haltech E8 with TII S5 BAC
 

I have the following setup that needs confirming or tuning please. Car specs are in Sig.
I have been trying to find an idle issue for years!!!

From what I have picked up so far is the BAC Freq. is meant to be 244hz from other threads.
Remember 89 TII S5 BAC.
https://cimg2.ibsrv.net/gimg/www.rx7...c10d7823b9.png

More crazy stuff I think I found.
Fuel Zero throttle map
https://cimg5.ibsrv.net/gimg/www.rx7...a4147d7095.png
Ignition Zero throttle map
https://cimg0.ibsrv.net/gimg/www.rx7...023be07d5e.png

those bar charts gave me some bad flashbacks! i find using the table to be much much better...

the BAC frequency is supposed to be 244hz, but yours is set to 140.

so if we take a step back, what Mazda did, is that the stock ecu is using an idle map and a zero throttle map, although you can set the haltech to have enough resolution that i don't think you need it on a stockish port engine.

second, for idle control Mazda used timing and the BAC valve, timing works quickly, and the BAC is slow. see pic
https://cimg2.ibsrv.net/gimg/www.rx7...2c6744a692.png

and 3rd, if you look in the service manuals, the rpm is set in such a way that the BAC valve is raising the rpm, but not by a lot, so the bac is not doing a ton of work.

as a tuner, your job is to take that in and decide what of that you want to implement on your tune. we didn't find out about this timing feedback until fairly recently and most people aren't using it (its also why the S5's tend to surge and bounce)

have fun!

Looking @ this thread towards the end there have been posts about aaroncakes @ 91.5Hz some have success @ 100hz
https://www.rx7club.com/2nd-generati...1017365/page2/

Thoughts?

I also got told to disable the zero throttle maps.

the Mazda book says 244mz, and why would you do anything different? i'm sure other frequencys work, but there are enough variables tuning the ecu that this just adds one and wastes time

the Mazda ecu runs zero throttle maps, for timing and fuel, the haltech has enough resolution that you can duplicate Mazda's strategy without them, so i wouldn't use them, however they are there and as the tuner it is your choice to use them or not

your job as a tuner is to give the engine the fuel and spark that it wants, how you do it is up to you.

Which Mazda Book?
I have reviewed the Mazda FSM & Training Manuals and do not see any data on the BAC frequency.

i'm not sure the frequency matters too much, there are 2-3 other variables to tune as well, just pick something and start tuning.

make sense? the factory setups start minimizing the use of the BAC valve, as time goes on, i think partly for emissions, and partly because timing reacts more quickly.

with the haltech, you need to choose a method, and set the ecu up accordingly.
https://cimg3.ibsrv.net/gimg/www.rx7...5a4601a38f.png

Wow . where did you get that infor from? it is not in any of the FSM for 2nd Gen RX7.. Is it FD/3rd gen FSM? Also are the BAC the same between generations?

Foxed.ca - Mazda RX-7 Manuals there is a shop manual, two FC training books, and i think 2 SAE papers, there is a lot to read!

the FD bac is physically different, but it works the same, its a simple device

So this was from and FD shop manual and not a FC S5 manual.
Found it in the FD 93 Service Highlights pdf F-45

Their functions are the same but should I trust it that it is actually the same electronic design?
The Ohm spec is the same.
Trust or no trust?