Remap of an Audi with a DPF?

spwilki

New member
Points
26
Location
United Kingdom
Car
A4 2.0 Tdi quattro
Hi all. Just recently joined the site and am after a bit of advice/
I've not long bought an Audi A4 (07) 2.0 tdi quattro 170. It's an ex company car and I've had it serviced and a bit of work to sort out the obvious problems (EGR pipe and valve had been damaged due to a fire under the car, which I had replaced). I've come from a 55 plate BMW 320d and I find the Audi a bit 'weak' in the lower rev range, especially in 1st and 2nd gear.
I've approached a Bosch tuning garage for an ECU remap and he says that they can't remap the car. Not a 100% sure why, but I think it was something to do with the DPF and that the engine doesn't take well to a remap. I've been looking at other tuning companies online and they claim to be able to conduct the remap.
Does anyone know if I'm on a hiding to nothing with this or if the engine will take a particular remap without causing me any future problems
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
Celtic Tuning did my 2001 Peugeot 406 2.2 HDi and this presented no DPF problems at all. However, my car had the earlier style DPF which used a fuel borne catalyst to assist in the regeneration phase of the DPF. Celtic claims to be able to deal with Euro IV and Euro V compliant diesels so I seriously suggest giving them a call.

I also suggest that you totally avoid tuning boxes.
 

spwilki

New member
Points
26
Location
United Kingdom
Car
A4 2.0 Tdi quattro
Many thanks Jarrus.
Just a quick one for anyone out there with regards this. I've been looking into getting the DPF removed, but are there any disadvantages of having this done? Is it just another exhaust gas filter for recirculation? I've looked at a couple of straight through pipes but will it make my car higher on emissions or can I get this sorted on the remap?
Looking further would you recommend an enhanced air delivery parts. One of my friends has mentioned a K&N induction kit (?) but I don't know how this would improve performance, is it just about the engine 'breathing'?
I'm not really a 'petrol or diesel head' but once I've got the engine up to speed (remap) what can I look at next. I don't want to change the exterior of the car, I'd just like that extra bit of boost through the gears.
Any input gratefully received.
Cheers to all for the advice so far.
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
The DPF is in the exhaust and mounted directly upstream of the catalytic converter. Removing it will cause the car to be very sooty and smoky under acceleration. In all probability it'll fail the MoT emissions test as well.

Personally I'd leave it in place and let Celtic map around the DPF regeneration requriements. Remapped diesels often re-generate more readily than standard cars due to the higher exhaust gas temperatures. This translates directly into quicker burn-off for the accumulated soot particles.

Induction kits probably aren't as useful in the diesel world due to the relatively low revs at which the engines operate. Also, with a DPF, the regeneration will be compromised because during the regen phase the ECU does all sorts of tricks to increase combustion temperature. This includes bypassing the intercooler and drawing in hot air only.

You'll probably find the induction noise quite irritating with an aftermarket kit. Diesel engines have no throttle so it'll be taking great big gulps of air all the time.
 

jarrus

Pro Tuner
Points
337
Location
West Midlands, UK
Car
Suzuki Swift Sport
DPF removal may not cause an MOT failure, but as said the amount of soot coming from the exhaust will increase even on a standard engine and on a remapped engine even more so, I would say that the best thing to do is to ask celtic there advise and go from there, but if it was me personally I would remove it, for several reasons if possible but if removing it will cause a MOT failure then again I would personally leave it, I dont believe in driving a car around a car on the public highway thats technically illegal, you could put it back in for the mot then remove it but thats what i dont believe in, if it needs to have it for the MOT then it should be used all the time, same goes for cats on diesels and petrols, there are many people on the roads thay do this, remove the cat completely then only put it back for mot day, IF IT NEEDS IT THEN IT SHOULD BE THEIR ALL THE TIME!!! My car had a cat from the factory and i removed it but i dont need one for the mot so my car is road legal.... But the new MOT regs may mean i need to retro fit one now but such is life, ill get a hoffman 100 cell cat...

Sorry for the rant....
 

jarrus

Pro Tuner
Points
337
Location
West Midlands, UK
Car
Suzuki Swift Sport
as for induction kits... They are highly subjective, it totally depends if your standard system is up to the job,

From what ive seen audis and vws or anything vag for that matter does tend to suffer in this department, the place to concentrate on is the pipe work from thr front of the car to the airbox (called a front pipe) cotton or foam drop in filters are a waste of time and money as there is very little extra airflow to be gained and probably accounts for only about 2% of the total restriction
 

jarrus

Pro Tuner
Points
337
Location
West Midlands, UK
Car
Suzuki Swift Sport
use larger pipework and less bend and pipe work thats smooth inside, you could probably get something together for 1/4 of the price of an induction and will probably do a better job,
 

jarrus

Pro Tuner
Points
337
Location
West Midlands, UK
Car
Suzuki Swift Sport
The smoke is part of the fun, lets everyone know you're driving a diesel, not too much though else the plod will be asking questions

Diesel engines are funnys things in comparison to petrols.....

For example most diesels from the factory have there air fuel ratio very very lean (under full load all the other times its even leaner) 19:1 - 20:1 seems the norm and most remapper richen that up to 18:1 under full acceleration, some to 16:1 for big power applications but even those figures are technically lean,

Believe it or not diesel stoichiometric air fuel ratio is 14.6:1 but at this air fuel ratio the engine would churn out loads of black smoke but make a big amount of power
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
The beauty of a diesel engine is that the air:fuel ratio is not crucial for engine operation. No throttle, no pumping losses etc etc. A diesel engine can run as lean as you like.
 

spwilki

New member
Points
26
Location
United Kingdom
Car
A4 2.0 Tdi quattro
Many thanks again Jarrus and HDI fun.
Few things to take on board. I'm totally with you (it wasn't a rant!) with regards having the car legal at all times. I want to enjoy it and not cause anybody else any dramas in the process (bit of smoke if its being given a 'boost' is not necessarily gonna cause people that much of a headache).
Been in touch with celtic and they've sent me out a pretty comprehensive email detailing what I'll get out of it. Phoned them today and they've given me a chat through as well as a quote.
Cheers once more, no doubt be picking your brains again in the not too distant future when I've heard about something else I might be able to do
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
Many thanks again Jarrus and HDI fun.
Few things to take on board. I'm totally with you (it wasn't a rant!) with regards having the car legal at all times. I want to enjoy it and not cause anybody else any dramas in the process (bit of smoke if its being given a 'boost' is not necessarily gonna cause people that much of a headache).
Been in touch with celtic and they've sent me out a pretty comprehensive email detailing what I'll get out of it. Phoned them today and they've given me a chat through as well as a quote.
Cheers once more, no doubt be picking your brains again in the not too distant future when I've heard about something else I might be able to do

You won't be disappointed with the increase in performance. It is immediately noticeable. Over a few hundred miles the ECU will 'learn' its own parameters and things get even stronger and smoother.

A good remap is quite a complex process. Firstly the tuner will check that the car is working correctly before doing anything else.

The initial phase of remapping is to smooth out the power delivery. This is long before the fuelling and boost are altered to increase performance.

Good tuners look at sense data from the engine/ECU long before anything is altered.

Once the peaks in power delivery have been shaved off, boost pressure, fuel rail pressure, fuel timing etc can then be altered to offer more torque across the rev range. In many ways it's an art more than it is a science.

I promise you that you'll like the results.
 
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