I have never dynoed before and i would like to maximize my 200/hr dyno session. I have datalogit so i was wondering should i make a bunch of maps that are minutely different and then load them to see what direction to go or just go with the set up i have and tweek it as i go ?
1R1

 

First compare your maps with other cars with the same engine mods. You should be in the same ballpark as them. Especially if theirs has been dynoed, tested and proven. Change to these if needed.

BUT, first measure your AFRs with a GOOD linear O2 sensor and adjust your fuel for the boost range you plan to run. I did mine at 12psi and 14psi. This depends also on how much power you want to make and porting and turbos. Lower power allows leaner mixtures, and high power requires richer mixtures. Many threads on the single turbo forum about AFRs and timing.

For mine, about 320rwhp I am running high of about 11.8 and low of about 11.4 at 12psi boost. At 14psi boost both are dropped about .2. My highest EGT after a 0 to 150mph run was 825F. This can be done on a dyno but then you must richen them up a little as a normal chassis dyno does not fully load the engine. Best done on the street in 4th gear.

After that you can start adjusting timing. Start with you map set with 2 degrees removed from IGL and IGT for run 1. Run 2 go with the maps as they are. Run 3, maybe add 2 degrees to IGL and IGT if you dare and if you really think you maps are not advanced enough.
Afterwards analyze the torque curves for area of low timing. Go read my dyno tuning threads that I did with my engine.

 

Um, since you are in chicago, You could just come down here for a weekend and tune your car.. We have a FJO Wideband and road dyno. Which would be great for tunning your car.. then go to a real dyno if you want more comparable #s...


-Zach

 

Chuck, when you mention a high of 11.8 and low of 11.4 at 12psi, what RPM range does that cover? My dynos have usually been from about 2200 to about 7800.

I guess my main question is, by what RPM have you settled into that range?

-Scott

 

Scott,

I start my run from about 2000rpm in 4th gear up to at lease 7500 rpm. Because boost does not reach the dialed in amount until about 3200-3500 rpm(non-seq), the AFRs below that are higher. They settle down by 4000rpm. At lower boost levels, higher AFRs are safe
due to less thermal stress and lower temperatures in the intake air.

 

skotx,

I think what you may be getting at is you may have seen much leaner a:f at lower RPMS.

All this testins is with a wideband BTW. We have found this to be true with both cars, modified cars, and cars with Power FC's as well as other ECUs. A:f is typically in the 13-14:1 range at boost and below 3000 RPM. Since my car is eager to make 15psi at very low RPM (2000 or so) I add fuel even down there to bring the a:f down into the 12:1 range.

Not sure if it is necessary (Mazda apparently didn't think it was, given the programming of the stock ECU) but I do it anyway. I and others (one with an almost stock car and a stock ECU) have noticed a tendency for the car to knock at low RPM when lugging. For this reason, I recommend people avoid lugging their engine below about 3000 RPM regardless of their tuning preferences. If you want to play it even safer, richen up your boost areas at lower RPM.

Wade

 

Remember Wade that Mazda designed their fuel maps around a var that would see 10PSI at around 3K RPMs.

We're just lucky they didn't throw a 7PSI fuel cut in below 3K!

 

Take your car up here to Milwaukee.. Our local speed shop up here has a dynomax. $65 for a couple of logged runs, and something like $95/hr for tuning with the wideband. Had my car there for the before PFC run, to make sure everything was OK. Made about 260 rwhp with just a DP and CB.

Dan

 

That might have been mazda's target (10psi at 3k) but a lot of stock cars can make full boost much lower than 3k... and a lot of stock cars also boost more than 10psi on the primary.

Not tuning the a:f properly for a load range because they didn't think people would be getting in that load (esp. when a stock car can do it) doesn't make a lot of sense to me, personally I think they meant for it to be leaner in those low RPM ranges for whatever reason (boosting while in cruise control or highway driving?).

Maybe it's okay for new engines but older cars with dirtier engines tend to knock like that. Jeff Hoskinson found his almost stock R1 knocking at low RPM, mine did before I richened up the mixture, though I also try to avoid lugging the engine. Our engines had 50-60k miles at the time.

Wade