UrS4 2.2T Avant project

[diesel des]

Man your pumps must use lots of power. Do you use a seperate fuse and relay for each pump? If not it might spread the load better?

[macspring]

but when got more torque the cut out appeared.

Obviously the engine uses more petrol to give that torque which was requires more effort from the two pumps, which is this case was too much effort / electrical draw demanded by the two pumps.

Good idea suggesting the separation of the wiring, ( and possibly also the plumbing ), of the pumps for fault tracing, and replacement or upgrardes in the future.

Good that the fault was found and was as 'easy' as it was to fix. Hate to see any frivolous fault stopping progress on this 'old spare parts' engine.

[Thuppu]

I'm using only one 80A relay for all pumps(2x044+1x255lph) but separate fuses. One 40A for the 044's, and a 20A for the single 255lph. I could put a own relay for the Walbro and a better fuse box with bigger fuse for the 044's. I wan't to have both 044's behind the same fuse so they both stops if it burns. It could be quite dangerous at WOT if only the other pump drops off.

[macspring]

I wan't to have both 044's behind the same fuse so they both stops if it burns. It could be quite dangerous at WOT if only the other pump drops off.

Agreed, you're right.

That's why your doing what you're doing and I'm not.

LOL.

[Acki]

Measure the voltage at your pumps. Maybe you wiring is to thin.

[Thuppu]

Aaahahaaa... Guess what was back when I drove home yesturday evening?

Now I bought a heavy duty 100/180A relay and a midi fusebox, both with bolt connectors. Still have to get som hard core wiring... So simpple thing can be so hard.

[Rikki Kitto]

Earplugs and fire extinguisher !

Exactly

[Thuppu]

Still trying to resolve the cut out issue. Seems like the fault must be in VEMS output(p259 chip)..?

I did a simpple diagram of the twincharge setup:

[diesel des]

Nice sketch. Helps a lot!

[Thuppu]

The cut out issue seems to be VEMS output failing. I did unplug the stock J17 fuel pump relay, put 12V in the 87A and 87F output terminals, and did a few test runs. No issues what so ever. So I'll guess the VEMS P259 output is the trouble here.

Here is a log file. The IAT/MAT temp rised up to 56C degrees. The boost seems to taper down on higher rpms. Don't remember how it was before, it feels lamer in the top end, but i'm not sure. Any thoughts of the log?

[diesel des]

I still think that driving the supercharger even with no pressure on each side will cause drag and heat. It's still pumping air.

Could you try a drive with the belt not driving the supercharger and a shorter belt driving the alternator. Then look at inlet temperature boost and power up top.

Maybe the inlet valve at the turbo inlet is causing the turbo a restriction. Have you tried measuring pressure and temperature there?

[Thuppu]

Of course it will, espeasilly when revving it to overdrive 18000+rpm, but not close to what it would be against pressure. Nothing comes for free. 56C isn't bad temps with e85. Havn't mesured anything, but I have been thinking about the valve. Airflow wise it isn't the best design. I have done a inlet cone for the valve that I will weld on. In the other hand, I propably don't need to rev up to 8000rpm when the usable curve starts from 2000rpm. But I wan't to try on dyno how it goes, what the figures look like. I will also swap to bigger turbo when I go on dyno...

[diesel des]

Thomas before you change anything measure pressure and temperature at the turbo inlet/check valve setup. Fitting a bigger turbo or different inlet check valve may reduce performance if there are other issues. Figure out what's going on now and move from there. It's not hard to measure these things and try removing a belt.

Cheers des

[diesel des]

Don't spend money and time that isn't required.

[Thuppu]

Small vid of the one-way valve action.

https://www.youtube.com/watch?v=7hT_F-KeJDM