Will a remap help my towing?

[cliffy]

Hi all - I've got a 10 yo Berlingo Multispace 1.6 Hdi 90bhp - the Plus model - with 98k on the clock. Recently changed the clutch, timing belt & water pump. I tow a small caravan (Bailey Pursuit II - all up caravan weight c. 1000 kg, which was chosen as it "matches" at c. 85% of Lingo weight). My missus, my dog and I had great brollydays in the Highlands with the caravan in both 2020 & 2021, and we're looking forward to more....one day!

It tows 'ok' except for steeper hills, but I am wondering:
1. Whether I could remap it to say, 105 or 120 bhp, for more torque, and would it help, and
2. What the pros and cons are...and whether I'd need to change any hardware - e.g. injectors...?

Any feedback appreciated.

[Sol]

The 90 and 75 engines are identical other than the software in the ECU. After that (100, 110 etc), the injectors and turbo change, even the turbo control system is different.

A remap would see you get to around 120 hp with only a stage one map and no hardware changes, which I expect will make a hugely noticeable difference. Especially in terms of low down torque for towing.

The only thing you'll find is internally when towing, it will make more smoke and the DPF will of course, catch it. So that will need more regens. Also your almost at 100k, when the ECU will start complaints that your DPF is nearly at the end of its life. It can be pressure cleaned of course but the ECU then has to be told a new one has been fitted using DiagBox before the warnings will stop. It starts a countdown to 'no start' which is based on miles with messages like 'risk of clogging' etc. Fairly easy to sort with a DPF clean and a software edit.

Don't be tempted to get rid of the DPF during the map or it will just smoke and fail MOTs.

DPF cleaning is not to be confused with the regeneration the ECU does naturally, as the DPF eventually gets a level of oil ash in it that can't be removed by itself without a professional clean. This ash is the result of a regen burning the soot off that the filter had caught.

[mission]

With a stage 1 tuning you should be able to get arround 115 bhp and 215 NM torque, maybe even a little more. Stage 1 pretty much means a remap only. there is no need to do any hardware modifications like mess with the intercooler or anything.

A decent stage 1 doesnt have any cons as far as I know, if done properly ofcourse. A 90 bhp engine might be the exact same as a 120 bhp engine with just a different ecu. Easy way for the manufacturer to make more money sinds they only have to build 1 engine. Also cars are designed to work everywhere in the world in whatever condition so the ecu is mapped to a generic "safe mode".

A stage 1 will still be in the safe zone for the engine, but the engine will be way less restricted and especially with towing youll notice across the rpm range all will feel a bit smoother.

At work we tuned the entire fleet. We always order the biggest engine with the lowest BHP. Like VW sells the Crafter with the 2.0 TDI with a useless 102 bhp, after a stage 1 we get about 150 to a 160 bhp and thats about 1500 euro cheaper then ordering the van with a stronger engine. I have a Caddy wich went from 110 bhp to 180, and thats only a stage 1 remap.

[cliffy]

With a stage 1 tuning you should be able to get arround 115 bhp and 215 NM torque, maybe even a little more. Stage 1 pretty much means a remap only. there is no need to do any hardware modifications like mess with the intercooler or anything.

A decent stage 1 doesnt have any cons as far as I know, if done properly ofcourse. A 90 bhp engine might be the exact same as a 120 bhp engine with just a different ecu. Easy way for the manufacturer to make more money sinds they only have to build 1 engine. Also cars are designed to work everywhere in the world in whatever condition so the ecu is mapped to a generic "safe mode".

A stage 1 will still be in the safe zone for the engine, but the engine will be way less restricted and especially with towing youll notice across the rpm range all will feel a bit smoother.

At work we tuned the entire fleet. We always order the biggest engine with the lowest BHP. Like VW sells the Crafter with the 2.0 TDI with a useless 102 bhp, after a stage 1 we get about 150 to a 160 bhp and thats about 1500 euro cheaper then ordering the van with a stronger engine. I have a Caddy wich went from 110 bhp to 180, and thats only a stage 1 remap.

[cliffy]

Thanks Zion and thanks mission, much appreciated.

I drive pretty conservatively generally, but have regular 70 mph dual carriageway trips too that ensure regens occur, and that won't change...Looks like a Stage 1 tune would suit my towing needs, doesn't it? I'll work out when once I've booked trips away!

[mission]

Thanks Zion and thanks mission, much appreciated.

I drive pretty conservatively generally, but have regular 70 mph dual carriageway trips too that ensure regens occur, and that won't change...Looks like a Stage 1 tune would suit my towing needs, doesn't it?   I'll work out when once I've booked trips away!

Yep id say go for it

On me daily driver (Seat Ibiza 1.2 TDI)  I went from 75 bhp with  180NM to 107 and 245NM (Dyno tested). Also with the standard mapping the turbo didnt work below 2000rpm, it now kicks in at just over 1250 rpm, has a little higher boost pressure and duration making towing and driving hills so much better. Also it makes the driving more relaxed because your not always busy changing gears and can stay in a higher gear for longer.

It also improved the fuel economy quit a bit sinds the engine now runs better and has to work a little less hard to get things done.

@Zion Im not sure I agree on what you said about the DPF, at this moment we run 60 tuned diesels (all with the EGR valves removed, so even more work for the filter) without issues. Oldest van got its Stage 1 when it had 50 miles on the clock or so, its now done over 250K and still no issues. Also no problem at the MOT at all, but maybe the Uk rules are different then we have here in the Netherlands

[Thisisnotaspoon]

Diesel ECU tuning is a bit of a brute force exercise. Diesel engines (particularly Turbocharged ones) are not stochiometric, they run at an excess of air.

Diesels also run high compression, so 23:1 compression + 1bar from the turbo = ~46:1, actually less due to adiabatic compression but you get the gist that it's a lot more than the 10:1 a petrol car runs at.

Higher compression = higher temperatures (that damn adiabatic compression again).

High temperatures = NOx, which means everything from city smog to respiratory disease and early deaths.

What diesel tuners do is usually twofold:

1) Delete the EGR. This actually has relatively little effect as there's already an excess of oxygen and the EGR has closed under acceleration anyway. It only opens under ower loads e.g. just cruising along.

Unfortunately, that also means lots of Nitrogen (air being 78% N2, 21% O2, 15 CO2 and others). N2 has a very high specific heat ratio, which means it causes higher levels of adiabatic heating under compression. To reduce this the EGR recirculates the exhaust to dilute the incoming air as CO2 has a lower ratio of specific heats than either O2 or N2.

2) Increase the boost pressure, more pressure = more heat under compression remember. But you can push the point where the engine runs out of oxygen too.

3) More diesel (there isn't another way of making a bigger bang). You do this by just opening the injectors for longer. This then leads to problem 2. PM2.5, particles <2.5um in diameter which are small enough to get lodged in the cells of your lungs (bigger stuff gets trapped in the mucus and you cough/sneeze up). Longer injector durations produce inefficient combustion and thus more smoke. More powerful models will use bigger injectors to minimize the time they have to be open while delivering the same amount of fuel.

"3" is why re-tuned engines feel "more responsive". You pretty much up the amount of diesel delivered to the engine for a given combination of accelerator position, manifold pressure, and engine revs. The real simple tuners simply interrupt the signal and add a multiplier (e.g the ECU says duration 3x10^-3, it simply multiplies this by 150% to get 4.5x10^-3, and thus you get your 50% more torque).

There's no way around those issues. It's just how engines work and how they are built.

The reason your car doesn't come with 50% more power out of the factory isn't that PSA were being killjoys. It's because they will have tuned the engine to the PM2.5 and NOx limits.

Re-tuning without regard for those is basically saying a big F*** Y** to the rest of the world.

[Pedronicus]

Re-tuning without regard for those is basically saying a big F*** Y** to the rest of the world.

And failing the next MOT maybe?

[Sol]

More fuel, more poke, more smoke. Stands to reason the DPF is having to catch more soot particles on a diesel where the fuelling is increased.