Tuning my Cupra TDI (PD150) - Remap, EGR, DPF and Mufflerectomy

[MrSix]

Hi Guys,

Over the next few weeks I'm having a bit of a tinker with my car and I'll be documenting the process for future reference. Because of this I need a bit of advice on a few things.

As I'm having the car remapped and I'm looking to start with the best possible hardware set up before I go tweaking the electronics.

EGR Delete
What benefits will I see (if any) from deleting the EGR and what is necessary to carry out the job. Is the "A01" kit here all I'd need.

DPF Delete
Do the MK1 Leon Cupra TDIs have a DPF? I've found lots of people doing it to the MK2 but nothing on the Mk1 so far.


As well as the above I'll also be doing the following:

Mufflerectomy
Removing the back box and replacing it with a straight through 2.5" pipe and tip with before and after power runs to see if there are any gains to be had by performing this cheap and fabled mod.

Standard airbox and filter, uprated panel filter and an open cone filter
I'll be comparing all three (before the mufflerectomy) to see if there are any gains to be had by 'upgrading' from a standard paper filter.

Remap
I'll then be remapping the car after we've achieved the most gains from the mods described above. I'm still running the standard clutch and so the map won't be an aggressive one, rather a tune that makes the car pull harder in gear - especially third and fourth.

Eibach B12 Sportline kit, Pro-Spacers and Anti-Roll kit
I have a full Eibach suspension set up coming over from Germany that comprises of Bilstein dampers, Sportline springs, Pro-Spacers and front and rear anti-roll bars.


This should leave me with a well rounded, economical daily driver with a bit of grunt and nice handling...now we'll just wait and see the results!

I'm expecting to see around 180bhp from the above and I could go even further (220-240bhp) by adding a Sachs clutch and DMF, hybrid turbo, hard pipes and bigger FMIC but for now I'm just looking at getting as much power as I can from cheap and simple mods.

 

[MrSix]

I had a Leon Mk1 PD130 and I'm pretty sure they don't have a DPF. They may have an EGR valve which CAN gunk up and cause rough running. Never had it with mine when I sold it at 130,000 miles.

They definitely do have an EGR valve and from what I've read it seems to be that if you're gonna tinker with the engine then it's worth getting rid of it. The only downside is that the car judders a bit more when you turn it off - but that's no biggie.

Turbo engines can be sensitive to back pressure. I'd be wary about the mufflerectomy unless there is prior experience on the cupra forums or you prove the benefits on a dyno.

It's a huge thing in the TDi tuning world and lots of people on seatcupra.net have done it and report nothing but goodness (slightly beefier exhaust note, improved spool up and more audible turbo whistle). I'll be interested in seeing the benefits during a back to back dyno run. If I lose power then that stock exhaust goes back on!

I'd be doing a filter upgrade and remap if I were you. I believe the TDI 150 already has a front-mounted intercooler, correct? To go significantly further than that, you're looking at a different turbo.

Again, i'll fit an uprated filter if it offers dyno proven gains. There's hugely conflicting views on this - some saying that there's only benefits if you're running big power and some saying that you'll never "out breathe" the standard set ups. Dyno will prove it.

Suspension mods sounds good. Would also be worth looking at better brake disks and pads, especially for the front.

Yeah I'm looking at the TT front brakes - just got to let the wallet cool off a smidge first

 

[MrSix]

A DPF afaik was only on the mk2 but there's a really easy check if you want to make sure - see if you have a warning lamp like the left of these two. I must admit I didn't even think you needed a kit, just a blanking plate. I saw some guy use the bottom of a beer can to make one on briskoda.

From what I know the benefits of the EGR delete are you won't be recycling the air so theoretically performance may be better in that there's more oxygen to burn (the valve is closed when you put your foot down though so no real performance increase when it matters) and your intake system will only have nice clean air going through it instead of a mix of dirty and clean so is likely to be cleaner over it's life. This mod might be a problem when it comes to your MOT but in practice you might be OK.

Don't think I have a DPF then...which is a bonus - i've heard lots of trouble with them when mapping the new A3 TDIs.

As for the EGR delete being a problem at MOT - how so?

 

[MrSix]

egr makes a mess of the intake manifold

before you go anywhere you want the inlet manifold off to clean the gunk out

same with the intercooler, clean all the oil out

Yup, all basic servicing will be carried out before I do anything.

no point chucking money at it until youve taken care of the basics and you wont gain anything with a performance filter over the paper one

That's a confident sounding man! I hope you're right, will save me a few pennies

 

[MrSix]

Probably need injectors too?

Be aware, a few people report a loss of torque with *just* a decat.

The cat will stay in place, it's just the backbox that gets chopped out. As I said, if there's no performance gains then it won't be done. I've got the benefit of a hub dyno throughout the modifications so I'll be sure to only make beneficial changes

100%

youre using the same airbox as you get in a golf/a3. the airfilter itself is larger than what you get in a B5 audi S4 or RS4

my S4 was beyond 300bhp, the RS4 made 380bhp from the factory, with a paper filter

your airbox and paper filter can flow sufficient air!

as for the inlet manifold, the gunge can really reduce the size of the air tracts, so definately sort those. it made a huge difference on my pd130 and that was an engine that was only 3 years old.

the intercooler will be internally coated with oil making it less efficient at cooling. a good clean out helps loads

do the cupras have "vented" wheel arch liners?

Good to know about that mate, didn't realise it was the same set up.
Is there anything special to clean out the intercooler?

And no, it doesn't have vented arch liners.

what eva u do dont get an open cone filter,, heat soak = fail

Yeah that what I thought, especially with a big hot diseasel engine!

I'm being a moron sorry, NOx isn't an MOT test.

No problem!

mine felt nice after i ditched the EGR and had no mot issues but that was nearly 10 years ago

Sweet! Is it just a case of blanking it off or is there a kit I need to buy?

 

[MrSix]

Lots of before/after dynos then? Awesome

Yup...runs should look something like this:

1) Stock run
2) Cone filter
3) Uprated panel
4) Best of 1,2 or 3 and mufflerectomy
5) Best of 1,2 or 3 with (or without if no gains) mufflerectomy and EGR delete
6) Custom remap

 

[MrSix]

this will sound ghetto but i used a beer can to make a "gasket" which blanked the egr, i also disabled the vac line that goes to it. this was in the days before egr blanking kits were available. ive known people who have ran perfectly fine just by disabling the vac line.

as for the cooler, just remove and clean out with solvent. id renew the jubilee clips though.

as for the arch liner, i cant remember what sort of intake temps you get with a diesel but lower is always better, it may be worth considering modding the arch liner, that made a nice improvement on my A4.

Noted, thanks mate.

 

[MrSix]

Yeah I'm looking forward to having things off for a good clean. The place I'm taking it just serviced their next project car - BMW 328i estate and they saw 5bhp from an oil change (!!!) dyno proven as well. Synionics oil or something...the Subaru rally team are using it apparently. They were gobsmacked especially as the car had been well serviced etc all it's life by the owners father in law. Anyway I'm not expecting those gains from fresh fluids but every little helps and my OCD is put at ease knowing things are all clean

 

[MrSix]

dynos mean very little. you can twiddle a few knobs and make it read whatever output you want, dont pay attention to it unless unless there is a known calibration car used for before and after runs if you want to be that specific haha

Im talking dyno run > oil change > dyno run. No fiddling, they didn't care if they got more power, but were very surprised they did!

 

[MrSix]

I'm not gonna even start on this debate, they were the results so interpret them as you will. My point was that a good clean won't do any harm.

 

[MrSix]

The car is going in today for the first lot of work - we'll probably manage the air filter test and mufflerectomy today and relevant power runs and then complete the EGR delete and remap on Friday.

I'll post back the results when I get them.

 

[MrSix]

Sure, ill get it priced up when im there and report back.

 

[MrSix]

Right then, yesterday I took the Leon down to Thor Racing in Coventry for it to be tuned.

First of all we had the standard car on the dyno (which is a hub dyno, so figures are at the wheels rather than at the engine).

The standard car made 130.7bhp and 236.9lbft at the wheels which equates to roughly 150bhp at the engine - pretty much bang on the manufacturers stated power.

We then ran the car without an air filter to replicate the very best airflow to see if fitting a high flow panel or cone filter could potentially make a difference. Over four power runs the car made identical power (within the tolerances of the dyno). Thus bringing us to the conclusion that on these PD150 engines, as standard an aftermarket filter offers absolutely no performance gains whatsoever - the only difference was a more noticeable induction note.

We then had the car back out in to the workshop and performed a "mufflerectomy" which involves cutting off the backbox just after the exhaust pipe runs over the rear beam. The backbox is then repaced with a straight 2.25" pipe and a new tip (i'm running a Cupra R style oval). We were all very surprised at how little difference in sound there was once the backbox had been removed. On startup there's now a slightly lower growl but on idle there is no audible difference between stock and no backbox - the difference comes when changing gear and you can hear a slight "chirp" from the turbo from outside the car (which I quite like). Inside the car you wouldn't be able to tell if it had been done or not and there's no droning on the motorway either at any speed or RPM.

The car was then put back on the dyno to see if the mufflerectomy had made any difference to the car's power and we were quite shocked to see that by this simple £60-£100 mod had actually made 6.2bhp at the wheels and 8.4lbft of torque. Over four more dyno runs we saw the power figure staying at a consistent 136.9bhp and 245.4lbft torque which equates to approximately 160bhp at the engine.

Now that the car was clearly breathing better, we removed the air filter again to see if an aftermarket high flow filter would make a difference. But once again the dyno results showed no gains in power. Leading us to the conclusion that the standard induction system provides sufficient airflow.

Conclusion
So all in all a very good days work having leveraged an extra 6.2 wheel BHP and 8.4lbft torque from just a simple, cheap modification. The added benefit was that I saw my average MPG increase by 6-8mpg on the motorway run home.

The next stage is remapping the car and I'll report back on Friday with the results of that.

 

[MrSix]

i dont think that proves that at all. no air filter doesnt strictly mean "most efficient".

any form of airbox has aerodynamic characteristics, some better than others which effects power output

Bonnet up, airbox lid off, cold air cascading over the intake and engine bay in general. Argue all you like, but it's good enough for me to be sticking with my standard paper filter.

 

[MrSix]

In the same vein you should have run it with no exhaust see how far that got you......

Not sure I'd fancy running my daily car with no exhaust

Always liked the Cupra TDi, might be my next purchase after seeing this

I've tuned my 306 HDi Mr Six, the backbox mod seems quite a common thing to get the backpressure off the turbo.

My car is up from 90bhp to 150, which is a hell of a difference. Not sure how much it weighs compared to your Cupra.

I am very pleased with the car and being able to squeeze extra power like this by making cheap and easy modifications adds to the pleasure. I'm sure I'll be beaming ear to ear once it's remapped Although I fear it's a slipperly slope that'll involve an Allards hard pipe kit, Sachs clutch and hybrid turbo in a few years.

 

[MrSix]

My point is a total removal of all restriction isn't necessarily the best way to get the most power.

How long does it take for your ECU to adapt to the increased amount of air it could suck in on the Dyno?

So what are you saying then?

And I have no idea - but we did multiple runs until we achieved a consistent figure.

 

[MrSix]

It's a slippery slope for sure

I ended up fitting an intercooler, making up all my pipework, upgrading the brakes, de-catting the exhaust, replacing the backbox with a mongoose that needed adjustment to make it fit! , replacing the interior with GTi seats (door cards are the same) purchasing two different maps for the ecu, Buying a flashing tool to flash the ecu and then replacing the clutch!

I did all the above myself at home here on the farm, Hybrid turbo and uprated clutch would be the next step along with fuel pump work, but I'm not slipping down that slope again

hah! That's quite incredible tuning really from 90bhp to what? 170bhp at the end? How long until the internals need replacing after all that?

 

[MrSix]

Just a brief update - the car is going in for remapping tomorrow now. Friday was cancelled because Pete at Thor came down with man flu, so rebooked for Tuesday.
Currently sitting at 160bhp so would hope to see somewhere around 180-190bhp after a bit of software.

Since having the exhaust off I've noticed an increase in MPG by an average of 8-10 on a run. I'm putting this down to the extra 10lbft torque which means that at 60-70mph the economy is much improved...town driving seems the same now.

When I get my pit bike and trailer hooked up again it's also be interesting to see what I average on the way to the track. Before it was 48-50mpg with the majority of the journey towing at 70mph on the M6...I'm expecting now to see mid 50's hopefully.

 

[MrSix]

8-10mpg is pretty epic

is that using the mfa figures or old fashoned calculator way?

Just using the on board average mpg readout - comparing before and after.

 

[MrSix]

Jesus christ, some of the replies in this thread almost make me want to just forget posting up the results and keep it to myself.

The dyno isn't accurate, the MPG isn't accurate, the moon wasn't aligned correctly when you did that run...blah blah blah.

All of the results that I've documented have been 1:1 before and afters - measured using the same instruments with the same tolerances whilst maintaining every variable possible within my reasonable control.

If that's not good enough for you then get out of my thread and ignore my findings.