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| down-tuned my 8:1 23psi g10 to run on 87 octane; rather than 91 or 94 | |
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| Tweet Topic Started: Sep 8 2009, 02:47 PM (979 Views) | |
| Dallas | Sep 8 2009, 02:47 PM Post #1 |
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the motor loves it, I know lower octane burns faster than higher, so I was able to lean it out passed the 15.2:1 (and 30*) I had at this specific point 2200rpm cruising. to 16.5:1 afr and 26degrees timing. its actually MORE drivable now (but was surgey at 16.5 and 30degrees) on 20 bucks, I go 55-60km further on regular than I do on premium (which was anywhere from 140 driven hard, to 200 driven nice). this motor prefers lean mixture/less timing vs richer/more advanced timing. I drive a minimum of 200km/day. this is basically a $5 savings per day, everyday. and I drive like 25days a month. so were talking 125$+ savings each month. I am consistently getting 230-260km on 20 bucks now, and im driving it pretty hard. and the best part is, even with the meth turned up (to use more) and have 2-3degrees timing out up high on boost, it doesnt feel any slower whatsoever. so next time I get on the dyno, it will be with 87 octane+meth, and it will still make more than the 132whp it made. just thought id share, screw premium fuel and the damn oil companies. it hasnt even pinged once since I put the 87 in it, perhaps I should bring my timing back up on the dyno and consider using straight meth rather than 50-50 |
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| Johnny Mullet | Sep 8 2009, 08:24 PM Post #2 |
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Fear the Mullet
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Looking forward to those Dyno results! |
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| mwebb | Sep 8 2009, 09:41 PM Post #3 |
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FOG
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so you are running at 26 degrees btdc with 87 octane fuel and boost .... without noticeable pre ignition or "ping" . hmm i do not see much improvement if any for using premium fuel in my non boosted car with timing set to 25 degrees btdc but i need 2 more tanks of fuel to get a good average before i switch back to 87 octane i have introduced too many variables with the new cam |
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| Cobb | Sep 8 2009, 10:54 PM Post #4 |
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BANNED
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If you drive it nicely, you can use cheap gas. Thats what I did in my tacoma with the supercharger. Now to prevent it from pinging at all I had to use shell v power with a bottle of 104 octane booster. Seems if I stood on it once the torque converter locked up at 50mph and I wanted to hit 70 at full boost or 15psi and full throttle it would ping like a mutha. Otherwise with just preminum fuel or the cheap stuff I saw no difference. |
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| Dallas | Sep 9 2009, 01:48 AM Post #5 |
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not base timing, this is the actual ignition timing at that rpm/load it idles at 16degrees, and the dist is set to 10* (so thats my lowest) it runs on a megasquirt. I even have it at 42degrees passed 3000rpm at low load, and 16:1 afr there. so if I cruise the highway in 3rd at 4500rpm or whatever, its taking 42degrees timing |
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| Dallas | Sep 9 2009, 01:53 AM Post #6 |
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I just tweaked the timing and fuel at the peak tq (where you will knock the most) and I have a set of det cans (google it if you care) which detect knock directly to my ear, so I can adjust it before the engine even audibly makes noises of destruction. even pulled the plugs after a full 23psi pull in 3rd gear up to redline (170some kmh!!) shut car off and the plugs had zero signs of detonation.... which means once I get on the dyno we can push it even further. it made 132whp on 91octane with roughly the same timing as it is now on boost... which was 20 degrees iirc. since the dyno (on 91octane) we got way more timing in it but didnt have a chance to re-dyno... ive since brought the timing down to a safe level for now... who knows, it feels just as fast, and I dump more fuel in up high just for peace of mind. we had up to 27 degrees at 7500rpm and 23psi after the dyno with zero ping. actually, here, this is my timing map currently. ![]() and believe me, I dont understand the meaning of "nice driving" Edited by Dallas, Sep 9 2009, 02:01 AM.
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| Cobb | Sep 9 2009, 09:12 AM Post #7 |
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BANNED
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Yeah the tacoma was known to have timing issues. It basically advanced til ping, then retarded and repeated. I think a few companies offered piggy back computers that retarded it to give more power. I never got that far, but did use 3 electrode plugs of a cooler reading and of course the cooler tstat. Interesting the later models used a 7th injector. Yeah, timing, fuel and boost are all key. I met a group of guys in DE with modded sleepers. I saw this guy with an eagle tallon awd. The grill was missing, head lamps clouded over, poorly window tint. He got on the dyno and pulled 407 hp with 30lbs of boost. He had a black cloud of smog come out the back and held a 12 to 1 fuel ratio. |
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