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BIG Single vs. dual turbos

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Old 02-14-2006 | 05:13 PM
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BIG Single vs. dual turbos

was wondering what is the best for the money? I was looking at the ATS Aurora 5000, the ATS MST which are both single turbos able to push 50 psi I believe. Or would a dual turbo setup be better where I can push 80 PSI in some cases. Just curious. Lemme know what you think
Old 02-14-2006 | 05:57 PM
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Depends on what you want to do and your power level. Personally, you can't beat a set of twins for spoolup and EGT control. You just can't. The only problem with them is that unless you build them yourself they are going to cost you a small fortune. Not to mention that if your an auto that you have to remove your tranny heat exchanger, and you have to move/remove your passenger side battery. Now, with that being said, a good set of twins will out spool any single on the market for the most part and provide cooler EGT's.

For a single, you can find them that spool very fast if you don't go to big. My KSB-1 is quite a bit bigger than my HY35 was yet it spools almost as fast. The ex housing size has a lot to play in that. If your staying under about 550-500hp and don't mind a little lag a warm EGT's, then a single is the way to go. If you want instant spoolup with cool egt's, you can't beat twins. The phat shaft turbos seem to be very popular.
Old 02-14-2006 | 06:09 PM
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You might tell us a bit about you truck too...a lot of difference between a 12v and 24v as far as chargers go

Chris
Old 02-14-2006 | 07:56 PM
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[QUOTE=BigBlue]Depends on what you want to do and your power level. Personally, you can't beat a set of twins for spoolup and EGT control. You just can't. The only problem with them is that unless you build them yourself they are going to cost you a small fortune. Not to mention that if your an auto that you have to remove your tranny heat exchanger, and you have to move/remove your passenger side battery. Now, with that being said, a good set of twins will out spool any single on the market for the most part and provide cooler EGT's.

For a single, you can find them that spool very fast if you don't go to big. My KSB-1 is quite a bit bigger than my HY35 was yet it spools almost as fast. The ex housing size has a lot to play in that. If your staying under about 550-500hp and don't mind a little lag a warm EGT's, then a single is the way to go. If you want instant spoolup with cool egt's, you can't beat twins. The phat shaft turbos seem to be very popular.[/QUOT

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Blue
You are correct about the heat exchanger in the Piers set but not all of them
I did not have to move/remove my pass battery with my Piers kit but have heard of other members removing theirs with other vendors kits.
And yes I would agree that nothing beats twins for spool up. Yes they cost alot but I say they are worth the money
Old 02-14-2006 | 09:09 PM
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There is no way on earth that I would spend $2300 on a single. Period. I dont care what single it is or whats done to it, or what some marketing moron says it will do. When it comes to good, quick efficient boost in the higher pressures, there is no substitute for compounds. Plus, if you are skilled at welding and fabbing pipe, they are cheaper than a good single. You use your existing HX35 with a different exhaust housing perhaps, depeding on your setup, and a nice cheap mass produced HT3B. Lot of guys on here have done em themselves for under $1,000 total.

Mine will be done this fall when I get severl other higher priority projects completed first.


Just say no to marketing-hyped $2000+ singles.......



KP
Old 02-14-2006 | 09:57 PM
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Originally Posted by ratsun

Blue
You are correct about the heat exchanger in the Piers set but not all of them
I did not have to move/remove my pass battery with my Piers kit but have heard of other members removing theirs with other vendors kits.
And yes I would agree that nothing beats twins for spool up. Yes they cost alot but I say they are worth the money
I know. But I figured I'd just throw it in there just to give him as much info as humanly possible without having to list every makers kit and what they remove/keep.
Old 02-14-2006 | 10:50 PM
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I wouldn't buy an A5k til they put a wastegate on it. just my 2 cents.
Old 02-14-2006 | 11:15 PM
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i think the twins vs single battle all lies in what power you wanna make, and what you do with the truck.

for me i want 475-500 in a daily driving/racing application for as little money possible, so a big single is good for me, but if i was gonna be towing heavy trailers everyday id go twins for the better spoolup and EGT control. when i play on the street or at the track i can get enough fuel flowing to spool a big single pretty quick and the EGT's will be in check for the short speed bursts.

twins are sweet ill agree, but if you only want 350-400hp in a truck you can drive everyday, and throw a travel trailer or toy hauler behind it, i believe a little bit of fuel and a good hybrid or small schwitzer variant is plenty enough to keep the heat down while towing or playing around
Old 02-15-2006 | 09:17 AM
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Originally Posted by 600 Megawatts
There is no way on earth that I would spend $2300 on a single. Period. I dont care what single it is or whats done to it, or what some marketing moron says it will do.

Just say no to marketing-hyped $2000+ singles.......
Have you personally tried any of the new hybrids to verify your statement? There are a lot of guys out there running singles that make in excess of 600 HP and are very nice driving trucks. Granted twins are nice but you really don't have to have big boost numbers for big HP, our shop truck makes over 600 RWHP on a moderate sized single limited to 45 lbs boost. A good air charge is much more important than a big boost number.

I have run twins on my trucks as well as numerous hybrid singles, the overall preformance of a good set of twins that is set up correct is wonderful but they are not without their problems. They are complicated to install compared to a single, more prone to exhaust leaks, and are a bear to work on. A single is simple, works well, and can be installed and setup to make almost identical HP. Most guys do not make their own twins (good twins are TIG welded, power coated, properly wastegated, etc) hence a large difference in pricing from a single. You can also run a big single on a stock headgasket, with twins O-rings are a must on the pre-third gen trucks.

I feel that both twins and singles have their place and it is up to each user to decide which route is best for them.
Old 02-15-2006 | 09:54 AM
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Originally Posted by Grimwulf99
was wondering what is the best for the money? I was looking at the ATS Aurora 5000, the ATS MST which are both single turbos able to push 50 psi I believe. Or would a dual turbo setup be better where I can push 80 PSI in some cases. Just curious. Lemme know what you think
You're going to need a lot of things before you'll hit 80psi. Clutch/tranny, head studs, o-ring, and injectors come to mind. Fill out your sig

You just need enough air to burn the fuel you have so more boost isn't always better.
Old 02-15-2006 | 02:23 PM
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Twins are the way to go, no matter what power level we're reaching at.
I don't think BMW for example would have chosen to elevate price of their cars just for sake of being extraordinary, and using two-stage charging only as a marketing gimmick. Passenger car market is very price driven. Manufacturers are looking to save every nickel they can.

Quick boost buildup, and high boost levels with ease in a two-stage turbocharging system. What is there not to like even from an OEM standpoint?

https://www.dieseltruckresource.com/...ad.php?t=86948
Old 02-15-2006 | 02:57 PM
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Artsi L,

I don't agree that twins are the best for every application. That's like saying the v-8 engine configuration is the best hands down. It's all about different applications. There are very few instances where a blanket statement like that is accurate, and this is one where you are incorrect. I'm sure others will chime in.

Waylan
Old 02-15-2006 | 03:31 PM
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More fuel for this thread: http://www.eere.energy.gov/vehiclesa..._sweetland.pdf

I'll rather let Borg Warner do the argumentation on my behalf over this issue. I hope you don't mind my may out of this heat
Old 02-15-2006 | 04:23 PM
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I can't get your link to work. Either way, saying 2 turbos is always the best choice is saying bigger/more is always better. In that case, let's put 3, 4, or more turbo chargers on there. Each individual turbo should be better able to cover its rpm range better than fewer turbos. Then you will say, but 2 turbos is sufficient to cover the operating rpm range required. My point exactly..........it all has to do with application. The big rigs have alot of underhood room to have several turbos.....yet all that I know of only run 1 charger. Some may say the 30-06 is the best gun hands down, no question about it. Not when you're hunting squirrels to put meat on the table. Everything depends on application. That's why they make elmer's glue and superglue.

Waylan
Old 02-15-2006 | 07:36 PM
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No its not just a bigger is better deal, not at all. And twins have nothing to do with covering RPM ranges. When you are talking about boost numbers in the 45+ psi range, its just far more efficient to get these pressures with two stage compression. Its just the way it is when you are talking about centrifugal compressors. Its not a diesel truck thing or twin turbo thing, or a Cummins thing. Its a centrifugal compressor thing. Period. Do some reading on high pressure multistage centrifugal compressors. You will understand.
Also factor in that with twins you are also expanding the exhaust gasses and converting heat into work with compounded (in series) turbines and the system efficiency gets even better as a result of that. Read, read, and READ some more about turbines in industry and power generation and then read, read, READ some more about multistage high speed centrifugal compressors. Trust me. Don't listen to the salesmen on the Trucks TV show, just learn about compounded (series) compressors and turbines outside of the automotive market and you will understand.


If you want to argue over singles vs. twins for 35 Psi of boost than fine, I will agree with you that is a pressure ratio which can comfortably be had with decent efficiency with a single and the advantages previously stated in this post regarding simplicity, engine bay room etc are totally valid.

But, bottom line, for boost pressures over 45 Psi twins are ALLWAYS better, period. I will stand by that statement no matter how many flames are thrown around on here. Operating on a 4:1 or higher pressure ratio in one stage of a centrifugal compressor is just too far away from where a centrifugal compressor should be.


KP



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