Disappointing Dyno Result

[Sonic]

I've owned the car now for over 3 years, and in that time i've done quite a few mods!

Back in 2007 i had the car dyno'd as the Weston Performance meet. The car was completely stock besides a milltek cat-back, and it produced 246 flywheel bhp and 272ft/lb torque.

I've just had the car dyno'd today, complete with many mods including RS2 airbox, wagner intercooler, reverse inlet manifold, milltek turbo-back exhaust and v-stream homefry, at a local place which has the same dyno as Weston.

In v-stream mode the run made 231 flywheel hp and 256ft/lb torque, n-stream mode made 234hp and 251ft/lb torque.

I'll post up hp/boost, hp/torque and hp/lambda graphs in a minute along with a video of the run, but it's clear there's a problem.

Gutted. Absolutely gutted

[Error404]

have you checked the usual sensor connections, WGFV and done a boost leak test etc mate?

[Dan]

Damn, that sucks.

What does it feel like to drive? compared to when you got it?

[UrS4boy]

It might have been the same brand dyno (aka "rolling road") but that means nothing. The calibration of these same brand dynos has to be identical to achieve comparible wheel horsepower results. Even then, on a cooler day, you will may more hp than on the exact same dyno on a warmer day. And then there is fuel, 95 RON? 98 RON? And don't even start on what one dyno operator enters as the correction factor between wheel horsepower (what the dyno measures) and crankhorse power. This is the source of endless (and pointless) banter on many internet car forums ("My dyno results are better than your dyno results") :corey::corey:

Bottomline: You are not comparing apples and apples with these two different dynos/times/weather/operators. Therefore don't get too upset.

[s2_bo]

Sounds like a boost leak to me.....
Good news is that as soon as you fix it it will be like a new car again

[Dingo]

Tis true that all dyno's give different results, but you must have a problem as thats well down, I run V stream too and see around 300, last time I had a prob I took it to the same RR and I had lost 25-30 hp and I knew it wasnt running right, it turned out to be a bad maf conection, hope you sort it soon.

[Rusty]

AFR graphs would be useful, below 10 is a sure sign of leaking boost. Should be between 11 and 12 on Paul's chips, perhaps dropping to 10.5 up top IIRC.

You'll get it fixed mate, it'll be something simple. Get a boost leak test kit and do the whole system, onyl way to check the vacuum lines etc. out.

[s2_bo]

I have a mitivac tool which is great for checking vac lines.
If you need to borrow one i could send it up to you.

[EspenW]

Are you sure you weren't quoted whp (actually measured) and not crank hp (guesstimated)?
A quattro car with approx. 300hp at the flywheel will yield approx your numbers as wheel horsepower (as measured by a Mustang or Dyno Dynamics dyno (what Weston uses))
Post your graphs from the old and new dyno pulls

[Rocco]

Andy,do you have a boost gauge in the car??

check everything, but if you think that it pulls hard ,dont trust in the rollers¡¡

look my car...... in one month i was in 3 different rollers. the first one did 307cv with 455nm ¡¡

in the second 334cv and 505nm

and in the third......... 395cv with 644nm


with the same parts of course

[EspenW]

Andy,do you have a boost gauge in the car??

check everything, but if you think that it pulls hard ,dont trust in the rollers¡¡

look my car...... in one month i was in 3 different rollers. the first one did 307cv with 455nm ¡¡

in the second 334cv and 505nm

and in the third......... 395cv with 644nm


with the same parts of course

That is nuts, but not surprising....

[EspenW]

Instead of wasting time and money on dyno runs (except when mapping), get a Racelogic Performance Box and measure in gear acceleration like 60-90mph instead.
Alternatively, just use Vagcom and log the time it takes from 4200rpm to 6500rpm in 3rd gear. Even the £10 vagcom copies will do this just fine. This is the so called FATS test that is extensively used by the B5 crowd. Very accurate, repeatable and costs nothing. In addition, a huge database of times exists, so it is easy to judge performance level.

[Ross]

Spoke to Andy about this earlier, suggested cleaning all connections and checking for leaks - peak boost was ~1.1bar so definitely not right!

There was a scooby on the dyno that ran 250, as it ran similar figured at his last run that's a pretty good benchmark. The car is definitely down ~50bhp and the same in ft/lbs I'd say...

There is a known coolant leak so my suggestion is get that checked - hopefully it's the HG - sort it all out and make sure it's airtight, no codes etc when put back together make sure it's seeing a solid 1.4bar and get it back on the dyno.

[Rusty]

Altitude sensor perhaps.

[LHD_Kid]

Or, maybe knock sensor(s) ?