From Audi 100 to urS4 in a week

[hunker7]

Just try and get over 4000 rpm in 5th...

I'll give it a shot

[UrS4boy]

... If replacing the clock with a boost gauge was easy, many many UrS owners would have done this ages ago. Truth is I know of one or two that have done it.

Here is one of those who have abandoned the stock gauges (and clock), Hap Maguire (aka, the Hapster, aka UrS4guy on the forums). Looks like he used Autometer Phantom line gauges (same line as the boost gauge I posted (and used to use before the Marshall one))

[hunker7]

That looks superb I think.

[hunker7]

4th gear went over 6k rpm to 110mph. Then went straight into 6th and revs didn't go past 4000 rpm.

[UrS4boy]

4th gear went over 6k rpm to 110mph. Then went straight into 6th and revs didn't go past 4000 rpm.

Well that tells us that the engine itself is capable of getting over 4000 RPM.

6000 RPM with stock-sized 225/50/16 tires and a 1.03 4th = 168.7 kph (104.8 mph) which seems right.

Shifting into a 0.73 6th gear at that speed would be about 4250 RPM. Since peak stock hp is at around 5950 RPM, when you shifted from 6000(ish) RPM (ish) to 6th with RPMs around 4250, you fell back on the HP curve and maybe could not maintain that speed. But that said, it seems like there is TOO MUCH rolling resistance happening. Perhaps under-inflated tires (should be around 32 psig), bad wheel bearings creating drag and/or a brake caliper (or 2) that is sticking on (have you ever felt your wheels (carefully) after a highway run (little or no braking)? A sticky caliper or bad wheel bearing will generate a lot of drag = heat).

[Majorcina]

I had similar problem when my knock sensor died,in 3rd at around 4000rpm it felt like turbo shud down. There was no power coming from the car. I am not sure if this helps you buy it looks similar to me

[hunker7]

Well that tells us that the engine itself is capable of getting over 4000 RPM.

6000 RPM with stock-sized 225/50/16 tires and a 1.03 4th = 168.7 kph (104.8 mph) which seems right.

Shifting into a 0.73 6th gear at that speed would be about 4250 RPM. Since peak stock hp is at around 5950 RPM, when you shifted from 6000(ish) RPM (ish) to 6th with RPMs around 4250, you fell back on the HP curve and maybe could not maintain that speed. But that said, it seems like there is TOO MUCH rolling resistance happening. Perhaps under-inflated tires (should be around 32 psig), bad wheel bearings creating drag and/or a brake caliper (or 2) that is sticking on (have you ever felt your wheels (carefully) after a highway run (little or no braking)? A sticky caliper or bad wheel bearing will generate a lot of drag = heat).

In fifth gear, pushing it very very hard for some time, it goes over 4000rpm.

If it was a wheel bearing it should make some noise if it car create such a big drag. Calipers are fine, as I rebuilt them when I bought the car. Newsh test drove it, and it is sluggish going through rev range. Tyres are not under/over inflated either.

Is there any sensors on the gearbox that could be playing up?

I had similar problem when my knock sensor died,in 3rd at around 4000rpm it felt like turbo shud down. There was no power coming from the car. I am not sure if this helps you buy it looks similar to me

I know what you mean, but there is no shunt it just won't go past. Like a limiter.

[newsh]

Yes, I thought the car was down on power, I wondered if it was blocked cats but I think Janis has looked inside them and they're ok. didn't feel like there was any problem with friction or brakes holding on, in any case they'd have set on fire by now with the amount of motorway miles that have been done. It could be bad fuel pump or blocked filter maybe?

[hunker7]

If there was a fuel deficit wouldn't there be shaking when there isn't enough?

Only thing is this that I noticed couple of days ago, the inlet pipe is squashed

[UrS4boy]

C4 UrS Fuel System: From the Tank to Injectors and Back Again

If there was a fuel deficit wouldn't there be shaking when there isn't enough? Only thing is this that I noticed couple of days ago, the inlet pipe is squashed

Twisted? Mangled? Fk'd up behond all recognition (Fubar'd)?

The good news is you have found your problem.

The bad news is you have to fix it. (and you need that double-flared end). Why is a 17 mm socket involved?

C4 UrS Fuel System: From the Tank to Injectors and Back Again:

http://forums.quattroworld.com/s4s6/msgs/226410.phtml

[hunker7]

Not f'ed up completely. It is twisted though. ill see if I can get it sorted 17mm socket was involved because I was trying to take it apart,unsuccessfully.

[UrS4boy]

Not f'ed up completely. It is twisted though. ill see if I can get it sorted 17mm socket was involved because I was trying to take it apart,unsuccessfully.

NO. It is completely Fk'd man. This is your problem: fuel restriction under high demand.

Re-check my post. I edited it to include a photo and a link.

[hunker7]

Thanks, I'll see what I can do why doesn't it shake when there isn't enough fuel?

[newsh]

It will go lean, knock and the ecu will retard ignition and try to add more fuel, it will basically just hold back.

[macspring]

You're blessed that it is as 'simple' as this, the car should be much improved once you resolve this.

Looking forward to your post after it's fixed.