? about amount of HP my car made

[25thmustang]

A track will definately be more inconsistent. A dyno guy should be able to duplicate numbers on a car in similar conditions. Neither is the be all and end all as to what the car can/can't do, but combined they tell you what the the combo/driver can do on a certain day/dyno.

 

[5spd GT]

A track will definately be more inconsistent. A dyno guy should be able to duplicate numbers on a car in similar conditions. Neither is the be all and end all as to what the car can/can't do, but combined they tell you what the the combo/driver can do on a certain day/dyno.

:Word:

 

[Mustang78]

i believe it, if you're telling the truth you have one sick 331! On a comparitive note i know a guy with a FIA cobra replica, he built this 331 before they had stroker kits using parts from different manufacturers to make it work. He definately knows his stuff. Anyway he designed the cam himself, lots of compression, AFR heads(not sure on the size), forged internals, etc.. and it makes 520HP at the wheels with a carb, keep in mind he's borderline professional and knows his stuff so i would say 420HP is definately reachable..

 

[ninety15.0]

I agree with 25th and 5spdGT...the Dyno is more consistent than the track...

The dyno may not be the best indicator of "real world power" because of how it simulates "load" but i dont see how you think the throttle man at the dyno is a large variable in the equation.

You really dont think that track prep, tire pressure, clutch temperature, launch RPM/technique...etc dont have more of an affect than the throttle man at the dyno? please! For an extremely consistent racer...the track is a good indicator of power.

How bout this example:

Take two cars that weigh the same exact amount. They have the same exact powertrain. One car has stock suspension with no chassis stiffening. the other car has a full drag specific suspension with chassis work. The stock suspension car will likely have a slower ET but higher trap speed. Does this mean it has more power?!!?!?!

 

[5spd GT]

How bout this example:

Take two cars that weigh the same exact amount. They have the same exact powertrain. One car has stock suspension with no chassis stiffening. the other car has a full drag specific suspension with chassis work. The stock suspension car will likely have a slower ET but higher trap speed. Does this mean it has more power?!!?!?!

And to further that example...

Since the ET of the full-suspension car is so much greater (up to 1 second), does this mean that the ET car is putting out more power?



For guys that live at the track and do this for a living, I agree with the track 100%. This is not reality, to 99% of guys driving around, on forums, or just doing this for a hobby like you and me.

The dyno has more standards that can be met.

I see a lot of times when comparing ET and MPH at the track, many do not consider the altitude. Air is pushed into the engine by atmospheric pressure at 14.7 psi, so what happens when you run at a higher elevation? The PSI decreases, and so does the level of "push."

 

[NKau]

And to further that example...

Since the ET of the full-suspension car is so much greater (up to 1 second), does this mean that the ET car is putting out more power?

No, because the TRAP SPEED is what you use to calculate power, not the E.T. Traction does play a part in trap speed, but not a monsterous part. Regardless, you can look at a timeslip and SEE the differences though. With a dyno, you are basically forced to make assumptions. There are definitely more variables at a track. Altitude is something that can be corrected for.........wind for example cannot. I still think a timeslip shows you more than a dyno will. How do you account for variability between dynos? Some dynos are very accurate, some are not.

You're telling me that you'd believe someone who claims to have made 260 rwhp with a stock 5.0 motored AOD car on the dyno just because it was dyno'd, and don't think that a timeslip might be a better teller of the story?

 

[5spd GT]

No, because the TRAP SPEED is what you use to calculate power, not the E.T. Traction does play a part in trap speed, but not a monsterous part. Regardless, you can look at a timeslip and SEE the differences though. With a dyno, you are basically forced to make assumptions. There are definitely more variables at a track. Altitude is something that can be corrected for.........wind for example cannot. I still think a timeslip shows you more than a dyno will. How do you account for variability between dynos? Some dynos are very accurate, some are not.

You got it in bold

Some drivers are accurate, some are not

You're telling me that you'd believe someone who claims to have made 260 rwhp with a stock 5.0 motored AOD car on the dyno just because it was dyno'd, and don't think that a timeslip might be a better teller of the story?

Nope, I am not telling you that. I would first ask, what parts

The reason why the track stipulation is so big with some guys is because they listen to guys that deal at the track with the big boys. This trickles down to us little guys. Those cars are dialed in more than an atomic clock.

Our cars are not...

 

[347HO]

5spd GT... just how many cars have you dynoed?
How many engines have you dynoed, then had chassis dynoed?
Using the almost worthless dyno numbers, how many times have you ran your trap speed what the dyno hp numbers indicate?

Dynamometers are good for tuning, to be used as a tool. Interestingly enough, you can instantly realize if the dyno lied to you after your first few trips to the track.

IF you want to get into this with more depth and experience than I have to offer, come on over to the "tech" board. We will be happy to go over it.

 

[5spd GT]

5spd GT... just how many cars have you dynoed?
How many engines have you dynoed, then had chassis dynoed?
Using the almost worthless dyno numbers, how many times have you ran your trap speed what the dyno hp numbers indicate?

Dynamometers are good for tuning, to be used as a tool. Interestingly enough, you can instantly realize if the dyno lied to you after your first few trips to the track.

IF you want to get into this with more depth and experience than I have to offer, come on over to the "tech" board. We will be happy to go over it.

Easy, let us not get our underwear in a bunch.

I am not a dyno tuner. I do not own a dyno.

A bad driver can make a car with lots of horsepower look like it has 20-30% less HP than it actually does to the race weight.

With dialed in cars that are tuned at the track, the track is a better method, no doubt. This is not the case for 99% of the guys.

Why do we see typical h/c/i combinations in the 290-300 rwhp, and the HP curve is similar in a shifting range, but we see MPH ranges from 98-115 MPH?

- Drivers
- Track Location
- Track Conditions
- Temperatures
- Shifting RPM
- Shifting Speed
- Traction
- Launch RPM
- Wind
- Etc.

These things can vary so much.

Example:

A an older friend of mine dyno'd 522 RWHP in his '03 zo6 (Procharged). I never dyno'd my '93 (roughly 290-300 RWHP), and race weight was very close between the two rides.

He was running just 3-4 MPH faster than me. Why?

He was not the best driver.

Whether me or him put my car in 4th gear and stabbed the gas, they would dyno the same. But, when we swapped drivers at the track, the MPH increased and the E.T. dropped.

The dyno did not show this, because it took out the variable.

What do you think?

Ask to start a new myth topic It would be interesting.

 

[5spd GT]

They both are tools

There is not one that overrides the other. They both have their respective places based on different situations.

 

[347HO]

ET is not what I'm looking for here.
Trap Speed and maybe weight of car is all I need to get you a very good hp number. I'm not saying it will be exact... it will be "close".

What I'm saying... even a bad driver can be told not to smoke it through the 60'.
Acquire many runs, average them out, do the math. BINGO.

 

[5spd GT]

I am with you. I know the formula you speak of

So what does a bad driver do to his average? I have seen some consistently bad runs, if that makes sense.

 

[NKau]

Example:

A an older friend of mine dyno'd 522 RWHP in his '03 zo6 (Procharged). I never dyno'd my '93 (roughly 290-300 RWHP), and race weight was very close between the two rides.

He was running just 3-4 MPH faster than me. Why?

He was not the best driver.

Have any of his timeslips? He either wasn't making 522 RWHP, or was the worst driver known to mankind, taking a second at a time between 3,000 rpm shifts. That example goes a little beyond mild driver error IMO. Even an average driver should have that car trapping in the 120-125 mph range. It's what the laws of physics dictate, not the laws of the dyno

 

[347HO]

It's what the laws of physics dictate, not the laws of the dyno

Word!

When you want to know "what it is", use real world data. IMO, use the dyno to help get you there. I just find it more fun to spend 20.00 at the track and get 8 runs in, than 200.00 or more to get one/two runs in on the "machine".

 

[5spd GT]

Have any of his timeslips? He either wasn't making 522 RWHP, or was the worst driver known to mankind, taking a second at a time between 3,000 rpm shifts. That example goes a little beyond mild driver error IMO. Even an average driver should have that car trapping in the 120-125 mph range. It's what the laws of physics dictate, not the laws of the dyno

I have a track slip pre-blower.

I was trapping 2 mph faster than him even at that point. His car after-blower should have been hitting close to 130 MPH.

Your right, he was not a good driver.

I used an extreme example, but there are guys not much better than this.

I have beat an '01 zo6, beat several ls1s, and some other cars that should have been faster, but the driver did not utilize the tools he was given very well.

 

[5spd GT]

It was $60 the last time I was present at a dyno for 3 runs. We were not racing a dyno, as they say, but just curious. It shows what the car is capable of by taking out many more variables.

$15 at the closest track for runs all night

 

[25thmustang]

The mph thing doesn't give you an idea of the power a car makes. After all you have to take into account every variable. Weather, wind, tire size etc... and still the numbers won't be that close. According to calculators my car should be over 300 to the tires on a lot of track days, yet there have been other days into headwinds the numbers drop a ton.

How about our 295 rwhp car @ 3000-3100 lbs that trapped 112-113? Or my friends 3000 lb coupe that made 225 rwhp yet trapped 105 mph on nice day at Atco. This same car in cool air at etown trapped 101.

I think looking for power numbers, a dyno when the variables are punched in right are going to give you what you want more so than the track. The track to me shows what the car/driver does or can do, but the dyno shows you what the car tosses down for power, when everythin is factored right.

That being said I go to the dyno once every couple of years, I hit the track many times a season!

 

[7-UP BILL]

Me thinks our chains are being yanked.

 

[89streetbeast]

to the original poster:

with what you listed you're hp and tq numbers are within specs no matter what anyone says. carb cars will relaistically make more power than a efi car with the same crap , only diference is all the efi crap bogs you down. on a carbed car you dont have to worry about a computer telling you're motor what to do. no smog, no egr, no injectors, no 02's no timing advance etc. someone said earlier in the post that you should me making 270 or somethin at the rear wheels. pretty sad thats what my old 84 made with a bone stock bottom end, ported 85 closed chamber heads, weiand single plane intake and a 600 carb. your 420 is deffinately within range. with more fine tuning and some "good" porting of the heads and intake you should be in the 450-475 range if you know what you're doing. seen it, done it.

not to piss anyone off but just my .02

 

[Mr. Rustypwnz]

well it sounds like he built it right!!