Dyno fudging the numbers??

[dynaguy03]

My engine builder is dyno'ing my new motor on a superflow dyno and im wondering can the dyno be used to create higher numbers in hp tq?.
How would i know if the numbers on the dyno werent manipulated to falsely achive the numbers??

thanks
In advance

[bubbabbc]

Yes, they can, and yes, many do this very thing. Some engine assemblers that don't have their own dyno will purposely use a dyno facility that will "fudge" the numbers. This is more common place then most racers realize. My dyno guy took our best pull, and then showed me the way to do this. It's quite interesting.

[dynaguy03]

So did he happen to share with you what to look out for.?.. i worried im gonna get bogus inflated numbers

[hammertime]

So did he happen to share with you what to look out for.?.. i worried im gonna get bogus inflated numbers

bring us the #'s we will tell you if they are close or not ..

I've dyno'd a few motors, one was on a happy dyno the other not so happy. Both made same HP .. one is a full 2 tenths faster then other.

[dynaguy03]

Hammer... trouble is i dont wanna pay him till he makes the honest number we agreed on- deal was last third to be paid upon making 600+ hp and over 550tq. on the dyno.. on this sbc.
I got screwed last round with a different guy (AR racing in Sumerduck Va) i dont wanna get another pc of - u- know what!!

[hammertime]

tell us what the motor is we will tell you if its going to make 600

[curtisreed]

Why don't you pick the dyno?

Curtis

[dynaguy03]

Ok here it goes...

388 ci sbc 13-1 -,canfield heads extensive bowl ,port and runner work, 208-160 valves - super victor intake, plenum work, AED 850 carb, 1 in spacer, jesel shaft rockers, comp cams roller lifters, rockers,mech roller cam.. i dont have the cam card and everything is still at the builder, eagle rotating assembly J&E forged small dome pistons, ati super dampener, msd dist./wires, im thinking the cam is the key he only mensioned 640 in 630 ex.(not corrected) . dont know duration until i get the cam card- his claim is this simular combo at 358 ci made 622 hp - that particular motor is is a 3400lb all steei 69 camaro running 10.39 i have seen it run that number in the 90 plus degree heat all day on gas with a 750 AED.

[Pdmracing]

ALWAYS ask what the correctiuon factor is! I was dynoing my RR car befor & after every race, All @ the same dyno. well one day it was reading some great post race numbers, then the guy remebered he was dynoing some car club & jacked up the correction factor so they wouldnt bitch!

[bjuice]

Hammer... trouble is i dont wanna pay him till he makes the honest number we agreed on- deal was last third to be paid upon making 600+ hp and over 550tq. on the dyno.. on this sbc.
I got screwed last round with a different guy (AR racing in Sumerduck Va) i dont wanna get another pc of - u- know what!!



The one Big thing that has been missed here is the real purpose of a dyno and why it was created. Its purpose was to fine tune a motor NOT to find max HP and TQ...This day and time i understand this is why many people dyno motors but it was not the intended purpose of its design.



the HP and TQ readings are the reported Numbers where the engine is tuned at its maximum (optimal) performance.....its normally not the highest HP and TQ the engine could make

a perfect example of what i am saying here is that you can lean the $hit out of an engine and literally burn it down on the dyno and its gonna make more HP and TQ on the Dyno right before it becomes a 500lb ash tray.. .

so with that said you want to find MAX HP and TQ readings or have a properly tuned dynoed engine ? :roll:



My 2 cents..
_________________
bjuice..
" There is more than one way to skin a moving cat".

[dynaguy03]

Ok Gents .. thanks everyone for your input.. The day on the dyno actully was only a few hrs. over 2 days. We broke the cam in first day and checked everything.. let it cool down overnight re-tourqued the heads and went over everything again
Day 2 we made a few pulls - made 2 jet changed on a 750 carb and adjusted the timing a few times. By the readings he explained the 750 was too small so i threw on my 850 made 2 pulls adjusted jets again .
Was pretty drama free.. the peak hp was at 6805 rpm the peak tourque was @ 5900 but stayed the same till 6150rpm.
Wound up 624hp and 553ft/lbs within a rpm range of 4300-7000 on this 388ci chevy. Im pretty happy.
Of coarse we could have worn it out on the dyno but i felt once we tweaked it .. carb and timing it was smooth sailing
Thanks for all your comments and input!

Keith

[dynaguy03]

388 ci sbc 13-1 -,canfield heads extensive bowl ,port and runner work, 208-160 valves - super victor intake, plenum work,port matched, AED 850 carb, 1 in spacer, jesel shaft rockers, comp cams roller lifters, rockers,mech roller cam.. i dont have the cam card and everything is still at the builder, eagle rotating assembly J&E forged small dome pistons, ati super dampener, msd dist./wires,crank trigger. Comp cams custom cam 640 in 630 ex. installed at 108 -timing 37 degrees.

[promodjohn]

You are paying all that money for the dyno so insist on being there with the builder.If they don,t allow that I would not trust them been burnt too many times.USE SOMEONE ELSE!!!!!!!!!!!!!

[CarbGuy]

How would i know if the numbers on the dyno werent manipulated to falsely achive the numbers??

thanks
In advance

Simple, get both the raw (uncorrected) numbers, and the corrected numbers. Then find out what the weather was during the dyno test (Air inlet temp, humidity, and barometric pressure) from that you can go online and determine what the air correction for that day should have been. If the correction is right you're usually pretty good. Depending on the type of dyno used there are other ways, but as stated before a dyno is a tuning tool used for baselining an engines performance, and that's it.

[cncmotorsports]

Sounds like your dyno numbers are pretty close for a super flow dyno, they generally ready 5-8% higher than most other dyno's. On Our DTS dyno, I would guess it would have made around the 585-590 HP mark.
Either way sounds like all is well.
Would have been neat to have tried the AED 950HOM on there, bet it would be good for another 10-15 HP