Thread: Dyno (rant) thread

ummmmhummmm honny child

we've had a bit of this on our forum in the UK, and one thing that some people on there and here come out with i just don't understand....

it's all very well being all laid back about it sayin meh it's only a tool for tuning, i'm not bothered with willy waving and bragging rights etc - but thatsnot what it's about.

Firstly, i wholeheartedly agree that dynos are predominantly a tuning tool, and for consistent tuning you should be going back to the same one. However, we are all in the same game here...spending our hard earned cash on making more power, having more fun, more speed etc etc...

So, think of a scenario like this. You're rockin your stock 120hp de, you're bored and want some more fun, so after reading on here about certain spec lists, expected power outputs, 1/4 times, you save up your pennies and buy everything you need for say a pretty tasty ve build.

You painstakingly build that engine up; the shiny forged pistons, rods, race bearings, that pretty 4-1 mani and those monster cams.

Tune day comes and after your tuner wors his magic the dyno comes up with 160hp.

You, having read a lot of similar builds on here, were expecting 200hp.

Now it's all very well saying yeh but ifthe butt dyno says its fun who cares but i don't buy that. If you spent all that time and money on building something you thought was gonna give you 80hp over your bone stock de, but your dynos saying you only gained 40hp, I'm pretty sure you'll be left feeling a little short changed?!

Case in point is my own build over here in the UK, pretty common ve build for you guys...12.5:1 CPs, n1 cams, 4-1 header, 3" exhaust etc etc. Having seen plenty of these builds in the US gain 200whp i was expecting similar.

However, having not seen a single similar ve build in the UK when i went to have it tuned on my tuners dyno dynamics machine I felt a bit wounded when i made 173whp.

Now ok, i can console myself saying the dyno dynamics reads low, and it feels fast but i don'tknow how low exactly. Perhaps on a US dynojet i'd make 210whp, perhaps only 185?

Point is it still leaves me wondering if i should be looking into lost HP and if i am kinda shortchanged, or if everythings spot on and i should be happy. Sure, the car feels fun, but is it as much fun and fast as it could/should be given the build.

I know i can look at a/f ratios, compression figures to see if everythings healthy but it still leaves me wondering.


Annyywwaayyyyyy, that was freakin long way of sayin not much, long story short i'm with the OP on the fact that, forgetting braggin rights etc, dynos should damn well be consistent so that we don't get these US vs AU figures comparisons, trying to work out what means what, so that everything is comparable and we know if our time, money and effort has either paid off or we suck at building engines and need to try again!

all dyno's are different ol pal, no point looking into that 173whp (10whp more but 30lb-ft less than my old bolt on DE) too much. should have listen to me an gone to Hi-Tech Motorsport for a better nights sleep

david

thats my point david, i ain't bothered about that dyno being low or losing sleep. I know its low, i know my cars quick - it'd absolutely murder your old de figures or no figures :P lol

my point is they should all be pretty standard to within a few horses to avoid that kind of situation.

hence - dynojet ftw

ftw you hope. however i do understand what you mean. ANY machine is only as good as the operator FACT

i'm not sayin dynojet ftw cos it'lll give me higher figures, its not about me hoping for anything.

thats not my point, i'm sayin dynojet ftw cos they're more consistent from one machine to the other. It seems the operator can't fuck up a dynojet like they can with a dyno dynamics or others which have a lot more input settings.

like how surrey rr reads loowwww, yet another dyno dynamics not far down the road seems to read pretty normal, how the hell should that be able to happen.

or how the hell did jez @ horshams s13 iirc, make 480fly hp on surrey, and 460wheel hp on janspeed dynojet?!!

thats an absurd difference

dynojets im convinced don't give high numbers. They give real numbers though a simple algorithm that measures hp. accelerating a known weight at the rate at which a horsepower is measured. 550lb 1 ft per sec. The measure is simple, and that is why it is hard to get wrong.

Using an eddy current dyno on the other hand presents some other complications. There are a lot more complications with the more "advanced" dynos.

^ i totally agree

a few stock cars i know of that have gone on a dynojet have made near stock figures

however, when i say i favour dynojets i seem to get shot down or accused of the willy waving, bragging high figures stuff! lol

willy waving from a good dyno figure? a good figure comes from a good setup END! V

My Dyno Dynamics read 13% lower than a local Dyno jet. So lets say looking at that 173whp if it was tested on my DD and doing the calculations that would have translated to a 195whp if it was placed on a DJ after the tune on the DD. Looking at that figure then being 5whp off some of the other set ups you are comparing to then its not that far off.
Unless that 200whp u speak of were made on a Dyno Dynamics to begin with.

I do agree there are inputs one can mess up on some of the Eddy current dynos if the operator is not consistent or truthful.

This is the reason I do like the new digital DD where the weather station can not be altered and weather conditions are inserted automatically by the weather station.

At the end if you want to be respected as a tuner and taken seriously, then repeatability has to be in the foremost when the tuner is testing vehicles and not try to cheat the client to seem like the car was making way less power before the tune and then inflate the final figures the dyno spits out to make the tune seem all that better.
Well as it was mentioned earlier, the measuring stick is at the 1/4mile and the trap speed.