Tuning Boxes

[Dieselman]

AFAIK it's something to do with emissions testing at manufacture - i.e. they have to build them to pass tests so will then build in tolerances to pass those tests. The tuning boxes are fitted post sale so don't have to worry about such things and in effect smooth out any fueling adjustments the mfrs have to make to get round the tests. i.e. if the emissions test is measured at 2000rpm then the fuel will be wound back at that point to pass the test and the rest of the power curve will be engineered to fit.

I may be wrong.... Dieselman - you're well informed on these subjects, can you elaborate - have I got the wrong end of the stick?

This is basicaly correct.
Certain emmissions are measured at the design/manufacturing stage and never again, so are ignored by tuners.

 

[Dieselman]

Hi all,

Most tuning boxes for common rail allow slightly higher fuel rail pressures by intercepting the rail pressure sensor voltage. Higher pressure means increased fuelling which in turn will result in a slightly higher turbo boost. Most tuning boxes for common rail diesels do not interupt or change the injector timing.

Fuel savings are to be had if you don't use the extra available power.

The 250/300 type engines run a VP37 type pump that will use a different box that changes the quantity adjuster commands for the diesel pump.

I use tuning boxes on my diesels and find a good increase torque/power. If you go too far with the VP37 type box it will smoke. If you go too far with the CR type box the engine will see an overboost type fault and will drop into 'limp home' and the car will need to be turned off and restarted to get turbo boost back.

regards,

Job

Thanks for that Job, I wasn't thinking too straight re the CR type. Presumably the box alters the pressure sensor value.

 

[Paul Govier]

SimonsMerc

Where can i get one of these Tandem Tuning boxes? Will it fit my new CLK 220Cdi?

Thanks

Paul

 

[MrCow]

I've just bought a tuning box for my C220 CDI Sports Coupe from www.dieselchiptuning.co.uk. It casts £400 including VAT and postage.
The box has three perfomance settings and I run it contantly on the highest which is supposed to give around 35bhp - maybe more. If you're going to run it on the highest setting you're supposed to fit a K&N panel filter or similar so that it can breathe properly or you'll get black smoke when you drive it hard (which I do sometimes, but it's not that bad). I'm finding it quite hard to find somewhere that sells them for my car.
It does make the car a fair bit more fun to drive, I'd say it's probably Audi S3 quick, so I'm quite happy with it.
Also, the other good thing the tuning boxes is that you can sell them on when you're finished with it and get some of your money back.

 

[SimonsMerc]

Heyas,

I bought from ebay - this is the unit I bought. http://cgi.ebay.co.uk/Mercedes-CDi-...992257871QQcategoryZ32094QQrdZ1QQcmdZViewItem

The seller's name is tandemtuning. Still very happy with it, £230 well spent

-simon

SimonsMerc

Where can i get one of these Tandem Tuning boxes? Will it fit my new CLK 220Cdi?

Thanks

Paul

 

[ckember]

I also have one from tandem tuning on ebay, been fitted to my c270 about 4months, the extra power/torque are noticeable, on a long run mpg up about 5mpg. I find the extra pull through the rev range very good. seen off a couple of bad boys and a few boxsters and 530d's. So far only not sure of the top speed, but had the speedo at xxx, don't know who's reading this!!!!

This is my everyday car, so when I spoke to the insurance company they originally quoted an extra 10% pa. bbut Then they phoned back and said 5%. When the paper work finally came through no change in premium.This is with Mercedes Benz insurance, under written by norwich union. not bad.

I would love to try out a rolling road just to see what the improvement actually is

 

[se97mlm]

II posted this last time this thread came up, but these tuning boxes are a "hot-potato" for me!! I will now and explain why fitting these "tuning-boxes" could cause major problems and expense


FOR CDI ENGINES
The amount of fuel injected into the cylinder is controlled by the length of time the injector is open, and the pressure that the fuel is at. so to get more fuel in, you can either lengthen the drive pulse to the injector or increase the rail pressure.

All the tuning box does is lower the voltage reading from the rail pressure sensor, fooling the ECU into thinking the rail pressure is lower than it is. The ecu then increases the output of the HP pump to increase the rail pressure to what it thinks is the correct value. SO now you have a pressure in the rail much higher than it should be.

Granted, over most of the rail pressure map this is not too much of a problem, but if you drive a lot at 100% load (foot to the floor) and at engine speeds greater than 4000rpm, you run a great risk of breaking your pump. This will put shards of metal into your rail and wreck the injectors. If the pump seizes, it can take the drive components to it as well. Bear in mind that for a Bosch CP3 pump running at 1600bar (2nd generation CDi) the force needed to support a pumping plunger is ~3800N (imagine a 380kg mass on something diameter 5,5mm, supported by a thin film of diesel stopping it from rubbing against a moving coated metal surface). If you increase the pressure to say 1800 bar, that force increases to ~4300N (430kg in the above analogy). Believe me when i say the pump manufacturers have trouble making this interface survive- ask any service guy how many common rail systems are changed each week per dealer. One dealer mechanic had noted 5 in the week i last visited him, and that's just one garage!

RESULT = 4 figure bill

FOR ALL DIESEL ENGINES
If you increase the injected quantity on any Diesel engine you will increase the peak cylinder pressure which in turn can lead to melted pistons and valves.

We have had this testing engines on dyno with surprisingly little increases in fuelling (~5mg/stroke)

RESULT = Another 4 figure bill

Just as an afterthought: Logically how can a couple of guys in a shed with no budget to a better job than a major car manufacturer with no disadvantage?! It takes thousands of hours to set up modern Diesel engines
for performance, emissions, reliability and driveability. Contrary to the stupid articles these companies churn out as advertising there are really NOT massive tolerances involved. If you all knew how close to the edge these engines are you would be shocked!

p.s. a little bit of black smoke isn't too bad really, just looks horrid and is a good excuse for people to trumpet how dirty Diesels are. It's just that not all the fuel injected is being properly combusted. In fact, it can be argued that modern Diesels can do more harm, as the smaller particulate sizes can penetrate further into the lungs.

p.p.s. i will be on holiday for the next week, so may be slow answering any questions!

 

[Sean Sherry]

very interesting article ! Would you care to comment on the tuning boxes for petrol engines, specifly kompressors. One tuner promises 230k preformance from a 180k spec.car [ 180k-200k & 230k are all 1.8 litres] [the 230 has a lower c/r ] Higher boost is via altered signals from MAP sensor & air flow sensor. thanks, Sean [down under]