MoTeC Global Forum

Do rotaries require more accel enrichment than piston engines?

Ive tried running it with overrun fuel cut and without, also adding extra fuel on overrun to keep the fuel in the inlet on overrun.

This particular engine is a stock RX8, 3 injector per rotor type. (6speed gearbox)
Injectors are staged, 1 at port (primary) 2 higher up (secodary)

Thanks

Martin

Hi Martin,
I take it from the logging you get a big lean spot when you hit the throttle? Have you tried increasing the accel enrichement sensitivity?

What sort of settings do you have?

Hi Mark,

Yes that lean spot is the problem as you get on the trottle.

IJPU = 10ms
Baro reading was 84.7 Kpa during this session
Could it need any more than this??

Hi Martin,
How does your project looks like ? Is it an original 13BMSP or did you modify something ?
Is the problem over the entire RPM range or only at a certain point.
I added the accel setting of our peripheral ported rotary.
Maybe this helps.

Hi,


THis is a GrpN Track car, Still with complete original wiring. Ive just added 2 sets of Millspec connectors to splice into the chassis harness and engine harness to pick up neccesary wires. The standard display cluster, abs pump, alternator are all working. THe motec controls all engine parameters, Fuel, Ign, DBW. These are not shared with the standard ECU, allthough swopping back to standard ECU takes 2minutes.

The Engine is still stock (13B MSP), and yes the problem is over the whole RPM range. The thing is that it wants more fuel than i expect it to take so this is why im looking for a problem elsewhere. But first id like to find out if this is really uncommon for Rotaries to want so much Accel Enrichment.

I must add that the fuel is Premixed, the OPM is diconnected.

Thanks for your accel table, i appreciate your input!


Thanks
Martin

Had a look at your Accel Settings , just a few Q`s...what is your IJPU? and what is your Accel sensitivity?


Thanks
Martin

Hi Martin,
Our IJPU is 20 ms but it could be a bit less because our Effcy% is max 60 %.
For Fuel acc sens see doc.
The engine run's with RX-8 primaries and 1600cc secondaries
We run it at 0,93 lambda.

Hi Martin
The short answer to your question is YES, I have not tuned a lot of Rotaries but the ones I have, had some big numbers in the Accel, over 100 in some cases with the IJPU at 12. The only problem with settings like this is you need to make sure your throttle sensor has no noise on it as this will cause false triggers so to speak.

Take a close look at the hysteresis settings for the secondaries, and the amount of enrichment associated with the secondaries coming in.

Your 1600cc secondary injectors are highly non linear in the lower range which is adding to the problem.

And yes, rotaries typically need large amounts of accel enrichment.

The short answer to your question is YES, I have not tuned a lot of Rotaries but the ones I have, had some big numbers in the Accel, over 100 in some cases with the IJPU at 12. The only problem with settings like this is you need to make sure your throttle sensor has no noise on it as this will cause false triggers so to speak.

Pete, numbers of over 100 in what table ? What sort of setup do you have in the accel ignition tables ? I'm working on this at the moment so any advice helpful.