MaveriK Posted March 31, 2005 Share Posted March 31, 2005 Hi, looking for a little help and i will apologise now as i am not the most technical person. Got a Jap import that is stock other than a Gredy boost controller and a mongoose exhaust to the best of my knowledge. First turbo is working fine but the second one is over boosting and thus the ECU cuts the power during thrashing sessions. The second one is running at around 1.2bar but if you manually open the wastegate with a pump and block the pipe off all works perfectly. Makes me think the wastegate is a bit sticky?. Anyone come across this before and know how to get around it? Link to comment Share on other sites More sharing options...
terribleturner Posted March 31, 2005 Share Posted March 31, 2005 I take it you havn't got a fuel cut defeser of some sort installed?? Link to comment Share on other sites More sharing options...
MaveriK Posted March 31, 2005 Author Share Posted March 31, 2005 No, place i took it to said that wasnt a good solution as that sort of boost would damage the engine/Turbo's. Is that not the case then? Link to comment Share on other sites More sharing options...
terribleturner Posted March 31, 2005 Share Posted March 31, 2005 Im having a stupid day at the moment and can't think properly. Are you actually hitting 1.2 bar? or is it set to reach that?? Also when you say the ecu cuts the power is it like you hit a wall?? just like the engine just dies and drops out?? Can't remember what stock fuel cut is at the moment. Should be able to find it on a search though. Link to comment Share on other sites More sharing options...
terribleturner Posted March 31, 2005 Share Posted March 31, 2005 Have aread of this, and see if it's similar. Of course ignoring that Chris is talking about the Decat. Link to comment Share on other sites More sharing options...
MaveriK Posted March 31, 2005 Author Share Posted March 31, 2005 Just confirming with the company that it was hitting 1.2bar and yeah, a big nasty hard wall. Link to comment Share on other sites More sharing options...
terribleturner Posted March 31, 2005 Share Posted March 31, 2005 Have you got a boost gauge installed?? Sounds to me like you don't, and if so then this should be high on the list of things to get. Also i'm thinking that a FCD or VFCC is also something you need. 1.2 bar is the max your stock turbos are gonna take. Personnally i'd also think about turning the boost down a little to say 1bar, just to play it safe for the moment. Link to comment Share on other sites More sharing options...
gaz1 Posted March 31, 2005 Share Posted March 31, 2005 Hi, looking for a little help and i will apologise now as i am not the most technical person. Got a Jap import that is stock other than a Gredy boost controller and a mongoose exhaust to the best of my knowledge. First turbo is working fine but the second one is over boosting and thus the ECU cuts the power during thrashing sessions. The second one is running at around 1.2bar but if you manually open the wastegate with a pump and block the pipe off all works perfectly. Makes me think the wastegate is a bit sticky?. Anyone come across this before and know how to get around it? same thing happened to me, found out the garage changed the exaust and decatted it put the catt back on fine since Link to comment Share on other sites More sharing options...
Nic Posted March 31, 2005 Share Posted March 31, 2005 Hi Maverik, Need a bit more information here to work out what the issue is. 1. How do you know you are making 1.2bar, do you have a boost gauge fitted or is this what the garage have told you? FYI the stock fuel cut is at 1bar, so if you are making 1.2bar before you are getting fuel cut, either the boost reading is not correct or you already have a Fuel Cut Defender fitted, which has raised the fuel cut to 1.2bar. 2. Does the car have any catalytic converts fitted? The Supra comes with 2 as standard, the first on the downpipe from turbos and the second futher along exhaust under front seat area. 3. Have you tried turning the boost controller off, are you still making 1.2bar with it off? 4. Have you just purchased the car, or has it just started to boost higher than normal? If you can provide as much info as possible then we work out what to do. Link to comment Share on other sites More sharing options...
MaveriK Posted April 1, 2005 Author Share Posted April 1, 2005 Thanks for all the help so far. 1) The garage have all the kit to monitor the pressures. The back turbo is peaking at around 1.3 which looks to be because the wastegate isnt opening all the way up as it should. 2) Both Cats have been replaced with a Mongoose system. Garage seemed to think that this could be the issue (Back pressure) and want to put old system back on which obviously will drop me a load of BHP which i would rather not do if there is a safe way around it. 3) System quite happily overboost with the system turned off, set on low or high boost. 4) Had the car since January, its running at around 450BHP which i am more than happy with. TTurner, got most of the toys fitted but with the Gredy even set at its lowest it still does it. Link to comment Share on other sites More sharing options...
Steve W2 Posted April 1, 2005 Share Posted April 1, 2005 A standard mongoose exhaust *I'm pretty sure* will not replace both of the cats. You need to buy a seperate pipe to get rid of 1 or both of them. If you have both cats removed your car will boost to around 1.2 with the boost controller turned off. If it does generate this withouth any problems you will have a fuel cut defender fitted. You need to get a pressure gauge fitted to determine what the pressure you are running when you get fuel cut. You may find that the FCD it sounds like you have fitted is adjustable, in which case it may only be set at 1.1Bar for example which is now causing a problem if you have just removed the cats as you are likely to be boosting higher than that. You need to: 1. Stop listening to that garage, it doesn't sound like they know there arse from their face as far as a Supra goes. 2. Get a pressure gauge fitted. 3. Find out if your cats are there or not. 4. Turn off your boost controller. 5. Tell us what pressure you get fuel cut at. 1.2 bar is regarded as the highest safe pressure to run J-spec turbo's at. Most will be okay at this pressure, some don't like it. It's all a bit 'suck it and see' Link to comment Share on other sites More sharing options...
Nic Posted April 1, 2005 Share Posted April 1, 2005 Don't wish to offend, but it sounds like the garage don't know what they are doing. The Supra is quite a complex car to work on, especially the sequential turbo system, a garage that does not know what they are doing will just cause you more problems. So first bit of advice would be to take the car to someone with experience of working on Supras. 1. If you are boosting to 1.3bar and then hitting fuel cut then the car must already have a Fuel Cut Defender fitted, as the stock fuel cut limit is 1bar. So it sounds like you have a FCD fitted that has raised the fuel cut limit to say 1.25bar. Therefore the first thing I would do is check if a FCD is fitted. This is easy to do, lift up the carpet on passenger side footwell, unscrew the black cover and check if there is a small box wired into the ECU wiring harness. 2. The garage is talking b*ll*x you don't need to fit the stock exhaust back on. Removing the cats and fitting a freer flowing exhaust is the most common and first performance mod that most people do. This allows the turbos to spool up faster and for the boost pressure to be raised thus creating more power. What is common though with a Japanese Supra is that once the cats are removed the exhaust becomes too free flowing and the wastegate is no longer able to control the boost sufficiently so you will get high boost spikes. What you need to do is to fit a restrictor ring in the exhaust. This is just a plate (which bolts into the exhaust) with a smaller diameter hole that will restrict the flow of the exhaust. This will lower the peak boost to a safe level. Contact Chris Wilson who can supply and give you expert advice. I would highly recommend taking your car to Chris Wilson as he is THE supra expert in the UK. He will be able to give the car a thorough going over and will be able to give you invaluable advice, would be well worth the drive. 3. The restrictor ring should allow you to set the peak boost to say 1bar, you can then use the boost controller to raise this to say 1.1-1.2bar. 4. Don't mean to piss on your fire, but 450bhp on stock turbos is a little optimistic. Is this the figure the seller of the car gave you? Hope this helps, let us know how you get on. Link to comment Share on other sites More sharing options...
Nic Posted April 1, 2005 Share Posted April 1, 2005 Forgot to mention, as Steve says get a boost gauge fitted too. Link to comment Share on other sites More sharing options...
Nic Posted April 1, 2005 Share Posted April 1, 2005 BTW, the sequential turbo system works by spooling the first turbo and then BOTH turbos together. Not the first and then the second as I think you were describing in your post Link to comment Share on other sites More sharing options...
MaveriK Posted April 6, 2005 Author Share Posted April 6, 2005 Thanks again for all the help. Had already got a boost gauge fitted and have purchased a restrictor ring which is hopefully being installed tomorrow. Will let you know the out come. Link to comment Share on other sites More sharing options...
Nic Posted April 6, 2005 Share Posted April 6, 2005 Thanks again for all the help. Had already got a boost gauge fitted and have purchased a restrictor ring which is hopefully being installed tomorrow. Will let you know the out come. Did you find a Fuel Cut Defender fitted? Link to comment Share on other sites More sharing options...
MaveriK Posted April 7, 2005 Author Share Posted April 7, 2005 Could not see anything attached but there was a splice in a single wire off the ECU that headed off under the carpet as it was getting late i couldnt be assed to dig all the fluffy up so have left it for now. This is going to sound stupid but if i get an FCD to overcome the fuel cut out i am not going to damage the engine am i? And once installed lets say it goes the way of the DODO what is left to protect the engine? Link to comment Share on other sites More sharing options...
terribleturner Posted April 7, 2005 Share Posted April 7, 2005 You want a VFCC from Thor i think. This will not remove it which is dangerous, but just moves it to allow more boost. Link to comment Share on other sites More sharing options...
MaveriK Posted April 8, 2005 Author Share Posted April 8, 2005 Ok, so the ring is fitted and i am now boosting to a max of .9bar. Obviously this now seems a little flat but at least i have a level to run from. I just want to clear up all the info i have, are we saying its ok for me to run 1.2Bar on my setup as long as i fit an FCD or VFCC. And i guess it will be trial and error to increase the size of the hole in the restrictor ring to get to 1.2Bar. Link to comment Share on other sites More sharing options...
terribleturner Posted April 8, 2005 Share Posted April 8, 2005 1.2 is safe for your stock turbo's. The VFCC/FCD will mean that your car will be happy at this boost without dropping the power when you get there. Does your boost controller have 2 or more settings?? You can have the higher one set to 1.2 and the other set to like 1bar. Don't forget too that on colder days (mornings especially) your boost will creep up which means that yor 1.2 will go over that, again hitting FC and dropping the power. Link to comment Share on other sites More sharing options...
Nic Posted April 8, 2005 Share Posted April 8, 2005 Ok, so the ring is fitted and i am now boosting to a max of .9bar. Obviously this now seems a little flat but at least i have a level to run from. I just want to clear up all the info i have, are we saying its ok for me to run 1.2Bar on my setup as long as i fit an FCD or VFCC. And i guess it will be trial and error to increase the size of the hole in the restrictor ring to get to 1.2Bar. Great, you don't need to increase the hole in the restrictor ring as you have a boost controller fitted. My car only boost to 0.9bar with boost controller turned off, I just use the boost controller to raise the boost, which is what you can do. I would try raising boost to 1.2bar first and see if you get fuel cut above 1bar. If you don't get fuel cut then you must already have a FCD fitted, if you do then you will need to get a FCD fitted. Your max safe boost will depend what mods you have got and the condition of your intercooler/fuel pump, suggest you do the following next: 1. Check condition of intercooler, if it is the original then it may be well past it's best (missing, crumbling cooling fins etc.) and not up to coping with coping with higher boost in hot weather. 2. If you have the original fuel pump fitted then it may also be past it's best (depending on age of car.) As a safety measure it would be a good idea to fit a new pump. I'd recommend fitting a Walbro 255l/h pump, contact Mig/Terry S at Vortex, the Walbro pumps are relatively cheap at around £80 and very easy to fit. Fitting this will give you peace of mind that your fueling should be okay for 1.2bar. Link to comment Share on other sites More sharing options...
MaveriK Posted April 27, 2005 Author Share Posted April 27, 2005 OK, so everything is now fitted and running ok. Got the THOR VFCC fitted and the very nice guys at Norris Designs (http://www.norrisdesigns.com/) have set that and the boost controller up. Now running like a dream, again thanks to everyone who had input in this thread. Link to comment Share on other sites More sharing options...
Nic Posted April 27, 2005 Share Posted April 27, 2005 OK, so everything is now fitted and running ok. Got the THOR VFCC fitted and the very nice guys at Norris Designs (http://www.norrisdesigns.com/) have set that and the boost controller up. Now running like a dream, again thanks to everyone who had input in this thread. Great glad to hear it Maverik Link to comment Share on other sites More sharing options...
dangerous brain Posted April 27, 2005 Share Posted April 27, 2005 Mine kept overboosting to buggery with a blitz boost controller installed very very badly. Even with the 1.2 bar restrictor ring fitted it still managed to whack its way around to 1.7 and even 2 bar at times. Needless to say this prevented total WOT til I finally got it sorted when slowdog removed the damn blitz controller and returned the car to its stock boost controller. Lo and behold it never goes above 1.2 bar So says defi gauge recorder. Link to comment Share on other sites More sharing options...
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