??Some questions about wastegates and using one in a SC'd application??
I'm just not totally clear on teh exact internal workings of a wastegate to know if this is a feasible way to boost the low rpm torque curve for a SC'd car. I don't want to order one to experiment with to find out its mechanically impossible due to my above concerns. Thanks for any help.
<strong> I really doubt that this will work for SC'd applications, as all the wastgate does, is vents off exhaust gas pressure, when intake psi reaches it's desired level, it then routes the excess exhaust past the turbo, directly into the downpipe or exhaust, i'm not sure how you could even make this work on a Blower car, as exhaust has little to nothing to do with the boost, ezcept for increasing motor backpressure increasing boost, boost in sc'd applications are all dependant on pulley size, not exhaust flow, so i belive you are going to get nowhere with this. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I don't think they're talking about mounting the wastegate on the exhaust. I think they are talking about mounting it to the intake so that when you reach a preset psi, the valve opens and releases any additional boost into the atmosphere. Therefore, theoretically, you slap on a smaller pully and instead of reaching 8psi at 6100 rpm's you could reach it at 4K rpms and then maintain that 8psi through the remainder of the rpm band, like the turbos do.
I think this is a very interesting idea. My only question is about air intake temps. By compressing 12psi of air(even though only 8 is reaching the manifold) I would think you would be significantly increasing air intake temps. Although theoretically by releasing pressure you would cool the air back down. I'm just not sure if going from 0psi->12psi->8psi would result in the same temp as going from 0psi->8psi... ?
Let me know how this turns out guys.
BH
ssmokin, I looked for the place it was 200 at, but couldn't find my link. I found it through google.
edit--$210 here http://www.roadraceengineering.com/tial.htm
<small>[ March 09, 2003, 07:10 AM: Message edited by: AzzHauler ]</small>
Gary
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<strong>
ssmokin, I looked for the place it was 200 at, but couldn't find my link. I found it through google.
edit--$210 here http://www.roadraceengineering.com/tial.htm </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by red ws6 99:
<strong>
Why would you want to spend the time and money to adapt a wastegate, when you could use a relief valve or any one of the other devices that are already used for the exact purpose you are talking about?
Gary </strong>
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I haven't seen anything(relief valve,other devices) around that applies to bleeding off excess psi for a SC. I'm trying to do exactly what "Blown Hawk" described in his post. I would appreciate it if you shared the location of these already produced products because it would make things much easier. Thanks
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by:ZYA_LTR
<strong>
Just for the fact that you would have to run your tubing down to like 1 5/8" tube to get it to flow through the wastegate is not very smart, plus you then are adding more tubing, because you then have to route the air from the blowoff and the wastegate back into the air tract, complicating the whole system. because you are placing a strain on the air, and causing backpressure on the impeller, stressing it out, which is the reason why we have blowoff valves. I think this is an ok idea in theory, it won't work in a practical application, by downsizing the tubing, you are restricting airflow, also causing the air to increase temp.
Actually on the ATI kit, you are supposed to vent the blowoff air back to the inlet side of the blower, if you check the directions, even though most don't though
Plus the fact thatyou are also causing a huge bottleneck in the air tract, resticting flow, and increasing IAT by compressing the air through a smaller tube.</strong>
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The theory is not to install it in the intake tubing.Think of the system as it is and now add the WG onto it (air box,flange welded to one of the pipes,etc).Our SC's (centrifugal)are set to work on a specific boost curve based on pulley and rpm. This only allows us full boost at redline(ex:5lb pulley with 5-6psi max boost; 1psi 3000rpm,2psi 3500rpm,3psi,4psi,5-6psi redline). The only way to tweak this curve would be to pulley higher but cause a controlled boost leak(enter the wastegate or other device) that would limit the max psi(ex: 12lb pulley with 5-6psi max boost; 2psi 2500rpm,4psi 3000rpm,5-6psi 3500rpm).Now we'll see full boost from 3500 and up and see boost coming in lower in the rpm band.
It's not being used as a blow-off or relief valve which is only vacuum referenced to open during shifts or light throttle cruising.
If you are planning on using a mechanical means of regulating the supercharger boost, then more than likely, you are going to run into problems with your system chattering
IE You reach 9 psi of boost, your 'wastegate' opens, the boost drops to 4 psi, your 'wastegate' closes, your boost spikes to 9 psi, you 'wastegate' opens....etc....
In order to get this to work, I think that you are going to have to come up with some form of control system or find some way to dampen the system.
Just my opinion.
Good Luck,
Kevin
Gary
Scott
<strong> I think this is possible, but I think that you are going to run into a few problem with controls.
If you are planning on using a mechanical means of regulating the supercharger boost, then more than likely, you are going to run into problems with your system chattering
IE You reach 9 psi of boost, your 'wastegate' opens, the boost drops to 4 psi, your 'wastegate' closes, your boost spikes to 9 psi, you 'wastegate' opens....etc....
In order to get this to work, I think that you are going to have to come up with some form of control system or find some way to dampen the system.
Just my opinion.
Good Luck,
Kevin </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I had this concern also. It's going to depend on the sensitivity of the wastegate diaphragm. Will it go from full closed to full open when it hits the springs set pressure? I'm hoping that it will open slowly enough to avoid the "chatter" effect. If it doesn't,I could always add a restricter plate on the vented side of the valve to minimize drastic pressure loss in the intake. Maybe a restricter that would whistle(if you don't mind the noise) so you could not only have a visual(boost gauge) but also an audible signal that the WG is functioning.
<small>[ March 13, 2003, 12:57 AM: Message edited by: SSmokin 01 ]</small>
<strong> You dont need anything design for a car. You just need a standard adjustable relief valve or sometimes called a pop-off valve. You just need to know what pressure you want it set at and desired flowrate out of the relief. There are plenty of manufacturers. You guys cant afford the kind of valves I use at work they start at $800 and go up from there (Fluid Mechanics). I could do a little search and see if anyone makes an expensive/quality valve.
Gary </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I'm open to any alternatives since I'm just experimenting.I'm leaning more towards modifying a WG rather than using a relief(pop off)valve because it will be opening/closing not only off of a set pressure but also by the boost signal. This would cancel the need to know a set flow rate for when it opens.Hopefully it doesn't run into the "chatter" issues mentioned in the previous threads.
Theoretically I should also be able to install an adjustable boost controller to turn up the boost(relative to max psi achievable for the current pulley choice) for race gas,track duty,better traction,better tune,etc.
I'm also worried about the continuous open/close cycling the relief valve will see. Normally(correct me if I'm wrong) there operation(low duty cycle) only comes into effect when the system they are plumbed into experiences some extreme anomily in line pressure that it normally doesn't see.
Again I'm open to any ideas or info you have to offer. I'm going to make this work one way(low cost) or another(low cost).
Thanks
<small>[ March 13, 2003, 12:53 AM: Message edited by: SSmokin 01 ]</small>
heres a link http://www.jeremybazan.com/turboxsbov.jpg
it is a Turbo XS Type H BOV
I can post a video of my car doing a burnout at the track and you can hear the BOV opening when I throttle the car during the burnout.
J
<strong> I posted my BOV a while back but I didn't get much response and all told I took some heat for it with people saying I would have a tuning nightmare. WELL nothing has happened so far and it works awesome and sounds cool, my passengers freak out when they hear it open.
heres a link http://www.jeremybazan.com/turboxsbov.jpg
it is a Turbo XS Type H BOV
I can post a video of my car doing a burnout at the track and you can hear the BOV opening when I throttle the car during the burnout.
J </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Are you using the BOV as your surge valve? Or are you using the BOV in the manor SSmokin 01 is talking about? Definitely post up that video.
BH




