Which Nathans Twins to go with?
08-13-2008, 04:52 AM
#31
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08-13-2008, 05:23 PM
#32
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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...
08-13-2008, 05:26 PM
#33
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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.
08-13-2008, 05:39 PM
#35
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There are a couple S400 variants-- Bullseye lists anything from 72mm to 91mm inducer size, and flow variance between those could easily be 40-50lb/min.
I like the 4202 the best. 4508 for bigger power.
jmo
08-13-2008, 07:48 PM
#36
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08-13-2008, 09:32 PM
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Ok Soulezoo I want "in da club" so to speak. I finally have my twins from Nathan.
My 4202 is not the BB version. Still the spool is very nice and coming from 70k worth of sps66 it sure is weird to see 50psi of boost with less than 1100 deg egt. Hell the things make 45+psi with just flux1's and TST timing. I haven't pushed them at all yet, and since I haven't done the ARP bit I will limit boost at 55psi, for now, but WOW what a difference.
So what do ya say can I get in??
My 4202 is not the BB version. Still the spool is very nice and coming from 70k worth of sps66 it sure is weird to see 50psi of boost with less than 1100 deg egt. Hell the things make 45+psi with just flux1's and TST timing. I haven't pushed them at all yet, and since I haven't done the ARP bit I will limit boost at 55psi, for now, but WOW what a difference.
So what do ya say can I get in??
08-13-2008, 09:40 PM
#38
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Ok Soulezoo I want "in da club" so to speak. I finally have my twins from Nathan.
My 4202 is not the BB version. Still the spool is very nice and coming from 70k worth of sps66 it sure is weird to see 50psi of boost with less than 1100 deg egt. Hell the things make 45+psi with just flux1's and TST timing. I haven't pushed them at all yet, and since I haven't done the ARP bit I will limit boost at 55psi, for now, but WOW what a difference.
So what do ya say can I get in??
My 4202 is not the BB version. Still the spool is very nice and coming from 70k worth of sps66 it sure is weird to see 50psi of boost with less than 1100 deg egt. Hell the things make 45+psi with just flux1's and TST timing. I haven't pushed them at all yet, and since I haven't done the ARP bit I will limit boost at 55psi, for now, but WOW what a difference.
So what do ya say can I get in??
08-15-2008, 12:43 AM
#39
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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.
Depends on what your' goals are! I ran the stocker / gt 4202 for several months and if you tow or want more than 500 usable hp forget using the stocker. The biggest problem is drive pressures../egts. The set works great for daily driving and lites the same as stock, but put a load behind it or anything above 35 psi and drive pressures go through the roof. At 35-40 psi drive pressures were 70-80 and at 52-55 psi drive pressures were 100+. Due to pressures and temps I could barely tow with just my injectors 350 hp and could use no additional power. I spent many hours working on the wastegate and tuning with 0 results. My last attempt was to modify the exhaust housing on the stocker. This did help reduce some but overall the same issues were present high drive pressures and egts. I finally gave up and went with a II ps 62-12 as a sec which resolved all issues. Driive pressures are 1-1 at 55-60 psi, egts average 900 and with a load of 12k 1100 max and this was with additional power. When I was shopping last Oct, there were very few people running this set up and feed back was next to nothing with all not having a clue on drive pressures. Save yourself alot of grief and go with a larger sec over the gt 4202.
08-15-2008, 06:52 AM
#40
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It's worth mentioning that the problem with this setup^^ is the stocker, not the GT4202 underneath it.
The problem with the stockers at higher HP levels is that the turbines are just too small and the housings are too tight. If you sacrifice some spoolup to go larger on these (and reduce the amount of gasflow bypassed via wastegate), then the efficiency goes up a good boit because you are extracting useful work from the flow TWICE with two turbines.
But realistically, in order to have a really "efficient" two-stage setup, you'd have to give up a lot of spoolup. It would end up looking something like a Silver 64 over a GT4202. While the Silver series from II is pretty laggy because the turbines are oversized relative to what they need to be, that oversized turbine becomes your friend when you have a lot of extra gasflow to deal with as in a twins setup.
This is why VGT could be really exciting for a small charger if it could be implemented effectively. You get the tight spoolup early, but drastic reductions in restriction on the high end-- it expands the operating range of the turbine a bunch.
jh
The problem with the stockers at higher HP levels is that the turbines are just too small and the housings are too tight. If you sacrifice some spoolup to go larger on these (and reduce the amount of gasflow bypassed via wastegate), then the efficiency goes up a good boit because you are extracting useful work from the flow TWICE with two turbines.
But realistically, in order to have a really "efficient" two-stage setup, you'd have to give up a lot of spoolup. It would end up looking something like a Silver 64 over a GT4202. While the Silver series from II is pretty laggy because the turbines are oversized relative to what they need to be, that oversized turbine becomes your friend when you have a lot of extra gasflow to deal with as in a twins setup.
This is why VGT could be really exciting for a small charger if it could be implemented effectively. You get the tight spoolup early, but drastic reductions in restriction on the high end-- it expands the operating range of the turbine a bunch.
jh
08-15-2008, 09:23 AM
#41
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Depends on what your' goals are! I ran the stocker / gt 4202 for several months and if you tow or want more than 500 usable hp forget using the stocker. The biggest problem is drive pressures../egts. The set works great for daily driving and lites the same as stock, but put a load behind it or anything above 35 psi and drive pressures go through the roof. At 35-40 psi drive pressures were 70-80 and at 52-55 psi drive pressures were 100+. Due to pressures and temps I could barely tow with just my injectors 350 hp and could use no additional power. I spent many hours working on the wastegate and tuning with 0 results. My last attempt was to modify the exhaust housing on the stocker. This did help reduce some but overall the same issues were present high drive pressures and egts. I finally gave up and went with a II ps 62-12 as a sec which resolved all issues. Driive pressures are 1-1 at 55-60 psi, egts average 900 and with a load of 12k 1100 max and this was with additional power. When I was shopping last Oct, there were very few people running this set up and feed back was next to nothing with all not having a clue on drive pressures. Save yourself alot of grief and go with a larger sec over the gt 4202.
It's worth mentioning that the problem with this setup^^ is the stocker, not the GT4202 underneath it.
The problem with the stockers at higher HP levels is that the turbines are just too small and the housings are too tight. If you sacrifice some spoolup to go larger on these (and reduce the amount of gasflow bypassed via wastegate), then the efficiency goes up a good boit because you are extracting useful work from the flow TWICE with two turbines.
But realistically, in order to have a really "efficient" two-stage setup, you'd have to give up a lot of spoolup. It would end up looking something like a Silver 64 over a GT4202. While the Silver series from II is pretty laggy because the turbines are oversized relative to what they need to be, that oversized turbine becomes your friend when you have a lot of extra gasflow to deal with as in a twins setup.
This is why VGT could be really exciting for a small charger if it could be implemented effectively. You get the tight spoolup early, but drastic reductions in restriction on the high end-- it expands the operating range of the turbine a bunch.
jh
The problem with the stockers at higher HP levels is that the turbines are just too small and the housings are too tight. If you sacrifice some spoolup to go larger on these (and reduce the amount of gasflow bypassed via wastegate), then the efficiency goes up a good boit because you are extracting useful work from the flow TWICE with two turbines.
But realistically, in order to have a really "efficient" two-stage setup, you'd have to give up a lot of spoolup. It would end up looking something like a Silver 64 over a GT4202. While the Silver series from II is pretty laggy because the turbines are oversized relative to what they need to be, that oversized turbine becomes your friend when you have a lot of extra gasflow to deal with as in a twins setup.
This is why VGT could be really exciting for a small charger if it could be implemented effectively. You get the tight spoolup early, but drastic reductions in restriction on the high end-- it expands the operating range of the turbine a bunch.
jh
I'm glad to finally see some hard data to back up my personal theory.
I can't wait to order my set of turbos...
08-15-2008, 09:54 AM
#42
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So much info!!! Thanks everyone! Well after talking over things with the Mrs., I don't think I can afford anything over the stocker/S400 set-up and still be able to afford the injectors/studs/and springs, plus a couple little touches here and there. I e-mailed Nathan and asked him for some other prices, so we'll see. If I do go with the Stocker/S400, does this give me enough room to grow later? Would I be able to keep the S400 and replace the stocker with something else down the road?
08-15-2008, 10:27 AM
#43
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If I do a twins setup it will be either a 62/65/13ss over a S400 or my 62/71/13ss over an S400 or S480. Decisions, Decisions. Right now I am not really considering the stocker over an S400. What I will probably do is sell my turbo and get a nice shinny new polished 62/65/13ss over an S400 and declare finished except for sticks, studs, and maybe a Helix II.
08-15-2008, 11:43 AM
#44
If I do a twins setup it will be either a 62/65/13ss over a S400 or my 62/71/13ss over an S400 or S480. Decisions, Decisions. Right now I am not really considering the stocker over an S400. What I will probably do is sell my turbo and get a nice shinny new polished 62/65/13ss over an S400 and declare finished except for sticks, studs, and maybe a Helix II.
08-15-2008, 12:03 PM
#45
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Judgeing from your other posts about turbos and lag and such I think the 62/65 over an S400 would be your best bet. It should spool nice and be enough air for 700. Also (I figure you are aware of this but I am unsure of costs) but you can just send your turbo in and have them put a 65 mm wheel in it and it may be cheaper.