Can a tuner answer: final drive ratio on dyno results

[Benman]

Dyno numbers give you bragging rights, ET's give you win lights. A dyno is just a tool used for comparison, each dyno has to be calibrated and used properly, just as a torque wrench or a micrometer. If you use the same dyno before and after mods, operated by the same person, calibrated the same way, then you are most likely to get an accurate evaluation of performance gained, or lost. And yes corrected DA also figures into the equation. In all my years around race tracks though, I have yet to see a single dyno make a pass.

[weSS1LEy]

Originally Posted by jeff657756

Unless you have been to another dyno and confirmed or have some sort of track time, then you are thinking about it too much. I made 460whp with a big cam ('14 1LE) and some people thought something was wrong. Went back same dyno same cam but with 13lbs boost made over 830whp. So which is right? Who knows.

Going to a different dyno next month. As for track time, no options around here and I don’t have the skillz anyway lol

[Benman]

Originally Posted by weSS1LEy

Going to a different dyno next month. As for track time, no options around here and I don’t have the skillz anyway lol

Track time is not necessary unless that is what you want, the most important thing is for YOU to like your ride and enjoy the mods. You will find no matter what dyno numbers you post there will always be detractors and supporters.

[PepeLePew]

Originally Posted by Benman

You will find no matter what dyno numbers you post there will always be detractors and supporters.

Great comment Benman!

Wess1LEy - ignore the detractors... they will always be there. And when they try to say you results are wrong using false theories, it is usually comes from their own insecurities. I suggest you take your car to the same dyno after you put the cam in to see the impact from your baseline with no mods as well as impact from your last set of mods. Otherwise, you may be scratching your head to determine if the cam made an improvement or not. And if it were me, I would proudly post my results in the Dyno sticky with your graphs.

[sixty9fordkiller]

Originally Posted by Benman

Dyno numbers give you bragging rights, ET's give you win lights. A dyno is just a tool used for comparison, each dyno has to be calibrated and used properly, just as a torque wrench or a micrometer. If you use the same dyno before and after mods, operated by the same person, calibrated the same way, then you are most likely to get an accurate evaluation of performance gained, or lost. And yes corrected DA also figures into the equation. In all my years around race tracks though, I have yet to see a single dyno make a pass.

[weSS1LEy]

Thanks guys! I’ll post my graphs soon

[Hulk]

Gear ratio is a torque multiplier. If gear ratio and tire diameter are not entered into the computer it can not correct for it.

If I ran my car with 3.23 gears and got a time and then ran it with 3.92 gears the car would go faster. Did this change the engine horsepower.? No, this changed the RWHP.

If this is not true please explain it to me

[_Onyx_Wolf_]

Originally Posted by Hulk

Gear ratio is a torque multiplier. If gear ratio and tire diameter are not entered into the computer it can not correct for it.

If I ran my car with 3.23 gears and got a time and then ran it with 3.92 gears the car would go faster. Did this change the engine horsepower.? No, this changed the RWHP.

If this is not true please explain it to me

I gotta agree with this statement makes sense

[Benman]

Originally Posted by Hulk

Gear ratio is a torque multiplier. If gear ratio and tire diameter are not entered into the computer it can not correct for it.

If I ran my car with 3.23 gears and got a time and then ran it with 3.92 gears the car would go faster. Did this change the engine horsepower.? No, this changed the RWHP.

If this is not true please explain it to me

True to an extent, except it has been accepted, at least by drag racers, that MPH and not ET establishes horsepower estimates, et establishes efficiency. All things being equal a gear change may well result in a quicker et, the MPH at the traps is not likely to be affected very much, at least minimally at best. Just my .02.

[JimCT_9C1]

Originally Posted by Hulk

Gear ratio is a torque multiplier. If gear ratio and tire diameter are not entered into the computer it can not correct for it.

If I ran my car with 3.23 gears and got a time and then ran it with 3.92 gears the car would go faster. Did this change the engine horsepower.? No, this changed the RWHP.

If this is not true please explain it to me

A steeper gear is a torque multiplier AND a speed reducer. They cancel out to give the same HP.

HP = Torque x RPM / 5252

Using the above numbers, the wheel torque is increased by 3.92/3.23, but the wheel speed is reduced by 3.23/3.92. HP is unchanged.

Hope this helps.

Jim

[Bo White]

Dynojet doesnt care what gear you have

[Bo White]

Dynocom doesnt either

[Bo White]

Originally Posted by Hulk

Gear ratio is a torque multiplier. If gear ratio and tire diameter are not entered into the computer it can not correct for it.

If I ran my car with 3.23 gears and got a time and then ran it with 3.92 gears the car would go faster. Did this change the engine horsepower.? No, this changed the RWHP.

If this is not true please explain it to me

Not true.
Lower gear created a more useful range of the same power curve as before.

[christianchevell]

Yes steeper gear ranges are good to get to higher RPMS quicker,
times matter when you have to shift more thus the stock times of the 1le being slower due to a additional shift coming in 4th compared to a ss......3:45 versus 3:91, and you enter gear ratio on a some dynos or its automatically calculated with its software what really matters is the torque which it measures which the HP is figured off of...…………………..

SO a higher revving gear will switch the torque curve and make more torque lower in the curve but also it does not gain any HP, it just changes the speed at which you have to make the rear wheels turn to get to a certain speed...all kinds of things matter on dynos, load bearing or non load bearing , tire size, tire slip,etc…… And a numerical higher gear will though limit top end speed slightly, along with gas mileage usually as you have to rev more to get to the desired speed.

You cant change the rwhp but slightly changing out gears on a dyno sheet; especially if gears are entered in the equation, like BO said you just changed up the Toque curve what moves a heavy object.... Torque. I am not sure about all dynos but they are different in many ways and some will show lower and some higher. Mustang dynos being load bearing have more real world numbers for actual driving compared to some that do not load bear unless they are adjusted right ;and all are at first invention based on like zero altitude or the altitude of Detroit, or Michigan etc..... where they made the first one and so entering into the program for a dyno should be a remote weather station and the altitude things like that matter just like they matter at the track.....

Gear can make more torque lower in the band but it cannot change HP, and being that a Dyno sheet is based off HP calculated off of Torque it can affect a printout, but usually not much as everything changes from one RPM to another and there are different readings that matter at the bottom of the sheet and you look at the power curves....on a good dyno sheet you get the minimum and maximum and average...here a old dyno from my last engine....


Now with a different engine my torque is much higher, my average HP way higher, my torque comes on earlier and much higher just from stroking yet my Hp is lower as its not what matters for me, for me keeping the engine together until I have money in the future ..( daughter neuroscience ugh), had me install a much milder cam but I like power so stroking it made it be more powerful....and everything matters more with the same dyno measuring it so I can compare, someday with a new set of LS7 heads from GPI I hope as I am not into FI, I daily drive mine..I work.... the old engine was just my 13 with tsp 235/239 cam and CAI with headers and HFC.., I prefer my new engine with much lower lift and less duration for now because I go faster and take it easier on the valve train until I get past a couple more years paying down debt. Life is what happens while your busy making plans...LOL Have a nice day I am rambling on again...…..
SO short on ink this engine ; let me translate....40 more ft lbs off the line 30 more Hp thanks to torque off the line, average torque up 32 hp up 36..... looks like higher torque up 35 and loss of 15 hp maximum readings ...basically what I was expecting more torque lower and more torque to move me in a flying Muscle brick....LOL somewhat Like some try to do with gears to lower their Torque curve and get into higher revs and higher torque right away when its actually the same engine just multiplying its torque down lower due to the gears a shift in the curve...…. kind of like my curves shift only mine is magnified from stroking/ build.