FairladyZ

Why? Then why does everyone dyno in colder weather, say that their car feels stronger/faster, and tend to get better et's in the 1/4?

Are you saying that the correction factor is more?

Brandon@Forged

Colder air is more compressed, therefore more air in the same amount of space as in hot weather. More air = more power, usually. And about the a/f ratio, I thought it was supposed to stay under 14 throughout the whole powerband, or is it 15?

sakred

iTrader: (4)

i know the guy who owns the dyno. it reads low. its an awd twin roller dyno. and the guys a dick. i didnt give him any of my business. go to shawn church from church automotive. hes a great guy and knows allot more then anyone around about what he does. he also has an extensive library of Z dynos you can comepare yours too. 310-713-6171 tell him i sent you

Hammad

Brandon@Forged

laswyguy, might want to try a load-bearing dyno, like a dynapack.

287HP

When ever you spin the rollers, the dyno gives an actual reading. The actual reading is what your car is putting down on that particular day. The colder and denser the air, the higher your actual numbers will be, this is true. However, the SAE correction then takes that actual number and estimates what the whp would be if the temperature was 77 degrees fahrenheit and the atmospheric pressure was 29.92 inches of mercury. So if you put down 250 actual rwhp and the temperature was 40 degrees, the SAE corrected number will be lower since it estimates that number based on a higher temperature(77 degrees). Perfect dyno weather is actually in the weather with temperatures in the 70s, this gives the least variation between actual and SAE. So that is why I would like to know what his actual numbers were? To really see what his car is putting down without the SAE correction. Also, colder weather does always mean denser air, you can have very cold temperatures with very low pressure.

FairladyZ

Yep thats what I thought, thanks.

Z1 Performance

iTrader: (564)

FWIW I have had my car on a Mustang, Dynojet 248C and Dynapack..I have yet to see more than a 5 hp difference among them all.

Running leaner does not net you more power. Maybe he explained it incorrectly, maybe you misunderstood. You want to run the leanest mixture you can without detonanting and/or without pulling timing. Every car will be different in this regard here. Some NA cars might want a 13.2:1 ratio to achieve this, others might want a bit leaner. The actual number is of little consequence since dynos are a totally relative thing...there is basically nothing static about it as everything is subject to discussion. The only thing your dyno and AF curve is relative to is other Z's dyno'd on that dyno.

As a general rule, mid 13's AFR should net you a good blend of power and timing without having the ecu freak out and pull timing. This is a general rule of course, YMMV. On my own car I run around a 13.3 (flashed over a year ago). I have routeinely datalogged my timing a few times since that timing and have yet to see the ecu pull any timing, telling me it's happy with the map I got.

Saying dynos "read low" or "read high" is a misnomer - they are relative tuning tools, not the be all and end all of a horsepower figure. The SAE correction is much the same thing - it allows you to dyno the car regardless of the conditions and get a reasonable idea of how it would run under the dyno's ideal conditions. It's just another piece to the puzzle if you will

As for all the AFR info being passed around here, we should set some guidelines. Stoich AFR is 14.7:1 - this is the target the ecu shoots for under very light sustained loads or while idling for emissions reasons. Under heavy load (more throttle, in gear), the "best" AFR for your car can often be unique for your car - that is, there is a general range you want to shoot for (low-mid 13's NA on pmp gas), but that exact value will depend on your car, your mods, your gas, you get the idea

Hope that helps clear things up a bit for you

Adam

zzzya

iTrader: (2)

With a reflahsed ECU, the timing has also been adjusted, advanced, which can cause pinging, usually at higher rpms, even if the AFR is where you want it to be. My second reflash was a tad on the rich side in the low 12s through to redline, yet I was hearing some pinging at the higher rpms on the Dyno. Since I knew I needed the AFR to be leaner, I also requested some timing to be pulled from 5000 rpms up so as to decrease the likelyhood of pinging even worse at the higher rpms with the third reflash. For me the third time was a charm and the car pulls harder than ever with no pinging or areas in the rpm range with hesitation.

Z1 Performance

iTrader: (564)

My timing was untouched on my flash as best I can recall....advancing did not net me any gains and retarding resulted in egt's going higher than needed and torque falling off even worse than with the stock ignition map. The majority fo changes AA did to my car were on the fuel tables, and it paid big dividends in my case

SR20DEN

iTrader: (2)

This is why I recommend that most people just get the L Spec software from TS. It costs less, raises the rev limiter to your desired amount, allows the TB to open 100% all the time unlike the stock software and removes any speed limiters. And in my experience most VQ35s like to run between 13.0 and 13.5 & VQ30DE-Ks like to run a little higher than that.
Piggybacks are nice to have and IMO are essential for anyone that wants to get the best performance out of their vehicle with the stock ECU. This of course is for most of use that do not have access to a Techtom programmer. However at a minimum the L spec reflash is required to solve the rev limiter and Throttle body issues. So simply avoiding the ECU reflash altogether isn't viable.

laswyguy

iTrader: (1)

Dude.. I would agree, my butt dyno tells me my car is boning out. NO doubt way faster than stock, no comparison. What blows me away is that cus hes an evo and sti tuner, those suckers are putting 400 to the wheels tuned mad crazy. Im not really worried about the HP numbers, only thing that concerned me was the AF dont want to run lean and ruin my engine. I thought that was power was reached at 13:1 and I think some poeple argued that their car ran stronger after reflash/piggyback tuning. I guess the main question here is, lets say I spend the 800-1000 for a piggyback and tuning, and I adjust my AF to the perfect 13-14 or whatever the ideal is. What could I expect to gain in terms of HP. Anything less Id say forget it.

laswyguy

iTrader: (1)

Here you go the actual uncorrected numbers were Max HP 245, Torque 235 which I feel alot better about. Temp was about 69% degrees so pretty cold.

laswyguy

iTrader: (1)

damm wrong chart . Heres the right one.

287HP

Much Better!

zzzya

iTrader: (2)

I'm pretty sure the TS mapping does advance the timing. Those that I have spoken with that have made big power with a reflash needed a fair amount of advance from stock for NA cars.

Z1 Performance

iTrader: (564)

but I dont have an ecu flashed by TS, mine was flashed by Altered Atmosphere on their dyno during the course of an 11 hour session I did not need timing to be added at all to net big gains

FairladyZ

You could gain a FEW ponies from 5500-6500. You are going rich there. Before 5500, your perfect right on the money. Not worth the extra dollars IMO.

You have to remember their cars are F/I. So easy for cheap power.

DriveI65

Our car club had a dyno day yesterday and after reading this I feel pretty good about my stock 2003 with over 50k miles. This was the 1st time I've ever seen a dyno and the first run was a smooth acceleration instead of flooring it in 4th from 2000 rpm. I pulled 235.06 uncorrected and was told that corrected for temp and pressure it would be 245.

Dyno chart

Alberto

iTrader: (14)

Get your ECU reflashed if you dont have the 04 Z that seems to not accept the flash-or after time take things back to stock. I have similar mods as you minus headers, and I "only" put down 252 whp and 239 ft lbs...and that was with A/F's over 15.1 ! I have an 03' so I reflashed my ECU and my A/F's are at a perfect 13.1 across the board and I now put down 262 rwhp and my TQ jumped up to 252 rwft lbs-all this with no headers. If I were you, I would look into getting my a/f into the 13.1 - 13.5 range, it really makes a big difference. And if you send in your ECU to Technosquare, send them your dyno with a/f so they can also tune off that. Good luck with your car. I read about some people sending in their 04' ECU's to Technosquare knowing about the potential problem they might run into and they b*itch when their ECU's over ride the maps and pull back timing cuz they are runnign lean. Its not Techno's fault, Im sure they will come up with a fix when they have it, until then some of you 04' guys should have waited to mod...

laswyguy

iTrader: (1)

can anyone tell me if there will be any advantages of running a one stop colder plug since im borderline lean? Being that im already lean, nitrous set up is out of the question?