
I'm going to be running a relatively stock 5.3L with pistons and rods only. I have decided i want a pump gas only set up so all my goals/use will be on straight 91 octane. so with that in mind i think 8:0-8.5:1 comp will be safe enough to allow some good power on 91. I will be running a manual trans but have not narrowed it down yet to which one.
goals:
- street car with occasional track days. (4-5/yr)
- 600whp (reasonable?)
- fast spool (not instant, but minimal lag)
- NOT a drag set up
Now I'm going for a bottom mount setup in a c4 corvette so fitment is tight. and with me on a modest budget BB/GT series turbo's are out of the budget. so with that said I'm thinking t3/to4e or maybe with a to4b cover.
I'm thinking a t3/t04e 50 trim stg3 .63a/r might work but I'm clueless on v8's and there turbine needs. (used to Honda's don't kill me
) I haven't seen much talk on turbine sizing with twins. So??So do you guys think the 50 trims will let me reach my goal?
Do you think i would lose to much flow if i had to run a to4b cover vs. the to4e?
Do i need to run a larger turbine housing?
don't use compressor trim in the v8 world. Just wheel size. Trim is only for the custom big wheel small housing stuff.
But I'd assume 50trim is way to small. LS motors move some air unlike older V8's.
Just as an example, guys are running single 76-78 mm on rod bolt, z06 cam stockers.
I'd go with a 58-61mm compressor and the biggest t3 you can get.
It will be near instant boost anyway with the small housings.
isn't a stg 3 a t3 ptrim?
small exh means low rpm, small stock cam, 5500 shift.
8-1 will be too low and probably need custom pistons.
Lots of guys running 9-1 at your power goal.
Cam selection will depend on what turbines you run and CR.
What car you building?
But I'd assume 50trim is way to small. LS motors move some air unlike older V8's.
Just as an example, guys are running single 76-78 mm on rod bolt, z06 cam stockers.
I'd go with a 58-61mm compressor and the biggest t3 you can get.
It will be near instant boost anyway with the small housings.
isn't a stg 3 a t3 ptrim?
small exh means low rpm, small stock cam, 5500 shift.
8-1 will be too low and probably need custom pistons.
Lots of guys running 9-1 at your power goal.
Cam selection will depend on what turbines you run and CR.
What car you building?
Thread Starter
Teching In
Joined: Jun 2010
Posts: 27
Likes: 0
From: West Fargo, ND
don't use compressor trim in the v8 world. Just wheel size. Trim is only for the custom big wheel small housing stuff.
Ok, yeah I'm learning the different terminology slowly. ha
I'd go with a 58-61mm compressor and the biggest t3 you can get.
These would be 54mm turbo's. I had thought of maybe running s256's but the Garrett's have better housing selection in the smaller stuff.
It will be near instant boost anyway with the small housings.
isn't a stg 3 a t3 ptrim?
the stg3 is a 65mm-56.61mm in/ex the p trim T4 is 74.2mm-64.6mm.
small exh means low rpm, small stock cam, 5500 shift.
8-1 will be too low and probably need custom pistons.
Lots of guys running 9-1 at your power goal.
So there are no durability issues with 9:1? I really don't feel like freshening this up every year, kinda just want to build it once and on the safe side.
Cam selection will depend on what turbines you run and CR.
A friend offered me a comp cam 54-412-11 with 212/218 and 114 lobe separation. He said it was a mild cam and that's what i have gathered.
What car you building?
Ok, yeah I'm learning the different terminology slowly. ha
I'd go with a 58-61mm compressor and the biggest t3 you can get.
These would be 54mm turbo's. I had thought of maybe running s256's but the Garrett's have better housing selection in the smaller stuff.
It will be near instant boost anyway with the small housings.
isn't a stg 3 a t3 ptrim?
the stg3 is a 65mm-56.61mm in/ex the p trim T4 is 74.2mm-64.6mm.
small exh means low rpm, small stock cam, 5500 shift.
8-1 will be too low and probably need custom pistons.
Lots of guys running 9-1 at your power goal.
So there are no durability issues with 9:1? I really don't feel like freshening this up every year, kinda just want to build it once and on the safe side.
Cam selection will depend on what turbines you run and CR.
A friend offered me a comp cam 54-412-11 with 212/218 and 114 lobe separation. He said it was a mild cam and that's what i have gathered.
What car you building?
The 65mm threw me.
I'm looking at that same cam.
You know you can bore a 5.3 to a 5.7 bore and be fine usually on wall thickness?
You end up with an iron 347. - 3.622 x 3.905
That's my plan with 2 T4 ptrim .68 T61's.
With a stick I'd go with the .58 ar or SC61's which come with a t3 ptrim setup.
I got my 58mm practice turbo's almost new and cheap because they went to small on an LS1. They thought it was the 2.75 inlet T04x housing. I think it was the ptrim .58 OC housings backing up the exhaust.
Check this out.
https://ls1tech.com/forums/forced-in...ame-motor.html
I'm looking at that same cam.
You know you can bore a 5.3 to a 5.7 bore and be fine usually on wall thickness?
You end up with an iron 347. - 3.622 x 3.905
That's my plan with 2 T4 ptrim .68 T61's.
With a stick I'd go with the .58 ar or SC61's which come with a t3 ptrim setup.
I got my 58mm practice turbo's almost new and cheap because they went to small on an LS1. They thought it was the 2.75 inlet T04x housing. I think it was the ptrim .58 OC housings backing up the exhaust.
Check this out.
https://ls1tech.com/forums/forced-in...ame-motor.html
Thread Starter
Teching In
Joined: Jun 2010
Posts: 27
Likes: 0
From: West Fargo, ND
The 65mm threw me.
I'm looking at that same cam.
What are your thoughts on it with F/I? This may be a question for another thread however.
You know you can bore a 5.3 to a 5.7 bore and be fine usually on wall thickness?You end up with an iron 347. - 3.622 x 3.905
Yeah, i know you can bore these. I decided on the 5.3 for durability reasons. I figured the drop in displacement would be more then made up by the turbo's.
That's my plan with 2 T4 ptrim .68 T61's.
With a stick I'd go with the .58 ar or SC61's which come with a t3 ptrim setup.
I got my 58mm practice turbo's almost new and cheap because they went to small on an LS1. They thought it was the 2.75 inlet T04x housing. I think it was the ptrim .58 OC housings backing up the exhaust.
Check this out.
https://ls1tech.com/forums/forced-in...ame-motor.html
I'm looking at that same cam.
What are your thoughts on it with F/I? This may be a question for another thread however.
You know you can bore a 5.3 to a 5.7 bore and be fine usually on wall thickness?You end up with an iron 347. - 3.622 x 3.905
Yeah, i know you can bore these. I decided on the 5.3 for durability reasons. I figured the drop in displacement would be more then made up by the turbo's.
That's my plan with 2 T4 ptrim .68 T61's.
With a stick I'd go with the .58 ar or SC61's which come with a t3 ptrim setup.
I got my 58mm practice turbo's almost new and cheap because they went to small on an LS1. They thought it was the 2.75 inlet T04x housing. I think it was the ptrim .58 OC housings backing up the exhaust.
Check this out.
https://ls1tech.com/forums/forced-in...ame-motor.html
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Teching In
Joined: Sep 2009
Posts: 27
Likes: 0
I've got two mp 70's with .68ar. I was planning to do a 6.0 but found a 5.3 for $175 with 90k on it. I'm going to give it a try, need to pick the right cam and this too will be a street car most of the time. When it breaks or doesn't work i'll use the engine and go out to a 5.7.
john
john
If cost is an issuse, you might want to go with ebay turbos. Im starting to contemplate them. Godspeed has come out with turbos now, and have read revies about there otherstuff being prety good. I thing i read that one board member here has run a godspeed for over a year with no problems.
Thread Starter
Teching In
Joined: Jun 2010
Posts: 27
Likes: 0
From: West Fargo, ND
If cost is an issuse, you might want to go with ebay turbos. Im starting to contemplate them. Godspeed has come out with turbos now, and have read revies about there otherstuff being prety good. I thing i read that one board member here has run a godspeed for over a year with no problems.
Anyone have more info on t3 based turbo's?
Thread Starter
Teching In
Joined: Jun 2010
Posts: 27
Likes: 0
From: West Fargo, ND
