Rolling Road result

Post by **GrahamS4** » Sat Feb 02, 2008 8:07 pm

PS. I have had my car on a dyno dynamics in the wrong mode (6F) and I can confirm it will read down on power at the flywheel. The power at the wheels figure you have (if you got one) should be ok though.

Post by **jeffw** » Sat Feb 02, 2008 8:10 pm

If it's for 2 wheel drive car then presumable it will only measure one roller and then correct for 2wd losses ?

Post by **grizz** » Sat Feb 02, 2008 8:11 pm

If they show 399 at the crank that we know is wrong , the whp should be 400 to be 500 at the crank .

Post by **S2tuner** » Sat Feb 02, 2008 8:12 pm

jeffw wrote:If it's for 2 wheel drive car then presumable it will only measure one roller and then correct for 2wd losses ?

The problem with DD is that losses are NOT measured in any case. They are only extracted from an internal database of typical losses curves (HP vs road speed or RPM) for most common cars.

Post by **GrahamS4** » Sat Feb 02, 2008 8:15 pm

To give you an idea, after my S4 remap (anticipating 320BHP) I had the car on a dyno dynamics. Run in Shoot_6F I got 249.1 BHP at the wheels and 301BHP flywheel. TFlywheel figure too low, a stock S4 has greater losses.

Same car, only additional change an RS4 exhaust fitted, run on Thorneys dyno dynmaics in Shoot_44 had EXACTLY the same power at the wheels and 334BHP at the flyhweel.

Basically I think your car had the power measured correctly and if you got a power at the wheels figure, I think that to be correct, but it then corrected the figure completely wrong when trying to give you a flywheel number.

Post by **jeffw** » Sat Feb 02, 2008 8:39 pm

I don't have the wheel HP figures. If we take your example I would end up with a Wheel HP figure of 330.8 (using your correction figures for 6F (0.847)) give a 44F (0.749) figure of 441.65 BHP or a remapped with milltek RS4 type figure.

Post by **jeffw** » Sat Feb 02, 2008 8:48 pm

Now where is Barry and John!

I presume that this is a reference to MTM claimed figures ? If so, spill the beans ....

Post by **GrahamS4** » Sat Feb 02, 2008 8:54 pm

jeffw wrote:I don't have the wheel HP figures. If we take your example I would end up with a Wheel HP figure of 330.8 (using your correction figures for 6F (0.847)) give a 44F (0.749) figure of 441.65 BHP or a remapped with milltek RS4 type figure.

I wouldn't take the figures so literally.

I know Mihnea says the corrected figures are not meaured and I don't dispute that but there is quite some hocus pocus as to how the dyno dynamics comes up with them as we had multiple cars giving similar power at the wheels with varying flywheel figures.

Without wheel figures provided and flywheel figures given from the wrong mode, you really are due a refund.

Post by **chewy** » Sat Feb 02, 2008 9:25 pm

When i had mine on a DD, i had a shock at the figures to start off with. The operator had the ATW figure up on the projector. He later realised his mistake and my car was back to the claimed figures.

Post by **jimbo1234567** » Sun Feb 03, 2008 9:54 am

the operator must have been a <beep> as he couldnt even type your reg number in right

Post by **grizz** » Sun Feb 03, 2008 10:09 am

Mine makes 401 at the wheels and it shows 507 crank , i think the crank should be 520 -530 so loss of 120 bhp , That's why i think it should get 400 ish at the wheels .g

Post by **jb7_uk** » Sun Feb 03, 2008 8:13 pm

Just to add my 2p worth... i turned up just after you left unfortunately jeff, but as i was waiting for my mate to turn up i was last on the rollers with the standard B5 S4.

Needless to say i (and the few spectators that stuck around) was quite surprised to see my car only make a paltry 171Bhp !!!! he did 4 or so runs, one was 208, on at 171 and the last (for which i have a printout) showing 164bhp!!!

Thinking there was something wrong with the rollers after hearing Jeff and Matt's stories i was just gonna nod and agree but the monkey in the garage then proceded to tell ,e that my car was broken, that i had lambda and other air flow problems and that i needed to fix the problems, clear the fault codes (as my car had apparently gone into limp mode!) and then i'd be back up to 265bhp.

Not impressed, if others are persuing a refund, then definitely count me in!!!

Post by **GrahamS4** » Sun Feb 03, 2008 8:24 pm

You could still have faults reading that low tbh.

Post by **GrahamS4** » Sun Feb 03, 2008 8:56 pm

It's quite odd I think. Rolling roads are not cheap. Not cheap at all. You wouldn't just buy one for the workshop on a whim. They are quite big and as I said the cost. A cost I believe so sizeable, you'd really have to have a business plan and faith in the product to do something for your business.

An AWD dyno dynamics certainly isn't a cheap option that I am aware of and I think it is quite an informed buy. Got a rough figure £ anyone?

So, you'd really think a garage that has actually invested in one, would know how to operate it?

Post by **jb7_uk** » Sun Feb 03, 2008 8:59 pm

true, but the car's been driving fantastically for last few months, prob the best its ever done since i did bipipe etc. It's also just had new cambelt etc done in Dec07, and woody did a service back in sept07... not skipped a beat since until the minor idler pulley in dec which led to full cambelt worksbut back up to perfect running since.

It performs consistently as it should on the road, my @rse dyno tells me that there's no way my car is running less power than my old 190bhp 2.8Q

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