why do big stall cars dyno so low? lets calculate.....
#21
Originally Posted by Zombie
The rwhp calculators use the simple HP formula. I'd say they are much more accurate than mustang or dynojet dyno numbers. It takes X amount of HP to move Y amount of weight in Z amount of time. It can be calculated using Net HP = Weight in pounds* (Speed in MPH/228.4)^3 It's probably the best way to figure out what kind of power you are putting to the ground.
I'll say it again, a dyno can read in garflabs, it doesn't matter as long as it tells you that you made more or less garflabs when you made a change.
FWIW My numbers are from a mustang dyno as well.
I'll say it again, a dyno can read in garflabs, it doesn't matter as long as it tells you that you made more or less garflabs when you made a change.
FWIW My numbers are from a mustang dyno as well.
Engine on DTS dynomometer no accesorries with electric water pump made 536hp 405tq
Put engine into vehicle ( stick shift) engine made 456hp 383tq with mechanic water pump and full accesories.
Vehicle runs 10.8 at 126mph.I would say there is far to much measurement there to dispute. I can post up miles of data that would show your RWHP estimator to be vastly inacrruate.It just doesn't take that much power to go that fast in a 3500lb car.
On the big converter thing with them showing low number on the dyno do a stick auto swap on any vehicle wtch the ET and MPH drop going to the auto. Swap back to a stick the MPH goes back up and so does the ET unless you dealing with a proshifted car.
Yes converters do cost power if you make 380 or so with a a4 big stall car on a mustang dyno expect to go 11.20-11.30 at 117-119 mph.I will dig up the RWHP vs et for F car charts if i can find them.
#23
Originally Posted by CollinsAutomotive
Ok then lets ask the question this way. what do you think the odds of your car making 700fwhp are ??? I can tell you that the mustangs are plenty accurate.
Don't confuse accuracy and consistancy. All dyno's i've tuned on have been consistant, dynojet and mustang. As for how accurate they are I don't know. I'd say both would be closer to accurate on stick shift cars.
FWIW I've watched a t56 4000lb car make 500 rwhp on this same mustang dyno. He ran 12.2 @ 119. Yet my 3800lb th400 car made 470 rwhp and went 10.5 @ 130. That is not very accurate if a 200lb lighter car with 30 less hp equates to 11mph difference in trap speed.
If someone wants to know how much power the car makes I just go off the calculated HP numbers. If they want to race, I tell them the dyno number The MPH you trap at the track really tells you what's going on. There is no substitute.
Dyno's are best used for tuning and troubleshooting, not getting HP numbers.
Last edited by Zombie; 11-02-2006 at 11:05 AM.
#24
Originally Posted by Zombie
Odds of me having 700HP at the flywheel?? 100% (if you go off the HP formula) 0% if you go off the dyno numbers. It takes 650hp to the wheels to get 3800lbs to acellerate to 130mph in 1320ft. I think I can say the drivetrain sucks up 50 hp. All comes down to how you want to measure it.
Don't confuse accuracy and consistancy. All dyno's i've tuned on have been consistant, dynojet and mustang. As for how accurate they are I don't know. I'd say both would be closer to accurate on stick shift cars.
FWIW I've watched a t56 4000lb car make 500 rwhp on this same mustang dyno. He ran 12.2 @ 119. Yet my 3800lb th400 car made 470 rwhp and went 10.5 @ 130. That is not very accurate if a 200lb lighter car with 30 less hp equates to 11mph difference in trap speed.
If someone wants to know how much power the car makes I just go off the calculated HP numbers. If they want to race, I tell them the dyno number The MPH you trap at the track really tells you what's going on. There is no substitute.
Dyno's are best used for tuning and troubleshooting, not getting HP numbers.
Don't confuse accuracy and consistancy. All dyno's i've tuned on have been consistant, dynojet and mustang. As for how accurate they are I don't know. I'd say both would be closer to accurate on stick shift cars.
FWIW I've watched a t56 4000lb car make 500 rwhp on this same mustang dyno. He ran 12.2 @ 119. Yet my 3800lb th400 car made 470 rwhp and went 10.5 @ 130. That is not very accurate if a 200lb lighter car with 30 less hp equates to 11mph difference in trap speed.
If someone wants to know how much power the car makes I just go off the calculated HP numbers. If they want to race, I tell them the dyno number The MPH you trap at the track really tells you what's going on. There is no substitute.
Dyno's are best used for tuning and troubleshooting, not getting HP numbers.
Dynomometers good ones that can back up the numbers are very truthfull for hp.There are some things in those formulas that your using that are not accurate. the faster you go the less wieght becomes an issue and the more aerodynamics does. At around 95-110 mph your fighting air more then wieght.
#26
Collins, are you saying that an unlocked converter makes absolutely no difference in a dyno number? Unlocked converters can and do make a huge difference in accurate numbers.
I put no faith in dyno's except for tuning, the unit of measurement means very little to me. What I don't understand is why people care so much about dyno numbers? Track numbers are what really matter.
I put no faith in dyno's except for tuning, the unit of measurement means very little to me. What I don't understand is why people care so much about dyno numbers? Track numbers are what really matter.
Last edited by Zombie; 11-02-2006 at 01:47 PM.
#27
Originally Posted by Zombie
Collins, are you saying that an unlocked converter makes absolutely no difference in a dyno number? Unlocked converters can and do make a huge difference in accurate numbers.
I put no faith in dyno's except for tuning, the unit of measurement means very little to me. What I don't understand is why people care so much about dyno numbers? Track numbers are what really matter.
I put no faith in dyno's except for tuning, the unit of measurement means very little to me. What I don't understand is why people care so much about dyno numbers? Track numbers are what really matter.
As for the dyno telling lies don't try to tell me a car that makes 280hp on the dyno is going to run 10.50's and conversly a 700hp car is going to run 14.50 unless of course something is horriably wrong.
The dyno can be a very accurate tool to diagnose what is wrong with an underperforming car. The problem is that there is a myth that dyno numbers don't mean squat which is straigth BS and those underperforming cars never get sorted becuase the mentality is that the dyno is irrelavant. The issue is you have to use a known quantity.In my case its the mustang 1750de dyno. I know how it comapres to ET and MPH at the track. We have found fixed and helped get many cars to run better at the track by using this tool. The dyno can ony tell you what the potential is its upto the customer and the shop to optimize the vehicle to get the best ET possiable.
#28
I think my car is about right..my best et is a 12.21@110mph..From looking at this board, I have one of the lowest MPH's for that ET..My car dynoed 334rwhp with the Vig 3600 and had a 1.66 60' on that run, No spin, hardly no gas, That's all she had..Since then I installed a SS4000, From the feel of it I think I can drop off another 1/10th So to sum it up Dyno Numbers don't tell everything but they do help...I would take ET as opposed to MPH any day of the week.
#29
Originally Posted by Dan
I think my car is about right..my best et is a 12.21@110mph..From looking at this board, I have one of the lowest MPH's for that ET..My car dynoed 334rwhp with the Vig 3600 and had a 1.66 60' on that run, No spin, hardly no gas, That's all she had..Since then I installed a SS4000, From the feel of it I think I can drop off another 1/10th So to sum it up Dyno Numbers don't tell everything but they do help...I would take ET as opposed to MPH any day of the week.
#31
Originally Posted by Dan
I think my car is about right..my best et is a 12.21@110mph..From looking at this board, I have one of the lowest MPH's for that ET..My car dynoed 334rwhp with the Vig 3600 and had a 1.66 60' on that run, No spin, hardly no gas, That's all she had..Since then I installed a SS4000, From the feel of it I think I can drop off another 1/10th So to sum it up Dyno Numbers don't tell everything but they do help...I would take ET as opposed to MPH any day of the week.
#32
Originally Posted by GregWS6&z28
no you dont. i have run many 12.1-12.2's at 110mph. my 60 foots were the exact same. I see that alot with stalled cars vs manual. they will be a few MPH lower for the same given ET
#34
Originally Posted by gator's 99TA
so if we use 340 rwhp x 1.15 = 391 rwhp if i didnt have any converter slip. this would mimic a stick shift b.c the clutch disc is locked and doesnt slip (or extremely minimally).
#35
An interesting anecdote to share:
My old combo with a T-trim Vortech on a 383 made 550 rwhp through an A3. My brother's mod'ed '03 Cobra made 503 rwhp through a stick. I ran 10.40 at 133 and he ran 12.20 at 117 mph. 47 hp difference, similar weight, and the result is 16 mph faster?
Also, this is an interesting thread:
http://www.turbomustangs.com/smf/ind...?topic=12123.0
222 rwhp loss from switching from a 6 speed to an A4!
My old combo with a T-trim Vortech on a 383 made 550 rwhp through an A3. My brother's mod'ed '03 Cobra made 503 rwhp through a stick. I ran 10.40 at 133 and he ran 12.20 at 117 mph. 47 hp difference, similar weight, and the result is 16 mph faster?
Also, this is an interesting thread:
http://www.turbomustangs.com/smf/ind...?topic=12123.0
222 rwhp loss from switching from a 6 speed to an A4!
#36
Originally Posted by engineermike
An interesting anecdote to share:
My old combo with a T-trim Vortech on a 383 made 550 rwhp through an A3. My brother's mod'ed '03 Cobra made 503 rwhp through a stick. I ran 10.40 at 133 and he ran 12.20 at 117 mph. 47 hp difference, similar weight, and the result is 16 mph faster?
Also, this is an interesting thread:
http://www.turbomustangs.com/smf/ind...?topic=12123.0
222 rwhp loss from switching from a 6 speed to an A4!
My old combo with a T-trim Vortech on a 383 made 550 rwhp through an A3. My brother's mod'ed '03 Cobra made 503 rwhp through a stick. I ran 10.40 at 133 and he ran 12.20 at 117 mph. 47 hp difference, similar weight, and the result is 16 mph faster?
Also, this is an interesting thread:
http://www.turbomustangs.com/smf/ind...?topic=12123.0
222 rwhp loss from switching from a 6 speed to an A4!
#38
Originally Posted by engineermike
Same exact dyno - at Thunder Racing.
#39
Whats the reason for the 16mph difference in trap speed though, thats a huge difference. His results are similar to the ones I have seen that I posted about and mine were done on a mustang dyno.
#40
Originally Posted by Zombie
Whats the reason for the 16mph difference in trap speed though, thats a huge difference. His results are similar to the ones I have seen that I posted about and mine were done on a mustang dyno.