M3Evo 0 Posted March 21, 2006 Excuse the crapness of this diagram, but hopefully it'll illustrate the point: ttsetup.bmp So, we have two turbos set to blow through two intercoolers which feed into a common plenum on the engine. The little thin blue lines are the boost signal lines to the wastegate actuators which come from a point on the pressure side of one of the turbos. Now, assuming that one was set to 0.5bar and the other to 0.6bar, what would happen with the boost? Would the turbo set to 0.6bar cause the actuator on the 0.5bar turbo to open up more than it should so that 0.5bar is not boosting leaving 0.6bar doing all the work? Or would you end up with 0.55bar of boost with the difference being split? Or would they flit open and not so open when on boost? It's doing my 'ed in! Help! Cheers Alex Share this post Link to post Share on other sites
Rippthrough 98 Posted March 21, 2006 (edited) Excuse the crapness of this diagram, but hopefully it'll illustrate the point: ttsetup.bmp So, we have two turbos set to blow through two intercoolers which feed into a common plenum on the engine. The little thin blue lines are the boost signal lines to the wastegate actuators which come from a point on the pressure side of one of the turbos. Now, assuming that one was set to 0.5bar and the other to 0.6bar, what would happen with the boost? Would the turbo set to 0.6bar cause the actuator on the 0.5bar turbo to open up more than it should so that 0.5bar is not boosting leaving 0.6bar doing all the work? Or would you end up with 0.55bar of boost with the difference being split? Or would they flit open and not so open when on boost? It's doing my 'ed in! Help! Cheers Alex I think the 0.6 bar turbo would open the .5 bar wastegate (minus the pressure drop through the charge cooler), given that the systems are joined. Edited March 21, 2006 by Rippthrough Share this post Link to post Share on other sites
blue1.9 0 Posted March 21, 2006 Could you not set both the actuators to a very low pressure (say 0.2 bar) and then feed a pressure signal from the manifold through something like a dawes device manual boost controller set to, say, 0.5 bar before splitting the signal to the actuators....that way both turbos should be running at pretty much the same pressure. Not really sure about the situation you mention above, but it looks like it could be a problem if one actuator is set much higher than the other..... Alex Share this post Link to post Share on other sites
maturin23 10 Posted March 21, 2006 If it's going to be of any use I've got an unused Dawes Device I bought a few years ago for my Scooby, but never fitted it. You're more than welcome to have it for the project in return for a passenger ride in the Beige Beasty when she's fully boosted Share this post Link to post Share on other sites
Guest smokinslim Posted March 21, 2006 The little thin blue lines are the boost signal lines to the wastegate actuators which come from a point on the pressure side of one of the turbos. Would it not be a better idea to seperate the boost signal lines, so each turbo creates it own signal. That way it shouldn't matter so much if they're set at different levels. Seems logical to me but i could be completely wrong, don't know a great deal about turbos at the mo. Share this post Link to post Share on other sites
M3Evo 0 Posted March 21, 2006 Ooh, what's a Dawes device? Is it like an Amal valve? (or whatever they're called) If you're willing to part with it maturin I'd be very much obliged and more than willing to take you for a spin (although I do drive like a grandad ) I had thought that having the signal lines seperate might make a difference, but then I thought that it'd only have an effect during spool up when everything's changing pressure wise in the inlet system. If you'd been boosting for say one minute, the pressure should be (give or take) equal everywhere in the system. Got the car booked in at Emerald for mapping on the 9th of May so I need to get this sorted by then, although the obvious answer is to fiddle about with the actuators until they do the same thing for a given pressure, but that's a little limited when you're adjusting boost pressures with different thicknesses of washers! Cheers guys Alex Share this post Link to post Share on other sites
blue1.9 0 Posted March 22, 2006 (edited) Yes, a Dawes Device is basically the same as an Armval boost controller - both are designed to provide a pressure signal to the actuator only when a threshold pressure is passed....so if the actuators are set at a level well below the threshold pressure of the boost controller then the boost pressure from both turbos should remain constant at the threshold pressure. As they don't allow a pressure signal until the threshold, the turbos should spool up faster. Links: http://www.3barracing.com/product_7.htm used to be http://www.dawesdevices.com/ http://www.armval.co.uk/ Alex Edited March 22, 2006 by blue1.9 Share this post Link to post Share on other sites
Rippthrough 98 Posted March 22, 2006 Why do you want to set one at .5 and one at .6 anyway? Share this post Link to post Share on other sites
M3Evo 0 Posted March 22, 2006 Aaaaaah I see, it's a mechanical thing, been trying to get hold of a boost control solenoid so that the Emerald can control the boost and also so that I can map boost Didn't wanna set them to different levels, but they're not easy to adjust as the actuators aren't adjustable without the use of shims Share this post Link to post Share on other sites
maturin23 10 Posted March 22, 2006 Drop me a PM if you want the thingy! Share this post Link to post Share on other sites
