Dyno done today

That is brilliant... kudos to you.

One question, I have noted on my dyno that my AFR gets lean around 4800 rpm (just dips below 12.5), and also realised that peak power starts to come down from 127.3kw then picks up slightly at the same RPM.

I am getting my REVO dealer to get AFR fixed next week. The AFR goes as low as 11.9 which I don't like much. If I can fix all that to keep AFR of 12.5 throughout the rev range, does that mean I can possibly see some increase in power as well?

Co-incidentally power dips at exact same RPM as AFR starts to get mildly lean.

I need to show the graph, but the site wouldn't let me upload it...

(edit - managed to upload it! woop! - as you can see as AFR slightly improves, the power peaks again slightly... at higher rpm)

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Originally Posted by Sharkie

With a run temp of 32 degrees I was very happy with 139.6 and can probably expect another 2-3kw on a cooler day.

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Good results Sharkie. I hope you've now come to realise that there aren't absolute certainties for what mods equal what power, eg FMIC + DP = xxx kw atw. You're also insinuating that you should have hit well into the 140s. I hit into the 140s with more mods than you yet my results were always dismissed as inaccurate. It seems the dynos you guys use are unquestionably accurate but dynos that anyone else uses aren't.

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Originally Posted by GT3

It seems the dynos you guys use are unquestionably accurate but dynos that anyone else uses aren't.

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On this day we had 3 Polo's on the dyno under the same conditions. I only question dyno results done on their own with nothing to compare against under the same conditions. Previously we had 5 Polo's on at the same day and under the same conditions.

Any single figure provided will always be questionable. To remove any possible question, go to a dyno day and test with a few other Polo's under the same conditions.

I'm not saying this dyno is 100% accurate, but it is the 1 used by APR for all development work. It delivers consistent repeatable results. And according to APR under their extensive testing, they have achieved certain benchmarks. For instance:

APR ECU, APR FMIC & APR Full exhaust = 135-140kw atw
APR ECU, APR FMIC, APR Full exhaust & K04 = 151kw atw
APR ECU, APR FMIC, APR Full exhaust & K04 on race program = 160kw atw

anybody with APR ECU, APR FMIC & APR Full exhaust claiming (in isolation with no comparison on the day and conditions) more than 140kw atw have suspect figures. Not the cars fault, more likely the dyno setup.

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Originally Posted by Sharkie

anybody with APR ECU, APR FMIC & APR Full exhaust claiming (in isolation with no comparison on the day and conditions) more than 140kw atw have suspect figures. Not the cars fault, more likely the dyno setup.

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That logic would carry some weight if I hit 140+ only once. During development and testing, my car hit 140+ repeatedly on different days, different conditons, over and over. That's the true test for the validity and reliability of results, whether they can be consistently repeated, while still allowing for some degree of error.You've claimed you should be hitting 140+ based on the isolated conditions of a dyno day. First you need to hit 140+, then repeat it on different days, different conditions before you can claim that only your car is capable of 140+

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Originally Posted by insanekiwi

That is brilliant... kudos to you.

One question, I have noted on my dyno that my AFR gets lean around 4800 rpm (just dips below 12.5), and also realised that peak power starts to come down from 127.3kw then picks up slightly at the same RPM.

I am getting my REVO dealer to get AFR fixed next week. The AFR goes as low as 11.9 which I don't like much. If I can fix all that to keep AFR of 12.5 throughout the rev range, does that mean I can possibly see some increase in power as well?

Co-incidentally power dips at exact same RPM as AFR starts to get mildly lean.

I need to show the graph, but the site wouldn't let me upload it...

(edit - managed to upload it! woop! - as you can see as AFR slightly improves, the power peaks again slightly... at higher rpm)

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Air/Fuel ratio of 11.9 is actually quite rich... stoichiometric is something like 14.7:1.

Lean > 14.7
Rich < 14.7

I wouldn't worry at all about 11.9, thats well within normal for turbo cars.

I think dynos have been done to death.

My personal view is they are good tuning tool, in that they allow you to see the deltas associated with various mods -- the main thing is to keep going back to the same dyno, and operator, but you'll need to assume there are variances associated with environment (which most dynos seek to nomalise), operator, mechanical (tie down etc), tyres and pressures, etc, etc. There's possibly around +/- 5% variation due to these.

Measuring and comparing absolute power figures from different dynos, at different locations on different days is totally pointless, as the variance affects above are multiplied....hence the confidence levels are lower and experts on the interweb become totally sceptical :biggrin:

That said, nothing I've written above will stop people from engaging in these debates from time to time...but let's just not fool ourselves into believing "the truth" is out there :duh:

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Originally Posted by Timbo

I think dynos have been done to death.

My personal view is they are good tuning tool, in that they allow you to see the deltas associated with various mods -- the main thing is to keep going back to the same dyno, and operator, but you'll need to assume there are variances associated with environment (which most dynos seek to nomalise), operator, mechanical (tie down etc), tyres and pressures, etc, etc. There's possibly around +/- 5% variation due to these.

Measuring and comparing absolute power figures from different dynos, at different locations on different days is totally pointless, as the variance affects above are multiplied....hence the confidence levels are lower and experts on the interweb become totally sceptical :biggrin:

That said, nothing I've written above will stop people from engaging in these debates from time to time...but let's just not fool ourselves into believing "the truth" is out there :duh:

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Thats it buddy.

They're a diagnostic and development tool; not a time pervasive benchmark!

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Originally Posted by xtturbo

Air/Fuel ratio of 11.9 is actually quite rich... stoichiometric is something like 14.7:1.

Lean > 14.7
Rich < 14.7

I wouldn't worry at all about 11.9, thats well within normal for turbo cars.

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12 is more like it.

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Originally Posted by Kai

12 is more like it.

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Yeah, that's what I was thinking, mine was around 14.7 at about 500rpm, was 12ish for 90% of the rev range.