My dominator 2 turbo @ 390awhp on a MD
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From: Alamogordo, NM
I found this technical article but honestly it's hard for me to wrap my hands around all the terms until I study this stuff some more:
http://www.dresser-rand.com/controls/sc0498.htm
I found this youtube video of a GN turbo where he had Surge at WOT at lower RPM's, he rebuilt the engine to flow more so that the bigger turbo wouldn't surge as much:
http://www.youtube.com/watch?v=RIC4MOq5w9s
This one shows a highly modified car exceeding the surge line at WOT even at higher RPM's... not good!
http://www.youtube.com/watch?v=nCj6Spwl1CU
I've seen anti-surge ported compressor housings with various designs:
http://store.forcedperformance.net/m...de=NTGT3582HTA
If it's just at low boost at WOT likely that wouldn't be too annoying, I'm starting to wonder if the compressor is a bitt too big on the Dominator 2 as far as being matched to the flow of the 4B11T at low RPM's in stock form. Honestly I just don't know since I don't have any first hand experience. Since I'm considering a Dominator 2 like turbo with a Ball bearing center section, the faster spoolup may make this an even bigger issue until the engine can use all that air being forced into it.
As far as I've researched, you would need to replace the compressor housing to incorporate an Anti-surge ring where air that built up beyond what the engine could consume would haven a path to exit without crashing into the compressor blades. They can be the mutliple hole design or a slotted design like FP had in their turbo on that link. Another option would be to increase the flow through the engine somehow, one way is to have a ported exhaust housing which raises flow with minimal impact on spool. Similar results would be from clipping the exhaust turbine wheel or running a larger diameter one in relation to the compressor wheel. Replacing the stock O2 and UR DP with the all in one design O2 & DP combo would also help I would imagine. That tubular manifold from Xtremeboost would also speed up exhaust out of the engine along with portwork to the head.
I would contact DTM and see what the next step would be as you may be just a slight mod away from eliminating the compressor surge.
http://www.dresser-rand.com/controls/sc0498.htm
I found this youtube video of a GN turbo where he had Surge at WOT at lower RPM's, he rebuilt the engine to flow more so that the bigger turbo wouldn't surge as much:
http://www.youtube.com/watch?v=RIC4MOq5w9s
This one shows a highly modified car exceeding the surge line at WOT even at higher RPM's... not good!
http://www.youtube.com/watch?v=nCj6Spwl1CU
I've seen anti-surge ported compressor housings with various designs:
http://store.forcedperformance.net/m...de=NTGT3582HTA
If it's just at low boost at WOT likely that wouldn't be too annoying, I'm starting to wonder if the compressor is a bitt too big on the Dominator 2 as far as being matched to the flow of the 4B11T at low RPM's in stock form. Honestly I just don't know since I don't have any first hand experience. Since I'm considering a Dominator 2 like turbo with a Ball bearing center section, the faster spoolup may make this an even bigger issue until the engine can use all that air being forced into it.
As far as I've researched, you would need to replace the compressor housing to incorporate an Anti-surge ring where air that built up beyond what the engine could consume would haven a path to exit without crashing into the compressor blades. They can be the mutliple hole design or a slotted design like FP had in their turbo on that link. Another option would be to increase the flow through the engine somehow, one way is to have a ported exhaust housing which raises flow with minimal impact on spool. Similar results would be from clipping the exhaust turbine wheel or running a larger diameter one in relation to the compressor wheel. Replacing the stock O2 and UR DP with the all in one design O2 & DP combo would also help I would imagine. That tubular manifold from Xtremeboost would also speed up exhaust out of the engine along with portwork to the head.
I would contact DTM and see what the next step would be as you may be just a slight mod away from eliminating the compressor surge.
You (and the rest of us) may have been better off going with the Dominator 2.5 with it's 47 lb/min compressor wheel instead of the Dominator 2.0 with it's 52 lb/min compressor wheel. You would be getting around 360 wheel HP on a mustang dyno if you switched out turbo's but it may cure the compressor surge in addition to having faster response times due to the lighter weight of the wheel and the ball bearing center section.
Keith
Keith
Well i am going to contact nick and see if there is a fix. I love the turbo just that surge is bothering me. But the car is fast and pulls nice.
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From: Alamogordo, NM
Not bad at all Joe, I bet you could get 11's too! Try lowering the tire pressures to 25-30 psi range and try lower boost off the 2 step and see what gets you minimal tire spin in 1st gear. Another option is to get the special slick tires that Oscar pulls off 1.4x 60's on plus they also get you some MPH in 4th gear due to a larger diameter if I'm not mistaken.
Also when you get the chance, can you go WOT in 4th at like 2k rpm's and let me know what rpm you reach 20 PSI at? Would be interesting to compare to the stock turbo as I'm planning on looking at a Dominator 2 sized turbo with a Ball bearing center section within 6 months.
Also when you get the chance, can you go WOT in 4th at like 2k rpm's and let me know what rpm you reach 20 PSI at? Would be interesting to compare to the stock turbo as I'm planning on looking at a Dominator 2 sized turbo with a Ball bearing center section within 6 months.
That is good info to know, so the Dominator 2 spools to 20 psi about 900 rpm's later but is 52 lbs/min flow versys 38 lbs/min which means it's likely producing similar HP 600-700 rpm's later than stock and then passing it of course. Really that is a minor sacrifice to get full boost levels to redline and 120mph trap potential.
If that compressor surge is barely happening it very well could just take 1 or 2 mods to swing things back in balance. Let us know what you end up doing!
If that compressor surge is barely happening it very well could just take 1 or 2 mods to swing things back in balance. Let us know what you end up doing!
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From: Alamogordo, NM
^^^^ Also where i live i am about 4,500 ft above sea level. So if you live a lot closer to sea level the faster the spool will be. Just something to think about.
Ah good point, can anyone with a stock turbo at altitude report back the RPM they spool to 20 psi starting at 2k in 4th? That would be a good comparison to see how it effects spoolup. 4th seems to be a good gear since 3rd just flies by too fast and 5th is lugging it too much.
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From: Alamogordo, NM
^^^^ mmmmmm ya i am sure i would gain around 2-4mph. Of the line it spun a lil but the track is pretty good so my car stuck for the most part. Shifting into second it would break lose a lil again but not to bad.
Interesting how the Dom 2 with meth but at altitude has very similar spoolup to the GT3076R and trap speeds are also limited by the rev limiter in 4th gear. Sounds like compressor surge is just going to be a problem the earlier you spool these larger turbos as well.
BTW "Joe's Evo X", I did find some work arounds for the compressor surge in 5th at 3400-3800 rpm's. You can either limit boost in that RPM range just below where it surges or play with the throttle maps and limit max TPS in those areas so that when you mash the pedal you are modulating the throttle automatically right along the surge line of the turbo.
I'm still doing some comparisons in 3rd and 4th gear for spoolup and airflow through the engine before and after to make sure it's not impacting performance too much. So far the impact is minimal but I need further testing.
BTW "Joe's Evo X", I did find some work arounds for the compressor surge in 5th at 3400-3800 rpm's. You can either limit boost in that RPM range just below where it surges or play with the throttle maps and limit max TPS in those areas so that when you mash the pedal you are modulating the throttle automatically right along the surge line of the turbo.
I'm still doing some comparisons in 3rd and 4th gear for spoolup and airflow through the engine before and after to make sure it's not impacting performance too much. So far the impact is minimal but I need further testing.
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From: Willougby ohio
I know this sounds crazy but has anyone considered a hard launch in say oh I don't know second gar to save one shift. Yes I know that second is taller than first but with enough rpm and clutch fee the 60ft may not be so differant and the shift time saved at speed may make the time better. I know it's a crazy idea but for giggels might be woth a shot and might give you a better shot at 5th gear. I thinlk it can help with these kind of mods on your car .
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From: Mitchigan
^^^you are dreaming, I dare you to try doing that...you will smell clutch so badly and might even ruin the clutch
don't ever try that and why would you say such a silly thing anyway? pull your head out of your azz
don't ever try that and why would you say such a silly thing anyway? pull your head out of your azz
I have the same issue, but I dont think its my BOV. I have a stock 8 turbo and it does it in 4th-6th at low rpms if I wot. I changed my bov from a turbo xs to a forge RS with a stiffer spring and it is still doing it. My only other thought on this is waste gate chatter, so I had a spring added to my wg and it helped a little. I am looking to get a 9 turbo in the near future and a hp wga hopefully it will solve my issue and open up a new light to yours? maybe the same issue?
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