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63Fiberbuggy Samba Member
Joined: January 15, 2007 Posts: 217 Location: SC
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Posted: Tue Nov 25, 2014 7:51 am Post subject: exhaust design effect on turbo performance |
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I recently replaced dual carbs w/Garrett T3 turbo fed w/Weber DCOE-45; and unit came with exhaust system (J-tubes, collector/header, flange to turbine housing). Still working thru tuning process; however, in reading from Garrett website, a question came to mind regarding effect of "unequal" length exhaust runs leading to the collector. Per Garrett, to optimize turbo performance, following is recommended:
- make the exhaust primaries equal length to balance exhaust reversion across all cylinders; and to maintain pulse energy to the turbine; for best power, tuned primary lengths can be used
In measuring mine, lengths vary significantly due to exhaust design; and I browsed photos of samba member's turbo applications, taking note that many appear to be "unequal" as well. So, questions are: how much effect have folks noticed with unequal lengths; any lag/lurch? Any recommendations for suppliers that offer tuned exhaust kits?
Thanks for support getting the most out of my turbo upgrade. |
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miniman82 Samba Swamp Donkey
Joined: March 22, 2005 Posts: 9515 Location: Southern Maryland
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Posted: Tue Nov 25, 2014 9:45 am Post subject: |
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No effect whatsoever on the street, mine even sounds like an inline 4. It's mainly race appllications that play with pulse headers/split turbine housings, which does make a big difference. _________________ Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747
Glenn wrote: |
satterley_sr wrote: |
I just wanted to bitch but I'm getting no sympathy. |
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Eaallred Samba Member
Joined: May 18, 2003 Posts: 5756 Location: West Valley City, Utah
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Posted: Tue Nov 25, 2014 11:54 am Post subject: |
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I heard it makes very little difference. That said, I just switched to an equal length header to feed my turbo, but I've made other changes as well so i'll have no idea if it makes a difference or not. _________________ Eric Allred
You have to remember something: Everybody pities the weak; Jealousy you have to earn. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Tue Nov 25, 2014 1:04 pm Post subject: |
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It is better to make the tubes as short as possible, and only as large as needed. If you have to lengthen them to make it equal then........... don't. |
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fastfil Samba Member
Joined: November 25, 2006 Posts: 356 Location: Sunshine Coast, AUS
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Posted: Tue Nov 25, 2014 1:07 pm Post subject: |
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Unequal length exhaust should give faster spool up but the turbine will choke earlier. _________________ "...swingaxle...transaxle...same diff." |
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clonebug Samba Member
Joined: January 29, 2005 Posts: 4026 Location: NW Washington
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Posted: Tue Nov 25, 2014 8:59 pm Post subject: |
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I use a cheap-ass sedan header and homemade up pipe to my turbo and have no troubles with spool.
Could it be better???? Maybe......but I have less than $100.00 into the header and it has worked fine for 4 years now.
Boost comes in at 2500 rpm and I have 15 lbs by 3500 rpm.
Any turbo is better than no turbo....... _________________
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63Fiberbuggy Samba Member
Joined: January 15, 2007 Posts: 217 Location: SC
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Posted: Thu Nov 27, 2014 3:57 pm Post subject: |
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Thanks for advice guys! I'm gonna stick with what I've got for now. Other mods at time of switch to turbo included: bore & stoke up from 1776 to 2180, counter-weighted crank, FK8 cam, SuperFlo heads w/1.4:1 rockers & dual springs...so, I'm feeling plenty under pedal, just curious if benefit there to tune exhaust. |
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