Dastek graphs - lets see them!

[rapidcossie]

Gerry,

 

my post was not meant to be a piss take or do i have anything against dastek or anyone that works there.

 

my car has been on AVA's rollers tons of times but im my own man not theirs LOL

how does your calculation differ from a dyno dynamics RR whre massive losses are seen?

just cant believe than one car losses less than 40 bhp to the wheels?

 

AVA will never guess flywheel figs as the dont measure them.

 

how much is a power run Gerry as i have been thinking about getting a flywheel figure for a while?

[craig mac]

Japerformance have Dyno Dynamic rollers and they give you the fly wheel figure and wheel

However they do not give you a torque figure

Craig

[Dastek]

Hi Euan,

You are now saying that your post was not a piss take, but comments such as :

question the operators all the time its the only way you can work out if they know what they are doing or NOT in this case...

as well as the many other posts on various forums, calling us mongs, monkeys, numpties etc.. would make me think you have something against us [8-)]

To answer your question, our rollers actually calculate the losses on the coastdown (see my previous post detailing the formula) where as the Dyno Dynamics applies a factor for a particular transmission type (but you can see the differnce just g/box oil temp makes, so how accurate this method is, is anyones guess) or they multiply the wheel power by a % (24% or 1.24 multiplier in the case of EVO's) the reason there is such a big difference in wheel power to engine power on their machine is due to the fact that they run small diameter rollers which leads to high loading & deformation on the tyres, the smaller rollers also mean that the retarder rotates at a higher rpm for the same road speed, & as the power required to just spin over the retarder increases with rpm, this is yet another power unmeasured, & finally because the roller diameter is smaller, the amount of force required to pull down the car on the rollers to gain sufficient tranction is greater, the tyre deformation & heat exchange is greater leading to greater difference between the wheels & the engine.

With regards the 40bhp losses, if I'd run it in 6th, it probably would have lost over 100bhp, but the engine output wouldn't have changed, but at least with our dyno it would have shown this.

I realise AVA don't give flywheel figure (& this is not a dig at AVA, as I know them & think they are good guys, but a general question of anyone that relies on wheel power only) but how would you explain to two customers that have had the same spec engine built by the same engine builder, that in one car it produces more power at the wheels than the other, due to any of the following or combination of A) Diff ratios different Gearbox ratio's different (say 5sp V's 6sp box) C) Wheel alignment wrong D) G/box oil viscosity or temperature variation E) Tyre sideall profile (35 V 55) F) More pull down strapping force required for the short geared car G) Mechanical fault such as brake caliper sticking on or wheel bearing fitted by a numpty (see previous MR2 screen grab) etc. etc...

So I will say it again (even though you only partially quoted me on Passion Ford []) 'Wheel power is meaningless without coastdown data (I've even highlighted the last bit that you failed to quote on PF [])

As for prices, if you want a straight forward run with nothing more than graphs of flywheel power & torque, AFR & boost, we normally charge £40 + VAT, if you want turbo speed, injector duty cycle, intercooler in/out, engine pumping losses, fuel pressure, fue flow etc plotted, then we charge £60 + VAT per hour for how long it takes us to do it (as you can imagine it can get time consuming to fit all these sensors & gather the data) but for you []

Seriously if you want to come along & see our equipment in action & discuss some physics, I'd do it FOC, if I can convert you I can convert anyone []

Cheers,

Gerry

[Gumball]

Gerry said-

 

Seriously if you want to come along & see our equipment in action & discuss some physics, I'd do it FOC, if I can convert you I can convert anyone ]" src="/emoticons/emotion-2.gif">

Cheers,

Gerry

-------------------------

well in that case i dont believe you either. I bet you couldnt convert me for free[]

[wrxmania]

Yeah - "I don't believe Gerry at all and need converted" - list below:

1.  GUMBALL

2. WRXMANIA []

[G.Mac]

After my experience with AVA, I still think they suck dong but if I get a free run..

1. Gumball

2. WRX Mania

3. G.Mac

(always living in hope!!!!.....lol[])

Graeme

[rapidcossie]

  Quote

Hi Euan,

You are now saying that your post was not a piss take, but comments such as :

question the operators all the time its the only way you can work out if they know what they are doing or NOT in this case...

as well as the many other posts on various forums, calling us mongs, monkeys, numpties etc.. would make me think you have something against us [8-)]

To answer your question, our rollers actually calculate the losses on the coastdown (see my previous post detailing the formula) where as the Dyno Dynamics applies a factor for a particular transmission type (but you can see the differnce just g/box oil temp makes, so how accurate this method is, is anyones guess) or they multiply the wheel power by a % (24% or 1.24 multiplier in the case of EVO's) the reason there is such a big difference in wheel power to engine power on their machine is due to the fact that they run small diameter rollers which leads to high loading & deformation on the tyres, the smaller rollers also mean that the retarder rotates at a higher rpm for the same road speed, & as the power required to just spin over the retarder increases with rpm, this is yet another power unmeasured, & finally because the roller diameter is smaller, the amount of force required to pull down the car on the rollers to gain sufficient tranction is greater, the tyre deformation & heat exchange is greater leading to greater difference between the wheels & the engine.

With regards the 40bhp losses, if I'd run it in 6th, it probably would have lost over 100bhp, but the engine output wouldn't have changed, but at least with our dyno it would have shown this.

I realise AVA don't give flywheel figure (& this is not a dig at AVA, as I know them & think they are good guys, but a general question of anyone that relies on wheel power only) but how would you explain to two customers that have had the same spec engine built by the same engine builder, that in one car it produces more power at the wheels than the other, due to any of the following or combination of A) Diff ratios different Gearbox ratio's different (say 5sp V's 6sp box) C) Wheel alignment wrong D) G/box oil viscosity or temperature variation E) Tyre sideall profile (35 V 55) F) More pull down strapping force required for the short geared car G) Mechanical fault such as brake caliper sticking on or wheel bearing fitted by a numpty (see previous MR2 screen grab) etc. etc...

So I will say it again (even though you only partially quoted me on Passion Ford []) 'Wheel power is meaningless without coastdown data (I've even highlighted the last bit that you failed to quote on PF [])

As for prices, if you want a straight forward run with nothing more than graphs of flywheel power & torque, AFR & boost, we normally charge £40 + VAT, if you want turbo speed, injector duty cycle, intercooler in/out, engine pumping losses, fuel pressure, fue flow etc plotted, then we charge £60 + VAT per hour for how long it takes us to do it (as you can imagine it can get time consuming to fit all these sensors & gather the data) but for you []

Seriously if you want to come along & see our equipment in action & discuss some physics, I'd do it FOC, if I can convert you I can convert anyone []

Cheers,

Gerry

 

gerry, I touch goats!