A little history on my setup.

I am running e85, twin walbros, 1200/1600cc injectors. I made 401whp on 16psi and I am currently running about 18psi. s5 6 port (stock port), 9.7 rotors. T70. Haltech e6x, Stock t2 ignition.

Under full throttle if I run any richer than 11:1 it starts to break up. On my 401whp run I stayed right about 11.5:1 and it was clean, but if it drops a half point lower than that it would break up. I want to start running 20 psi and I would like the afr to dump to 10.8 but whenever it does it starts missing.

I am assuming that I need a spark amplifier, would this alleviate my problem? Any suggestions?


Happy Easter.
Thanks.

 

HKS twin power is the simplest solution for your setup. That is what I currently use. On the FC ignition system you mount a single box and splice in 4 wires.

 

Yea I was looking at those, they seem like a good solution.

I have noticed that between tuning my car, even when I had stock turbo and 93, it would struggle with rich AFRs. Yet when tuning a piston engine it has no problem running as low as 9:1 afrs.

Is this a common rotary characteristic?

 

its due to the ignition system design. with wasted spark, the coil has to fire twice in one revolution, and as RPM goes up, the time available to charge the coil becomes less than time needed to charge the coil fully. its like running an injector over 100% duty cycle.

on a stock engine power drops off with the spark energy, so its not really a problem, but make more power or rev it higher, and it can be.

the simplest solution is to not run wasted spark, but the haltech can't do that

so the next best is the hks box, or an MSD

 

I understand that wastespark has its flaws. I have not seen any rotary able to run extremely rich AFRs (sub 10s) yet several piston engines can (also with wastespark and much more primitive ignition systems).

I know personally that I can not run extremely rich without hiccups at any rpm, so I think its unrelated to wastespark. If I noticed this only at high rpms I would agree.

This is not ideal conditions so its not really a big deal to me, just an observation. In no way am I saying I want to run rich, just curious why it is unable.

Either way an ignition upgrade is in line if I want to dip into higher boost.

 

I'd recommend a set of the Mercury coils over the CDI boxes. Just my $.02.

 

think about it, wastespark the coil fires twice per revolution, with 1 coil per plug the coils fire once per revolution, no big deal to you, but half as much sparking = twice as much time to charge.

 

I went with a Crane HI-6R and LX92 coil per leading plug, left the trailing alone.

When I dynoed I was in the 10s the whole time with a dip into the 9s in the high rpms and no breakup.

After rebuilding an engine I pull the fuel pump fuse and disable the injectors while I crank it to build oil pressure- the engine fires and stumbles on the engine assembly lube (wheel bearing grease and transmission oil).

Rotary has no problems running rich once you get it to light off.

 

+1

 

if you can gap your plug's close them to 20 on leading

 

PS you are talking in petrol AFR's incorrectly assuming 14.7:1 1.0 lambda stoichiometry.

You need to talk in lambda or equivalence ratio for the information to be meaningful.

The ideal mixture for E85 is 'incorrectly displayed' as 10.4:1 AFR on a wide band o2 sensor calibrated for petrol mixtures.

This is a whole non issue as you should work in lambda. For E85 power is supposed to start falling richer than .71 lambda.

I've had success with e85 mixtures around .78 lambda using E85 and I can't light richer than that using cheap leads BUR7/9EQ plugs and factory FC3S ignition coils.

I also plan to change to a new ignition system around 100mJ and then tune to .71 lambda/7:1 air:E85 ratio.

 

Yes I am using Petrol afr numbers and tuning with Petrol AFR just fine and that is not the issue. I think we all understand that when I refer to 11.0 AFR I am not running on an ethanol scale. I do wish my equipment was capable of running in lambda.

As I posted earlier I noticed that even when running 93 going rich induced bad missfires.

I am going to research these mercury coils, but will likely go with a single MSD box on the leading side for now.

 

I didn't have good luck with a single MSD box on the leading for my personal car (88 T2). As soon as I switched to HKS Twin Power all my ignition problems went away. That is on 93 octane E10 gasoline FYI.

 

Go leaner on the fuel. I was running 12.5 AFR(petrol AF) on E85 and was going good. 11.0 is way to rich. And we where up to about 24 psi on it.

But i was also running Autronic SM4 with 500R CDI box and Crane Cams PS92 coils.

At 530rwhp i had 98% duty cycle on 4x1680cc injectors so you won't get too much more HP out of your setup i guess. Maybe 440-450rwhp with the 1000/1680 injectors. But go leaner and ul get there.

JT

 

definitely lean it out some more. too rich