poor dyno result why?

[Jarred]

My speedo reads more correctly on my mk 1. I believe it does anyways. I didn't get a chance to check with GPS, but the 185/60/14's seem to pull the speedo up about 5-10% (rough calc) over the original 155/80/13.

This also effects the odometer. I'm not sure exactly how. could explain my terrible fuel econ though!? (along with running too rich...)

[LoriJarrod]

I'd just take the dyno result with a grain of salt. Chassis dyno's are tuning tools, with the added bonus of giving you an approx power reading to compare with your mates, all in the comfort of a workshop with a low degree of breakage risk.

The best way to gauge your power output is trap speed at 400m.

[velly_16v_cab]

we ran a 16v mk2 on 17's then on 14's....it made a 15 bhp @ the wheel difference but the flywheel result was the same.


Yes you should take the rolling road restuls with a pinich of salt, its just pub talk figures mainly anyway....its how the car drives on the road/track it all comes down to.

[Mischa]

give the cars to the stig

[shaneth]

Note to self.... Dyno threads are like chip threads, not even worth starting.

Jason mate, i said to you way before the dyno day that i didnt think that noise sounded right. If you think that you may be loosing some power then get someone to look it over it couldnt hurt as davemack said.

[Jarred]

Don't take dyno results so lightly. they can show up some issues people are having, and do give you a rough number to work with (for future mods)

but the most valuable info from a dyno run is the curves. (as some people have shown in the other thread) This information can be quite useful for anyone wanting the most of of their cars, for street/track use, it doesn't matter.

(this is pretty basic, and I'm sure most of you know it, but it's worth mentioning)
The curves tell you where you power is. ie. a Vtec has all it's power at the end (RHS) of the graph, which means that to get the most out of a Vtec you need to rev it's t*ts off, all the time, to be in the power band.

and the same way, you can tell where the boost is best for you pogos.

It helps to know (by more than just feel) where your power is. So you can learn that you don't need to rev it beyond X Rpm cause the power starts to drop off at X rpm. and like wise with torque. best torque curves are smooth and flat, giving you linear accel and const 'force'.

if you know where your torque lies, you know where to be when you are coming out of corners!

I hope that made some sense to you all. Just my opinion on dyno/dyno charts but yea. I'd prefer a power curve that looks more like a torque curve more so than a Vtec power curve anyday. Power; at any RPM..? I can live with that.

just my opinion

[GT3]

Note to self.... Dyno threads are like chip threads, not even worth starting.

Yeah don't let all that dyno stuff do ya head in. Keep into perspective.

[LoriJarrod]

At least you had a go GT3.

Cool vid.

[jasn78]

Note to self.... Dyno threads are like chip threads, not even worth starting.

Jason mate, i said to you way before the dyno day that i didnt think that noise sounded right. If you think that you may be loosing some power then get someone to look it over it couldnt hurt as davemack said.

yeah shane one possiblity none of us though of that mechanic bought up is whistling noise sometimes means turbo gasket on the way out.

[shaneth]

fair enough, would still want to get it checked..... did he say it was going or gone.

[DubSteve]

I'd get it checked out, interesting to see the dyno's can make a difference that can be so annoying

[jasn78]

will be getting it check in the next week hopefully.

[Jmac]

Sorry i couldnt make it too would have been good , bit any dyno runs ive been to has had the big fans like some one mentioned, when you are on the road you are not stationary man and when you are on that dyno with no fans the air turbulence is heaps different not to mention the temp, never saw anyone spray their intercoolers either???? Like some have mentioned you need to go through your car especially check hose clamps boost pressure , hook up vag com and check measured values. Codes too. All very important. Temp huge factor here , look run your car in the crisp morning air it is a different vehicle. Sidi by side no car will be the same , check your reading and use it for Your vehicle and dont compare no point , a multitude of things in the mix.
My 2c
Jmac

[ralphk]

yeah shane one possiblity none of us though of that mechanic bought up is whistling noise sometimes means turbo gasket on the way out.

Whistling / sawing sound...gets worse as you go. Turbo bolts / and litlle gasket. I have had this redone a few times now. My car measured 139.5 on the dyno Shane had 88 (stock I understand). This means that my car is putting out 60% more than stock. Probably explains things not holding that well together, guess the car wasn't engineered for this. Blown hoses (or clamps not holding) x 3 now, loose turbo bolts this is now a standard fix up about every 6-7000km...oh yeah forgot to mention blew the diff and gearbox and yep not a cheap repair bill.

From my experience I would only recommend the following mods - Chip/Suspension and brakes - spend the rest on driver training you will probably get more out of it. This is ofcourse unless you have reasonable size pockets.

From memory I read somewhere on this forum that the Polo GTI is not exactly suitable as a track car and if you want a Dyno car then one should probably start with cubic inches, take an SS Commodore strap on a supercharger and voila lots and lots of power.

[Celestine]

Honestly, people really need to reconsider and rethink that dyno readings from the day wasnt 'perfect'. I too believe people need to stop reading so much into those dyno readouts.

Temperature and heatsoak are major factors that have already been pointed out.

Another issue that caused some concern for me is that all cars were being tested in 4th gear. This is sometimes an inaccurate indication as for instance Subaru STI's are dyno'ed in 3rd gear. Just a few too many of these other factors could have caused discrepencies should have been considered.

So people, dont feel down and just 'get over it'. Simpler test is to just put them side by side and go for it