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Injection amount vs E85
Ive recently got my twincharged ( m90 and 69mm gt45 ) 2jz running again. This time around its got 10:1 compression on 25psi boost. Ive been tuning it on 98 and 50/50 water/methanol.
Total 98 flow is around 1500cc to 2200cc depending on rpm ( 5000 to 7000 ). I started spraying 1800cc/min, 1500cc direct port and 300cc pre turbo but still had slight signs of sparkles on the plugs ( no audible, well by ear ), so I upped it to around 23-2400cc by adding a second pre turbo nozzle and upped the pressure a little which has seemed to work. It had me thinking how much you would have to inject to keep up with E85's knock limit. As at the moment I'm injecting technically M30, M40 plus the water. Or over 100% water/meth to fuel. http://i966.photobucket.com/albums/a...pscvjujiug.jpg https://www.youtube.com/watch?v=awHJHKUOx_g Cheers |
Re: Injection amount vs E85
If you run it at a petrol equivalent indicated AFR of 10.2 or about lambda 0.69, you run way too rich in my opinion. That will even promote knock.
Is the 50:50 by weight? Running so rich in the presence of water reduces burn speed a lot. It costs power. I'd retune it to lambda 0.78-0.85. No need to run any richer on so much mix. One of the reasons you might experience more power on e85 is its higher burn speed compared to your current super rich mix. The ignition timing numbers will not directly be comparable due to the different burn characteristics. |
Re: Injection amount vs E85
I understand what your saying but the way I look at the afr is there is approx 50% methanol to 50% fuel going through the engine. The afr target for a boosted methanol engine is around 8.0 or 0.55 lambda, gas target is 11.0 or 0.75. So I figure running an afr in between these would be correct, so around 9.5afr or 0.65 lambda at 50/50 meth/fuel. So Im at around 9.8afr to be the same so 10.5 is still leaner. I tried leaning it out to 11.2 at the track with no gain in et or mph so I richened it back up. Also the plugs lost there fuel ring which scared me a little lol. I understand the water does its thing but at some stage you would have to go richer than a lean gas scale reading. Cheers
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Re: Injection amount vs E85
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Have you ever run an engine with proper knock control before you posted this? I have many times and I can tell you first hand across lots of different set ups that there is direct correlation to excess fuel ration and WM50 rate that shows greatly reduced knock levels as you get more petrol in there. I've run these down to 0.670 L. |
Re: Injection amount vs E85
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Re: Injection amount vs E85
Hello Peter,
Ears, a TurboXS knocklite and later a J&S Safeguard plus gauge. No Motec or Syvecs capability, but in a early Elise you can hear it knocking pretty well as there is no sound insulation and the engine sits close behind your head. Now at least my puny SC Rover K made less power on rather rich AFRs and knocked with less advance. Could be exhaust valves getting hotter or whatever. Lot's of nonlinearities. Maybe I was all wrong and should have drowned that bugger in fuel despite it performing rather poor. You also posted similar observations on way rich not being any good in the past. You advocated AFRs of 11:1 and higher. I can dig out a few examples from you, but can't be bothered on a ipad. From: http://rotarycarclub.com/rotary_foru...p/t-10423.html "*At full boost pressure* The AFR on average is 11.3:1 with the current WI setting, it only goes towards 11.4:1 at revs past 7400rpm to stop the power from falling off where I need to hold rpm to say 8300rpm to save making a gear change be it on a straight or hold out 5th gear for 200+mph top speed as my car is geared for too :). Lower boost pressures (0.5bar to near 1.0bar) the AFR is around ~12.0:1 setting (more so because any more excess fuel is not required, especially with water injection or even without) Anything with more excess fuel really takes away allot of power. My EGT was always around 980 deg C or so with the correct ign timing, this set fuel mixture, and WI rate. Anything outside of these settings results in lower power, too high an EGT, misfire, or and less measured performance (< too over cooled *fuel or combination of fuel and water*, or not enough ignition advance especially) in my standard 90-140kmh testing I do." "Default Re: Injecting water into a rich a/f mixture is not a good id Quote: Originally Posted by Richard L Not so long ago, a user of our WI system has lost some 40+ WRHP during a dyno tuning session, not surprise to know that he was quite disappointed. Only after a few months later and have discovered that his engine is tuned to run an a/f ratio of around 10.5:1. I would really like to hear from anyone if they have suffered the same experience? Great thread Richard ! I have seen this in my own current car, but I put it down to non audible misfires. When I have had a super strong ignition system on various other cars I have done I have not seen losses in that magnitude but they def do exist. __________________ http://www.riceracing.com.au RICESP > F40 > Zonda > ZR1 Water Injection Specialist "Can't be defeated!, don't know the word!, shoulder to shoulder!, we'll fight the world!, WE CAN'T BE BEATEN!!!"" In the end, it won't matter as long as you can extract the most from a given set-up. :-) You have also worked on lower boost levels at the time you posted you observations. Could very well be that at 30PSI and higher things look different these days. I went NA for 2018 :-) |
Re: Injection amount vs E85
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Re: Injection amount vs E85
Miss fire and knock are two different things, so not much point quoting that really.
Was just talking about your statement as its opposite to what I have see these days, using the only knock capable ECU that is proven at places like LeMans (Life Racing/Syvecs). I've got allot of cars running with much higher energy CDI systems than back then, all on WM50 and regardless of engine type, they will show lower knock with great excess fuel (I have only tested to ~9.5:1 AFR). Each one of them will take more ign timing and make more power when running this with WM50 than they will if run at 0.730L or 0.760L or higher... Thus I pretty much default to 0.700L myself, this is for cars running 8.2:1 to 9.0:1 CR, petrol and WM50, like the poster here I can't see difference in performance on these combination run to 3500mB (MAP), but do see lots of reduction in thermal stress on the engine and turbo shown by EGT sensors. Only negative is increased fuel use, but given on these cars it makes up less than 1% of time on load then its meaningless to a 'street car' that is raped on road. Other question is it the meth that needs it? It's just what the engine demands........ use anything other than a Life Racing/Syvecs engine management unit and you are doing nothing more than guessing as I have not seen anything else (used them all) that can actually run an engine at the knock limit all the time like these systems have proven to do when it counts (in professional endurance racing) not paper/web page or hobby racing series. :) |
Re: Injection amount vs E85
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All of this has been covered at length ~80 years ago anyway, where engines were run to knock limit with every permutation of excess fuel and WM50 ratio from 0.2 by mass to 1.5 all of the information is out there and the testing is comprehensive.... much better than anyone has shared on gagtube or on-line and lets not forget it was done by people who held relevant qualifications in the said topic too, not wikkipedo Goolaged knowledge for Generation nobodies that proliferate today via blogs etc etc. More often than not lack of ignition energy is the #1 culprit towards people (including myself back in the day) making wrong assumptions about the merits or otherwise of water injection and the many ways it can be set up and run. |
Re: Injection amount vs E85
Your work on ignition has been greatly appreciated here and elsewere.
Sounds reasonable that in certain conditions and suitable hardware more fuel can work well. I am aware of the WW2 literature and have read it as well. It is just not all directly applicable in a given car engine set-up. Your ignition issue is one of them. Could be that my experience of rich not performing well is fundamentally casued by ignition onset delays or other related issues. One aspect that made a bigger difference for the power I was able to extract was proper mix distribution and that the fine mist actually makes it into the cylinder. Modern curved plenum runners of dry flow manifolds are a major obstacle for central injection systems. You method is one of the ways to deal with droplet aggregation, make them very small to begin with. Cheers Marko |
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