Which Nathans Twins to go with?
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Which Nathans Twins to go with?
Well I have been e-mailing a bunch of info and questions to Nathan at MPI about what set of twins would be right for me. He suggested the Stocker/S00 or a 62/71/13 and a GT42. I am pretty much sold on the Stocker/S400, but I am curious about option #2. I figure it would be more expensive, but I am wondering if I should consider it or not. Current/future mods are in sig and I will be adding studs and springs too. I didn't want to bother Nathan anymore so I thought I would ask here.
#2
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Well the s400 and the GT4202r flow right about the same quantity of air. Difference is the 4202 will spool much faster. In fact, it will spool right along with your secondary and may be fully spooled before your secondary! The drawback is that turbo will be two to three times the price of the s400.
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Well the s400 and the GT4202r flow right about the same quantity of air. Difference is the 4202 will spool much faster. In fact, it will spool right along with your secondary and may be fully spooled before your secondary! The drawback is that turbo will be two to three times the price of the s400.
#5
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I find in my twinset that the lower turbo is often at or over the 30psi mark already before I reach full boost...
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#9
I asked Nathan the same thing. Response:
I have built kits for the stock turbo and a GT42 before but it hasn't worked out all that well. The turbine side is just too restrictive between the two. Mostly it is the stock turbo causing the problem. You can get away with it by using a S400 but not the GT42. So there are two combo's I'd consider, one is a Garrett stage 2 or 3 Dodge turbo and a BB GT42 or a modified stock turbo and a GT42. The modified stock turbo gives you a bigger turbine wheel to help the back pressure. You get basically the same thing in the Garrett. The only other option I would possibly consider is a S300G (Basically a BD super B) with a GT42. Any of those combo's will get you into the 650hp range and possibly 700.
I've run the stock/S400 combo with a external wastegate and it doesn't help enough to justify the expense because I can get enough wastegate flow out of the stock wastegate now. The problem is the drive pressures when you combine 2 really small turbine wheels together. It's some what the same with the BD towing twins. The other problem with those is the big turbo is just way too small to make a significant improvement over the top turbo by itself.
I have built kits for the stock turbo and a GT42 before but it hasn't worked out all that well. The turbine side is just too restrictive between the two. Mostly it is the stock turbo causing the problem. You can get away with it by using a S400 but not the GT42. So there are two combo's I'd consider, one is a Garrett stage 2 or 3 Dodge turbo and a BB GT42 or a modified stock turbo and a GT42. The modified stock turbo gives you a bigger turbine wheel to help the back pressure. You get basically the same thing in the Garrett. The only other option I would possibly consider is a S300G (Basically a BD super B) with a GT42. Any of those combo's will get you into the 650hp range and possibly 700.
I've run the stock/S400 combo with a external wastegate and it doesn't help enough to justify the expense because I can get enough wastegate flow out of the stock wastegate now. The problem is the drive pressures when you combine 2 really small turbine wheels together. It's some what the same with the BD towing twins. The other problem with those is the big turbo is just way too small to make a significant improvement over the top turbo by itself.
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Nathan upgraded my BD twin turbo set to a Super B (57/65/14) over a GT4202. They spool ridiculously fast.
Details here:
https://www.dieseltruckresource.com/...d.php?t=186665
The Super B is kind of like a newer (+04.5) stock turbo on the compressor side, but has a bigger exhaust side than stock.
Oh yeah... the GT4202 is also internally wastegated to give even more adjustability than just by having the top turbo wastegated. This means I can run a tighter exhaust side to get even quicker spool.
Still need to dyno though...
Details here:
https://www.dieseltruckresource.com/...d.php?t=186665
The Super B is kind of like a newer (+04.5) stock turbo on the compressor side, but has a bigger exhaust side than stock.
Oh yeah... the GT4202 is also internally wastegated to give even more adjustability than just by having the top turbo wastegated. This means I can run a tighter exhaust side to get even quicker spool.
Still need to dyno though...
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Nathan upgraded my BD twin turbo set to a Super B (57/65/14) over a GT4202. They spool ridiculously fast.
Details here:
https://www.dieseltruckresource.com/...d.php?t=186665
The Super B is kind of like a newer (+04.5) stock turbo on the compressor side, but has a bigger exhaust side than stock.
Oh yeah... the GT4202 is also internally wastegated to give even more adjustability than just by having the top turbo wastegated. This means I can run a tighter exhaust side to get even quicker spool.
Still need to dyno though...
Details here:
https://www.dieseltruckresource.com/...d.php?t=186665
The Super B is kind of like a newer (+04.5) stock turbo on the compressor side, but has a bigger exhaust side than stock.
Oh yeah... the GT4202 is also internally wastegated to give even more adjustability than just by having the top turbo wastegated. This means I can run a tighter exhaust side to get even quicker spool.
Still need to dyno though...
Julius I'm dying to hear some numbers...come on
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I have a 62-65-14 over a gt4202 on my auto and i run a stocker over a gt 4202 on my 6 speed. They both are amazingly quick to spool. Zero egt issues and very drivable. If you tow alot and want to be around 550 go the stocker as your primary, if you want to play alittle more go with a 62-65-14 over a gt4202. Both will amaze you.
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What elevation are you at in southern NM? Elevation plays a HUGE factor in how fast turbos spool up. I have a 62/71/13SS over an S474. It is a tad laggy here in Utah at 4000 feet elevation, but I've never really thought of it as an issue. UNTIL, I went to the California coast a few weeks ago. I was able to punch it from a stop and it was instant-spool! Completely changed the truck!
I'm considering dropping to a 65mm wheel on my top turbo to quicken spoolup here in Utah.
I'm considering dropping to a 65mm wheel on my top turbo to quicken spoolup here in Utah.