So I had my 02 SS dynoed it made 403 and 386 Mods are long tubes magnaflow full exhaust cam and underdrive pulley ls6 intake ported tb and maf with lid. Stock 323's. Stock untouched 241's Now I had it re dynoed with 410's same mods and had a significant drop in numbers 368 and 345 I was told that this was normal?

Comments?

 

Numbers were on a mustang dyno

 

i understand it was a mustang dyno but was it on the same dyno? first numbers look accurate the 2nd set is low 4.10s usually cost 5-7 hp not 40

 

you can fiddle with a mustang dyno to make it read higher or lower and many many shops do just that to keep their customers happy. He probably had you pumped up on the earlier one, then had the dyno set up properly for the 2nd... A properly set up mustang dyno will read 8-10% lower than a dynojet and that is exactly why people mess with them to make them read higer

 

I agree the gears should only cost 5-10 hp maybe. So why did the guy sat it's normal?

 

It was the same dyno same tuner the only change was the gears it didn't sound normal to me either.

 

unless you dropped a cylinder, or have some kinda serious drive train problem, it was the difference in how he set the variables on the mustang dyno... as i said before they are easily manipulated

 

8-10% is the power you are missing and that is exactly what the difference between a dynojet and properly set up mustang dyno... Just go dyno it again and have him pump up the cf for you and you'll get your numbers back..

 

i would take it o a shop with a dynojet, they still can vary by as much as 30 hp, but are at least not really able to be manipulated as much. Mustang's are just better for tuning not getting numbers to be proud of

 

man, you guys and the mustang vs dynojet argument.

 

Its because dynojets for the most part are consistent and mustang dynos are either high or low depending on how it was set up by the operator.

 

Adjusting the calibration on the mustang dyno shouldn't make it inconsistent unless they are fudging weather correction. Unless they are messing with the calibration in between vehicles which would make it impossible for them to ever get consistent numbers.

 

many people bump up the cf on mustangs to make them read closer to dynojets to please their customers, since no one likes seeing low numbers. Since op lost 40rwhp changing gears his prob is most likely related to dyno calibration unless his car feels really weak now and has some kind of mechanical prob. He didnt mention it feeling slower. If i'm not mistaken there are other things that can be manipulated on mustangs besides the weather cf in the background that you don't even know about unless you are the operator. /i could look them up, but does your shop use a mustang and if so what are they?

 

No I use a dyno com dyno which is very similar to a mustang. A dynojet is the only one I have used where the operator cant easily manipulate the numbers, easily being the key word, it can be done. There are several things you can change that would affect the numbers but having inflated numbers is the last thing a good shop would want IMO. If you calibrate a mustang dyno to read similar to a dynojet it will still be constant, now if your cheating the weather correction from car to car it will not be consistent. Theres a big difference in calibrating a dyno vs changing the cf each vehicle. Once a dyno is calibrated you shouldn't have to ever change it again. If you constantly change the calibration you will never be able to compare baselines for before and after.

 

I mean was this on the same dyno? I wouldn't expect any more than a 5-20 hp drop. I've routinely tested power differences between gears at that power level.

 

I found a cracked ceramic on the number 5 plug car didn't seem to miss fire but it did add a lot of power back to the car

 

How's the car feel now?