Just got back from the rolling road...

[Robatron]

Guys,

I have just got back from surrey rolling road which is run my a mate of mine, it was a great day out and I saw a couple of nice cars there one of which was a 620BHP Supra that was very impressive.

So after seeing how things were done I decided that I would stick mine on there and see what happens as I have an MTM chip in the car.

I will post up the results as soon as I am in the office on sunday so I can scan it, but I'm afraid it wasnt as high as I had expected. It managed 232.5 BHP and 285ftlbs.

They werent able to measure the boost but they are pretty sure it is boosting very well to achieve the torque figure (at 3500rpm) then for whatever reason just dumping it. I was hoping that maybe if I posted up the data sheet then a few of you could analyse it and tell me where something has gone wrong.

The rolling road is pretty reputable and everyone that was there today either had their figures bang on what they had tuned them to or matched within a few horsepower to their previous rolling road day at another venue.

Another thing to add, I did visit Doug at MRC a few months back where he picked up on a faulty Diverter Valve. This was changed and instead of wastegate chatter there was a very soft sounding discharge of air when lifting off the gas. This has gradually got louder to the point where it sounds like at atmospheric dumpvalve so I wonder if this has anything to do with it?

Any help is much appreciated.

[Greg_S]

Probably worth trying a new DV to see how it performs then

[Robatron]

Is it likely that a diverter valve can deteriorate over a space of a few months? If it is falty I will by all means change it.

Also, when I have the airconditioning on I get a huge cut out (exactly how people describe a boost leak), so I have been thinking that maybe I do have some sort of boost leaks that are more evident when under load. Is this possible?

I think its time for another trip to MRC to see if they can work their magic.

[blown_vr6]

Sounds like a boost leak to me be it leaking around the diverter valve or somewhere else.
Have you not got a boost gauge in the car? - any loss of boost?.

[Robatron]

Well it will become more apparent to some of you after I stick the figures up on here, but basically it is making boost then losing it as the torque surges to 280ftlbs and then drops at 3500rpm.

A couple of S4 owners from rs246.co.uk were there and they said that it seemed completely wrong and the sound of the dumping air was also very wrong.

I hope I get to the bottom of this!

Unfortunatly I dont have a boost gauge fitted in the car.

[dan_b]

Must be a boost leak Rob -have a check to see if there's a loose hose somewhere? Sorry to hear about the low figures

Sounds like also you're no nearer to fixing that aircon fault?

[Robatron]

The only thing I can think of is when my mechanic removed the samco hose from the intercooler, perhaps it wasnt put back on correctly as from that day I started to notice the fault with the aircon...

So I dont know, , I WILL get to the bottom of it eventually!

I'll have a feel around today to see if I can find any loose hoses, if not then I think the quickest way to solve this problem will be a trip to MRC.

[newsh]

I'm thinking a boost leak too, have a look round the short hose near the Throttle body.

[Robatron]

Right, I have been outside attempting to find any loose boost hoses that are visible from the top of the engine and I can't find any.

So I am probably (hopefully) looking at a faulty Divertor Valve or a loose samco hose on the intercooler. Failing that what else could it be?

[LHD_Kid]

Hi,
I had tons of problems with boost leaks etc, the only way to find them is with a proper boost test, using bungs and a compressor...
I am sure a member somewhere near will have a kit you could borrow, but it is really the only way....
HTH
Chris

[newsh]

I've got a kit but Terrybullwon (James) has it at the mo, you're welcome to borrow it or pop down here and we can test it.

[Robatron]

I may well take you up on that one John, but on the condition you tell me what you drink beforehand.

[stevieyid]

Take it to Newsh's car hospital. He sorted mine out for me, Can u feel the loss of power when u are driving?

[1975DCS]

Hi,
I had tons of problems with boost leaks etc

There are probably a ton of threads about boost leaks, so I am not directly replying to this message. But generally speaking: do most leaks occur due to hose failure or due to clamp failure? Or is it just a bad design from Audi? Anyway on some sites and Rally(cross) cars, I see some of those trick clamps. Maybe this wil solve the (clamp) problem?

[newsh]

I would say mostly hose failures through age, I'm running upwards of 360bhp on stock clamps but the old rubber hoses wouldn't take it, new ones might work for a while but you really need Samcos. Its not only the big hoses either, its all the little vacuum hoses too.