What affects a dyno run?

[96BlackSnake]

Besides obviously your power/torque...

I'd like to know everything please...don't hold back on this one...What can influence your car in the positive favor and vice versa?

 

[Miamifan1354]

Temp, humidity, elevation, engine temp, a/f, timing, if there is ice on the intake

 

[Romans8:28]

Others can/will add but here is a start.........

not part of the car:

Air temperature
dew point
barametric pressure
Elevation above sea level
type and condition of the dyno
dyno operator

As far as the car or in the car (applies to all cars regardless of modifications):

Mileage at time of dyno
Grade/brand of gasoline
Oil viscosity and brand/ syn verse non-syn etc
condition of clutch
motor temperature
Air-fuel ratio
timing

 

[96BlackSnake]

Others can/will add but here is a start.........

not part of the car:

Air temperature
dew point
barametric pressure
Elevation above sea level
type and condition of the dyno
dyno operator

As far as the car or in the car (applies to all cars regardless of modifications):

Mileage at time of dyno
Grade/brand of gasoline
Oil viscosity and brand/ syn verse non-syn etc
condition of clutch
motor temperature
Air-fuel ratio
timing

Cool, so out of those...what can I control?

 

[96stanggt]

Cool, so out of those...what can I control?

Grade/brand of gasoline
Oil viscosity and brand/ syn verse non-syn etc
condition of clutch
motor temperature
Air-fuel ratio
timing

All of these you can control either on your own or through a tuner...

 

[96BlackSnake]

Grade/brand of gasoline
Oil viscosity and brand/ syn verse non-syn etc
condition of clutch
motor temperature
Air-fuel ratio
timing

All of these you can control either on your own or through a tuner...

I hope you don't mind me asking, but what did your car put down with your mods?

 

[96stanggt]

That's actually a funny story, well funny now at least..........on my first pull on the dyno since doing the headswap, longtubes, and tune the bottom end took a dump on me!!!!! I didn't get any good #'s because something broke at 4 grand........so I've taken basically everything off the car and am in the process of selling it to buy an 03 cobra. The GT was just too expensive to make fast!!! :-D

 

[96BlackSnake]

That's actually a funny story, well funny now at least..........on my first pull on the dyno since doing the headswap, longtubes, and tune the bottom end took a dump on me!!!!! I didn't get any good #'s because something broke at 4 grand........so I've taken basically everything off the car and am in the process of selling it to buy an 03 cobra. The GT was just too expensive to make fast!!! :-D

The reason I ask is I have a friend who just did a PI head swap, has long tubes, a cai, o/r x with mag. catback...

But he has no tune...

Theres a dyno this saturday...what do you think he will put down?

 

[PhillyCobra]

You can have control over the following things on a chassis dyno:

Engine temp- You want ECT above 170 to allow full performance program, but as little above as possible. You want to ice intake.

Tires and wheels- The heavier the tire and wheel, the less the measured power transmitted to the dyno rollers. Also, you will gain a few HP (if you care) by inflating tires to 40 psi and cutting rolling friction.

Engine oil- You'll gain a few hp with synthetic. You get more power with 5-20 than with 5-30.

Transmission and differential temps- A lot of the 15% power loss between flywheel and rear wheels is friction-- you want the trans and rear oils warmed up. Run the car a bit on the dyno before you trigger the recording.

Airflow- A big fan both cools engine and might help a bit with power. Make sure your air filter is clean.

I would guess everything else is the tune and the accuracy and type of the dyno. I think the real point of a dyno is to measure changes you make with your car rather than to compare it with other cars.

 

[96stanggt]

The reason I ask is I have a friend who just did a PI head swap, has long tubes, a cai, o/r x with mag. catback...

But he has no tune...

Theres a dyno this saturday...what do you think he will put down?

With everything in my sig minus the headswap, lt's, and tune I put down 221/285. I should have been in the 275-280/295-315 range in hp/tq after the swap. He needs to get a tune.....Ken @ Modular Depot burned me an SCT chip and it was dead on. He has different cams and A LOT more airflow w/ those heads and intake, plus the lt's.....his car will run w/o a tune but he just spent all that $$ and time doing what he did, he might as well get the most out of it.....

 

[96BlackSnake]

With everything in my sig minus the headswap, lt's, and tune I put down 221/285. I should have been in the 275-280/295-315 range in hp/tq after the swap. He needs to get a tune.....Ken @ Modular Depot burned me an SCT chip and it was dead on. He has different cams and A LOT more airflow w/ those heads and intake, plus the lt's.....his car will run w/o a tune but he just spent all that $$ and time doing what he did, he might as well get the most out of it.....

Basically he wants to see what his a/f is and power numbers before the tune, that way he can see the affect the tune had after the fact...

understand what i'm saying?

 

[Black2003Cobra]

Agree with everything above. And if it's a Mustang Dyno, the load factors you enter can have an effect as well. (HP@50mph and weight). Also, the correction factor the dyno operator uses (SAE, STD, etc) can change your results. (As can where they place the sensor that meausures ambient temp!)