Engine remapping

InsideInsurance

Iceweasel wrote: »

Point taken about Porsche next model up.

But I think that you would find that it's extra power or extra mpg.

I can't see anyone getting both at the same time.

They claim you get both in the sense that if drive sensibly and you get the MPG savings or if you thrash it and get the power increase. You dont get both at the same time (ie thrash it to use the power and save fuel)

Gloomendoom

My car has been remapped to give around 25% more than standard, slightly more. It is a lot quicker but as somebody else pointed out, if I use the performance the MPG goes down. Normal driving has made no noticeable difference to the consumption.

I have another car with a tuning box fitted. I have no idea what the power increase but it is noticeably quicker when the box is switched on. Again, I have found the the mpg has decreased, even when driven less 'enthusiastically' the mpg is slightly less than with the box turned off.

The tuning box is not quite the same as a remap as the only parameter that can be changed is the fuel pressure. i.e. it is crude... but effective.

The downsides... insurance will cost you more and they usually invalidate any warranty. Also if you go mad with the power, you will need to make sure the rest of the drivetrain can handle it. My remapped car has auto gearbox that is happy to over 400 bhp so not a problem. With manual cars, the clutch is usually the weak point. A colleague remapped his Alfa and now has a permanently slipping clutch... not really an improvement in my opinion.

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Retrogamer

InsideInsurance wrote: »

So looking at another vehicle, a relatively new 3.5l non-turbo 302bhp automatic a @live@ company has said they believe they can reasonably get an additional 35bhp and 30nm of torque with no impact on fuel.

What other changes would you do to the car to assist with dealing with it? The same model of car also has a 4.7l/430bhp engine variety before you get into the "sports" variants so dont know how many components will be shared with its larger engined brother to say that they're already rated for the higher outputs

On a non turbo car i'm a lot more reluctant to believe you can get power increases from a remap, without fuel economy suffering.

The methods to increase engine power i prefer are ones that don't put that much more strain on the engine.

More efficient air intake & exhaust system and better spark plugs (although spark plugs do very little) would be as far as i'd go as it gets expensive & reliability may suffer beyond that. You could go throttle bodies, camshaft changes ect but very intrusive and expensive compared to other things.

cootuk

I know some cars are detuned to pass EU noise emission tests, and have a flat spot at certain gears/rpm.
A remap could overwrite these settings to get rid of the flat spot, but probably then fail EU noise emission specs.

gilbert_and_sullivan

Someone should tell Porsche, they could get rid of all those brain boxes they employ and replace them all with dodgy blokes with laptops..

Would i entrust remastering a £70k car to a bloke in a glorified shed, not on your nelly.

forgotmyname

Plugging tuning boxes sold on ebay are not a remap. They fool the ECU into thinking the fuel pressure is lower than it really is. End of comments on that.

A proper remap where they alter the fuelling and boost pressures will give a genuine gain. And with a rolling road run included add the power where you use it most.
No point adding a generic setting if it puts all the power above 4000rpm where you never use it.

Extra power and torque can give better fuel consumption. Providing that you dont use that extra power all the time.
At a constant speed you may need slightly less throttle movement and less fuel to maintain that speed.

As mentioned the manufacturer dont do it because it may not hold up long enough for the warranty and may increase emissions above their target.

Same way most manufacturers sell the cars with several outputs, Sometimes its just down to the fuelling and boost map. Sometimes there are different sized injectors.

InsideInsurance

Retrogamer wrote: »

On a non turbo car i'm a lot more reluctant to believe you can get power increases from a remap, without fuel economy suffering.

They claim there would be no additional fuel economy, they technically didnt say it wouldnt worsen fuel economy.

That said, currently getting ~36mpg even without sensible driving so wouldnt be too bothered if that went down a small bit as had been expecting more around 30mpg when I was budgeting anyway.

Obviously loss of fuel economy is one thing, killing the engine is something else.

Nodding_Donkey

There is also the point that a new car has to go through type approval (or whatever they call it now) with things like emissions and noise levels tested at certain rpm. This can result in small flatspots that can be got rid of with a remap. It's not always about maximum HP, which most people will ever use and is just about bragging rights, but about improving the BHP/torque curve and making the car more driveable.

Ximian

I had a previous 2.0 TDI car remapped (Revo Teknik) and the remap made a huge difference to the car, the remap made the car more pleasurable to drive. My main reason for the remap was the advertised increase of fuel economy. The power increased but not significantly but the biggest difference was that the car was "better" to drive, before the remap, when accelerating I'd need to change gears very often, around 2.5k rpm the car would start to feel a bit flat so I'd need to change up a gear. After the remap, the car felt less restricted it almost felt similar to driving a petrol car, the car felt much less restricted.

Fuel consumption obviously increased initially, but after a few weeks I started driving more sensibly and fuel consumption dropped just a little: extra urban consumption was around 53 mpg before the remap and this changed to 56 mpg after the remap. City driving mpg stayed the same.

I never had any issues with the car and kept to the manufacturer's recommended service intervals.

Would I remap again? Probably not, for the following reasons:

1.) Car insurance costs increased, with the same insurer I was quoted an extra £430 by declaring an engine remap. I changed to a different insurer and the cost was slightly higher than what I paid the previous insurer. There are plenty forums with people asking the same question: should they inform their car insurance that the car has been modified, some replies are no they will never find out and some replies are yes definitely. I would always advise to always declare any modifications to insurance companies. There are car insurers out there that will insure modified cars (Green Light, Adrian Flux) but the extra cost to insure could end up being much higher.

2.) Most manufacturer's warranties will be invalidated if you modify the car. Although I never had any issues with the car luckily, I'm not sure I'd be willing to take a gamble again in the future.

3.) Cost to remap/modify, I paid ~£350 to have the car modified.

Factor in all the above and I don't think it was worth it in the long run. I doubt the minor increase in extra urban fuel economy covered the costs involved. At the time I seem to recall some claims that in two years time the fuel savings made will pay for the ECU remapping costs.

Revo Teknik FAQs: http://www.revotechnik.com/faqs/

forgotmyname

My 130bhp Mondeo is pushing 160bhp. They could have got it a bit higher bur it started to drop the torque at thevery bottom of the rev range.

So i got them to back it off as i wanted the max torque at 1500-1800rpm. Just where i want it when towing.

Problem is there are too many people out there with a spare laptop and some dodgy ripoff software and stolen engine maps.
The maps can wreck the ECU if your unlucky enough to want one thats corrupt.
Also they sell then as bespoke or custom. How can they do that without testing your car?

Not every car will have the same engine output at exactly the same revs. Production tolerances will be tighter than they used to be but variations will still happen.