far Posted November 18, 2003 Share Posted November 18, 2003 OK people,situation a week or so ago - im running aftermarket back box,airfilter - no other mods,both cats still in. I was getting a heavy cut at 5000k revs or when accelarating hard - this was diagnosed as Fuel cut and I am now going to order a FCD - question is should I see any performance increase from this ? apart from obviously allowing the car to go through the rev range ! Also anyone got both cats in and still get fuel cut ? with the mods im running should this really be happening ? Link to comment Share on other sites More sharing options...
outatime Posted November 18, 2003 Share Posted November 18, 2003 I did it the other way around, got the cats out first then got an aftermarket backbox. I didn't need a FCD until I got a SuperDrager 2, which means I was somewhere below 14-15psi without any cats. I think an exhaust gives a similar boost increase so you might be hitting fuel cut now its colder. Link to comment Share on other sites More sharing options...
SkyJawa Posted November 18, 2003 Share Posted November 18, 2003 It won't be a performance increase just fitting the FCD, it will mean as you say you'll be able to welly it with fully revs and it will allow as much boost as poss with the CAT's still in. So in that respect, it'll be faster as it won't cut, but an FCD doesn't give you more performance than your mods have already given you! Link to comment Share on other sites More sharing options...
Paul Laing Posted November 18, 2003 Share Posted November 18, 2003 Don't you need a Boost Controller or Bleed Valve when fitting a FCD? Paul Link to comment Share on other sites More sharing options...
outatime Posted November 18, 2003 Share Posted November 18, 2003 No, all a FCD (fuel cut defensor) does is allow the car to boost above a limit set by the ECU. On a UK car you may need a Boost Controller/Bleed Valve before you can hit fuel cut, if that is what you mean. J-specs produce more boost with a de-cat and backbox. Link to comment Share on other sites More sharing options...
far Posted November 18, 2003 Author Share Posted November 18, 2003 Thanks guys will defo get one Link to comment Share on other sites More sharing options...
Steve W2 Posted November 18, 2003 Share Posted November 18, 2003 Far - I think the TRL ones are regarded as the best ones as they dont just get rid of the fuel cut limit all together, they allow you to adjust it above your fuel cut point when running hihger boost levels. This is much safer. I cant find the thread but I have just bought a second hand one a couple of other people put a post up (in the last couple of days) saying they had one for sale too. Hope this helps. Link to comment Share on other sites More sharing options...
Paul Laing Posted November 18, 2003 Share Posted November 18, 2003 All the Americans use HKS or Greddy Link to comment Share on other sites More sharing options...
outatime Posted November 18, 2003 Share Posted November 18, 2003 Like SteveW2 said, the TRL VFCC is better than the Greddy BCC etc because it doesn't remove the limit completely - it raises it to a user determined level Link to comment Share on other sites More sharing options...
far Posted November 18, 2003 Author Share Posted November 18, 2003 Steve - thanks for this info dude - I am in touch with the person who is selling the other vfcc Outatime - I see what you are saying about the VFCC being better - jest read up on the difference and the extra safety factor in built into these has swung it for me . Just strange(to me) how Fuel cut is kicking in and I still have my cats in,I have searched & searched but I cannot find any similiar cases apart from obviously ones where fuel cut kicks in but cats are out.I trust this is the case though. :thumbs: Link to comment Share on other sites More sharing options...
SkyJawa Posted November 18, 2003 Share Posted November 18, 2003 Yup - in this country the TRL is regarded as best by far (excuse the pun ). The HKS removes the cut completely AFAIK, so could let the car boost to 30psi if something went wrong. Think the greddy is similar. The TRL one uses a clamped signal (I think) and is user definable, though shipped as about 18psi. This means that it will just hold back the signal from the ECU until the FCD itself sees the boost has got above the 18psi set level and then basically sends the signal to the ECU telling it to cut. Link to comment Share on other sites More sharing options...
Thorin Posted November 18, 2003 Share Posted November 18, 2003 Far : what boost are you running? Link to comment Share on other sites More sharing options...
far Posted November 19, 2003 Author Share Posted November 19, 2003 dude my car is stock just standard apart from zorst & airfilter Link to comment Share on other sites More sharing options...
Supraguy Posted November 19, 2003 Share Posted November 19, 2003 HKS is arse. The Greddy is by far better. The reason that the MkIV owners recommend the GReddy BCC over the HKS Fuel Cut Defensor (FCD)and the Free Fuel Cut Defensor (FFCD) is simple. The HKS unit reduces the signal coming from the turbo pressure sensor at a fixed percentage, which means that all the data coming from this sensor is corrupt. The FFCD fixes the value coming from the turbo pressure sensor at something close to atmospheric by capping the pressure input to the sensor. As the turbo pressure sensor (TPS) on the TT Supra sees increase boost, it sends an increased voltage (V) on to the ECU. When typical stock boost level is exceeded, the higher TPS V signal causes the ECU to invoke Fuel Cut; this prohibits excess boost. The BCC is simply placed in the middle of this wire from the TPS to the ECU. At peak-stock and lower boost levels, the BCC passes unaltered stock V signals on to the ECU. As stock boost levels are exceeded, the BCC inputs the too-high V signal from the TPS, but limits its output V to the ECU to peak-stock level. Fuel cut is now not invoked at over-stock boost. Link to comment Share on other sites More sharing options...
Thorin Posted November 19, 2003 Share Posted November 19, 2003 Originally posted by far dude my car is stock just standard apart from zorst & airfilter Then I wouldn't have thought you'd be running much, if anything, higher than stock boost. Sure you've not got a bleed valve fitted by the previous owner or something? Get a boost gauge so you can see for certain how much boost it's running. If it's still around stock levels I wouldn't have thought it was fuel cut unless something else was wrong too. Link to comment Share on other sites More sharing options...
far Posted November 21, 2003 Author Share Posted November 21, 2003 OK - so how do I find out if there is a bleed valve fitted ? where would it be and what would it look like ? Generally consensus was that this is stock fuel cut.What else could it be ? Link to comment Share on other sites More sharing options...
far Posted November 21, 2003 Author Share Posted November 21, 2003 Thorin I posted up on this thread and generally most people agreed it was fuel cut - but this occurs 15-16 psi ? if my car is stock surely I would be running much less boost ???im totally confused now look here for other post regarding this Link to comment Share on other sites More sharing options...
SkyJawa Posted November 21, 2003 Share Posted November 21, 2003 Still could be - jap cars behave different to exhaust changes don't they? so could be that on occassion it creaps too high? I'd say to still get the FCD and plugs mate, especially since you are considering the decat anyway - as you'll need them the moment you do that anyway - and you'll be able to see if it cures your current prob too.............. Link to comment Share on other sites More sharing options...
Willson Posted November 21, 2003 Share Posted November 21, 2003 Hose 2 in this pic From this page In the tech articles on mkiv.com Link to comment Share on other sites More sharing options...
Willson Posted November 21, 2003 Share Posted November 21, 2003 The valve is just a simple adjustable air valve tap type do-hickie. Link to comment Share on other sites More sharing options...
outatime Posted November 21, 2003 Share Posted November 21, 2003 Your car should be somewhere near fuel cut with a big exhaust on, even with the cats in. The cold weather might just be pushing it over. I'm sure you will lose the cats eventually, so you may as well get a FCD. Also, get a boost gauge asap, its not worth risking it. Link to comment Share on other sites More sharing options...
far Posted November 21, 2003 Author Share Posted November 21, 2003 Gonna get FCD & boost gauge as a bare minimum to start with, maybe this will resolve the problem - if not anyone know what else this maybe ? Link to comment Share on other sites More sharing options...
far Posted November 21, 2003 Author Share Posted November 21, 2003 The cold weather might just be pushing it over. . - this ties in with the nature of the cut - it only seems to happen when its quite cold and really only started happening in November - never ever happened in the summer. outatime - cheers mate will get a boost gauge asap Wilson thats great - I now know what to look for ! Link to comment Share on other sites More sharing options...
Willson Posted November 21, 2003 Share Posted November 21, 2003 Link to comment Share on other sites More sharing options...
Steve W2 Posted November 21, 2003 Share Posted November 21, 2003 Far - am getting my Nur spec fitted tomorrow and I haven't got my FCD fitted yet so will let you know if I get any symptoms. Could still happen with your car and exhaust and not mine though! Link to comment Share on other sites More sharing options...
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