Twins back pressure - PowerStrokeNation : Ford Powerstroke Diesel Forum
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post #1 of 50 (permalink) Old 07-01-2008, 03:13 AM Thread Starter
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Twins back pressure

okay i have a question about back pressure with twin turbos I thought every one said that with twins you should have half as much back pressure as boost, but wait the last two people i have heard talk about twins, were running more back pressure then boost, and i mean WOT I just need some education hear, as i never plan on running twins or even go past having more than a chip on my pick up, just curious

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post #2 of 50 (permalink) Old 07-01-2008, 03:15 AM
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Re: Twins back pressure


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post #3 of 50 (permalink) Old 07-01-2008, 03:56 AM
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Re: Twins back pressure

Someone mentioned something about positive cross over 2 me. I'm not convinced that it can be reached. I know that I get 1-1 or dam close to it for a good RPM/boost range but then things start to slide. I think that's why the move to VNTs has occurred.

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post #4 of 50 (permalink) Old 07-01-2008, 04:04 AM
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Re: Twins back pressure

positive crossover has been accomplished.

08' F250 4x4 w/ 3:55's
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post #5 of 50 (permalink) Old 07-01-2008, 04:05 AM
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Re: Twins back pressure

At full boost?
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post #6 of 50 (permalink) Old 07-01-2008, 04:15 AM
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Re: Twins back pressure

who is full boost?

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post #7 of 50 (permalink) Old 07-01-2008, 04:38 AM
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Re: Twins back pressure

Quote:
Originally Posted by bigrpowr View Post
who is full boost?

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post #8 of 50 (permalink) Old 07-01-2008, 04:50 AM
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Re: Twins back pressure

im still trying to learn about turbo operation and theories but doesn't a lot of it have to do with the comp map? if you reach full boost while still within the comp map you will retain the 1:1 or close with the right setup. its when you bost past the map on the comp that you start seeing a higher back pressure ratios. correct me if im wrong.

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post #9 of 50 (permalink) Old 07-01-2008, 04:59 AM
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Re: Twins back pressure

most of the open pulling trucks i have dealt with run a higher boost presure then drive pressure. If your boost is lower then your drive you need to look at your turbo setup

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post #10 of 50 (permalink) Old 07-01-2008, 10:47 AM
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Re: Twins back pressure

I was told you always need to be as close to 1:1 as possible, otherwise you're twisting your turbo shaft which can eventually snap from the strain...
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