antno Posted July 6, 2012 Share Posted July 6, 2012 Just wondering what fuel ratio people are running on the first turbo on wot. Getting .82 when the second turbo kicks in but seems a bit lean up to 4k Cheers antno Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted July 6, 2012 Share Posted July 6, 2012 .82 isn't an air fuel ratio... Quote Link to comment Share on other sites More sharing options...
dandan Posted July 6, 2012 Share Posted July 6, 2012 Assuming you're talking a lambda value of 0.82, that is an AFR of 12:1 Quote Link to comment Share on other sites More sharing options...
antno Posted July 7, 2012 Author Share Posted July 7, 2012 Yea sorry lambda value. Seing high 9,s on turbo one and part throttle. Turbo one has got very hot by the look of it and cracked in the usual place. Would be nice to ad a bit more fuel n bring the temps down. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted July 7, 2012 Share Posted July 7, 2012 High 9s is very rich for part throttle, if you're cruising on part throttle you would expect near stoich, obviously more rich if you were accelerating. Quote Link to comment Share on other sites More sharing options...
dandan Posted July 7, 2012 Share Posted July 7, 2012 Afr of 9 or lambda of 0.9 ? Very different numbers Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 7, 2012 Share Posted July 7, 2012 Also depends on the lambda sensor your reading this from, if its the std one, then if still in closed loop, which AFAIK stays pretty near stoic on low boost, if open loop, then its not very reliable for a stable reading. Quote Link to comment Share on other sites More sharing options...
antno Posted July 7, 2012 Author Share Posted July 7, 2012 Mean 0.9 lambda. 9 lambda would miss fire I would of thought far too lean. Using a motec plm. Just thought on the first turbo at .98 lambda was a bit lean at wot. At half throttle its 1.09. Just wondering what other figures people are getting. On a bpu car Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 7, 2012 Share Posted July 7, 2012 Still unclear, do you mean 0.9 AFR or 0.9v?? 9.0 AFR would be way too rich, is the Motec plm a 0 to 2v wide-band or 0 to 5v as the scales will differ. Quote Link to comment Share on other sites More sharing options...
dandan Posted July 7, 2012 Share Posted July 7, 2012 He said it's a Lambda value of 0.9 - that is the same as an AFR of 13.2:1 Quote Link to comment Share on other sites More sharing options...
hodge Posted July 7, 2012 Share Posted July 7, 2012 Bit of an off topic but how do you work out lambda to AFR? Quote Link to comment Share on other sites More sharing options...
antno Posted July 8, 2012 Author Share Posted July 8, 2012 He said it's a Lambda value of 0.9 - that is the same as an AFR of 13.2:1 That's what I mean. It stays lean half throttle all the way up to 7000rpm. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted July 8, 2012 Share Posted July 8, 2012 13.2 isn't lean, that's slightly rich. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 8, 2012 Share Posted July 8, 2012 Bit of an off topic but how do you work out lambda to AFR? Cant help with the calculation as i am crap at maths, i do have reliably accurate table that i use Lambdabda-AFR 0.686 10.08 0.696 10.23 0.706 10.38 0.716 10.53 0.727 10.69 0.739 10.86 0.750 11.03 0.762 11.20 0.774 11.38 0.787 11.57 0.800 11.76 0.814 11.96 0.828 12.17 0.842 12.38 0.857 12.60 0.873 12.83 0.889 13.07 0.905 13.31 0.923 13.57 0.941 13.84 0.960 14.11 0.980 14.40 1.037 15.25 1.078 15.84 1.121 16.48 1.169 17.18 1.220 17.93 1.276 18.76 1.337 19.66 1.405 20.66 Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 8, 2012 Share Posted July 8, 2012 That's what I mean. It stays lean half throttle all the way up to 7000rpm. Depends what boost your making on half throttle, also begs the question, can you actually make 7000RPM at half throttle under load?? I am finding the whole question rather misleading, as the OP first asks " what AFRs people are getting on the first turbo before the second kicks in" and he states his lambda is 0.82 = around 12.7 (not to bad for the transition point) as the ECU will keep things pretty lean unless its WOT. He then goes on to say he is seeing high 0.9s on part throttle and turbo one, (which would equate to close to stoic on part throttle, its all a case of load, unless he can provide more info nearly impossible to answer the question. 13.2 isn't lean, that's slightly rich. Not if your at full boost! which is difficult to answer the OP questions, as he needs to include the load factor. Quote Link to comment Share on other sites More sharing options...
antno Posted July 8, 2012 Author Share Posted July 8, 2012 You have answered my question pal. It sounds like its not uncommon to see close to lambda 1. It was on wot up to the second turbo, full load, making .8 bar and .96 lambda Quote Link to comment Share on other sites More sharing options...
dandan Posted July 8, 2012 Share Posted July 8, 2012 Lambda x 14.7 = AFR Quote Link to comment Share on other sites More sharing options...
hodge Posted July 8, 2012 Share Posted July 8, 2012 Thanks guys. Educated as usual. Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 12, 2012 Share Posted July 12, 2012 The stock system runs 13:1 AFRs on the first turbo by design, it only goes to about 3500rpm under that load and it's probably rather good for economy The floodgates then open between 3500 and 4000rpm when the second turbo kicks in. Another reason why parallel twins or a single turbo with no remapping is a bad idea -Ian Quote Link to comment Share on other sites More sharing options...
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