Air:Fuel Ratio

[pat1]

Nobody answered my question. Are both you guys tuners?

 

 

I'm not but I did stay at a Holiday Inn last night. Lol

Edited December 11, 2011 by pat1

[motoman]

Well since this has to do with turbos and AFR's i figured this would be a good link. Especially for the lesser informed like me!

 

My link

[bradyzq]

Nobody answered my question. Are both you guys tuners?

 

 

I'm not but I did stay at a Holiday Inn last night. Lol

 

I am.

[pat1]

I am.

 

 

 

Well with that said you should know what your doing but in my motor and my wallet I'm going to want my tune a little on the rich side(11.0-11.2), Just for the unexpected. Now if I was chasing every little horsepower and lived in a perfect world it would be different .

[bradyzq]

Thats a load of crap. Optimizing the tune for fuel milage is important for part throttle cruising and idle, but under full boost I couldnt care what it is. We arent building direct injection turbocharged sedans here that claim 50mpg.

 

 

 

Still guessing.

You really need to go out and drive the car year round to tune these as Ive discovered.

 

 

 

11.0-11.5 is not running way too rich. Im sorry.

 

 

And I care why? 500+hp is already way too much power for a little datsun on the street. The only thing you will accomplish by making more power is

A. Greater chance of detonation. Leaner is faster, but more risky.

B. More internet brownie points since you posted a dyno graph that made a couple more horsepower.

 

Perhaps if you worked on the tune and went over everything with a fine tooth comb, it could be safe and reliable. I am sure you are a good tuner and know how to tune, but you have to understand alot of these guys are just treating this as a job and not a passion. The beauty of tuning a motor is you assume no responsibility, there is no guarantee.

 

 

 

 

It meant to be a joke. It wasnt supposed to be related to this topic in anyway.

 

 

 

Doing a 5 second full throttle pull on the dyno is in no way the same as bagging on heatsoaked car on a hot summer day for 30 minutes, whether itd be on the street, or the track. I drive my car hard, and Im sure people who get their cars dynotuned are expecting to do so as well.

 

 

Hey everyone has their own beliefs and ways of doing things. To the OP, next time you get the car tuned, just tell the tuner to shoot for 11.5 and dont lead him into telling you that mid 12 afrs are fine because the engine made more power. Leaner is always going to make more power, but there are risks involved.

 

 

Aha, 5 second pulls. Yeah, you're not gonna load up anything with those. How about 15 second plus pulls, sometimes back-to-back, or even steady state (holding a fixed load and RPM) tuning as high as possible? That's what I meant, and that's what I do. You need some decent fans for that, but it's worth it in that customers' cars tend not to blow up out in the real world after they're tuned!

 

Again, I'll reiterate that I am not suggesting that a car should be tuned on the lean ragged edge. I am saying that 12.3:1 on one wideband can be in the 11's (or maybe 13!) on another, depending on fuel type, sensor health, placement, calibration, exhaust tip, or exhaust leaks. So don't give the number itself too much weight when you have a dyno (and maybe some knock listening device) to tell you a more complete story.

 

If you're out on the road or track, I guess you're a bit stuck, and have to rely more on the wideband's numbers. But isn't that why you go to a dyno tuner in the first place, to get the complete story?

[rayaapp2]

Aha, 5 second pulls. Yeah, you're not gonna load up anything with those. How about 15 second plus pulls, sometimes back-to-back, or even steady state (holding a fixed load and RPM) tuning as high as possible? That's what I meant, and that's what I do. You need some decent fans for that, but it's worth it in that customers' cars tend not to blow up out in the real world after they're tuned!

 

Again, I'll reiterate that I am not suggesting that a car should be tuned on the lean ragged edge. I am saying that 12.3:1 on one wideband can be in the 11's (or maybe 13!) on another, depending on fuel type, sensor health, placement, calibration, exhaust tip, or exhaust leaks. So don't give the number itself too much weight when you have a dyno (and maybe some knock listening device) to tell you a more complete story.

 

If you're out on the road or track, I guess you're a bit stuck, and have to rely more on the wideband's numbers. But isn't that why you go to a dyno tuner in the first place, to get the complete story?

 

I believe bradyzq is stating all the things I would like a tuner to tell me when I bring my cars in. My personal experience is that in general the rb25det likes a fat enrichment in the upper rpm range under heavy loading. Like I said though I dont tune for a living, but I do have moderate experience tuning. Translation I am no expert! From what I do understand I would trust what he is saying. There are worse things than detonation at the AFR's Im talking about if its not done correctly. Every engine is different even if its brand new and the same designation and therefore might have different characteristics/tune needed.

I have mentioned it before on this forum, that I do not trust most in car wide bands. I use it as a reference, but place little to no weight on its numbers. Over the years I have used gas analyzers and or the wideband on the available dyno to do the tuning and as I have mentioned I have noticed that the in car ones do not calibrate up. I broke down and spent several hours trying to make sure that the on board wide band was correctly calibrated, responding within 2ms, not biased in some way, that I indeed was dealing with a proper ground system, and there were no exhaust leaks. That was fun and the only answer in the end was that the in-car wideband was not completely accurate. All that over a .5 discrepancy. My personal belief is that even though the wideband sensor was placed in a spot that seemed to be optimal it was not sampling directly in the flow during all times and causing slightly erroneous readings. Personally I like to calculate lambda from a 4 or 5 gas analyzer that has a proper filtration system and has to be calibrated on a schedule to know Im correct and it obviously has to sample from a good source(not a leaking exhaust system).

 

What I am saying is that he is giving sound advice. In most cases that kind of AFR will result in cylinder wall wash down. And for some RB's that may be the case. From my experiences with the rb25det on a dyno(again only moderate experience) I found that fattening the mixture up gained more power. Its very possible that a more experienced might very well be able to out tune my tune. Im getting great MPG out of my personal tune, but its not MPG that we should be concerned with. That is a by-product of an efficient tune on a an efficient vehicle.

 

BTW, I dont know anyone doing 5 sec pulls on dynos other than non-tuners trying to get a max output number.

Edited December 12, 2011 by rayaapp2

[240zdan]

I believe bradyzq is stating all the things I would like a tuner to tell me when I bring my cars in. My personal experience is that in general the rb25det likes a fat enrichment in the upper rpm range under heavy loading. Like I said though I dont tune for a living, but I do have moderate experience tuning. Translation I am no expert! From what I do understand I would trust what he is saying. There are worse things than detonation at the AFR's Im talking about if its not done correctly. Every engine is different even if its brand new and the same designation and therefore might have different characteristics/tune needed.

I have mentioned it before on this forum, that I do not trust most in car wide bands. I use it as a reference, but place little to no weight on its numbers. Over the years I have used gas analyzers and or the wideband on the available dyno to do the tuning and as I have mentioned I have noticed that the in car ones do not calibrate up. I broke down and spent several hours trying to make sure that the on board wide band was correctly calibrated, responding within 2ms, not biased in some way, that I indeed was dealing with a proper ground system, and there were no exhaust leaks. That was fun and the only answer in the end was that the in-car wideband was not completely accurate. All that over a .5 discrepancy. My personal belief is that even though the wideband sensor was placed in a spot that seemed to be optimal it was not sampling directly in the flow during all times and causing slightly erroneous readings. Personally I like to calculate lambda from a 4 or 5 gas analyzer that has a proper filtration system and has to be calibrated on a schedule to know Im correct and it obviously has to sample from a good source(not a leaking exhaust system).

 

What I am saying is that he is giving sound advice. In most cases that kind of AFR will result in cylinder wall wash down. And for some RB's that may be the case. From my experiences with the rb25det on a dyno(again only moderate experience) I found that fattening the mixture up gained more power. Its very possible that a more experienced might very well be able to out tune my tune. Im getting great MPG out of my personal tune, but its not MPG that we should be concerned with. That is a by-product of an efficient tune on a an efficient vehicle.

 

BTW, I dont know anyone doing 5 sec pulls on dynos other than non-tuners trying to get a max output number.

 

5 seconds was an exxageration. Let it be 15 seconds, whatever, the point is the car is just doing "a pull".

 

Everyone has their own opinion and ways of doing things.

A tuner that tell me things like: Your tune isnt optimized under boost and youre wasting fuel, therefore well lean out the motor since the dyno told me to...

Or: The wideband readings arent accurate therefore it doesnt matter what the AFR is, the important part is the engine is responding well to my "tuning"

Or: Well do some BS mathematical equations to your IAT compensation chart, now go out and drive your car in the freezing winter or a hot summer day with your optimized 12.5 AFR tune and have fun. Better yet take it to the track and beat on it for 30 minutes straight dont even look at the AFR.

 

...Does not deserve my money or business. You as a "tuner" have to understand your customers and majority of the time are hard working individuals who saved lots of money for their expensive engines. Just because you get to play around with their investments on the dyno means you should make the tune safe, but still make power! If the customer requested a certain afr, lets say 12.5, then discuss with them the risks and proceed. (methanol injection or race gas is a different story) But for the most part you must understand the average person wont know too much about tuning, thats why they are bringing the car to you in the first place. That is my general opinion, take it or leave it.

Edited December 15, 2011 by 240zdan

[240zdan]

Well with that said you should know what your doing but in my motor and my wallet I'm going to want my tune a little on the rich side(11.0-11.2), Just for the unexpected. Now if I was chasing every little horsepower and lived in a perfect world it would be different .

 

It really is as simple as that.

[bradyzq]

5 seconds was an exxageration. Let it be 15 seconds, whatever, the point is the car is just doing "a pull".

 

Everyone has their own opinion and ways of doing things.

A tuner that tell me things like: Your tune isnt optimized under boost and youre wasting fuel, therefore well lean out the motor since the dyno told me to...

Or: The wideband readings arent accurate therefore it doesnt matter what the AFR is, the important part is the engine is responding well to my "tuning"

Or: Well do some BS mathematical equations to your IAT compensation chart, now go out and drive your car in the freezing winter or a hot summer day with your optimized 12.5 AFR tune and have fun. Better yet take it to the track and beat on it for 30 minutes straight dont even look at the AFR.

 

...Does not deserve my money or business. You as a "tuner" have to understand your customers and majority of the time are hard working individuals who saved lots of money for their expensive engines. Just because you get to play around with their investments on the dyno means you should make the tune safe, but still make power! If the customer requested a certain afr, lets say 12.5, then discuss with them the risks and proceed. (methanol injection or race gas is a different story) But for the most part you must understand the average person wont know too much about tuning, thats why they are bringing the car to you in the first place. That is my general opinion, take it or leave it.

 

Well, it's a pull unless it's not. Then it's steady-state tuning. I do both.

 

Which car would you rather have? One that runs well for 30 laps, and NOT BLOW UP before need a refuel Or one that runs well for 40 laps, DOESN'T BLOW UP EITHER, and then needs refueling. Benefits of the 2nd car include saving money, being able to run a car lighter in a sprint race, maybe cutting out one refueling stop in a longer one, having a bigger pit stop window of opportunity. Do you think fuel economy mattered to Audi when they were preparing the TDIs for LeMans? Just a little, perhaps. That's an extreme example, I know. But my point is still: why have needless fuel waste when you can have a safe tune that is more economical even at WOT?

 

Regarding the widebands: Most retail widebands use Bosch sensors. Most controllers don't naturally follow the Bosch sensor's curve very well, and as a result, aren't that accurate in some areas even when calibrated. That is just the wideband itself introducing the error. When you add in all of the other variables mentioned earlier, the error can get even larger. So, yet again, all I'm saying is that you should use the resulting numbers intelligently. Don't give the absolute number too much weight in your tuning decisions.

 

BS IAT math? LOL! It's called the Ideal Gas Law, and it's actually the direct basis of all speed-density fuel tuning.

 

YOU have to understand that if, as a tuner, one gets a reputation for damaging/blowing up engines on the dyno or later, then that tuner's career is going to be short. You also have to understand that my dyno is MY huge investment. I work hard for my money too, and I have yet to see a car on my dyno with an engine that costs nearly as much as the dyno.

 

I also understand that every customer's car is his/her baby. If it's a Honda with an ebay turbo kit or a quarter million dollar race car, the customer and the car get my respect. If this is not the case at the OP's tuner, then for that reason alone, changing tuners would be a good idea.

 

Regarding everything else, I am sticking to my suggestions.

Edited December 19, 2011 by bradyzq

[BLOZ UP]

Well, it's a pull unless it's not. Then it's steady-state tuning. I do both.

 

From what I understand, you can't tune anything but full-throttle runs on an inertia dyno. And even that is only after the fact from the data logs from the brief period the engine spends at each RPM and load cell.

 

To do any real tuning, you must use a loading dyno to hold at any RPM and load to dial in that cell right there. And this is only after you drive it on the dyno to warm up the engine, transmission, rear end, etc.

 

I used to work at a shop years ago, but I wasn't the tuner. I just got free dyno time and tuned my own cars, and a few customer cars.

 

To those saying that dynos can't simulate real street conditions, that may be true that it can't match it identically, but the loading dynos can easily be setup to simulate worse than normal conditions, and that's what you should tune in. Hotter coolant, worse airflow to the radiator, worst case. That way when they come off the rollers and beat the **** out of it, you know they'll have a margin of safety--and can't come back complaining that you blew up their engine.

 

Intertia dynos are only for max-power pulls. A lot of the eddy-current modules are being added to them now-a-days as people realize this.

 

Also, the proper way to use knock control is to turn off knock control while tuning, but still watch the knock sensor output. Then tune without the knock retard kicking in (and offsetting your timing values) but still paying attention to knock, to get the best case (which may or may not be near the knock threshold), then when done they simply turn knock retard back on and let the computer retard timing as necessary on the street.