64 over 80 twins

J

j-rod

Up to no good
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Jun 29, 2008
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Curious if anyone is running a set of twins of this size and what your thoughts might be. I did a quick search and saw a 66 over 80, but nothing specifically of a 64 over 80 for a VP truck.
 
I run a 64 over a 75/1.32 a/r. Spools great on the street and tows pretty good with big injectors.

I'd be curious to see how an 80 would do on my truck.
 
Mike, is it a 64/71-14 or something different. I'm thinking about running my Super B Special in a twins setup when the time comes.
 
Mike D said:
I run a 64 over a 75/1.32 a/r. Spools great on the street and tows pretty good with big injectors.

I'd be curious to see how an 80 would do on my truck.
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How big are your injectors?
 
SuperDave, Yes, it's a 64/71/14 originally from BD but it's since been rebuilt.

J-rod, I run an old set of hand me down M7 injectors. They used to be Tim Barber's back when he had a vp truck, then my buddy Brian Buchanan, now I got 'em.
 
Mike D said:
SuperDave, Yes, it's a 64/71/14 originally from BD but it's since been rebuilt.

J-rod, I run an old set of hand me down M7 injectors. They used to be Tim Barber's back when he had a vp truck, then my buddy Brian Buchanan, now I got 'em.
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Well that's pretty cool. I want twins, BAD. But can't get them until I graduate from UGA, which will be at the end of this upcoming Maymester. :rockwoot: So, until then I'm just researching and trying to figure out which bottom turbo to get.

I'm guessing that the 80 will spool slower than the 75? My truck will be street drivin also.
 
SuperDave4x4 said:
Well that's pretty cool. I want twins, BAD. But can't get them until I graduate from UGA, which will be at the end of this upcoming Maymester. :rockwoot: So, until then I'm just researching and trying to figure out which bottom turbo to get.

I'm guessing that the 80 will spool slower than the 75? My truck will be street drivin also.
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Yeah, the 80 will spool slower. And really, unless you are shooting for 900+ HP, I think most people would be happier with a 75 over the 80. Spool-up would be quicker and more fun to drive.
 
SuperDave4x4 said:
Well that's pretty cool. I want twins, BAD. But can't get them until I graduate from UGA, which will be at the end of this upcoming Maymester. :rockwoot: So, until then I'm just researching and trying to figure out which bottom turbo to get.

I'm guessing that the 80 will spool slower than the 75? My truck will be street drivin also.
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Hey man get your own thread LOL

JFlagg said:
Yeah, the 80 will spool slower. And really, unless you are shooting for 900+ HP, I think most people would be happier with a 75 over the 80. Spool-up would be quicker and more fun to drive.
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If I got a tight enough housing on the 80, I think I'd be alright. If I do a 62 on top I'd probably run the 75, but if I'm going to go big on the top, I'll do the same on the bottom.
 
SuperDave4x4 said:
yeah, that's what this forum is all about....:lolly:

So, are you leaning towards the 62 and 75?
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Honestly I don't know right now.

After seeing what Jamie put down with his 64 single, I'm inclined to run that for awhile, but I was looking into what options there were if I decided to go with twins down the road, hence the 80 questions. Running a 64/75 is an option I guess, but for whatever reason, the size difference between the two compressors does not seem "ideal" to me. I don't have any numbers to back up this statement, but it seems the most common setups are: 62/75, 62/80, 64/80, or 66/80. With the exception of Mike, I haven't heard of many running a 64/75.
 
The idea of the big secondary turbo(75 or 80 in this case) is to get the best flow necessary. Running a tight EH on it kinda defeats the purpose. You could do that on the primary and externally gate it to help reduce this as a choke point though. Not to mention, with a VP truck, do you really think you need to go that big with twins? I don't know your mods, but I highly doubt you have so much fuel you need the 80 to burn it. A 62/75 combo would be awesome with some Mach 7 or 8's IMO.
 
I'm also looking into some twins and would still like to use my 64. I'm leaning more toward a 80. $.02
 
JFlagg said:
The idea of the big secondary turbo(75 or 80 in this case) is to get the best flow necessary. Running a tight EH on it kinda defeats the purpose. You could do that on the primary and externally gate it to help reduce this as a choke point though. Not to mention, with a VP truck, do you really think you need to go that big with twins? I don't know your mods, but I highly doubt you have so much fuel you need the 80 to burn it. A 62/75 combo would be awesome with some Mach 7 or 8's IMO.
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I think you have your terms mixed up...primary is in the 75-80 range.

I agree that a tighter exhaust housing could hurt flow, but I don't see it being that detrimental. I'm not talking about running something as small as a .8 or .9 on it - something in the 1.10 range vs the common 1.32.

Like I said in my earlier post...I'm leaning toward a 64 as a single and considering what options may exist beyond that if I were to add another turbo in the mix with some more fuel.
 
j-rod said:
I think you have your terms mixed up...primary is in the 75-80 range.

I agree that a tighter exhaust housing could hurt flow, but I don't see it being that detrimental. I'm not talking about running something as small as a .8 or .9 on it - something in the 1.10 range vs the common 1.32.

Like I said in my earlier post...I'm leaning toward a 64 as a single and considering what options may exist beyond that if I were to add another turbo in the mix with some more fuel.
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Next time I'll say top and bottom so I don't get mixed up, lol. Just make sure you build them with the primary on bottom, so I'm not wrong again, lol.
:Cheer:
 
i run a 66/71/13 ss housing over a S480 with race cover ext gated and it is laggy....if you are planing on running them and it's an auto you will need at least a 2400 stall converter and a cam to help it spool.....but i will say once it lights hang on :evil
 
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