Grand Vitara ECU re mappable? More bottom end power

[Jay18]

I've got the J20a Grand Vitara and I read somewhere that the ECU wasnt remappable but I've seen a lot of companies claiming that they can do them on their websites..

If they are remappable does anyone know what gains can be had from it?

I know that recaps can gain better fuel consumption and more power but is there much of a difference?

Basically is it worth the £150-£300 to have it done?

[Anton]

Don't quote me on this (Rhinoman is probably the best person to answer this) but I think when they say that an ECU isn't remappable, they mean you can't remap it easily. But nothing is impossible. I know some ECU's need to have a chip physically replaced in order to remap, for example.

As for whether it's worth it, that's impossible to say. What kind of gains are promised? How much are those gains worth to *YOU*? Have you spoken to anyone who's had a remap done by these people?

Bear in mind that it's money that you almost certainly won't get back when you sell the Vit one day - it's basically "down the drain" as a remap doesn't generally improve resale values. In fact, a friend of mine has a Honda CRV that had been remapped, and it would stall at the lights. I'm not sure I would buy a vehicle that's been remapped by some random guy.

I'd be worried about vehicle reliability after Tony's problems with his CRV.

[Rhinoman]

I haven't yet seen one that is remappable, its not easy to source the correct chip and you would need an emulator to tune it before programming the replacement chip. Most of the companies that claim that they can remap them can only do the TD with the Bosch ECU, there is a lot of software available on the net for those.
If its been remapped correctly then the idle shouldn't be affected, only the higher load cells should be modified otherwise you run into problems with emissions, the lower order cells also need to be tuned on a dyno that can hold a steady load, most are just full power only.

[Anton]

No you're right, I'd have imagined that the values set for idle would not be worth messing about with at all, but the CRV stalled at the lights a few times while I was in it.

I have a feeling that some setting that affects the performance of the vehicle across the board may have been mucked about with by someone who really didn't know what he was doing. Something to do with the reading of the exhaust o2 sensor or something of that nature.

Then again, it's entirely possible that the CRV was remapped properly, and something else went wrong at about the same time.

[Rhinoman]

I have a feeling that some setting that affects the performance of the vehicle across the board may have been mucked about with by someone who really didn't know what he was doing. Something to do with the reading of the exhaust o2 sensor or something of that nature.
Then again, it's entirely possible that the CRV was remapped properly, and something else went wrong at about the same time.

Its quite possible that it was a separate fault but they may not have overlapped the tables correctly switching to one of the idle maps, there are typically around 120 maps and only a few get changed by most companies.

[Jay18]

Hmm, I'm looking for more bottom end power, as when towing the caravan its a bit sluggish but once it get to around 3000rpm it pulls well, may just be the fact that the maximum torque is around 3000rp

A remap would change the bottom end performance would it? Apart from maybe a gain in torque but not much below 3000rpm?

On its own it doesn't hang about at all but it is a bit slow with the caravan on the back, which is expected but I am planning on a bigger caravan closer to its 80% weight match and would like it to pull better when I upgrade..

Other thing is stand alone ECU? Like a megasquirt?

I'd love to turbo it so a stand alone ECU would be a step forward if I ever get to do it, only thing is they're about £300 - £500

[Anton]

You don't often pull a caravan, is it not something you can live with? I really doubt that an ECU upgrade is going to give you significant torque below 3000rpm. I could be very wrong about that though!

Best to talk to people who've actually had a remap done by the people you're thinking of going to.

However, I'd also say that if what you want is lots of torque, you'd be better off with diesel. There's a very good reason why tractors, articulated lorries, locomotives etc run diesel and not petrol.

[ScottieJ]

Upgrade to a V6

Will be cheaper than swapping over to an aftermarket ECU etc.

Or as Anton says, you only tow a caravan a few times a year? Is it really that much of an issue?

[Rhinoman]

You won't gain much at all from a remap, most of the gains on a stock engine come from timing advance, if you're towing then the margin available is going to be greatly reduced unless you go to super unleaded. An aftermarket ECU is likely to be far worse than what you have, generally they try to make do with only around 7 maps, proper tuning takes many hours on a good dyno and it'll always be a compromise, I'm not aware of any aftermarket systems that are road legal, without the necessary safety systems they are considered too dangerous for road use. MS is a truly awful system.

[RickUK]

The extra expense involved but with very little gain must make this a non starter,as a few other have mentioned if it is just a couple of times a year towing a van then just run it as it currently is.

Or as Scottie has suggested get a V6,mine is only the 2ltr version but boy it pulls like a train,infact its a real pleasure to drive it as the low down torque means i can cruise at 70 on the motorway but pulling very low revs,currently getting about 30-32mpg which i consider to be good for a big body.

Trying to extract extra grunt out of the standard 4 pot lump could become very expensive especially if only required a few times a year while using it as a 'tug motor'.