bse50

I called them in order to have an official confirmation and yes, 1200c in order to meet aci-csai and fia rules.
As usual, really hope this helps.

MazdaManiac

iTrader: (3)

Those are spectacular results.

lolachampcar

I had a chance to get back on the dyno yesterday and was pleased to learn something. I started this thread to learn what a good target A/F ratio was for normally aspirated RX-8 tuning. I knew Jim M at Racing Beat got some horsepower out of the car by leaning the A/Fs from their stock setting. At the same time, I kept reading posts saying there was no horsepower to be found with A/F ratios. I was also warned that playing with them could cause exhaust gas temperatures to climb so high as to damage the cat. This was all good information but a little confusing.

This brings me to what happened on the dyno. I was putting the new Cobb AP Stage 1, 2 and 3 tunes to the test and found some very interesting results. I’ve attached the data below for review but here is a quick summary.

I did a quick pass tune several weeks back just to introduce people to the whole reflash deal. I think it picked up something like 8 hp up top. See https://www.rx8club.com/series-i-engine-tuning-forum-63/reflashed-today-using-efidudes-138881/ for more exact numbers on horsepower over stock. The key point to that exercise was that we did just one tuning pass and tried not to go any leaner than 12.5:1 A/F gasoline with the tuning.

The above single pass tuning was the extent of my normally aspirated RX-8 tuning. Yesterday I put a car on the dyno with the Cobb AP Stage 1 file installed. It did not make significantly more power up top over my single pass tuning from several weeks ago. See https://www.rx8club.com/series-i-engine-tuning-forum-63/re-flasher-shootout-138065/page4/ for information on the horsepower gained through the different Cobb AP tunes. However, the Cobb AP Stage 1 tune was SIGNIFICANTLY leaner than my single pass tune. I saw 14:1 A/F gasoline under load at higher rpms. I then installed the Cobb AP Stage 2 tune. The owner of the car was already concerned at the 14:1 numbers he saw on the Stage 1 so we made a deal to kill the run if he saw anything he did not like. He had me shut things down when he saw 14.5:1 A/F gasoline.

My take on the data is that there is horsepower to be had from the leaning the stock file a bit (maybe up to 12.5:1 or so) but nothing to be had by going dangerously lean beyond that point. The results are nice in that Jim M is right, you can get more power than stock and the “you do not get horsepower from A/F ratios” crowd is right as well as there was no more horsepower to be had going from 12.5:1 to 14.5:1 or higher.

These are sweeping generalizations based on just a hand full of dyno runs so it is not a definitive study on the subject by any means. However, I think the results do help point out what might be useful and what should never be done.

Kane

iTrader: (1)

Yep, Ben Strader convinced me a while ago; but it is nice to see reconfirmation.

lolachampcar

What scares me is that the average guy might actually use these flashes. They paid good money for the tool and all they can do with it is use the flashes that come with it.

Those flashes do not produce any more horsepower over a conservative tune and yet they would seem to be dangerously lean. If what I have read about exhaust gas temperatures and their affects on the cat are true, someone could easily burn up a cat with even the Stage 1 tune.

The RX-8 does not tend to detonate in normally aspirated trim when stock. I wonder if it will want to running at 14:1 or even 14.5:1 under high load at torque peak.

lolachampcar

If I were you, I'd try the 12.5:1 stuff we did a few weeks back on NaarLeven's car. It made roughly the same horsepower up top and 12.5:1 should be plenty safe. You may want to lean out the mid rpm range a bit more to get that 15 hp bump but I would not think you would do anything like 14 to 15:1!

I can kick back up the Open Source Tune thread if people want to start trying some of these tunes.

Brettus

iTrader: (2)

Yep - pretty much what I've found also .
Runnig lean does have its dangers alright . When I first started tinkering I leaned it out to approx 13:1 and was running low octane gas as well . That ran fine till one day I was idling around a lot and went straight into a WOT run . A really bad series of detonations was the result . I backed off as quick as I could but it scared the craP out of me . From then on I have used only high octane .

lolachampcar

I make no claim for being a rotary tuning guru, but are you saying that 14:1 under load at higher rpms is a good idea? Is the car going to "drive better" if you run it so lean? Will the higher combustion temperatures (as indicated by higher exhaust gas temperatures) not bring you closer to detonation for the same ignition timing?

Spin9k

Holy A/F ratio! That's some lean mixture those runs produced. I'd be concerned running those A/F Here's my todays 'U' flash run (testing out my 'dude) showing several points with what Mazda is currently thinking is 'cat safe'. Looks like I could get a few points out of the high 11s and towards 12.5 or so if I would reflash.

lolachampcar

Data, I love it. It brings this whole process out of the dark and into the bright light of day.

Flashers shipping daily and I got your file right here buddy (now that I know there is no more power going leaner)....... When do you want your fans on? Need some more oil from that pump? How's about we bump that idle a smidge?

Kane

iTrader: (1)

Why does it seem like a courtroom around here sometimes?

We latch on to a part of an argument and spin a full rebuttal on it outside of context.

The AFR guys - of which I was one; are saying tuning for POWER... no one was trying to argue for longevity.

When dealing with a street tune you have to look at cat, all the mods, cooling ability, climate, driving style, elevation (ad nauseum) in order to determine the SAFEST AFR in the RANGE that all makes about the same power.

Does that help clear it up?

MazdaManiac

iTrader: (3)

Not particularly.

Kane

iTrader: (1)

<- Beats head on desk.

Kane

iTrader: (1)

HE HE, touche...








***!

r0tor

iTrader: (1)

Cobb only has a stage 1 tune ...

lolachampcar

Someone told me the tunes were Jeff's so maybe this is Jeff's work.

r0tor

iTrader: (1)

if there was stage 1, 2, and 3... then yes those were his maps

.. cobbs maps are on their website

MazdaManiac

iTrader: (3)

Look at the copyright info inside the tuning file on the AP.
If my name is in there, its mine.
Furthermore, if that tune is not being checked on the car it was set up for (each owner gets their own stuff), they it is set up to break the car since the calibration is stolen.
Piracy is a bitch.

Spin9k

What I intend on doing is a staged logging/add mods rampup. I want data to see the effect on the A/F ratio, MAF flow readings under open loop before making any map changes. Data logging with the 'dude is so simple I could do it for hours whilst drinking my latte FCOL No incar laptops, no wires, no mess, no fuss!

Now I'm only w/CATback as an engine mod, so perhaps a bit better exhaust flow is shown in the current map. When that's gone too, flow should be better still. Just for comparison sake, and to get a model for tuning, I'll stick in the RB Race flash that I have to see how that changes the logs vs. OEM flash.

Eventually, whenever I do get my Ignition Solution, I''ll be adding that and the RB Intake setup at once. I realize it's 2 mods but only want to take the car apart once for both.

Then I'll be ready to tune from the final resulting data

lolachampcar

I got some good advice from you not too long ago. It went something like this-
Know what you are talking about before you accuse others of stealing. You were right and I was wrong. I apologized.

Do you take your own advice and are you man enough to apologize when you are wrong?

MazdaManiac

iTrader: (3)

Apologize? For what? Are you saying you are tuning one of my customer's cars?
If so, I'm still correct, aren't I?

My god, you are one dumb mother-f'er. I'm sorry (there, I apologized).

You are really startling. You are like the kid who gets caught by his mother, matches still in hand, setting stuff on fire in his room and denies it.

zoom44

hey im trying to concentrate but the car wash is very distracting

Triperformance

So plain and simple what a/f ratios are we talking about here for a NA tune that has a Cat. and one that doesn't have a Cat.?

Cat a/f =
No cat a/f =

zoom44

13.1 ish for best power- watch you cat temps and rich it up a little if they get too high. a little richening will save your cat without sacrificing power

Triperformance

That A/F ratio is suggested for WOT right, what is a good low load or crusing and such A/F ratio?