Thumper Posted February 14, 2006 Share Posted February 14, 2006 Ok I have read different theory's but none reguarding non-crossflow 2 valve per cylinder engines. Right now my total timing is 39 degrees from 3500-6500. By 19psi it drops to 16 degrees so roughly 1.1 degrees per psi. This seems to fit most people theorys on how much to be pulled, but when I think of it as 16 degrees at 19psi that seems alot. Considering alot of cars stock timing is 10 degrees. So what do you guys think good timing or should I remove some more? How much timing pulled is too much? Thanks Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted February 14, 2006 Share Posted February 14, 2006 Is it stock compression? If so, here is what I was running 35 degrees max timing and had it all in by 3000 rpm's 8 psi 27 degrees total 15 psi 24 degrees total 21 psi 21 degrees total timing This was with a stock longblock (upgraded cam), T72 turbo and 93 octane pump gas and 550cc injectors Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted February 14, 2006 Share Posted February 14, 2006 mine is F54/P90a with L24 rods and AZC pistons, no milling to either surface, and a HKS 2mm headgasket, which everyone was saying is a 8.2:1 compression or right in there... Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 14, 2006 Author Share Posted February 14, 2006 Ok took a look at the timing maps. At 8psi = 31 degrees, 15psi = 20 degrees and 20psi = 16 degrees. We haven't tuned the engine for 20+psi yet. I will post my timing map in alittle bit. Quote Link to comment Share on other sites More sharing options...
Garrett76Zt Posted February 14, 2006 Share Posted February 14, 2006 Yeah your timing map looks a bit conservative. I'm running 21 degrees at 15 psi so im still kinda conservative as well. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 14, 2006 Author Share Posted February 14, 2006 Z-GAD was those with your supra motor? stroker? or 2.8? Well here is my map after I tweaked it alittle bit. Mostly pulled some timing at 8-10psi. Btw 8psi = 155kpa, 12psi = 183kpa, 15psi = 203kpa, and 20psi = 238kpa Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted February 14, 2006 Share Posted February 14, 2006 Those #'s were on a stock longblock L28. All my stuff is in kPA as well, I was just converting to psi . I still have my old maps on my laptop from the turbo L28 7.4:1 stock compression. With an 8.2 compression motor, you may need to back off timing earlier and more due to the added compression if you are planning on running pump (93). I remember having to take out most of my timing prior to 10 psi and then less gradual after that. If you are starting at 39 total with a 8.2:1 motor, you may only want 25-26 degrees at 150 kPa. I like to err on the side of safety and come up from the low end when tuning. Surprisingly, or not, my 2JZ timing maps are pretty close, but then again at 8.5:1, I am still only running around 17 degrees total at 20 psi. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 14, 2006 Author Share Posted February 14, 2006 On my stock turbo block 7.52:1 compression ratio I was running 33 degress at 140kpa and 30 degrees at 160kpa with never hearing detonation at all. And 73turbo240z on his 8.2:1 engine never heard detonation also intill it was 30 degrees out side. At 8-10psi level we are running 12:1-12.5:1 afr's. I think that to be on the safe side though I will pull 2 degrees more out of the map I posted at 140, 160, and 180kpa. At 20psi does 16 degrees look alright? Also if I do have a detonation problems up there what should be the lowest I put the timing 10degrees? Thanks Quote Link to comment Share on other sites More sharing options...
stinky Posted February 14, 2006 Share Posted February 14, 2006 16 sounds about right. I run about the same on my vg30et at around that boost level. Same turbo and ic btw. Keep in mind your particular engine combination (turbo, ic, pistons, exhaust) is different from most everyone else so its hard to compare. If you have the opportunity to dyno tune that will tell you exactly where you need to be. As it is I think youre about right as long as its not detonating and you dont have to run an extremely rich mixture. Try advancing it a bit and see what happens. Quote Link to comment Share on other sites More sharing options...
dapiper Posted February 15, 2006 Share Posted February 15, 2006 I ran 18° initial and 36° total on L28 N42 with Arias at 8:1 and MSD 6T and dizzy. Retard 0.5°/psi boost, hence 29.5° total at 15 psig with Sunoco 94 octane and 11:1 AFR. Turbo is Turbonetics H3 with 7 psi at 3K RPM heavily loaded in 5th gear using 0.79 A/R and 3" exh. Cam is 0.475" lift at 110° lobe ctrs and 238°I/248°E duration @ 0.025" Beyond 13-15 psi, use 5 gal TurboBlue in full tank and 0.35°/psi boost retard up to 18 psi. Beyond 15-17 psi, use C110 octane up to 23 psi boost and 0.35°/psi boost. Now using DIS and sequential EFI with 17° initial and 34° total and 0.5°/psi retard. AFR is 11.8:1. Measured inaudible knock using MSD knock alert into data ack (0-5V) at crossover which persists in higher gears. Soon to tune ign on Dyno. Cam timing may be off. Will advise results. Others? Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted February 15, 2006 Share Posted February 15, 2006 Also remember, not having audible detonation doesn't mean you do not have detonation. The audible stuff is when it is bad... Quote Link to comment Share on other sites More sharing options...
zguy36 Posted February 15, 2006 Share Posted February 15, 2006 dapiper, That sounds like a lot of ignition advance! What kind of horsepower number are you making with that much advance? It seems like you might be better to back your timing off and run a lot more boost. Quote Link to comment Share on other sites More sharing options...
dapiper Posted February 16, 2006 Share Posted February 16, 2006 You guys must be running kerosene with that little timing. Power fell off above 0.6°/psi retard (27° total at 15 psig) under my stated build specs. Note difference in fuel, cams, quench, head, CR, charge and head temp as well as how you hold your jaw have big influence on your results. Are your pistons dished and how much? What is your piston clearance to head? Spark plug heat range? Can't compare to Supra, since 4 valve and head design requires less advance which allows less time for detonation to develop. Too retarded is hard on exh valves and turbo. OBTW, max power on old analog ECU was 435 RWHP at 21 psi boost on my Dynojet. Quote Link to comment Share on other sites More sharing options...
zguy36 Posted February 16, 2006 Share Posted February 16, 2006 You guys must be running kerosene with that little timing We can't all afford turbo blue! I can't even get 94 at the pump here in Idaho, the best they sell is 91 Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 16, 2006 Author Share Posted February 16, 2006 We want to keep our cars as street as possible. No race gas and no additivies. Our boost comes 15psi by 3200rpms by 3rd gear so it builds alot quicker. Also remember these are not race engines they are either a stock junkyard motor, or an engine that has been rebuilt with new pistons so nothing fancy smancy. I think i'm going to try these settings for awhile and see what happens. Quote Link to comment Share on other sites More sharing options...
Ivan280zt Posted February 16, 2006 Share Posted February 16, 2006 Stock l28t bottom end with arp rod bolts. Big turbo, i/c, injectors, bpr8es plugs, haltech e6k, with boost coming (1-2psi at 3000rpm 15psi at 3800rpm)in timing is about 26 deg. At 4200rpm (where my torque peaks) its at 23 deg. then it goes back to 26-27 from 5800rpm-up. This is on 93 octane. Ivan Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted February 16, 2006 Share Posted February 16, 2006 sounds like i just really need to get my *** on a dyno. Quote Link to comment Share on other sites More sharing options...
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