Best place for remap and what to go for

[jaysrs4]

You've not had it that long is that correct?

I've had mine 3 months and I'm still not used to it! I think many would agree a standard RS4 is quick enough for UK roads and yours sounds like its been worked over by MRC - you must be used to some quick motors

[Jamiestanton]

Last two cars 2009 golf gti apr k03 upgrade 344 bhp and ford focus rs 382bhp my mate has the focus and it beats this rs4 the only way I beat him is when I launch from stand still I though these cars was faster last owner says this one is 450bhp

[jaysrs4]

Humm, okay - you've answered my question nicely

Surely its not just about power? An RS4 absolutely destroys both cars you mention in every other department - including in standard factory tune.

[lengster1]

You will get a belch of smoke the first time you rev it through the range after warming it up,this is normal it would seem with de cat,in 2009 they couldn't undue the power restriction in the first three gears,ive had both I know,suggest you go get the latest proper map,460 is possible with all mods done,a well tuned focus of the lights might be similar but you should kill it in every other driving situation and speed area,throw in a spot of dampness and serious tadda,stock RS4s with the power/torque reduction are frankly gutless at everyday driving speeds.

[Jamiestanton]

Humm, okay - you've answered my question nicely

Surely its not just about power? An RS4 absolutely destroys both cars you mention in every other department - including in standard factory tune.

Yeh defo I love the rs4 I just want a bit more power

[TonyHayers]

I'm currently running my gutted precats without a remap and without any issues. I've got a CEL which comes up after 50 odd miles, but it doesn't seem to affect anything else.

It's only a temporary situation til I get a remap (new oil cooler hit my budget at the wrong time).

[lengster1]

The CEL warning light isnt an issue? or the fact your fuelling is all over the shot especially when cold? You could be suffering bore wash etc etc sure the car will run but....the origonal design is for the pre cats to warm quickly and readings are taken from the both sets of lambda probes,you remove the pre cats and youve changed the whole way the system calculates engine temp and fuel requirements,sure it will run but to say without issues! Rather your motor than mine and i certainly wouldnt be doin it for long or driving it hard.

[lengster1]

When its properly mapped one set of lambdas are deleted from input into the ecu as there not accurate when stock cats arent being used.

[TonyHayers]

The CEL warning light isnt an issue? or the fact your fuelling is all over the shot especially when cold? You could be suffering bore wash etc etc sure the car will run but....the origonal design is for the pre cats to warm quickly and readings are taken from the both sets of lambda probes,you remove the pre cats and youve changed the whole way the system calculates engine temp and fuel requirements,sure it will run but to say without issues! Rather your motor than mine and i certainly wouldnt be doin it for long or driving it hard.

AFAIK the first, pre-cat sensor actually does the lambda testing/feedback to set fuel mixtures and the second one is there effectively for diagnostic purposes (making sure the first one is working properly). Car is idling fine the same as it was and is driving the same as it was. Of course, I appreciate that's not a perfect test, but there certainly aren't the normal tell-tale signs of a knackered lambda sensor.

Discussed with grizz before they fitted them and he said it would be fine but that I'd get a nagging CEL.

[TonyHayers]

Quick update: I did a VCDS scan and just to confirm the DTC is just a "catalyst efficiency" error which is triggering the Emissions Control System warning indicator. AFAICT that doesn't affect any fuelling. I reset it again, just in case.