Dyno results....any ideas?

[s2driveruk]

I had these done last year at ADI and meant to post them up but life got in the way...

Anyway, looking at others, they dont look quite right....can anyone help in the diagnosis?

Setup was:
ABY airbox with normal filter
Homefry
S/S cat back exhaust with single box - 2x2.5in off the cats. cats in situ (not for too much longer I hope!)
18inch alloys

Ambient temperature was quite high but not massively so and peak torque is pretty healthy still, just the plots not as linear as i'd expect....?

Thanks,
David








Run 1 AFRs


Run 2 AFRs

[Rusty]

Your AFRs are out indicating one of the following to me:-

Boost leak
Poor spark plugs
Other elecrical gremline / ECU fault code.

Boost leak test with some new plugs and getting the codes read should get things back on track.

Is there a hesitation when accelerating?

[gnutz2]

Wow thats pig rich after 4k.

looks like you have a boost leak.

[Rusty]

David, if you compare yours with my 273 run at Combe a while ago there are good similarities. I had a small boost leak, not enough to cause the car to cut out but plenty to cause issues.





This is one of the reasons I want a WB O2 so that I can monitor WOT AFRs without the need to go to a RR every time...

[s2driveruk]

Thanks guys, yeah I get the very ocasional stutter but its not constant, took it out this morning and it pulls sweetly through the entire range. Will have to check everything again when it drys up.

[K7ERG]

Why did they run your car in 3rd gear? Usually 4th on Dastek rollers.

Craig

[Acidburn]

Because we got told its normally 3rd for a 5 speed and 4th for a 6 speed.

Its been discussed on the forum before and agreed on.

[K7ERG]

Ok. Most of the runs i have seen have been in 4th gear on Dastek rollers. Well apart from Autos.

[Rusty]

Stutter can be a sign of the Lambada sensor. Not directly related to the WOT running but I found that the ECU fault code did cause poor running on WOT and the lambada sensor corrected that. Looks like you wnat a lambda, plugs, leads? boost leak test and some Tesco 99 and you'll be there

Get it checked at the VAG day by Paul at Circuit Motors.

[EspenW]

Rule of thumb is always to dyno in 4th, (or the gear that is closest to 1:1).
The higher the gear, the lower the loss to inertia, but the higher the loss to rolling friction, and the possibility for heat soak.
4th gear lets the turbo spool, and speed on the rollers isn't as high as in 5th (and 6th).
In this case, 4th gear would show higher numbers for both power and torque, especially torque, since that occurs at lower rpm and suffers the most from turbo spooling late in the low gears.

[s2driveruk]

Stutter can be a sign of the Lambada sensor. Not directly related to the WOT running but I found that the ECU fault code did cause poor running on WOT and the lambada sensor corrected that. Looks like you wnat a lambda, plugs, leads? boost leak test and some Tesco 99 and you'll be there

Get it checked at the VAG day by Paul at Circuit Motors.

Lambda is reasonably recent, definately well inside 30k miles
Leads all looked ok but they are probably due a refresh after 183k miles
Sparks could do with a refresh and they are sat on the shelf in the garage so will drop those in to rule out
Always runs on Tesco 99
I think I am going to be chasing down a boost leak to sort this out but replaced all clips and small gauge hoses/vac pipes when it was in pieces last summer. Hopefully I'll nail it quickly, cheers for the pointers all.

David