UR 10 Valve Engine

[s4boy]

Iknow you all run 20 valves, but I love the sound my UR makes with its MB 10 Valve in. Got the car in March 2011, and its engine was rebuilt 30,000miles ago, so I'm wondering if any one has any mods, turbo, cams etc I can do to up the BHP, not looking for race car performance just a bit more go. Plan is to start mods in Oct due to time / work commitments. So looking for ideas guys.........Cheers Mark..

[tommyboy]

Good full on service with the best oil's plug's,belts,fluids etc that you can get.
Check all piping for any leaks or split's.Check compression (all to make sure your engine's healthy beforehand)
Possible port and polish the head slightly.
Look into EFI fuel injection and bin the k-jet system (possible the biggest limiting factor in 10 valve engine if all is running Perfect)
What exhaust you got?...Can you de-cat a 10 valve so to speak.
new air filter possible K+N i think still do them.
think shrick do some cam's "272" or "282" if i remember correctly. Rather lumpy low down i have heard.

Some one more knowledgeable will let you know on the in depth.

[s4boy]

Cheers TommyBoy, also looking at turbo swaps if possible, car has a Scorpion stainless sysem and dialynx ex manifold on at present.

[tommyboy]

I am lead to believe the current turbo for the WR is more than adequate for up to 80 hp more over standard.EFI is probable the best route to go once all checks and your engine is running well.Port and polish the head.lightweight flywheel is another avenue to look down.

unsure if there are uprated spark plugs to go with.

Whatever you do..Do not do the zener diode mod and wind the spring . . cheap cheerful and broken at it's worse.

[prj]

Agreed, first step is to get some sort of tuneable EFI system...
There are not really any plug and play options. The non-pnp VEMS might be a good idea for a reasonable price.

[newsh]

You can convert to Motronic, quite a few people have done this.

As far as K-Jetronic goes, I've been running a Treser conversion WR for many years, it has all the Treser stuff, ported, cam, big valves, big fuel metering head etc. and a big spring (you need one with the porting as the pressure drops), a K26 hybrid and a modded ECU which allows it to run 1Bar of boost without cutting the fuel off, the Hitachi ECU cannot calculate ignition for any more than 1Bar so no point trying.

But first off make sure its healthy, most aren't. Make sure all the small vac pipes are good and the Fuel Pressure Reg is working and the Full Throttle enrichment is working, switch on Throttle Body operates a vacuum valve which applies boost pressure to the FPR, the diaphagm inside the FPR needs to be in good condition for the enrichment to work. Without this working the motor will run lean at full throttle and pink a lot.

[prj]

Why bother converting to Motronic when it will cost about the same amount of time & effort to convert to VEMS?
Motronic would need a lot of mapping to run right anyway, might as well install VEMS...

You know, I usually don't say these things, but as much as I like Motronic, everything has it's place, and while it is possible to do whatever given enough time and effort, I'd say it would not be the optimal solution

[newsh]

Hmm, a surprising post for you PRJ.

Pete Berry at White Cottage Quattros has done a few 10v UR Motronic conversions I believe, but yes, VEMS might be simpler, I don't have any experience there. Pete has also a done porting and a big valve conversion on my car to replace the original Treser head which had seen its day and supplied and fitted a hybrid turbo.

[20Vcqdriver]

what kind of power you looking at?
Friend with a WR is more than happy with his very near 300bhp using EFi and a ported head and I think different wastegate spring. If you want more then its change turbo time plus other limiting parts such as intercooler, exhaust manifold and system, though be careful about which cam you swap with as turbos do not like a lot of overlap I have been told...

[s4boy]

Cheers for the help so far, in reply to 20vcqdriver, I would be very happy with 300bhp, as at present when I drive the UR after the S4 (4.2 n/a) it feels
slow, so I just want to rasie bhp up towards the 300 or 300 if possible to make the car feel quicker than it currently is. So any ideas greatfully accepted.

[Gazjen]

You've got to be careful with the MB its quite a complicated set up for mechanical fuel injection unless you are going down the EFI route

it should be as quick as 4.2 s4 straight out the box so I would suggest getting it checked out by white cottage or phil payne to make sure its running properly to start with. You will probably find its not quite on form.

When I brought my UR (now on 20V power) I thought it was quick but a XR4i beat me that prompted a visit to Phil Payne and dare I say Corey Jones. It came back a lot quicker.

And then I swapped it to 20V, I do miss the sound of the 10V though

[s4boy]

Cheers guys really good advice and plenty for me to think about for now.........cheers mark

[Phil Payne]

I am lead to believe the current turbo for the WR ...

OP says it's an MB.

If so, first thing to do is pull codes and check the WoT switch. Then check with a diode light to see if the wastegate frequency valve is operating correctly.

[Phil Payne]

.. switch on Throttle Body operates a vacuum valve which applies boost pressure to the FPR, ...

Not on an MB - enrichment is driven by a duty cycle change to the fuel frequencyy valve.