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Old 11-16-2009, 02:50 PM   #1
acssa
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Default twin scroll vs single

So I got tiered of all the cracking of the APS TSR Kit and desided to dump it, I bought a Roger Clark kit from the UK...I have a RHD car.

Kept the TSR70 turbo and changed the turbine housing to a .82 single scroll.

What happend next was shocking but a great find...for me.

With the turbo being single I was sad to have more lag...but hey a driving slow spooling car is better than a broken standing quicker spooling car.

Saterday I took the car to the dyno to check the spool and to see if the map needed changing....

The shock was that the single scroll spooled quicker than the twin!!! Not much...50 rpm or so, but still quiker!

Answers please GURU's... is this twin stuff for real?
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Old 11-16-2009, 03:53 PM   #2
FuJi K
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well... what was the a/r on the twinscroll hotside??
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Old 11-16-2009, 04:14 PM   #3
acssa
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Both are .82 GARRET

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well... what was the a/r on the twinscroll hotside??
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Old 11-16-2009, 04:18 PM   #4
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so the twinscroll turbine housing said it was .82?...never seen that before.
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Old 11-16-2009, 04:34 PM   #5
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Was there a true twinscroll exhaust manifold used? or was it just bolted on to a single scroll up-pipe? too many variables here to make a proper assessment.
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Old 11-17-2009, 02:42 AM   #6
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It was a twinscroll TSR70 APS kit... everything for twinscroll....(cracking)header up pipe the works... housing number 441296-12 A/R-82 T3 Flange
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Old 11-17-2009, 10:24 AM   #7
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maybe cause the header was cracked/cracking u werent taking full advantage of the twinscroll hotside
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Old 11-17-2009, 10:48 AM   #8
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the header only crack after the first dyno...so the comparison is with both kits without cracks...

The only other difference is that the car had 17 inch wheels with 235/40/17 and with the single scroll 235/40/18 with 18 inch wheels
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Old 11-17-2009, 02:36 PM   #9
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Well as far as I know a twinscroll T3 or T4 .82 housing does not exist. YoOu probably had the .78 IIRC. AR is measured different for twinscroll, as there is about 10% of the opening that is blocked by the divider.

Anyway, you could tell the spool difference on the street, but on the dyno it says that the single scroll spools faster? As Demislayer said, too many variables here to make a proper assessment. Were both tunes with the same target boost? How do you qualtify which turbo spooled faster? Any dyno charts? Logs?
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Old 11-17-2009, 02:52 PM   #10
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I will get the dyno charts.... overlay

And it is a .82

Link posted below with the photo. the boost with the twinscroll was 1.68 bar and the single was 1.54bar



Quote:
Originally Posted by aboothman View Post
Well as far as I know a twinscroll T3 or T4 .82 housing does not exist. YoOu probably had the .78 IIRC. AR is measured different for twinscroll, as there is about 10% of the opening that is blocked by the divider.

Anyway, you could tell the spool difference on the street, but on the dyno it says that the single scroll spools faster? As Demislayer said, too many variables here to make a proper assessment. Were both tunes with the same target boost? How do you qualtify which turbo spooled faster? Any dyno charts? Logs?

Last edited by acssa; 11-17-2009 at 03:04 PM.
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Old 11-17-2009, 03:01 PM   #11
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Old 11-17-2009, 04:13 PM   #12
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Wow, first one I've ever seen or heard of!!

If all things were kept the same, differences can be made in the exhaust manifold...regardless, the single scroll tested with faster spool up. I'd then look to see the tune, as that can have quite an effect on spool up. However, it is hard to numerically diagnose a tune to see the effects on spool.
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Old 11-17-2009, 05:26 PM   #13
aboothman
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Huh, that is strange. I cannot track down where that housing came from, but it is certain that it is not a genuine Garrett turbine housing...despite what it says. BUT, I have already spent too much time trying to figure that one out haha.

I am suspecting a boost leak somewhere, or an exhaust leak that was not detected. I have had issues in the past with exhaust leaks and late spool....I would hit full spool, but it took longer.

There IS the possibility, however, that the Twinscroll kit was just poorly engineered. Maybe the manifold runners are too large?
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Old 11-18-2009, 02:26 AM   #14
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The housing part number is 441296-12
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Old 11-18-2009, 03:26 PM   #15
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Doesn't the TSR 70 have a single wastegate for both scroll sides?
In theory, that would mean that it isn't a 100% segregated twin scroll system, but I don't know how much that would really affect things.
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Old 11-19-2009, 04:20 AM   #16
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Yes...they devide it on the ewg....

Quote:
Originally Posted by Iron Giant View Post
Doesn't the TSR 70 have a single wastegate for both scroll sides?
In theory, that would mean that it isn't a 100% segregated twin scroll system, but I don't know how much that would really affect things.
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