I see this over and over again. People post dyno numbers on their cars and others feel the numbers are too high or low. Below, I have listed some reasons why dyno numbers can vary. I am sure some of you operate dynos and can add to the list and help others understand why these variations exist. Hopefully this will reduce arguments.

With all cars and kits specifically, a lot of things can make a car have different dyno numbers such as:

1. Type of dyno.
2. Procedure when dynoing, are engine, fluid temps being controlled etc. Many dyno shops do 3 quick pulls, whatever happens thus if a fan goes on, hp drops etc. We at Sport Z magazine understand these variables can make pulls way off thus we follow a detailed dyno testing procedure. We have been using Shawn Church for our recent tests and he always makes sure your pulls are consistent and accurate.
3. Strong motor vs. weak. As many of you know, some VQ's just pull more hp stock to begin with thus one guy can spend $2000 on N/A mods and still pull less than another Z that is stock. This is why it is important to do a baseline pull prior to any mods, and then after you do mods, use the same dyno, same procedure and note the gains. This will tell you how much gain your mod did, otherwise you will never be sure.
4. Tuning on kits etc make a difference in on how a kit produces.
5. With turbo and SC kits, amount of boost changes hp/tq.
6. Type fuel (octane rating)
7. Cheating...it happens unfortunately. Use your imagination on how and why.

I sure some of you can think of other variables, thus is off the top of my head.

 

Something I really don't understand is why stock Z's rwhp numbers are all over the places... some with as low as 220rwhp and some as high as 250rwhp and I read comments like " he got a strong Z from the factory", "

I mean, if all Z's are manufactured using the same parts (a little different in options and accessories but thats minor), same technology, isn't the rwhp number should be a bit consistent?

Please educate me!!

 

Read above, items #1,2,3,6,7

 

Is that mean if 2 stock Z's are using the same dyno and all variables are the same, they should have very close results?

The difference in power is attributable to dyno variables only and not the engine???

 

I dont believe the tolerances are loose enough to provide more than a TRUE 10whp difference between Z's if they were dyno'd on the same day on the same dyno. The reason you think some are weak and strong is because of all the reason you listed.

With the being said, operators or people that post numbers can squeeze a few more horses out with changing corrections-STD always reads higher than SAE on dynojets. Also, smoothing in some cases if at 0 will read a few more hp higher than smoothing say on 5-again on a dynojet. And some will not post SAE corrected numbers, dyno in great conditions and post that, when in SAE the numbers are actually lower.

 

If all other varibles are the same, back to #3 above.

 

I just think people want their dyno's to read like a dyno jet and correct them but when correcting them they tend to put higher number i think they should be done on the same dyno thats how we will really know who is on top and who's not.

 

I am still confused .... if all dyno variables are the same and you stated that a Z can have a stronger motor than another, then the power difference is basically coming from the motor and dyno unrelated.

Back to my original question now... how can a manufacturer produce two identical cars with one motor stronger than the other?????

 

This does not happen in reality.

 

I mean no offense by saying this, and don't get me wrong, I like having a hp sheet to show off, but I enjoy the measurement tool that is the seat of my pants during acceleration. One thing, I have done in the past is compare my dyno to an online hp calculator, I know that isn't accurate or maybe it is but most if not all of my dynos pale in comparison to the online hp calculator.