Extra 40-60 bhp from diesel cars?

Hi,

I was speaking to my mechanic at the weekend. He says there's a little modification you can make to a diesel engine that gives 40-60 extra bhp for no added fuel consumption.

It has something to do with removing the connector to the air flow sensor, possibly cutting a wire on it, and adding a little box of tricks to the circuit. He's done it on his VW and says it's fantastic.

Apparently it works by fooling the engine management systems into thinking there's more air going into the engine than there really is.

Has anyone heard of this? If it's true and it works, why aren't manufacturers building it into their engines???

Cheers,

Iain

Reply to
Iain McLaren
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Time for a new mechanic I fear.

John

Reply to
John Greystrong

Iain McLaren ( snipped-for-privacy@nospam.com) gurgled happily, sounding much like they were saying :

Uh-huh.

How much is he wanting to charge to do it to yours?

This guy's a *mechanic*?

Yes. Pushed as being for petrol engines, they've been all over fleaBay, but they seem to have nearly disappeared. Which says something about their efficacy.

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"The mod itself is a small resistor that tells your engine control unit (ecu) that all of the air coming into the engine is cold and therefore dense and packed with oxygen. The ecu then takes this info and tells the injectors to fuel slightly more. This in turn makes for a more powerful detonation in the cylinders and releases the full potential of your engine."

Except for the small detail that the lambda will detect that the engine's running too rich and reduce the fuelling.

On a diesel, the air coming in is unmetered, so there's only three ways to increase power - more fuel, different injection timing, and more boost.

Because it doesn't work.

Reply to
Adrian

A friend of mine is getting his TDi Fabia 'chipped' which appearently changes the injection timing to give another 30bhp. At what cost (apart from purchase price) I do not know.

Reply to
Mark Hewitt

Certainly you can chip electronically controlled engines but it costs. Surprisingly I have found a slight improvement in fuel consumption when normally driven, but not as much as indicated by the on-board computer. An increase of more than 15% tends to increase smoke unacceptably so to get the 40 to 60 hp you quote is unlikely without consequences, unless you have a supercar to start with.

Huw

Reply to
Huw

Huw (hedydd[nospam]@tiscali.co.uk) gurgled happily, sounding much like they were saying :

I suspect this isn't chipping, but the usual "cheap chip" bodge of stuffing a resistor into the intake air temp sensor, to make the ECU think it's getting cold dense air.

Reply to
Adrian

If pretty well any decent engine is modded to produce more power it will use more fuel when that extra power is demanded. Otherwise you could make an engine that used no fuel at all. Think about it...

And this is your mechanic?

You can increase the maximum power of a diesel slightly by overfuelling, but this will be accompanied by lots of smoke and is rather anti-social - oh, and illegal.

Many turbo diesels can indeed be relatively easily modified to produce a lot more power by re-mapping. This costs several hundred pounds. And the makers may well do just this on future models.

Reply to
Dave Plowman (News)

Nowt - I ain't got a Diesel! It was part of a general conversation to do with air mass sensors (mine was giving an intermittent engine warning light). He said they were available for £300, but he'd got his for about £180.

Hmmmm.

Reply to
Iain McLaren

: Huw (hedydd[nospam]@tiscali.co.uk) gurgled happily, sounding much like : they were saying : : : > Certainly you can chip electronically controlled engines but it costs. : : I suspect this isn't chipping, but the usual "cheap chip" bodge of stuffing : a resistor into the intake air temp sensor, to make the ECU think it's : getting cold dense air.

Can I get another 40 - 60hp out of my 2CV by pulling the choke out a bit, then?

Ian

Reply to
Ian Johnston

Ian Johnston ( snipped-for-privacy@btinternet.com) gurgled happily, sounding much like they were saying :

Apparently. After all, it works on all cars made after 1988, according to the fleaBay link I posted - and there's no difference on any other "normal" 2cv before that date.

Doesn't seem to work on mine, though. I must email the seller and ask.

Reply to
Adrian

The message from "Iain McLaren" contains these words:

Because they decide how long they want the engine to live and set the fuelling accordingly.

And if anyone's fool enough to believe they can get 40-60bhp extra they're living in cloud cuckoo land and deserve to be parted from their money as fast as possible.

Reply to
Guy King

I hope your friend has discussed his modification with his insurance company. When I was considering having the power on my Rover 75 CDT boosted by a manufacturer's modification from 116 bhp to 131 bhp, my existing insurer (Axa) advised me that they did not insure modified cars. When I phoned around I found one or two who would, - at ridiculously increased premiums. I've now changed my car to a Rover 75 CDTi, which has the higher power engine as standard, and Axa have continued to insure me with no increase in premium. Crackers!

Kev

Reply to
Uno Hoo!

The fuel consumption figures for the Rover 75 CDT automatic (116ps) and the CDTi automatic (131ps) are identical for urban/extra urban/and combined. For the manual equivalent the CDTi is 1 mpg worse on urban, 2.9 mpg better on extra urban, and identical on combined. Very strange !!

Kev

Reply to
Uno Hoo!

*BANG*
Reply to
Andy Hewitt

To add to what's already been said, the manufacturers could quite easily get much more power out of any engine if they so desired.

However, you need to consider that they have done maybe millions, if not tens of millions of pounds of research and development into making just a single engine for their range [1]. This engine not only has to perform, and be economical, but be reliable too. Drivability is also a major factor.

In all the engine is tuned as a compromise. It gives reasonable performance, at a reasonable economy, and has an acceptable life span. A large majority of drivers will probably want comfort and a smooth drive too.

To give you some idea, in the late 80's Honda produced a 1.5ltr V6 engine for Formula 1 cars, it was turbo charged, and in one qualifying session they obtained 1500BHP. Of course this lasted about 12 laps of use - or about 36 miles of your average track. They also only idle at about 3000 rpm too, and consume 60 litres of fuel every 15-20 laps.

You need a car to do a little more than this, so obviously you cannot produce such power.

The engine will have been designed to work for, say, 100,000 miles reliably at a reasonable power output. They will have calculated how much metal is required to strengthen the block so as to not fail through fatigue before this time.

In some cases you will note that an engine may well have been over-engineered, and will surpass this mileage by some margin, Volvos exceed 300,000 miles for example. Some cars may not make this at all, Alfas commonly fail at 50,000 miles (or less), but have the highest output of any normally aspirated 2.0ltr engine in mass production (see the pattern).

You only need to increase power by a small amount, 20BHP perhaps, to decrease the life span of an engine. However, the performance gain is actually quite minimal. Indeed, you may gain performance in some ways, and actually lose in others.

The engine tuning in not linear, and at some point in the rev range no more fuel is added, and no more advance is used on the timing. Unless you know where to change the timing, fuelling and air flow, you will most likely cause more problems than you save.

There is also no such thing as a free lunch. If you increase fuel to get more power, you will also increase the fuel used, thus harming the fuel economy.

Of course you could go the other way, and decrease power to increase economy and engine life, and not actually notice the difference as much as you'd think.

Reply to
Andy Hewitt

Not strange since none of these figures makes use of the maximum power. The maximum speed consumption figures would be rather more revealing.

It's also common to raise the gearing along with a boost in power - if the factory does it.

Reply to
Dave Plowman (News)

The message from snipped-for-privacy@spamcop.net (Andy Hewitt) contains these words:

This is the trouble with Max Power ideas - it's generally only the sort of plonker that's obsessed with peak output that drives at full throttle that often anyway.

Reply to
Guy King

That's true. There's certainly no quick fix for better economy though, better driving is about the cheapest thing to do.

Reply to
Andy Hewitt

The message from snipped-for-privacy@spamcop.net (Andy Hewitt) contains these words:

Only for those with the wit to do it.

Reply to
Guy King

It's pathetically easy to do it should be in the test! The simplest one to learn is if the lights just turn red a few meters ahead, instead of driving at 30mph up to them and slamming on the brakes, just lift of the throttle! nearly every trip I am in the left lane and do this and someone races past in the right lane and brakes hard to a standstill for the red, lights change and I just cruise past him (and lets face it, it's always a bloke!), as I am still moving!

I put this down to the fact I am rapidly becoming a tight old git!

You DON'T get there any slower but you do get there LESS stressed and it saves a lot of cash in the mpg state!

Will

Reply to
Will Reeve

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