I had an intake, FMIC, stock main cat, and aftermarket cat-back. I put it on the dyno at KDR. At 10psi, I was reading 12.4.1 A/F which is way too lean for a rotary. You can survive, but its on the fine line. I suppose if I didn't have the FMIC it would have made a difference, but again I ask, WHY RISK IT???

 

When KDR did the a/f test did they mount the sensor in the dp or stick a sniffer in the tail pipe? That makes a big difference. If you have a stock cat and they stick it in the tail pipe after the cat it'll read leaner due to the cat. I've never heard of anyone getting leaner than high 11's with the stock ecu and 10psi of boost no matter what mods.....even with ALL the bolt ons

The FMIC really shouldnt make much difference on a dyno.

I'm not saying your right or wrong, just that its different from the norm and I'm just trying to figure out why.

STEPHEN

 

It's not a question if Im wrong. Im right. As for tuning, yes it makes a huge difference where the wideband is placed. Rule of thumb is no more than 10" away from the turbo. Mine was in my dp when tested and it was a brand new sensor.
I don't see the debate. Im just telling you guys to be safe. I don't want what happened to me to happen to you. Im just trying to help out becuase I have experience on the topic. I wasn't lookin for an argument.

 

No one is looking for a arguement I even made a statement in my post trying to make it sound neutral, HOWEVER no matter how right you think you are its not the norm. My car tested mid 11's with intake and full exhaust and the stock ecu at 10psi of boost.

Rynburg dynoed BELOW 10's with the same mods you stated except the IC which doesnt make that much difference.

Numerous people have dynoed over the years with stock ecu's and different mods and been fine. Thier info is listed on Wades website. But I guess all that pending we should forget about eveyone else and go by you cause your right and everyone else that tested must be wrong.

STEPHEN

 

Funny thing is that I drove around like that for a year and a half then without changing a thing my engine blew 4 months after installing a PFC.....its cause the base map of the PFC is leaner than the stock ecu maps.

STEPHEN

 

Maybe the IC makes more difference than everyone speculates. But that is a big difference, it would be about 2 point difference just due to a IC. IF would be nice if someone had a before and after a/f reading with nothing changed but the IC.

STEPHEN

 

ahhhh, I hate to sound like an idiot but can you guys break down this wide band testing and what you are talking about...I have been lurking and reading in hopes of picking it up but it's not happening...

So what's too high or low on the lean scale and what are the consequences?

I have an exhaust temp gauge...should this help with telling if you are too lean o not too lean?

why wide band it? what do they actuall do?

Sorry if I sound like a dumb *** but this is all pretty new to me...

tanks yo

 

To be honest a egt isnt going to help you very much to determine a rich or lean condition.....it CAN under the right conditions but there are so many things that can affect egt that you cant really base your tuning on it alone

A wideband analyzes your exhaust and gives you a ratio like 11:1 or 12:1 which would be 11 parts air to one part fuel. The higher the first number the more air which means the leaner you are.

For saftly reasons you dont want to get leaner than 11's and if your running high boost or a big tubo high 11's are really a little high, low 11's would be better.

low mid 12's are pushing the limit and something as small as weather could cause your motor to let go.

Hope that helps a little

STEPHEN

 

Thanks, now I can continue to follow along helped a bunch dude...

 

Hi guys,

I just went to the dyno today with a hks dp, Racing Beat dual tip cb, and k&n twin cone intake. The dyno is a dyno dynamics so the numbers are about 15% lower than a dynojet. I put down 221 rwhp boosting about
10-12-9 (I changed the pills so make the spike less severe), and the A/F ratios dropped to 10.9:1 with the spike, then 10.7:1 and finally climbed back up to about 11.5:1 by the end of the run. This is with the stock ecu, so it seems like I won't be popping the engine from going too lean! The scanner is on the fritz, s I'll try to post the runs later... Just more info...

Kyle

BTW: The A/F ratios were taken from the tailpipe

 

With you still having a stock cat in place and taking reading from the tail pipe that mean that you are actually running richer than indicated.

STEPHEN

 

My car is listed on Wade's website. 93 R1, DP, CB, Efini y-pipe. Pegged the wideband at 10:1 after about 2500rpm to redline. Added M2 CF intake and got the same results. Boost was about 10-11 psi, outside temps were in the low 40's high 30's. Sensor was mounted in the DP where the stock O2 sensor was.

The only problem I saw was a little lean condition on throttle tip-in, that happened with both set-ups.

BTW, I had to change my WG pill when I added the DP 2yrs ago. I had boost spikes to ~14psi on transition.

Jeff

 

With me running that rich, would it be safe to run a midpipe (I already have one), or should I get a PFC first??

Also, if I were to get the PFC, then not add the mp, what kind of gains would be expected by playing with the fuel + timing maps?

Tanks for any help,
Kyle

 

without porting the wastegate, it would be very difficult to keep your boost at 10 psi, especially in 4th and 5th gear (creep) with a midpipe. Get the PFC first. If your A/F ratios are correct, you really won't gain much hp because you're already close to the ideal ratios. However, if like SPOautos said, you are running richer than indicated, you will gain some hp as you lean it out a bit.

Of course, that is staying at stock boost. With the PFC, you will be able to raise your boost and bump your hp up quite a bit.

FWIW, the A/F ratios I posted were read from a tailpipe sniffer, not a wideband O2 sensor, so I'm probably running even richer than indicated.

 

I wouldn't recomend that. Not only would that give you basically 4 mods, but you'd also have full exhaust. Without porting your wastegate you could get boost creep, and boost control would probably be beyond a simple manual boost controller. You would be right at the threshold of that "Gray" area that unless you have a fat wallet, you would probably not want to try. When you reach the "Gray" area, you don't have much margin for error, 1 bad tank of gas or the outside air temperature being too hot or too cold, could put you across the line. While Ernie T. may be too cautious when it comes to mods, I would have to agree, why push it? You could always try it, but I wouldn't stuff your foot into it without getting some baseline dyno info under varying outside temps etc. (as well as starting a rainy day fund, because it will rain) I would bet that several, and I mean SEVERAL, people have popped their engines with the setup you describe, all it takes is a little bad Karma.

Regards,
Frank

 

i'd just pickup a used reprogrammed ecu(m2,pettit,etc) for now if money's an issue. they sell for 400-500 and won't be hard to sell if you want the pfc later. also with the pettit unlimited you can swap out chips to go along with your mods. good luck to ya.

 

There's no need to get rude.

There is an explanation that agrees with everyone's findings. I would speculate that there was something wrong with Ernie's car, if it actually were running at 12.5:1 with only the mods he listed. Could be as simple as a weak pump, bad fuel filter, or an electronics problem such as a sensor that is misreporting.

My statements about the 3 mod rule are firm and I have plenty of data to back it up. Obviously there is no fine line where XX number of mods pushes your a:f over the edge, but in general, several mods won't do it. It is wise to wideband test your car after 3 or 4 mods, or ANY major mods like a turbo change or port job, just to be safe.

I would do this (wideband) long before spending money on a programmable ECU, which IMO is even riskier than stock without a wideband tune. The Power FC raises the fuel cut, removes knock control, and it appears to deliver less fuel than the stock ECU. Without a proper tune, this is even riskier than the stock ECU.

All these generalizations only hold water for a car that works properly from the start. Obviously, an engine can blow with no mods whatsoever if something is not right.

Wade

 

Horsepower/Torque

 

A/F Ratios/Boost pattern

Kyle

BTW: I might have gotten them backwards...forgot which one was 1 and which one was 2 :p