Dragonball Posted February 12, 2003 Share Posted February 12, 2003 OK Gurus of Boost Normally at about 90 leptons - put foot to the floor - kick down and then judder-pop-pop-judder - one time left a nice big puff of smoke behind Boost only to 1.1 - no controlling via SBC etc Spark Plugs? Pete- your VFCC coming in? Poor fuelling? How do I check this out please? Cheers Paul Quote Link to comment Share on other sites More sharing options...
Steve Cargill Posted February 12, 2003 Share Posted February 12, 2003 Hi Paul, do you still feel the first turbo and the feel the second one come in as normal? Does the boost hit 1.1 and then just not get any higher - a 'soft cut' type feeling? I think the VFCC raises normal cut, you'll get the traditional red triangle and brown trousers when it hits. What did it used to boost to? What plugs have you got fitted? I take it the puff of smoke was unusual. Have you got (did you have ...) normal ceramic turbos? Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted February 13, 2003 Share Posted February 13, 2003 I think the VFCC raises normal cut, you'll get the traditional red triangle and brown trousers when it hits. Correct. It'll be just like normal fuel cut but at 18psi. (But remember you can always remove it as well if you're in any doubt) What plugs have you got fitted? I'd recommend NGK 6097 (BKR7E) As for the other things do you have the following.... Super Unleaded Fuel? (If not why not!) Racelogic Traction Control? (Could be harsh traction setting and wheel spin) Also consider that fuel cut only cuts in after a prolonged period of exposure to high boost. I think it's something like 2s. i.e. you have to be at or above the fuel cut threshold for longer than 2s before the ECU kicks in. It may be that due to and uncontrolled boost system it's peaking above 1.1 for a short time, poor fuel or just plain bad luck is causing problems, the boost gauge is damped so maybe wouldn't see this slight peak rise in boost above 1.1. Just ideas..... Regards Pete Regards Pete Quote Link to comment Share on other sites More sharing options...
Dragonball Posted February 13, 2003 Author Share Posted February 13, 2003 I have the racelogic - new plugs (plat not iridium) - on super unleaded Out of those The 'soft cut' feels about right - like there is a dip / a pick up and then a judder/pop - and then away No brown trousers triangle (BTT!) (had that when setting it up once!) Turbos normal jap jobbies I thought it my be the racelogic cutting the spark because otherwise the back wheels would have fishtailed (but to be honest too scared to check this out on the roads at present with it switched off!) Mmmmm... Please keep theories coming Cheers Paul Quote Link to comment Share on other sites More sharing options...
Alex Posted February 13, 2003 Share Posted February 13, 2003 If it has only happened since the new plugs have been fitted then they would be my suspects. The gap may be incorrect. What brand and code are they? Though at 1.1bar you should be running SUL or Optimax. UL is ONLY suitable for completely stock .8bar Supras. Quote Link to comment Share on other sites More sharing options...
Dragonball Posted February 13, 2003 Author Share Posted February 13, 2003 Originally posted by Alex Holdroyd If it has only happened since the new plugs have been fitted then they would be my suspects. The gap may be incorrect. What brand and code are they? Though at 1.1bar you should be running SUL or Optimax. Sparks are pre-gapped iridium denso jobbies - so they should be all right Have edited - always use SUL Either over boosting (but SBC shows only 1.18 max) or Racelogic I think Have changed the SBC settings to reduce the gain at the higher speeds ie upped response at lower speeds and then reduced with faster speeds when I am more likely to use kick-down Dont get me wrong - car fan-bloody-tastic other than this Will see what happens - but keep 'em coming Cheers Paul Quote Link to comment Share on other sites More sharing options...
Nathan Posted February 13, 2003 Share Posted February 13, 2003 Personally I wouldn't use BKR7E. Then again, I wouldn't be running a grade 7 plug period. You need to get a proper boost gauge in there to see how it compares to the boost controller reading. DO NOT take the BC's reading as gospel. I don't think it's fuel cut if you're not getting the triangle flashing up. Fuel cut is invoked at the same time as the triangle. Regards, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 13, 2003 Share Posted February 13, 2003 Nathan, can you explain the comment about the Grade 7 plugs?? Quote Link to comment Share on other sites More sharing options...
Nathan Posted February 13, 2003 Share Posted February 13, 2003 Hi Terry, Just that they are simply not cold enough IMO. I always run the coldest plug I can that doesn't give missfiring or cold starting problems. We've fitted S40i's (equiv Grade 8) for years on BPU soops and their performance record is impeccable. I really can't emphasise how pleased we are with the HKS plugs. I'm honestly not plugging a brand here; if there was another plug that worked as well then I would reccomend that. I have seen just about all the different types of plugs used on Supras and many of them give high boost missfire problems. Some don't, but the HKS Superfires are a known quantity, and so if a Soop comes in with a misfire the plugs are the first area we look at. OK, it's a 100 quid gamble but it's not often that the problem stays.. I'm also aware that they are plenty of cars out there not running HKS plugs that seem fine. Thats OK, but it simply the fact that the HKS plugs are good for us as a commercial enterprise as we can rely on them 100%. I used to run S45i's (Grade 9) in my car and only then did I have some mild problems with cold running for the first few minutes in extreme weather. Very rare though, and certainly preferable to worrying about whether a lesser/warmer plug was going to fry on full boost at 180mph.. Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 13, 2003 Share Posted February 13, 2003 Nathan, I have never had an issue running 7's. I am going to try 8's if I raise the boost, but don't think any BPU+ cars will have a problem with 7's IMHO. HKS plugs................. Try Denso IK24's. 1/3rd less! Quote Link to comment Share on other sites More sharing options...
Nathan Posted February 13, 2003 Share Posted February 13, 2003 Terry, As I usually say to most; whatever works for you. Like I said, I run the coldest plug I can get away with. No point tempting fate IMO. With HKS plugs, they seem to spark consistently and well enough to run 8 or 9 grade where most plugs would struggle. For example, I used to run 'regular' grade 9 NGK's in my nitrous ZXR750 and the cold running was diabolical compared to the grade 7 it ran as standard. Had no choice though. I take on board that you have had no problems with your grade 7's; exactly what make/type do you use? The BKR's? It may just be that most of the plug problems we have come accross have been simply because the plugs are of a poor design/make/type rather than grade, but 8 is always what we have used on most soops with zero problems, so we'll stick with it. Like I said you can't do any harm by going as cold as you can with plugs, so I err on the side of caution. The IK24's: can you get them in grade 8 and 9? Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Dragonball Posted February 13, 2003 Author Share Posted February 13, 2003 Oi - bugger off and start your own thread! Jeez! Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 13, 2003 Share Posted February 13, 2003 I used to use BKR's bit switched to 6097's. Now run IK22 which are denso Iridiums. The IK24 appears identical to the HKS plugs on inspection. It is an 8. They seem to go in steps so if they make an IK26 that should be a 9. Quote Link to comment Share on other sites More sharing options...
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