I have a single turbo 20b. Got a great base map from Howard Coleman, and the car runs great. I backed off timing ~5 degrees in all rpm, and even more in boost from the provided base map to be on the safe side.

I know my timing is too retarded. I'm waiting on a pulley to get here so I can set TDC. Once that's done, how do I safely advance the timing? what parameter do the rotary tuners use to advance timing? is it strictly experience? MBT? EGT? when "x" extra ft-lb is made with a degree advance on a dyno? Thank you for any advice in advance.

 

Would love to see experience tuners chime in, this is a great question.

 

I haven't watched it, but their stuff is pretty on point.

https://www.hpacademy.com/previous-webinars/043-rotary-ignition-tuning-link-g4-vipec/

 

pretty good question to ask, i my self would like to learn how to tune timing on my 13b. i have my microtech setup good right now but i wish i have better understanding about to tune timing. C. ludwig. is a great video but you have to pay to watch it. and yes you have to pay to learn but most people just need some advice to what to look for.

 

Membership to the site is $20/month. You could watch every video they have and learn quite a lot for $20.

 

https://www.rx7club.com/engine-manag...etter-1089664/

another data point. i don't really have a conclusion, but the observation is to look at both FC timing maps and look how different they are. there is a bigger difference in timing than the power difference would suggest

 

^ combustion chamber shape changed between s4 and s5, so I wonder if some of the timing map changes are the result of faster burn on an s5. Maybe an s5 and later rotor/housing combo doesn't need as much spark because the engine burns faster.

 

true. the intakes changed too, along with the exhaust manifold, and turbo. also in 89 they started having to warranty the cat for much longer (7 years instead of 3). the S4 and S5 NA cars run very different AFR's after 4000rpm, it wouldn't surprise me if the turbo was the same. weirdly i've never had a wideband on a stock ecu turbo car

 

Running an s4 Bridgeport turbo keg on s5 electronics, S5 turbo and rtek 1.5 n374 ecu. Idle ran @19 in the beginning, below 4000 rpm 12.1 cruise after 4000rpm 13.5 cruise and 10.8 under boost. Adjusted to 15 @ idle 13.5 below 4000 rpm 16 above 4000 rpm for highway cruise and 11.7 under boost because it was to rich and I gained 25hp in higher rpm.

 

If I recall correctly the leading and trailing spark plugs on the s4 housings are closer together than that of the s5 and fd housings.. which would alter the timing. no?

 

Sparks instant relative to crank position, no. You could place the plug in the exhaust port and telling the ECU to fire at 20° BTDC is still going to fire it at 20° BTDC relative to the crank. Now, does moving the plug position make the engine want different spark timing? That's the question.

 

That is what I was trying to say. Theoretically the timing map should reflect the difference.