Barry Posted February 24, 2003 Share Posted February 24, 2003 ....without a boost controller. I took the restrictor out of the exhaust over the weekend, so now my stage 3's are really in their element being able to hit over 1.4 bar.!!!!! Ok, the car now goes like an absolute rocket, but I've not got the fueling in place yet to run that sort of boost. I understand that a boost controller is able to lower the max boost level (is this correct?). If it does, then all it will be doing is making the actuator open the wastegate earlier than usual, this is basically the reverse of putting on a bleed valve to give you more boost. Now, I'm able to achieve this on other turbo'd cars, simply by bleeding off air from the second port on the actuator, and I assume that this is all an electronic boost controller would do.? Does anyone have a diagram of the turbo's on the Supra and how the actuator circuit is plumbed in so I can see if the same rules apply. Or, have installation instructions for a boost controller (HKS, Blitz etc..). If it doesn't work this way then please correct me. I dont want to put the restrictor back in the exhust as having it out is letting the blower spool up a little quicker, plus I'm also hitting 0.7 bar off the first turbo.! Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2003 Share Posted February 24, 2003 AFAIK Leon has manage to get the boost down a bit using a boost controller, how far I dont know. Link to comment Share on other sites More sharing options...
Brian Jackett Posted February 24, 2003 Share Posted February 24, 2003 My understanding is that a boost controller cannot lower boost (that is why you use a restrictor) only raise it. You can play about with the restrictor to adjust how much you want it to restrict so obtain a maximum low boost. One that your fueling is happy with Link to comment Share on other sites More sharing options...
Barry Posted February 24, 2003 Author Share Posted February 24, 2003 I know there is a way on most turbo'd cars to do the opposite of what the bleed valve does to increase boost, I just wandered if anyone knows if could be done on the soop. If anyone has (or knows where I could find) a diagram of the actuator pipework then I'd be able to tell from that. Is the actuator a twin port one on the TT.? Boost controllers are able to prevent boost creap, I need to know how they do this. Link to comment Share on other sites More sharing options...
JamesG Posted February 24, 2003 Share Posted February 24, 2003 The Blitz boost controller in my J-Spec (no cats) doesn't really help reducing max boost. If the wastegate isn't big enough to flow away the air, then it doesn't matter whether or not it's fully open as boost will continue to rise regardless. I think that at lower boost levels such as part throttle, the boost controller can raise or lower boost as the flow rate of the wastegate is sufficient to flow most of the air away from the turbine. So, the solution is a smaller exhaust or a bigger wastegate to give better control of maximum boost. I've been reading up about boost control and this is the conclusion I've come to. Please someone let me know if you don't agree. James. Link to comment Share on other sites More sharing options...
Matt Harwood Posted February 24, 2003 Share Posted February 24, 2003 Leon DID reduce the boost on my car using my DSBC. - He got it from an eratic 1.4-1.5, down to a semi-stable 1.3-1.35. That was as low as he could get it. I wouldn't rely on this method though as my EGT's would still climb too high. I now use one of Chris Wilsons restrictors which holds the boost at ~1.15 and the DSBC to bring it back to 1.3 when I want a bit more fun. Sorry Barry, that doesn't really answer your question. Link to comment Share on other sites More sharing options...
Guest Martin F Posted February 24, 2003 Share Posted February 24, 2003 Originally posted by Barry Is the actuator a twin port one on the TT.? Yes, well the wastegate actuator on the front turbo is. For a reasonable explanation on the control process you need to read the details in the NCF '93 (new car features) manual on MKIV.com. Link to comment Share on other sites More sharing options...
Brian Jackett Posted February 24, 2003 Share Posted February 24, 2003 I think it does answer his question in that I really beleive that you cannot reduce boost with a boost controller. Sorry thats what I understand Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2003 Share Posted February 24, 2003 Brian is right, boost controllers can not be use to lower boost to any significant or reliable degree, you need something else to do that, as suggested more restriction in the pipe, i.e. the bit you just removed. If you put your ring back that will give your system maximum, you can then use your boost controller to get back to 1.3 or 1.4, but when you have the fuelling to match or your EGT’s will rocket. At least with the J spec exhaust manifold set up you get the boost for free! Link to comment Share on other sites More sharing options...
B3any Posted February 24, 2003 Share Posted February 24, 2003 Got the same problem, Controller wont reduce you'll need a restrictor ring. Link to comment Share on other sites More sharing options...
Barry Posted February 24, 2003 Author Share Posted February 24, 2003 Putting the restrictor back in then using a bleeder to up the boost is kind of silly really. Your getting the turbo to spin up more to try and push more boost through the engine so you have to try and force more waste gasses past the restrictor. I'd imagine that the result of higher boost with the restrictor in place would be an even bigger build up of gas in the exhaust (as it cant escape quick enough) and even higher EGT's? Correct me if I'm wrong. I like hearing all the different theorys, I'm not doing this just to argue. Its just my way of learning. Keep it coming... I 'will' find a way of limiting max boost without the restrictor, oh yes.! Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 24, 2003 Share Posted February 24, 2003 Barry those turbo's have a bigger wastegate machined in. Talk to Leon. Link to comment Share on other sites More sharing options...
Barry Posted February 24, 2003 Author Share Posted February 24, 2003 Originally posted by Terry S Barry those turbo's have a bigger wastegate machined in. Talk to Leon. Aaaahhhhh, cheers Terry. All I want to do is get the wastegate to open at a lower boost. Printed off some pretty good diagrams of all the hoses and what they do. I know there is a way of doing it as I've done in on other turbo'd cars. Its a shame that the actuator isn't adjustable for pre-load. Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2003 Share Posted February 24, 2003 Not arguing either. The stock manifold exit is 2.5" dia I think so that is the main restriction once cats have gone. I am not sure of the diameter of the hole in Chris's ring I never measured it, but it must be around the 2.25 - 2.5 mark. The big heat build up in the system is normally the cat near the exhaust manifold. Once that has gone the EGT's come down, until you start running lean. My 2.5", ring,3" Hiper on Stock Turbos run 1.15-1.2 and the highest EGT I have seen is 850. I don’t know what EGT's I had at 1.4 as I did not have the probe fitted, just the gauge to block up the pod hole. Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 24, 2003 Share Posted February 24, 2003 Hopefully Mr Chisholm will chip in. He & I were discussing a way to reduce boost at the throttle body. He was going to try it & I never heard anymore. Ian? Barry, those turbo's are kinda lively at 1.4 eh! Link to comment Share on other sites More sharing options...
Barry Posted February 24, 2003 Author Share Posted February 24, 2003 Originally posted by Terminator I am not sure of the diameter of the hole in Chris's ring I never measured it........ :D Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2003 Share Posted February 24, 2003 LMAO:p Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 24, 2003 Share Posted February 24, 2003 One othe thing Barry, That DP on the car is the biggest bore I have ever seen on a stock set up. Leon got it from the US & it is enormous. That isn't going to help much. Link to comment Share on other sites More sharing options...
Barry Posted February 24, 2003 Author Share Posted February 24, 2003 Sorry Phil, but I nearly wet myself when I saw that!!! Terry (or anyone else), do you know if anyone has ever fitted an adjustable actuator.? Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 24, 2003 Share Posted February 24, 2003 Not to my knowledge. Link to comment Share on other sites More sharing options...
Suprash Posted February 24, 2003 Share Posted February 24, 2003 Originally posted by Matt Harwood Leon DID reduce the boost on my car using my DSBC. - He got it from an eratic 1.4-1.5, down to a semi-stable 1.3-1.35. That was as low as he could get it. I wouldn't rely on this method though as my EGT's would still climb too high. I now use one of Chris Wilsons restrictors which holds the boost at ~1.15 and the DSBC to bring it back to 1.3 when I want a bit more fun. Sorry Barry, that doesn't really answer your question. Matt, this is something I dont understand. If your boost is hitting 1.4 like mine, and want to reduce it to a safer level, like 1.2, so you fit a restrictor ring, which reduces the boost, as far as Im concerned this method is the same as either leaving the cats in or fitting a smaller exhaust. But with the restrictor ring fitted and a boost controller fitted, how can the boost controller raise the boost with a restrictor ring still in place, surely if you have that physical ring in there the turbos cant spool higher than 1.2. Im not quite getting the end part, Matt C has explained this to me once, but I now appear confused again. Hope you see what Im trying to say. Link to comment Share on other sites More sharing options...
Matt Harwood Posted February 24, 2003 Share Posted February 24, 2003 I don't pretend to know the full ins and outs of how it all works, but I think what you're missing is that the restrictor, is just that. A restrictor. Not a stopper or blocker - Does that make sense The way I understand it is that the cats present a big restriction than not only restrict the turbos ability to spool faster and stronger but also create a big heat build up. So removing the cats reduces the heat build up, lets the turbos spool faster/stronger, but sometimes too much with both cats out and depending what exhaust you have. So to counter that, you put a restrictor back in place to find the happy medium. In my case, the restrictor brings it to a fairly stable 1.15, which I'm happy with for every day poodling around. I then use the boost controller to bring it up a bit more if I want to get a bit more from it. I'm prepared to be corrected Link to comment Share on other sites More sharing options...
B3any Posted February 24, 2003 Share Posted February 24, 2003 I think your spot on there Matt.... Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 24, 2003 Share Posted February 24, 2003 Originally posted by Ashley Willis Matt, this is something I dont understand. If your boost is hitting 1.4 like mine, and want to reduce it to a safer level, like 1.2, so you fit a restrictor ring, which reduces the boost, as far as Im concerned this method is the same as either leaving the cats in or fitting a smaller exhaust. But with the restrictor ring fitted and a boost controller fitted, how can the boost controller raise the boost with a restrictor ring still in place, surely if you have that physical ring in there the turbos cant spool higher than 1.2. Im not quite getting the end part, Matt C has explained this to me once, but I now appear confused again. Hope you see what Im trying to say. You are correct to a point. In an ideal world the wastegate needs opening out, as flow control around the turbos turbine SHOULD be controlled by the wastegate, and not by the restriction in the exhaust. However, altghough the wastegate will allow some porting, it isn't much, and is hardly cost effective to most owners. Putting a ring in allows a cheap and simple means of adding JUST enough backpressure to keep boost sane, and it is easily changed. With the cat(s) you have an effectively fixed size restriction, not really alterable at all. The main downside of the cat, and upside of a ring is the cat actually generates an exothermic chemical reaction, adding a load of heat to the engine bay, and this heat is storted for long periods due to the mass of the monolith and casing. A rings temp will fluctuate up and back down again very quickly as its mass is trivial. I agree though, it's not ideal, but the ideal of resized sequential turbo housings, bigger wastegate and electronic boost control are just too expensive for most to even contemplate. HTH Link to comment Share on other sites More sharing options...
Matt Harwood Posted February 24, 2003 Share Posted February 24, 2003 Errr, yeah, see, it's like I said... Sort of Link to comment Share on other sites More sharing options...
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