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RB Turbos??? New guy question
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08-16-2012, 02:46 AM | #45 | |
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The only way to offer twin turbos that perform similarly to a single turbo, as you will see, is to have them run non-OEM exhaust housings. Which means using a new manifold and a new downpipe/wastegate configuration. And you will find that under-hood real-estate is going to be an issue when trying to fit larger frame twin turbos. Unless you can bend the laws of space and time (or relocated the engine mount and modify the frame rail), that is going to be impossible. You will also have to use non-OEM induction plumbing which will post somewhat of a packaging dilemma since you will have to either route them in front and behind the engine or get all bendy and keep them on the hotside. Both solutions are better than using the stock induction pipes. But both are inferior to a straight, short-tubed intake. Lastly, all other things equal, a single turbo will always offer better compressor and turbine efficiency than two smaller turbos. Even if they were using the same aero/material as the single turbo. This is because compressor and turbine efficiency is largely dependent clearance between the wheel and the housing which is limited by machining technique. So two smaller turbos will have the same nominal clearance as a larger single. But their relative clearance (relative to the wheel diameter) is greater which means generally lower efficiency. Hope that helps -shiv |
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08-16-2012, 04:06 AM | #46 | |
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Yes, I do know why BMW decided having twins and later changed for twin scroll single N55, do you? You are moving from the subject to talk about "properly sized twins", what ever that means. Let's stick to the RBs, since that is what you referred to when saying Shiv's figures were somehow misleading. You see, "properly sized" could mean double the size of one single for someone, if you understand the exaggeration. If you are claiming that you can push stock frame twins further than 520WHP with "a good intercooler" alone, I have to disagree. The boost pressure needed would be so high that the IATs cannot be kept reasonable with any intercooler. Since the back pressure becomes high, the pressure drop of the intercooler becomes very important in addition to the cooling efficiency. What kind of pressure drops and efficiency percentages you were thinking of when you talked about "a good intercooler"? Also, what boost pressure you were thinking of for the twins? What compressor maps were you looking at? You were thinking of upgrading the MAP sensor and in which way are you going to manage the DME in case of non-stock TMAP. You started questioning the dyno figures Shiv stated because you have probably not been searching or looking for the actual dyno graphs. He referred to the need for higher octane to reach the figures in question with the stock frame twins and that relates to the vastly increased backpressure and also turbo efficiency dropping at the higher revs at the peak power. You could start studying by looking at the compressor maps of the said options. You could give us your professional opinion on the achievable power figures after you have studied the compressor maps and evaluated the level of the backpressure. I believe you know the static and dynamic CRs of N54? Are you claiming the stock frame turbos, with stock CR pistons and stock cams, don't need high octane to reach 520WHP? If yes, you could either demonstrate that by showing us a dyno of it, or calculate it for us having all the info available. We are basing our arguments on several dynos that would imply the power figures being flow and octane limited with the stock frame turbos. Last edited by jippii ensio; 08-16-2012 at 08:11 AM.. |
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08-16-2012, 04:23 AM | #47 |
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hehe funny
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08-16-2012, 06:17 AM | #49 |
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08-16-2012, 06:21 AM | #50 |
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they have NO tune for upgraded turbos but i am aware they will fix one for LOBA's turbos which are hybrids clipped turbine.
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08-16-2012, 09:36 AM | #51 | |
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it would suck if I had to get a completely new tune on top of the turbos. Thanks - Luigi
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08-16-2012, 09:50 AM | #52 | |
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Last edited by Tony@vargasturbotech; 08-16-2012 at 10:24 AM.. |
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08-16-2012, 09:58 AM | #53 | |
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08-16-2012, 10:20 AM | #54 | |
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08-16-2012, 10:48 AM | #55 | |
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08-16-2012, 10:57 AM | #56 |
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Huh? This was a conversation about the different options for aftermarket turbo upgrades for the N54. The Title of this forum is N54 Turbo engine / Drivetrain/ Exhaust modifications. Maybe you can let me know what the correct forum for this convo would be then. Thanks
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08-16-2012, 10:58 AM | #57 | |
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08-16-2012, 11:09 AM | #58 |
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just wanted to add that their is "supposedly" a little more gain left to be had with our hybrid twin upgrades, but single will always make more power
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08-16-2012, 12:00 PM | #60 |
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GIAC offered to tune my car if I purchased the RB turbos. I decided that a super good suspension setup was more beneficial than any twin/single upgrade would be; sad people don't realize that but ok, haha.
However I am still searching for a good compromise between RBs and shiv's option. Gintani's turbo upgrade is coming up quickly and ER already offered to build me an upgrade; just gotta find someone to tune it, LOL.
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08-16-2012, 12:39 PM | #61 |
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Gintani's getting in on the N54 game?? VAC said awhile ago that they were putting some R&D into a legit turbo upgrade too
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08-16-2012, 01:17 PM | #62 |
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Funny stuff. If price and warranty status weren't common denominators, i would go the single turbo route each and every time on this platform.
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08-16-2012, 05:36 PM | #63 | |
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Agreed, single is the way to go, just need various options for different applications.
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08-19-2012, 02:42 PM | #64 |
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08-19-2012, 02:49 PM | #65 |
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I know they're doing their own Performance Cylinder Head Upgrade & they also have the CP Pistons, Carillro Rods + VAC Rod Bearings, but is there anything else they've got cooking?
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08-19-2012, 11:54 PM | #66 |
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I don't care how great the single turbo might be, $10k is highway robbery. Seriously, ten thousand dollars for a turbo, manifold, downpipe, tune, and meth kit? The same in the Mitsubishi Evo world goes for no more than $5k.
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