zoom44

Make sure not to listen to anyone that makes statements like the quote above.

My advise?
FI of your choice (Others will tell you which turbo is best for your goals, personally I want hymee's SC) with flash programming,
rebuilt renny with stronger 3 mm seals,
better water pump,
all of the other "magic" that RE puts into an engine,
lighter flywheel,
change the fuel system to a return system,
changeover to running e85(unless you have a real problem locating e85 in your area
then go with a serious meth injection)
change to the newer tranny like Denny has.
new/better clutch of course
3inch exhaust with that CAT that Team likes

change the rear end gears.

ask Team about suspension

would you like body kit advise as well?

Red Devil

And how are you going to make those two work in conjunction with one another?

zoom44

the same way you tune for anything else? its no different tuning for one fuel than the other. Running and tuning with the e85 will give him a larger and more consistent margin of error than meth/water injection allowing him to run more boost.

hmm- there was supposed to be stuff about the ignition system in the earlier post. but basically get the BHR upgrade

Red Devil

That wasn't an explanation.

How are you going to compensate for the different lambda values needed on flash tuning between gasoline and E85? That is the big issue with making this work, imo. I don't see it happening on the factory 02 sensor.

If someone has done it, or can actually enlighten me with some hard theories on how to make this happen I'd love to hear it.

zoom44

the lambda doesn't change. stoich is different, e85 is 9.7 AFR but if you are tuning with Lambda you are shooting for the same slightly richer than 1 to avoid knock that you were for gasoline.

You have to be careful about the actual blend. Winter Blends can be as low as E70. If you tune on a winter blend you could be lean when the summer fuel hits the pumps.

So you can set up a summer tune and a winter tune and swap when its time or just leave a little extra room at the expense of some power and efficiency.

Ill take a look or ask hymee directly what lambda he found best power

edit best power on e85 appears to be about .8 - .75 lambda but doing some reading I also see people tuning close to .85. I haven't looked at Hymee's number yet

Red Devil

All that is well and good, but what I'm questioning is if the RX-8 pcm and it's associated hardware such as the o2 sensor can digest the information. From doing some FI tuning on the AP, I'm not certain it can handle the different values required from one fuel to the next. I suspect all parameters can be optimized for only gasoline.

I saw Hymee's E85 dyno numbers, but my understanding is that those are on an engine dyno running on a standalone interface.

I can't recall seeing anyone actually post the results of using flash tuning with E85. If it were possible, that would really be something.

zoom44

of course its possible. Cobb has done it with subies and a gtr http://www.cobbtuning.com/info/?id=5083&rsku=0. All of the "major" flash tuning outfits have done tuning with e85 for their particular niche. there's nothing special about the rx-8 hardware that prevents it.

The o2 sensor reads lambda. it doesnt care if thats lambda on e85 or 92 octane gasoline or propane.

at idle it will try to reach lambda 1. it will adjust the injection rate to get there. then it remembers that adjustment to meet the rest of the fuel table. it'll do the same no matter what fuel is there.

zoom44

hymee is double checking but Jeff posted up

Brettus

iTrader: (2)

You really want to wait over a year to be a guinea pig ?

Plus if Hymee doesn't sort out Protuner and Scanalyser USB before this comes out there will be much more than SC teething problems to deal with .

zoom44

yes i like hymees set up. and there's always cobb if the USB version doesnt get squared away.

Red Devil

Thinking about this more, obviously the o2 is reading lambda and just converting to AFR. The datalogging/display function on the AP reads out to ~11.3:1 as its lowest point - or .77 lambda. Assuming the factory pcm will accurately interpret and follow potentially lower lambda points than what the AP will display than perhaps...but that I'm not sure about...also, while good examples from other communities the variable is and still remains what parameters are in our PCM and how it handles lower lambda points

Brettus

iTrader: (2)

Actually 0.76 is the lowest the stock 02 sensor will go - I would think our ecu could handle that fine because I assume the 0.76 is lambda 'under load' not closed loop .
Your aftermarket wideband could be used to measure below that under load .

zoom44

yes correct that's in open loop wot. i was thinking .76 might be too rich. I would think .77 would probably be fine with good timing- but I don't know as I haven't tested it. Really I believe use the same lambda you made best power with on gasoline. It'll be close to best power with the e85 then you can adjust the timing and Bob's your uncle.

Of course this is my basic understanding having not tried to tune a rotary on e85. but we are getting away from the OPs intent. maybe we should move this bit to the tuning section?

edit: for the bob's your uncle

mac11

iTrader: (1)

the beauty of the cobb is that you dont need an aftermarket wb02

mac11

iTrader: (1)

per your link to cobb, they say it need to be richer than gasoline across the board, and beyond the .77 we are speculating as the lower bound of the factory sensor.

zoom44

I don't know why they think they needed that pig rich situation below 3k rpm but the rest of that chart is just under .8 for most of the rest with a few points above .8

mac11

iTrader: (1)

they do the same thing with gasoline too. quite a bit richer around 3k than the rest of the band. Since they only show a bit over 6,000 I'm guessing that to be the point where they see full spool on their turbos or torque peak on the motor in question. Either way, I'm not going to be the one to stand here and call Trey Cobb wrong. Care to do the honors?

shazy

I will say this. And Just This.
Good Luck!

ronx8

keep the rx8 as a daily driver. its not meant for going fast in a straight line.

spend the 20k on an FD and a single turbo kit and supporting mods. get it tuned.

that's easily 400-450rwhp.

mac11

iTrader: (1)

really? the FD was made for going fast in a straight line?

ronx8

can it support 400rwhp and go fast in a straight line?

mac11

iTrader: (1)

build a 9:1 renesis and run 400+ all day.


that still doesn't make either car "built to go fast in a straight line".

if you want a drag car, get a mustang and laugh at double your measly 400whp.

ronx8

mustang? lame!

rx all the way

mac11

iTrader: (1)

pick the right tool for the right job.

ctlums

iTrader: (1)

Break E85 down barney style...I mean pretend I am a third grader... This is far over my head but I am curious about the benefits.