Buschur Racing dyno thread.....new developments.
Keith,
Funny you'd mention that, had I not already taken the valves completely out of the turbo I would have done that. That was my first idea on how to fix this.
David Buschur
www.buschurracing.com
Funny you'd mention that, had I not already taken the valves completely out of the turbo I would have done that. That was my first idea on how to fix this.
David Buschur
www.buschurracing.com
Originally Posted by Ludikraut
Actually if you look at the TME compressor map, it does seem to be possible to max it out on pump gas (esp. 94 octane). I'm guessing that Dave's RS is hitting a VE of 95% or more in some spots, which means it may flow more than 600cfm near redline, which is definitely out of the TME's efficiency range.
On the subject of adding a stronger actuator spring to the wastegate ... how about a progressive spring (or maybe two stage spring)? That would let it open up a little bit at least at partial throttle, but it would take a lot more force to open it 100% at WOT.
l8r)
On the subject of adding a stronger actuator spring to the wastegate ... how about a progressive spring (or maybe two stage spring)? That would let it open up a little bit at least at partial throttle, but it would take a lot more force to open it 100% at WOT.
l8r)
and you don't want a waste gate opening at part throttle... not unless your boost is not suppose to be where it's suppose to be, enabling a waste gate to open at partial spool will only increase lag.
Originally Posted by Fourdoor
Hey Dave,
If having the internal passages open is killing spool up from some kind of turbulance or something, why not leave the internal gate intact and run a line directly from the boost source to the internal wastegate for good low end spool up, AND have your new O2 housing with external gate bolted on over the stock gate for actual boost control? If you can't do it with your tubular setup, you could take a stock O2 housing and weld the external gate to the wastgate passage of the O2 housing and weld shut the internal passage.... you KNOW that this would work.
Keith
If having the internal passages open is killing spool up from some kind of turbulance or something, why not leave the internal gate intact and run a line directly from the boost source to the internal wastegate for good low end spool up, AND have your new O2 housing with external gate bolted on over the stock gate for actual boost control? If you can't do it with your tubular setup, you could take a stock O2 housing and weld the external gate to the wastgate passage of the O2 housing and weld shut the internal passage.... you KNOW that this would work.
Keith
ah dangit... i'm not picturing what dave's sayin' here... if you can fit the wg in the port.... ok... but why is the normal evo a dual port... i thot the mr and revised 05 was dual port... what about hte regular evo 03-4 9.8 housing? aren't those the f'ed up ones that only have one port or something? does it turn out to be easier to remedy it on those hot sides?
Last edited by trinydex; Mar 25, 2005 at 12:12 PM.
The '03-'04 turbos for sure are dual port wastegates, well actually they are all dual port. Difference is the '03-'04's have two large holes that are completely seperate from each other with each having a seperate valve that covers each one. With the '05 MR turbo (and possibly all '05's I don't know haven't seen other '05 housings) it has one valve that covers two small wastegate ports.
The idea Keith had, as I said before, would probably work out very well.
David Buschur
www.buschurracing.com
The idea Keith had, as I said before, would probably work out very well.
David Buschur
www.buschurracing.com
Maybe I'm missing something here, but if you are saying that you have taken the swing valve completely out of the turbine housing, then that is your problem with slow spool and low power. The exhaust gasses are bypassing the turbine wheel through the wastegate ports that are now open. I must be missing something. I appologize if I'm insulting your intelligence. I will read the posts again.
There is an external wg that replaces the internal. The flapper door is no longer needed. The gases do not escape or bypass the turbine. The main concern is the slower spoolup.
It is the cavity that is left between the removed flapper door and the new flange and ext wg that appears to upset the airflow characteristics inside the turbine side under the current setup. (There is an empty pocket of air in there) Welding it shut and attaching the wg to the manifold appears to be the next best bet. Outside of that ever better would be to get a new cast 10.5cm2 hotside without an internal gate at all to keep it smooth for best flow charateristics.
It is the cavity that is left between the removed flapper door and the new flange and ext wg that appears to upset the airflow characteristics inside the turbine side under the current setup. (There is an empty pocket of air in there) Welding it shut and attaching the wg to the manifold appears to be the next best bet. Outside of that ever better would be to get a new cast 10.5cm2 hotside without an internal gate at all to keep it smooth for best flow charateristics.
Last edited by dsm95hybrid; Mar 25, 2005 at 10:56 PM.
the absence of the internal gates is most likely causing a backpressure type pressure differential similar to the surge porting you see on lots of well made turbos. the cavity is catching air particularly when the external gate is closed and instead of forming a boundary layer "across" the cavities they're somehow spitting the gas back at the on coming flow of the turbine. the reason for the lack of boundary layer across the cavity is probably exacerbated by the fact that there are TWO ports...
this of course is making more and more sense as i write it because if you think about it... the exahust gases move centripetally through the turbine. that means the location of wg ports is not exactly perpendicular to the flow but is at an agle with it, most likely an accute angle, but the same effect could be had with an obtuse angle.
assuming that the wg ports make an accute angle with the turbine flow then you get an exact case of surge port type backpressure differential. of course it'd be partial effect because the angle is not 180 with the flow like it is in surge porting.
if it makes an obtuse angle then what happens is the same as what happens in your evo when you just roll the rear windows partially down with the front windows up. you get a low pressure area right outside the ports and that scavenges the air out of them... until they have no more air in them in which case the ports are a low pressure area and they they vacuum the turbine flow back into the cavity causing BAD turbulance and this effect happens very rapidly causing a type of pressure differential oscillation. the WOWOWOW (and your ear drums feeling liek they're getting drummed) effect in the window example above.
this of course is making more and more sense as i write it because if you think about it... the exahust gases move centripetally through the turbine. that means the location of wg ports is not exactly perpendicular to the flow but is at an agle with it, most likely an accute angle, but the same effect could be had with an obtuse angle.
assuming that the wg ports make an accute angle with the turbine flow then you get an exact case of surge port type backpressure differential. of course it'd be partial effect because the angle is not 180 with the flow like it is in surge porting.
if it makes an obtuse angle then what happens is the same as what happens in your evo when you just roll the rear windows partially down with the front windows up. you get a low pressure area right outside the ports and that scavenges the air out of them... until they have no more air in them in which case the ports are a low pressure area and they they vacuum the turbine flow back into the cavity causing BAD turbulance and this effect happens very rapidly causing a type of pressure differential oscillation. the WOWOWOW (and your ear drums feeling liek they're getting drummed) effect in the window example above.
Last edited by trinydex; Mar 26, 2005 at 01:34 AM.
Originally Posted by davidbuschur
Keith,
Funny you'd mention that, had I not already taken the valves completely out of the turbo I would have done that. That was my first idea on how to fix this.
David Buschur
www.buschurracing.com
Funny you'd mention that, had I not already taken the valves completely out of the turbo I would have done that. That was my first idea on how to fix this.
David Buschur
www.buschurracing.com
Keith
Originally Posted by Richard Sierra
David, If you have not already, try the GM boost solenoid. It eliminated the taper for me.
I tried using the AEM to control boost, didn't work any better than a good manual controller. Neither did a couple electronic controllers I tried. That is what partly led me to the wastegates not staying shut.
Also, every single EVO has an adjustable actuator on it. I have tightened it as tight as it would go, put external springs on it. I typed all this info once. All this does is increase the spike with no difference in top end boost.
I've been doing this turbo stuff for awhile
David Buschur
www.buschurracing.com
Also, every single EVO has an adjustable actuator on it. I have tightened it as tight as it would go, put external springs on it. I typed all this info once. All this does is increase the spike with no difference in top end boost.
I've been doing this turbo stuff for awhile
David Buschur
www.buschurracing.com
We got the turbine housing today, have it installed on the car now. I was busy on our red EVO though and didn't get to dyno the RS. The red car made 634 again today, it's starting to get boring. Had some customers there and pulled it just to show them and make some noise.
This MR housing is a really nice piece. Much nicer than the TME 10.5 housing. I will dyno the car in the morning. IF this doesn't solve the slow spool up or if it does and won't hold boost up top I have the solution already figured out. It is going to be kick *** and am almost hoping I have to go through with it.
Next time I pull this car on the dyno, if the spool up is there and so is the top end boost I am going to push the car a little and try to break the 400 whp barrier on straight pump gas.........and on a tune I won't be afraid to give to a customer. Last pull was 392 whp with straight 94 octane and only 21.8 psi peak.
David Buschur
www.buschurracing.com
This MR housing is a really nice piece. Much nicer than the TME 10.5 housing. I will dyno the car in the morning. IF this doesn't solve the slow spool up or if it does and won't hold boost up top I have the solution already figured out. It is going to be kick *** and am almost hoping I have to go through with it.
Next time I pull this car on the dyno, if the spool up is there and so is the top end boost I am going to push the car a little and try to break the 400 whp barrier on straight pump gas.........and on a tune I won't be afraid to give to a customer. Last pull was 392 whp with straight 94 octane and only 21.8 psi peak.
David Buschur
www.buschurracing.com