Quick parts updates....
Originally Posted by Zeus
Things are getting more interesting by the minute... The low end surge hurts my soul (what's left of it) though, as I do alot of city driving in traffic under 3000rpm in 5th and 4th gear.
Originally Posted by MalibuJack
Ya know, even the stock turbo gets a bit of surge at low RPM when you lug the engine around like that, my solution to that was to play with different BOV's until I found something that would quiet down the symptoms.
Regardless, I'm looking forward to seeing how this works out.
Originally Posted by EVO8LTW
Does the BR440 do that too?
I have a precision GT3582RLE ball bearing turbo on my talon, it surges so bad with the to4E compressor housing that the turbo is just about worthless with that comp housing.
Originally Posted by umiami80
an external gate should do it. IMHO the 20G is too large of a turbo to be internally gated.
Originally Posted by MalibuJack
Ya know, even the stock turbo gets a bit of surge at low RPM when you lug the engine around like that, my solution to that was to play with different BOV's until I found something that would quiet down the symptoms.
now the question... WHY would the stock turbo surge with this larger compressor wheel at 2000 in fourth? at 2000 we're not moving much air... the 10.5 or otherwise should well be able to flow 2000rpm worth of air EVEN at the torque loads of 4th gear... what's the deal? and why would there be no surge at other times?
my understanding of surge is that under some given condition either the exhaust side or the intake side of the turbine is causing BOTH sides to stall or stop or choke. if you have too small of a hot side and your comp side is pushing too much air the hot side gets choked and your compressor wheel stops and the air it was pulling in crashes into it and there's a lotta bad stuff happening.
if your comp side is too small and you're able to flow out the exhaust but your comp wheel can't keep up then you could get surge again but that's a more fine tuned surge (if you could call something disastrous like that fine tuned) and requires the perfectly mismatched comp housing. so is this what's happening with the 21g?
Last edited by trinydex; Apr 27, 2005 at 09:48 PM.
Originally Posted by trinydex
what? i hope you're not referring to compressor surge...
ok... i agree that the stock turbo does surge... usually happens for me ONLY in second gear and when i let off partially at around 3-5 rpm and then get right back on it.... man does the car buck. i think it has something to do with a partial purge and then the buck causes a throttle input from my foot and that just sets off a terrible chain of events.
now the question... WHY would the stock turbo surge with this larger compressor wheel at 2000 in fourth? at 2000 we're not moving much air... the 10.5 or otherwise should well be able to flow 2000rpm worth of air EVEN at the torque loads of 4th gear... what's the deal? and why would there be no surge at other times?
my understanding of surge is that under some given condition either the exhaust side or the intake side of the turbine is causing BOTH sides to stall or stop or choke. if you have too small of a hot side and your comp side is pushing too much air the hot side gets choked and your compressor wheel stops and the air it was pulling in crashes into it and there's a lotta bad stuff happening.
if your comp side is too small and you're able to flow out the exhaust but your comp wheel can't keep up then you could get surge again but that's a more fine tuned surge (if you could call something disastrous like that fine tuned) and requires the perfectly mismatched comp housing. so is this what's happening with the 21g?
ok... i agree that the stock turbo does surge... usually happens for me ONLY in second gear and when i let off partially at around 3-5 rpm and then get right back on it.... man does the car buck. i think it has something to do with a partial purge and then the buck causes a throttle input from my foot and that just sets off a terrible chain of events.
now the question... WHY would the stock turbo surge with this larger compressor wheel at 2000 in fourth? at 2000 we're not moving much air... the 10.5 or otherwise should well be able to flow 2000rpm worth of air EVEN at the torque loads of 4th gear... what's the deal? and why would there be no surge at other times?
my understanding of surge is that under some given condition either the exhaust side or the intake side of the turbine is causing BOTH sides to stall or stop or choke. if you have too small of a hot side and your comp side is pushing too much air the hot side gets choked and your compressor wheel stops and the air it was pulling in crashes into it and there's a lotta bad stuff happening.
if your comp side is too small and you're able to flow out the exhaust but your comp wheel can't keep up then you could get surge again but that's a more fine tuned surge (if you could call something disastrous like that fine tuned) and requires the perfectly mismatched comp housing. so is this what's happening with the 21g?
Keith
A little OT.....
David, Are you PC logging or internal logging? I know your car is fast, but it is a full 1.2 seconds quicker than mine from 4,000 to 7,000 rpm in fourth. If it is a PC log, I would be interested in seeing if an internal log is any different.
David, Are you PC logging or internal logging? I know your car is fast, but it is a full 1.2 seconds quicker than mine from 4,000 to 7,000 rpm in fourth. If it is a PC log, I would be interested in seeing if an internal log is any different.
Too many questions, most of which I have covered already and not to be rude but I can't keep up anymore. The answers for which turbine housing comes with it, which one I recommend etc. etc. YOU can find the answers and probably learn something by reading this thread and the Buschur Racing Dyno Thread also found on these forums.
Now....
Richard, I use the internal logger sometime and the PC loggers other, they seem to be the same, I don't know why they would differ.
Took the RS to the track last night.
Horrible windy weather, raining on and off.
I could NOT 60' the car. Best one I had was a 1.84. Running the same straight 94 octane the car has always had in it.
My best at the shootout with the stock turbo was a 12.18 at 112.26 mph, I missed a gear or something, don't remember. Kevin in the RS though had the best time of the day with an 11.76 at 116.30 mph.
Last night the very first pass I ran 12.00 at 112.51 mph. I hit the revlimiter which for some reason was at 7000 rpm. That would have been my best pass of the night.
The best pass of four that I made was 11.94 at 118.40 mph.
Looks like the turbo is definetely making some extra power. As the MPH on a not so great pass was still up over 2 mph from it's best ever. The peak boost that run was 21 and it was 19.88 psi at 7500 rpm. So very nice steady boost. Stock turbo had to have much higher boost levels (spikes) to perform like this.
Here is the bad side, and the part that is going to hold us up from selling these. The compressor surge is not acceptable. It is HORRIBLE. My car is a freak, tuned and tweaked to perform as well as it possibly can on pump gas. I don't think most guys will experience the same thing I am.
The 21g on my car is the tit/alum wheel. It is not clipped. The solution maybe to just use a standard wheel, clip the tit/alum or maybe clip the stock. We also may have to use some type of anti-surge ring on it.
For now I am not comfortable selling it, it works very well and at higher boost levels on race gas it is going to be a real asskicker. I do not like the surge though
For those of you that don't think it will happen to you or think you can live with it, call and I will sell it to you. For those others, I suggest waiting for a few more experiments.
I will not sell one of these now without you sending in your core first and then refund you money when you do send your core, BTW.
David Buschur
www.buschurracing.com
Now....
Richard, I use the internal logger sometime and the PC loggers other, they seem to be the same, I don't know why they would differ.
Took the RS to the track last night.
Horrible windy weather, raining on and off.
I could NOT 60' the car. Best one I had was a 1.84. Running the same straight 94 octane the car has always had in it.
My best at the shootout with the stock turbo was a 12.18 at 112.26 mph, I missed a gear or something, don't remember. Kevin in the RS though had the best time of the day with an 11.76 at 116.30 mph.
Last night the very first pass I ran 12.00 at 112.51 mph. I hit the revlimiter which for some reason was at 7000 rpm. That would have been my best pass of the night.
The best pass of four that I made was 11.94 at 118.40 mph.
Looks like the turbo is definetely making some extra power. As the MPH on a not so great pass was still up over 2 mph from it's best ever. The peak boost that run was 21 and it was 19.88 psi at 7500 rpm. So very nice steady boost. Stock turbo had to have much higher boost levels (spikes) to perform like this.
Here is the bad side, and the part that is going to hold us up from selling these. The compressor surge is not acceptable. It is HORRIBLE. My car is a freak, tuned and tweaked to perform as well as it possibly can on pump gas. I don't think most guys will experience the same thing I am.
The 21g on my car is the tit/alum wheel. It is not clipped. The solution maybe to just use a standard wheel, clip the tit/alum or maybe clip the stock. We also may have to use some type of anti-surge ring on it.
For now I am not comfortable selling it, it works very well and at higher boost levels on race gas it is going to be a real asskicker. I do not like the surge though
For those of you that don't think it will happen to you or think you can live with it, call and I will sell it to you. For those others, I suggest waiting for a few more experiments.
I will not sell one of these now without you sending in your core first and then refund you money when you do send your core, BTW.
David Buschur
www.buschurracing.com
Wow... sounds interesting, yet disappointing all at the same time.
I hope it turns out to be a good "bolt on" option for "bolt on" cars when it is all sorted out.
Good luck David
I hope it turns out to be a good "bolt on" option for "bolt on" cars when it is all sorted out.
Good luck David
i would vote for the antisurge ring because that seems to be the cleanest out of the any option available for curing surge.
also... don't know if you guys know but the evo 9 comes with a revised turbo, larger compressor nozzle... so... this stock turbo tweaking thing could end up looking REAL good.
also... don't know if you guys know but the evo 9 comes with a revised turbo, larger compressor nozzle... so... this stock turbo tweaking thing could end up looking REAL good.
