Rywalls Posted January 4, 2016 Share Posted January 4, 2016 Had the supra on the dyno at evotune and it made 384bhp at the crank. I'm not sure how the fuelling or the afr is shown on a typical dyno graph but where the hp and tq curves were, the fuelling curve was almost off the chart at the bottom. I'll post up a pic of the graph asap. This was explained as the car running very rich and felt no where near as powerful as the other local bpu supras that have been on at dyno days. I was advised to fit a fuel pressure regulator to lean out the mixture which should bring the fuelling curve on the graph closer to the hp and tq curve increasing overall power. It's a low mileage vvti j-spec engine full bpu: Double decat, Walbro 255, iridium plugs, aftermarket air filter, hks bov, greddy boost controller, good condition stock intercooler and fcd. Not one for chasing numbers but I'm aware healthy bpu supras make 400hp and sometimes over. I have an adjustable fuel pressure regulator waiting to be fitted but is there anything else I could do with checking as I don't want to be covering up a potential problem by just fitting a fpr. Thanks in advance Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 4, 2016 Share Posted January 4, 2016 I have an adjustable fuel pressure regulator waiting to be fitted but is there anything else I could do with checking as I don't want to be covering up a potential problem by just fitting a fpr. Which you will be, as well as cocking up all the fuelling under all load conditions, running lean everywhere. Awful suggestion from whomever told you to fit it. Stick the dyno chart up so we can see it Quote Link to comment Share on other sites More sharing options...
wile e coyote Posted January 4, 2016 Share Posted January 4, 2016 as above The vvti does run rich Quote Link to comment Share on other sites More sharing options...
sebas Posted January 4, 2016 Share Posted January 4, 2016 If your BOV is not recirculation style then take it off and put back standard one. vvti have maf sensors and they dont like classic bovs. Paul Whiffin wrote somewhere (cant find that topic now) that definitely not recommended on the VVTi cars. Quote Link to comment Share on other sites More sharing options...
sebas Posted January 4, 2016 Share Posted January 4, 2016 Found it. post #17 http://www.mkivsupra.net/vbb/showthread.php?321126-Andreas-Green-Supra-single-turbo-build/page2 Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 4, 2016 Share Posted January 4, 2016 Is the BOV leaking? Might explain it. Also as above, if you want some flashy valve in your engine, at least get a recirculated one. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 4, 2016 Share Posted January 4, 2016 Before fiddling invest in a GOOD wide band O2 sensor and readout and actually view the mixture in real time, on the road. The better ones will write a log. All 2JZ-GTE's and most other high power turbo petrol engines run very rich at full boost, it's to keep the catalytic converters from overheating. A proper, aftermarket mappable ecu will allow you to weaken it if you remove both cats, to the benefit of economy and performance. Run either the stock recircuklation valve or blank it off entirely. I haven't run a BOV or recirculation valve on a modded turbo engine in twenty odd years. Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 4, 2016 Author Share Posted January 4, 2016 Cheers for all the comments really appreciate it. I'll get the dyno graph up tonight. Thanks for the link sebas. The bov is atmospheric at the moment however I do have the recirculation kit in the house on standby so I'll get that fitted. You'll all know alot more than me about this so forgive me if this is stupid but, I was under the impression that the maf sensor with an atmospheric bov only ran rich because once the throttle was closed the ecu pumps a load of fuel through but the bov has chucked all the air out. So on a dyno with WOT how could the maf/atmospheric bov combo cause the engine to run rich? Thanks for the info Chris, I'll get the afr gauge sooner rather than later. If it is just down to the fact that it's overfuelling with it being a vvti then will leaning out the fuel with the fpr be a safe move? I'll be getting a standalone ecu eventually ready for the single turbo conversion but this won't be for a while yet. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 4, 2016 Share Posted January 4, 2016 Don't try and lean out fuelling with an adjustable FPR you will likely make it too lean in other areas, and certainly not without fitting a full time wide band AFR gauge, just hold fire and get a decent stand alone or piggyback. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 4, 2016 Share Posted January 4, 2016 As above, wait until you have a proper mappable ecu before fiddling with fuelling. Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 4, 2016 Author Share Posted January 4, 2016 No worries guys thanks for the help. I'll get the recirc kit and afr fitted for now. What's the healthy numbers I'm looking for on the afr gauge? Quote Link to comment Share on other sites More sharing options...
Pete Posted January 4, 2016 Share Posted January 4, 2016 I have an AEM UEGO AFR with the typical Bosch sensor which offer serial output to ECU or your laptop on my VVTi. As above, put your foot down and it goes off the dial rich. For pure octane the stoichiometric mixture is approximately 14.7:1 . Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 4, 2016 Author Share Posted January 4, 2016 Thanks for that Pete. Well here are the graphs anyway I'm not too clued up so let me know what you guys think Quote Link to comment Share on other sites More sharing options...
Sheefa Posted January 4, 2016 Share Posted January 4, 2016 Hi mate On my old Supra TT Manual BPU I made 335rwhp at 1 bar so around 400 at the fly accepting reasonable transmission losses. My AFR's were spot on too, never dipped below 11. Here's a couple of my dyno graphs measuring boost and fuelling readings which may assist you a little. Good luck and hope you resolve soon with a straight forward fix. Greg Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 4, 2016 Share Posted January 4, 2016 When my J spec was BPU running 1 - 1.2bar I always saw AFRs going down as rich as 10 AFR, if fact most of the jap turbo cars I have owned have done the same on full boost, if fact it one of the reasons that a lot of jap turbo cars are easy to take a bit further by increasing boost a little without having to worry too much about lean fuelling an det. Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 4, 2016 Author Share Posted January 4, 2016 That's great thanks Greg gives me a good idea as to what I'm aiming for, appreciate it mate Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 4, 2016 Author Share Posted January 4, 2016 Cheers tricky Ricky, so you reckon thats about normal then? Trouble is you're not meant to push it much past 1.2 bar with the ceramic turbos on j-specs. Mines more or less topped out at 1.2 bar now but only makes 380 hp. Any idea what options I have for a piggy back ecu for vvti to safely sort the fuelling out? Quote Link to comment Share on other sites More sharing options...
Sheefa Posted January 5, 2016 Share Posted January 5, 2016 Cheers tricky Ricky, so you reckon thats about normal then? Trouble is you're not meant to push it much past 1.2 bar with the ceramic turbos on j-specs. Mines more or less topped out at 1.2 bar now but only makes 380 hp. Any idea what options I have for a piggy back ecu for vvti to safely sort the fuelling out? EManage Ultimate is a great unit for the Supra with proper fuel control mate. I think there were some issues UK specs and VVTI Supra's using the Emanage unit but am sure these were resolved. Syvecs out of your budget ? Old but maybe useful: http://www.mkivsupra.net/vbb/showthread.php?30172-Piggyback-for-VVT-i Quote Link to comment Share on other sites More sharing options...
np89 Posted January 5, 2016 Share Posted January 5, 2016 Would it not be a better idea to find out why it is overfuelling first before just wiring in an ecu to make the fuelling leaner? - just a thought Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 5, 2016 Share Posted January 5, 2016 Would it not be a better idea to find out why it is overfuelling first before just wiring in an ecu to make the fuelling leaner? - just a thought Its normal fella! Quote Link to comment Share on other sites More sharing options...
np89 Posted January 5, 2016 Share Posted January 5, 2016 I thought he said it was "off the chart" rich? Quote Link to comment Share on other sites More sharing options...
np89 Posted January 5, 2016 Share Posted January 5, 2016 Oh wait i didnt even look at the fuel graph he posted! Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 5, 2016 Share Posted January 5, 2016 380 BHP sounds very good to me, a lot of rolling roads give wildly optimistic readings! The fuelling isn't crazy either, and was probably measured with a probe up the exhaust rather than near the turbo exits. I wouldn't concern myself about it until you start serious mods with a mappable ecu and a proper, in the downpipe, wide band EGR gauge. Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 5, 2016 Author Share Posted January 5, 2016 EManage Ultimate is a great unit for the Supra with proper fuel control mate. I think there were some issues UK specs and VVTI Supra's using the Emanage unit but am sure these were resolved. Syvecs out of your budget ? Old but maybe useful: http://www.mkivsupra.net/vbb/showthread.php?30172-Piggyback-for-VVT-i Ah cool cheers mate I'll have a read through it. I know of people using the hks f-con v-pro gold and the hks valcon for the vvti cam but I'm sure these are discontinued now and pretty rare. I am wanting to go single in future and was looking into the syvecs but this won't be for a year or two, just wanted it to be running right on full bpu first to get used to the car before I went single Quote Link to comment Share on other sites More sharing options...
Rywalls Posted January 5, 2016 Author Share Posted January 5, 2016 380 BHP sounds very good to me, a lot of rolling roads give wildly optimistic readings! The fuelling isn't crazy either, and was probably measured with a probe up the exhaust rather than near the turbo exits. I wouldn't concern myself about it until you start serious mods with a mappable ecu and a proper, in the downpipe, wide band EGR gauge. You're right, 380 isnt a bad figure I suppose, just comparing it to the other local bpu supras I think I just had my hopes up for it creeping into the 400's with it being a lowish mileage vvti too. But like I said I'm not one for chasing numbers aslong as it's normal and the car is running safe then I'm a happy bunny. Fmic and cams are on the list once the afr gauge is installed and the recirc kit is on so that should bump it up a tad. Cheers for all the help guys much appreciated Quote Link to comment Share on other sites More sharing options...
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