part of the answer to a very good question

[Vic_Ferrari]

I'm wondering why there is such a wide variance between everyones cars when it comes to tuning. For example, there are many people here with just a 2.80 and exhuast, yet the rwhp numbers are so differnet (sometimes like a 40-50rwhp difference).

The question is why? Is there a lot more to tuning then just timing and fuel? I just don't understand what is causing the huge differences between differnet tuners.

Good question.
The answer isn't so simple but to try and keep it simple... it comes down to:

-The tuner and his ability
-The dyno
-The dyno operator
-Fuel quality
-Conditions
(all of these variables are much bigger than listed here)

For instance, dynojets read higher than Mustangs or Superflows.

Lets assume any two identical dynos:
If the IAT sensor location is in a "hotter" location, the SAE correction will come up.

Also, SAE correction is supposed to be the same assuming two dynos are IDENTICAL and calibrated IDENTICALLY (which is almost never, but lets just assume this for now tio make it easy).

Dyno#1....Michigan: car makes 460 actual RWHP, 450 RWHP SAE corrected. Ambient temp is 40 degrees Farenheit and humidity is low.

Dyno#2....Florida: car makes 430 actual RWHP, 450 RWHP SAE corrected. Ambient temp is 110 degrees in dyno room and humidity is high.

Ideally, you would think that both of these cars make the same power if conditions were the same because the SAE correction "fixes the difference in conditions"
This is somewhat correct but there is another variable here!......
.....What generally happens when the car perceives a hot IAT?.......it pulls timing! (and loses power not only because of crappy air, but less timing! SAE correction does not factor this in!)
The car run in hot conditions may actually make a higher SAE corrected number if run on the other dyno in cold conditions....

...just something to think about

Vic

 

[Uncle Meat]

C'mon Vic..... We all know you are just trying to make excuses for that low RWHP number your car makes down there in Florida!

U.M.

 

[EvilEyez]

Haaaaaaaaaa. Nice one meat man. So back to this Dynojet vs Superflow debate. Who gives a rats A$$. Go to a respected shop in your area, get the best tune you can get, dyno, and then take it to the track. Unless, Vic wants to tell us where he got his superior tune, and I'll go down to Florida and check it out, while I'm there I'll hit up Panama City for spring break, Hells yeah, it's been a while since my first.('99) So how 'bout it Vic, give us the details on your super dyno shop and tune.

 

[Uncle Meat]

Unless, Vic wants to tell us where he got his superior tune, and I'll go down to Florida and check it out, while I'm there I'll hit up Panama City for spring break, So how 'bout it Vic, give us the details on your super dyno shop and tune.

Pssssttt.... I'll let you in on a secret.... Vic IS a tuner....

U.M.

 

[EvilEyez]

Pssssttt.... I'll let you in on a secret.... Vis IS a tuner....

U.M.

???Vis???

 

[Uncle Meat]

???Vis???

Sorry.... fat fingered a key! I meant Vic.

 

[EvilEyez]

Sorry.... fat fingered a key! I meant Vic.

Ohhhoooooo, I see. I'll keep it on the down low.

 

[Tat98Cobra]

Good question.
The answer isn't so simple but to try and keep it simple... it comes down to:

-The tuner and his ability
-The dyno
-The dyno operator
-Fuel quality
-Conditions
(all of these variables are much bigger than listed here)

For instance, dynojets read higher than Mustangs or Superflows.

Lets assume any two identical dynos:
If the IAT sensor location is in a "hotter" location, the SAE correction will come up.

Also, SAE correction is supposed to be the same assuming two dynos are IDENTICAL and calibrated IDENTICALLY (which is almost never, but lets just assume this for now tio make it easy).

Dyno#1....Michigan: car makes 460 actual RWHP, 450 RWHP SAE corrected. Ambient temp is 40 degrees Farenheit and humidity is low.

Dyno#2....Florida: car makes 430 actual RWHP, 450 RWHP SAE corrected. Ambient temp is 110 degrees in dyno room and humidity is high.

Ideally, you would think that both of these cars make the same power if conditions were the same because the SAE correction "fixes the difference in conditions"
This is somewhat correct but there is another variable here!......
.....What generally happens when the car perceives a hot IAT?.......it pulls timing! (and loses power not only because of crappy air, but less timing! SAE correction does not factor this in!)
The car run in hot conditions may actually make a higher SAE corrected number if run on the other dyno in cold conditions....

...just something to think about

Vic

This is good stuff. I played around with IAT locations myself - and that alone makes a huge difference, never mind ambient air temps


peace

 

[Vic_Ferrari]

I work for, uhhhhhhhh.....
huh huh huhuhuh huh huh...that was cool.

Damn meat.....shooting for the "C" and hit an "S".....THAT's a fat finger!



What the hell happened to the private message buttons in this damn forum?
...Maybe that was another forum....

What are these forums coming to? In the corral forum, if you type a 4 letter word, it replaces it with "kiss me kss me kiss me!"

 

[Vic_Ferrari]

temp

This is good stuff. I played around with IAT locations myself - and that alone makes a huge difference, never mind ambient air temps


peace

Yeah....that sensor probe is good for like 43526435628436435263 HP if you drop in on the furnace.
So many dyno operators.....so little integrity =o)

Another thing too is setting up test profiles correctly.
A "good" dyno will allow the test to automatically begin and end at the same MPH automatically everytime.
When I'm doing WOT runs, I set it up so I'm already at WOT BEFORE it starts reading data....so it'll be the same everytime.
A lot of these guys just "start" the test manually and then bring the throttle to the floor.....
Can you be 100% sure you increase the throttle at the exact same rate run after run? Of course not.....but a small difference can mean different load, and different timing, fuel values, etc...
If you put a car in an emulator, you'd be amazed (as I'm sure you've seen already) how differently the computer perceives just the smallest change in throttle and/or load.

anyways....
just more jibber jabber

 

[5.0's 4 ever]

Vic what shop do you work at if you don't mind me asking.

 

[Vic_Ferrari]

Shoot me a PM and I'll tell you. =o)

Regarding WOT runs, I should elaborate:

My entire emphasis is not only at WOT.....I do a SUBSTANTIAL amount of part-throttle testing....part throttle is just as important as WOT.
Tuning is done through extensive testing at many different load/rpm/throttle positions.
Power runs, however are done entirely at WOT.