dstanggt50
Founding Member
Let's get a discussion on what is a better means to show potential: Dyno or Track?
- Thread starter 5spd GT
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just4bob50
Active Member
Dyno's are great for finding out how much of a difference a certain mod or group of mods made to your motor provided you use the same dyno in each case. At the track ET is the combination of power, traction, driverskill, and how hard the driver is willing to beat their car. MPH is almost always indicative of horsepower. When my car was NA my best 1/4 was 13.58 at 101.7 now with my 6psi charger my new best 1/4 is 13.01 at 108.8 with an open rear. My highest trap speed was a 109.1 on a 13.2 pass. ( one legger in the box and wheel hop through 1st and 2nd.) So im obviously making enough power to go mid 12's once my rear is rebuilt.
Grn92LX said:
Yeah, but not all the drivers are the same. Not all tracks are the same. Not all temps are the same. Not all the shift points are the same. Not all shift timing is the same (very very very difficult to acheive). Not all sticky track prep is the same.
The dyno software allows you to put down the weight/gearing of the car. Traction is there at all times unless you simply overspin the rollers.
Grn92LX said:The track is just flat out fun and cheaperIf a driver is on point and consistent they can tell easily if a mod/change helped or hurt their performance.
The track is fun and cheaper. It is hard to be consistent. How can you shift at 5,348 rpm everytime? To see what you gained. Do you pull that lever down at the same average speed everytime? How many people have pulled back to back runs at the same E.T. and mph at the track?
Even just rubber left from the car in front of you can affect the take-off from run to run. You grab something different each time...and you do not have to mess with tail winds which is a big factor as well.
Dynos are most often in a semi-enclosed area.
just4bob50 said:
Yep, and the dyno would show that power that your making that gets you that 109.xx mph
So do you want your car going around saying that you run 13.2? Of course not, because you know good and well you could hit 12's easy and they dyno shows that thru the power numbers
25thmustang
Mustang Master
My 1/8 traps are mid 85 mph basically every pass!
As far as twisting it, I know what you mean and you are right a dyno is better to compare with yourself and mods!
As far as twisting it, I know what you mean and you are right a dyno is better to compare with yourself and mods!
I see it as a 50/50, or at least a very close debate.
On one hand, you can take a car like a Supra, which is known to be a dyno Queen and just destroy the rollers, and it's not uncommon to see 1000hp from a turbo Supra....but then you just about NEVER see one going faster than 9s, even with 1000hp.
On the other hand, you can't say that the track is the final word because of driver ability. One guy might only run 10 flat in that 1000hp Supra, but another well experienced driver might turn something in the '9s. Also, some cars just don't get their dynoed numbers to the track as well as others.
On one hand, you can take a car like a Supra, which is known to be a dyno Queen and just destroy the rollers, and it's not uncommon to see 1000hp from a turbo Supra....but then you just about NEVER see one going faster than 9s, even with 1000hp.
On the other hand, you can't say that the track is the final word because of driver ability. One guy might only run 10 flat in that 1000hp Supra, but another well experienced driver might turn something in the '9s. Also, some cars just don't get their dynoed numbers to the track as well as others.
jwzg
Member
I'll quote Ed Curtis here:
"Talk is cheap. Take it to the track and prove your point!"
This is an absolutely pointless discussion.
"Talk is cheap. Take it to the track and prove your point!"
This is an absolutely pointless discussion.
jwzg said:
But it might not show the potential of the car.
I have an FTI cam, believe me, I know the quote well. Not pointless.
Some aren't getting what I typed.
I'm not talking about two people benchracing about dyno numbers.
95COBRA241
New Member
Comparing dynos to drag strips is comparing apples to oranges. IMO opinion they both are just individual factors in comparing a car's overall performance. There are other factors like braking, handling, top speed etc. For arguments sake a 550 hp GT will get spanked in the 1/4 mile by a 550 hp mustang with slicks, skinnies, drag socks & springs. But on a road course or even the street the GT leaves in it the dust. So what does it prove? IMO if you have a 550hp street mustang at least you can say for a few grand your car is on par with a $150,000 car.
Michael Yount
Mustang Master
I don't think there's a one-size-fits-all to answer this particular question. There are actually LOTS of variables to either approach - dyno or track. And both can be very good predictors of potential.
For many hardcore, successful racers the track is a perfectly good way to test their changes. They know their cars EXTREMELY well, they're consistent (car and drivers) and they have a lot of data as to how performance changes with their car at different tracks and under different conditions. Given all that -- they can very easily isolate very small performance changes for better or worse and know if they're headed in the right direction. And since, at the end of the day, success for them is ONLY measured by who got to the other end more quickly (8 seconds or 24 hours later) -- it's ONLY their performance at the track that matters. There are LOTS of cases where picking up a few HP at peak on the dyno didn't result in a quicker time at the track because other parts of the output curve were impacted as well -- in a negative way.
The other issue is that (and it's kind of unspoken in the thread) there's an implication that the kind of track racing we're talking about is drag racing. There are just as many autocrossers and road racers out there who do track testing too. And their performance envelope is also impacted by 2 items which the chassis dyno won't help you with - braking and cornering. In those areas - the dyno won't help at all. You've got to go to the track. And my experience has been that I gained WAY more in quicker lap times by optimizing my braking and handling than I ever did with HP additions. Beyond that -- as far as potential HP gains from mods -- it's REAL easy to see on the road course because you have long pulls in higher gears where traction is rarely an issue. If the braking and cornering speeds haven't changed - so you're exiting a turn at the same rpm in the same gear you always do -- but you're pulling 300 more rpm at the braking point for the next turn (end of the straight) -- then you've found some significant HP that's helping you on the track. In fact, you cant' use the same braking point -- as you find HP (more rpm is the measure) you have to have an earlier braking point because you're going faster. I tuned my road racer exclusively like that -- looking at rpm at the end of the longest straight -- traction not an issue. Driving skills were an issue though - you have to consistently take the turn leading ONTO the long straight.
The dyno can be a very helpful tuning tool. Almost all professional and successful racing outfits use engine and/or chassis dynos to help test things BEFORE they get to the track. And what they learn at the track is used to help them quantify what they saw on the dyno. In that way they use their on-track experience to help make their dyno runs even more predictive and predictable. But I think they'll also tell you that you have to be VERY careful to control variables on the dyno. I've seen 15-20 HP differences on chassis dyno runs on back to back pulls - the same combo with no engine changes at all; the only difference being changing air pressure in the rear tires, and tightening the tie down straps another click or two. The sad thing is that if you're trying to to test to find relatively minor changes you have to be very careful. Ambient temperature changes, oil temp/tranny and rearend fluid temps, minor mixture changes, tire pressure changes (which occur as the tires heat up from successive runs) can all result in measurable differences in output. When you're looking for 3 hp from a timing change, and you can have a 5 HP variation due to fluids heating up -- well, you see the problem. As a general rule of thumb -- I'd say HP comparisons are only valid for changes made during the same strap down session on the same dyno by the same operator with careful measurement of things (mostly temps) that impact output at the wheels. The minute you take it off and strap it back down -- you've changed things enough to NOT be able to definitely identify small output changes. Let alone comparing two different car's runs on different dynos at different times. That kind of comparison is closer to simple entertainment than it is to anything resembling an accurate or factual comparison of the 2 vehicles.
So, I'd say that both dyno and track have their place. Either can be predictive of potential -- but as with anything else - you have to know what you're doing. Having said that - I confess - I get just as much of a kick out of spending 3 or 4 hours at a 'dyno-day' watching different cars spin the rollers as I do at the drag strip.
For many hardcore, successful racers the track is a perfectly good way to test their changes. They know their cars EXTREMELY well, they're consistent (car and drivers) and they have a lot of data as to how performance changes with their car at different tracks and under different conditions. Given all that -- they can very easily isolate very small performance changes for better or worse and know if they're headed in the right direction. And since, at the end of the day, success for them is ONLY measured by who got to the other end more quickly (8 seconds or 24 hours later) -- it's ONLY their performance at the track that matters. There are LOTS of cases where picking up a few HP at peak on the dyno didn't result in a quicker time at the track because other parts of the output curve were impacted as well -- in a negative way.
The other issue is that (and it's kind of unspoken in the thread) there's an implication that the kind of track racing we're talking about is drag racing. There are just as many autocrossers and road racers out there who do track testing too. And their performance envelope is also impacted by 2 items which the chassis dyno won't help you with - braking and cornering. In those areas - the dyno won't help at all. You've got to go to the track. And my experience has been that I gained WAY more in quicker lap times by optimizing my braking and handling than I ever did with HP additions. Beyond that -- as far as potential HP gains from mods -- it's REAL easy to see on the road course because you have long pulls in higher gears where traction is rarely an issue. If the braking and cornering speeds haven't changed - so you're exiting a turn at the same rpm in the same gear you always do -- but you're pulling 300 more rpm at the braking point for the next turn (end of the straight) -- then you've found some significant HP that's helping you on the track. In fact, you cant' use the same braking point -- as you find HP (more rpm is the measure) you have to have an earlier braking point because you're going faster. I tuned my road racer exclusively like that -- looking at rpm at the end of the longest straight -- traction not an issue. Driving skills were an issue though - you have to consistently take the turn leading ONTO the long straight.
The dyno can be a very helpful tuning tool. Almost all professional and successful racing outfits use engine and/or chassis dynos to help test things BEFORE they get to the track. And what they learn at the track is used to help them quantify what they saw on the dyno. In that way they use their on-track experience to help make their dyno runs even more predictive and predictable. But I think they'll also tell you that you have to be VERY careful to control variables on the dyno. I've seen 15-20 HP differences on chassis dyno runs on back to back pulls - the same combo with no engine changes at all; the only difference being changing air pressure in the rear tires, and tightening the tie down straps another click or two. The sad thing is that if you're trying to to test to find relatively minor changes you have to be very careful. Ambient temperature changes, oil temp/tranny and rearend fluid temps, minor mixture changes, tire pressure changes (which occur as the tires heat up from successive runs) can all result in measurable differences in output. When you're looking for 3 hp from a timing change, and you can have a 5 HP variation due to fluids heating up -- well, you see the problem. As a general rule of thumb -- I'd say HP comparisons are only valid for changes made during the same strap down session on the same dyno by the same operator with careful measurement of things (mostly temps) that impact output at the wheels. The minute you take it off and strap it back down -- you've changed things enough to NOT be able to definitely identify small output changes. Let alone comparing two different car's runs on different dynos at different times. That kind of comparison is closer to simple entertainment than it is to anything resembling an accurate or factual comparison of the 2 vehicles.
So, I'd say that both dyno and track have their place. Either can be predictive of potential -- but as with anything else - you have to know what you're doing. Having said that - I confess - I get just as much of a kick out of spending 3 or 4 hours at a 'dyno-day' watching different cars spin the rollers as I do at the drag strip.
Dark Knight
Founding Member
The problem with the dyno is that every one is different. I've lost HP from one dyno to another, but picked up MPH at the track.. if you're at the track, someone will probably have a portable weather station and you can do the corrections the same as a dyno computer will. The dyno is great for fine tunning AF ratios and timing, but the numbers dont mean much excpet plus or minus from the baseline.. just go bump up your tire pressure, make a pull and see what happens . 
They also wont show any gains from things like cold air kits etc.. they can show the potential of an engine, not a car..weight and suspension are equally as important, if not more so than engine HP and TQ.. and that goes for road racing as well as drag racing..
They also wont show any gains from things like cold air kits etc.. they can show the potential of an engine, not a car..weight and suspension are equally as important, if not more so than engine HP and TQ.. and that goes for road racing as well as drag racing..I'm talking about drag racing and dyno comparison as I have stated and inferred all along. Road racing has even more variables to get consistency.
Dyno has less variables to flunder IMO.
On a dyno you can see other areas of the curve affected. I am not talking about peak numbers.
Mod for mod, the dyno seems to show a better situation on what is going on...
Dyno has less variables to flunder IMO.
On a dyno you can see other areas of the curve affected. I am not talking about peak numbers.
Mod for mod, the dyno seems to show a better situation on what is going on...
Michael Yount
Mustang Master
Michael Yount said:
Lol...
Roadracing deals not just with straights but curves (handling) and slowing down at different intervals (braking) and goes for longer than 9-15 seconds at a time (drag strip). The differences would be even more negligible if you noticed a 1/10th of a difference racing at a road course or autocross event.
the dyno is a more accurate way to compare an engine's potential, but doesn't take into account the car's weight, traction, aerodynamics, or the driver obviously. a well set up 400hp car with a good driver will likely waste a 500hp car with stock suspension, street tires, and a bad driver.
the track is potentially a better real world indicator, but there are so many variables that it'll never be 100% "accurate" (meaning you'll never run the exact same time every pass), especially for most of us who aren't full time racers with all-out racecars.
both are useful... but if I was going to race someone and wanted to know what chance I had of winning, I'd much rather know track times. that way the car setup and driver are taken into account, and you at least have a ballpark idea of what it'll run.
the track is potentially a better real world indicator, but there are so many variables that it'll never be 100% "accurate" (meaning you'll never run the exact same time every pass), especially for most of us who aren't full time racers with all-out racecars.
both are useful... but if I was going to race someone and wanted to know what chance I had of winning, I'd much rather know track times. that way the car setup and driver are taken into account, and you at least have a ballpark idea of what it'll run.
5spd GT said:
I guess that depends on your definition of "better gains". A mod that's going to make your track time better is going to obviously add numbers to the dyno too.
EDIT: that is at least if we're talking about engine mods and not suspension mods.
25thmustang
Mustang Master
For the average guy the dyno will be a better indicator, for the racers, the track... I know what you mean and yes a dyno will show if power was gained or lost better than a track, but the fact remains it all depends on who wants to know, and what they want to know!
25thmustang said:
Sounds good to me
About the power gained on whether the track or dyno is better let me give an example. At the end of the track season 2 years ago I ran a certain time. That spring (with no additions) I ran 3mph faster on my first run
The dyno would show the same power but just because my driving got better doesn't mean that I added something. The dyno would show that...but some say well "so and so gained 2mph with no other changes except XXXXXX". Makes me wonder how much was towards that part or track prep/temp/driver/etc. The dyno would show a closer representation of what actually happened IMO.
