Jake Posted June 5, 2004 Share Posted June 5, 2004 My car has been on the the dyno at Thor today. The good news : At the hubs, my '93 Auto RZ made 350.5 Hp @ 5904rpm and 1.17bar, which I think isn't bad for a car which is completely standard apart from having both cats removed. The bad news : Pete had to do my runs with a delicately balanced throttle to keep the boost below 1.2 bar because above that I've got a serious problem which the Air/Fuel Ratio and Detonation. If given full throttle, at 4000rpm when the second turbo comes on song the AFR is 11.0, which I believe is OK, but it then rapidly rises and by the time the revs have reached just 4875rpm the AFR is up to 12.86, which Pete tells me is dangerously high. His collegue (who's name I didn't catch) was checking under the bonnet at this time and said it was detonating badly. Pete recommeded a new fuel pump and then a FSE if the pump didn't improve things. Unfortunately we didn't have time for him to fit any of these parts today. If I post pics of the dyno plots perhaps you guys who know about these things might advise me whether I should improve the fueling somehow or whether I should just restrict the boost to 1.2 bar. Aren't dynos great? I wouldn't have know about these problems until I blew the engine up if I hadn't done this today. You might say that I should have noticed the Det but I honestlycan't hear it from inside the car at speed. -- Jake '93 RZ Auto Quote Link to comment Share on other sites More sharing options...
Darren Posted June 5, 2004 Share Posted June 5, 2004 I would take Pete's advice! All the tuners say if you want to run 1.2bar in a Supa fit an uprated Fuel pump! An FSE wouldn't do any harm either! Quote Link to comment Share on other sites More sharing options...
Marco Posted June 5, 2004 Share Posted June 5, 2004 I hope you can sort things out before the Amsterdam trip Jake! Nice to meet you btw Pete's collegue is called Nod, he's an ex-collegue of mine when we were still making computergames Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 5, 2004 Share Posted June 5, 2004 A question for those in the know - I have heard either 11.7 or 12.5 as being the ideal afr under boost. Which is it? I know stoich is 14.6, so 12.5 sounds decently rich to me, and Corky Bell recommends it in his book, but if Pete Betts thinks 12.86 is dangerous (whereas it would be edging towards borderline if 12.5 was the correct afr) I'd like to know what others think... Post up yer dyno plots, Jake. -Ian Quote Link to comment Share on other sites More sharing options...
Jake Posted June 5, 2004 Author Share Posted June 5, 2004 Hopefully these will make more sense than my attempted explanation . . . Torque_and_BHP Torque_and_AFR Boost_Pressue Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 5, 2004 Share Posted June 5, 2004 Just phoned the ever-helpful Chris Wilson and he says 12.5 is OK but aim for 11.7 to be safely rich, and I'll readily agree with that, especially with piggyback tuning. There are only minimal gains of power in leaning off to 12.5 and no adverse effects (barring fuel consumption lol) of running 11.7. -Ian Edited to finish the sentence, doh Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 5, 2004 Share Posted June 5, 2004 Well, judging by the red line graph, where you hit 1.3bar, the AFR was heading north scarily fast, good job Pete stopped The red line on the torque and power curves show a huge power increase because it was going so lean (extra power for a brief amount of time, then no power because the engine went pop). The 1.2bar run, the blue line, shows a real tailing off around 6000rpm. If you got a restrictor ring and it deffo held to 1.2bar or less, but certainly no more, I still wouldn't take it over 6000rpm. A beefier fuel pump would be a good idea - UK spec or Walbro. If you could fit that, and only that, then do the dyno runs again that would give the community a *very* valuable set of data. -Ian Quote Link to comment Share on other sites More sharing options...
Jake Posted June 5, 2004 Author Share Posted June 5, 2004 Originally posted by Ian C Just phoned the ever-helpful Chris Wilson and he says 12.5 is OK but aim for 11.7 to be safely rich, and I'll readily agree with that, especially with piggyback tuning. There are only minimal gains of power in leaning off to 12.5 and no adverse effects (barring fuel consumption lol) of running 11.7. Wow, that's really good of you to ring Chris! (He'll be billing you not me, right?) Interesting - thanks. BTW, what do you mean by "piggyback tuning"? Quote Link to comment Share on other sites More sharing options...
Jake Posted June 5, 2004 Author Share Posted June 5, 2004 Originally posted by Ian C The 1.2bar run, the blue line, shows a real tailing off around 6000rpm. If you got a restrictor ring and it deffo held to 1.2bar or less, but certainly no more, I still wouldn't take it over 6000rpm. I've got a ring I bought from CW months ago, I'll pull my finger out and get it fitted soon. Originally posted by Ian C A beefier fuel pump would be a good idea - UK spec or Walbro. If you could fit that, and only that, then do the dyno runs again that would give the community a *very* valuable set of data. You mean get it re-dyno'd after fitting the pump but before fitting the restrictor ring, right? OK, that's what I'll do. Quote Link to comment Share on other sites More sharing options...
JamesArup Posted June 5, 2004 Share Posted June 5, 2004 Jake ... I had the same kind of result a few weeks ago on the Dyno. They didn't even do full power dyno run as the Det was sounding pretty messy (sounded like a bunch of keys jangling about). Anyway - I'm having an uprated fuel pump, 550 injectors + SAFC2 fitted this week by Matt and the Vortex guys, so I'll let you know if that solves the problem Cheers, J Quote Link to comment Share on other sites More sharing options...
Wez Posted June 5, 2004 Share Posted June 5, 2004 Originally posted by Jake BTW, what do you mean by "piggyback tuning"? These are electronic fuel/ignition controllers that fool the stock ECU by intercepting the signals, hence the word piggyback. Quote Link to comment Share on other sites More sharing options...
Wez Posted June 5, 2004 Share Posted June 5, 2004 If i remember correctly for optimum power you want to run 10% rich over stoich which in most setups maybe considered a little to lean, people do run richer as the added fuel is a safety margin plus it brings the temps down as the unburnt fuel is also being used as a coolent. Quote Link to comment Share on other sites More sharing options...
Dragonball Posted June 5, 2004 Share Posted June 5, 2004 Originally posted by Jake Pete recommeded a new fuel pump and then a FSE if the pump didn't improve things. Unfortunately we didn't have time for him to fit any of these parts today. M8 - have both of these sitting here The pump even I could do - so go for it!! Quote Link to comment Share on other sites More sharing options...
Jake Posted June 5, 2004 Author Share Posted June 5, 2004 Originally posted by Paul E M8 - have both of these sitting here The pump even I could do - so go for it!! How much? Also, if it's sooo easy, I want the price for YOU fitting it ! Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 5, 2004 Share Posted June 5, 2004 Jake, that's exactly what I mean - fit the pump and do another run, obviously keeping a very close eye on the fuelling at 1.3bar and anything over 6000rpm. Get those dyno plots and upload them. Luckily the pump is under £100, I know Vortex have them in stock, as apparently does Paul "Vulture" E so I hear It's an easy job if you've done it before The plastic ring thing is a bastard to take off (and put back on!) and the banjo bolt on the fuel feed pipe is hard to undo as the whole pump cage rotates instead, so have fun Also I asked CW for my own purposes - tuning mine with the E-Mangleage. Just thought it would be relevant to this thread Wez has piggyback tuning spot on, it's not a replacement ECU so it's never going to be as accurate to map. This, in my opinion, is only an issue if you are going for a full-on race setup, where 100% is only just good enough so you have to run a knife-edge map to get full power. Besides, the stock ECU runs very rich under boost anyway... -Ian Quote Link to comment Share on other sites More sharing options...
fisherjohn Posted June 6, 2004 Share Posted June 6, 2004 Downside to not doing the fuelling and / or restricting the boost. Blown turbos / plugs / piston / ( engine rebuild ) Lot of work / lot of skin off knuckles / lot of exasperation. I did exactly that with mine, as could not wait to blast it, it ran lean and detonated, 4 plugs blown to pieces thru the pistons and second turbo. Quote Link to comment Share on other sites More sharing options...
TLicense Posted June 6, 2004 Share Posted June 6, 2004 For typical A/F ratio's under boost and at RPM's have a look at this courtesy of AEM EFI basics. Regards Tony Quote Link to comment Share on other sites More sharing options...
Wez Posted June 6, 2004 Share Posted June 6, 2004 Originally posted by TLicense For typical A/F ratio's under boost and at RPM's have a look at this courtesy of AEM EFI basics. Regards Tony Just to add to that 100kpa is approx 1 atmosphere therefore 200kpa is approx 1 bar boost. Quote Link to comment Share on other sites More sharing options...
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