Getting the S3 RR'd

[Hadders]

Hi chaps,

I'm due to go to a RR day on Saturday with another forum, but the guy who runs it says he had problems running the last S3 on his rollers. Now I know you can remove the Haldex fuse and get it done in fwd only so I have a couple of questions.

a) Which fuse?

b) When the result comes through, I'm guessing that some sort of calculation needs to be made to work out the true figures? This is on the understanding that the Haldex still routes the power but the Haldex clutch simply doesn't engage due to the fuse removal thus the power at the front wheels only isn't 100%?

Cheers peeps :thumbsup:

 

[Westy]

The fuse panel/owners manual should tell you which fuse is the haldex controller fuse.

With the fuse pulled the haldex controller wont engage the rear wheels. The RR should be able to give you a caculation of power at the flywheel and at the wheels.

 

[Hadders]

The fuse panel/owners manual should tell you which fuse is the haldex controller fuse.

With the fuse pulled the haldex controller wont engage the rear wheels. The RR should be able to give you a caculation of power at the flywheel and at the wheels.

Cheers mate. I was being lazy as the manual is in the car and I am at work and only just got the news about the RR having the trouble. I'll take a look later for that.

With regards to the disengaging of the unit though, I was under the impression that running in 2wd didn't give terribly accurate readings as part of the Haldex would still work even with the fuse removed, it was simply the Haldex clutch wouldn't engage? Am I completely wrong with this?

 

[Westy]

Unfortunately the only way to get a more accurate figure would be on a 4WD RR. I'm going to Bill's on Saturday for a RR and that is only 2WD too.

You are right. All the prop and gubbins will still be turning but the haldex wont engage the clutch to move the rear wheels, there's no other way to do it though.

 

[Hadders]

Unfortunately the only way to get a more accurate figure would be on a 4WD RR. I'm going to Bill's on Saturday for a RR and that is only 2WD too.

You are right. All the prop and gubbins will still be turning but the haldex wont engage the clutch to move the rear wheels, there's no other way to do it though.

It's a shame really as the RR I'm going to is 4WD but this wouldn't be the first time I've been to a RR day and they've said they can't run Haldex v1 systems in 4WD. I'm guessing there's no magic number to multiply it by to get a close result, otherwise I'm looking at getting a really low figure that won't be a true representation of what it's running at? There's little point in me running if that's the case

 

[s3dave]

The haldex gives a jerky line as it keeps coming on then off, 2wd with the fuse pulled is fine

 

[Hadders]

I guess I'll have to invest in a HPP at some point instead

 

[<tuffty/>]

There is no accuracy issue, S3's run in 2wd unless required anyway... a decent dyno will measure coastdown losses which will give you your flywheel figure... (subject to dyno lottery of course)... you are not in 4wd on coast down regardless of road or dyno so losses will be the same...

Running haldex connected on some 4wd dynos can cause jittery results as the controller is trying to combat wheelspin by varying the torque going to the rear wheels..

Never had any issue with running mine on a 2wd dyno, Welly's S3 is prob the most dyno'd S3 I know next to mine... lol... that did ok bhp wise :thumbsup:

<tuffty/>

 

[Hadders]

There is no accuracy issue, S3's run in 2wd unless required anyway... a decent dyno will measure coastdown losses which will give you your flywheel figure... (subject to dyno lottery of course)... you are not in 4wd on coast down regardless of road or dyno so losses will be the same...

Running haldex connected on some 4wd dynos can cause jittery results as the controller is trying to combat wheelspin by varying the torque going to the rear wheels..

Never had any issue with running mine on a 2wd dyno, Welly's S3 is prob the most dyno'd S3 I know next to mine... lol... that did ok bhp wise :thumbsup:

<tuffty/>

Fair enough. Well if we have trouble running in 4WD (which it sounds like it will) I'll just run in 2WD instead. Thanks for the info guys.

 

[superkarl]

Fuse 31 if I remember correctly

 

[badger5]

Hi chaps,

I'm due to go to a RR day on Saturday with another forum, but the guy who runs it says he had problems running the last S3 on his rollers. Now I know you can remove the Haldex fuse and get it done in fwd only so I have a couple of questions.

a) Which fuse?

b) When the result comes through, I'm guessing that some sort of calculation needs to be made to work out the true figures? This is on the understanding that the Haldex still routes the power but the Haldex clutch simply doesn't engage due to the fuse removal thus the power at the front wheels only isn't 100%?

Cheers peeps :thumbsup:

where are you going and what make of dyno is it?

 

[Hadders]

Taking it to Euro Spec in Guildford. They have a Dyno Dynamics 450DS apparently. They're Jap specialists but we have a right old mix of stuff running on the day

 

[badger5]

oh dear.. Dyno dynamics
brace yourself for low figures

 

[DJ_Troopa]

I thought Dyno Dynamics were 1 of the best rollers out there? Torque of the Devil is just around the corner from my work place and they're packed with big performance cars all the time so their rollers can't be bad?

 

[badger5]

I thought Dyno Dynamics were 1 of the best rollers out there? Torque of the Devil is just around the corner from my work place and they're packed with big performance cars all the time so their rollers can't be bad?

DD would have you believe this yes.
Not the case tho.. and I do not like these dyno's personally at all. They only measure atw figures and "add" a figure to get the flywheel figure.. They do not do coastdown losses to determin the fly figure, just adding a % type factor which to me is pretty abysmal.

Expect lower figures on DD rollers.
They call it the heart breaker.. I call it unrealistic personally.

enjoy the day tho.. all measurements relative to others on the day should be a laff. Just dont get too hooked up in the figures game. Its endless and fruitless.
check your print outs for the rpm range being realistic to your cars actual rpm, as I have seen several DD plots which showed cars "apparently" revving to 8500rpm when they had a 7200rpm rev limit. Shoddy setup by the dyno operator in those examples, whilst they try and ******* thru as many cars as quick as they can, and not neccessarily as thoroughly as they should!

 

[Hadders]

Cheers for the info :thumbsup:

I'm primarily going to experience the whole day. I wasn't going to get too hung up on numbers to be honest. I'll certainly let you know what happens anyway!

 

[badger5]

good luck. be open minded.. and enjoy..
make sure its tyres are properly inflated and its fluid levels are correct.