Grand Vitara ECU re mappable? More bottom end power

[Jay18]

I do only tow with it maybe 4/5 times a year so it is something I can live with...

I might just do a cold air intake and a cat back exhaust, I believe the ECU will adapt to the extra air available

Plus I think it needs a new tail section as it has a previous advisory for it being corroded and there being a leak in a join, so might be worth having a stainless one made up somewhere

[Rhinoman]

If you have an EOBD tool then you can check the air temperature under load, it might not be worth doing a CAI. A cat-back won't bother the ECU.

[ScottieJ]

I might just do a cold air intake and a cat back exhaust, I believe the ECU will adapt to the extra air available

I very much doubt you'll see any power gains to make it worth the expense. Save your money The engine will only pull the amount of air that it needs in, changing the air intake or air filter won't make any difference unless the engine is restricted....I.e if it's been modified or tuned elsewhere so it requires more air than standard.

Yea some standard n/a performance cars have gained a tiny bit of power from them, but there's a lot that have no increase or even loose power.

[Rhinoman]

A lot of CAIs don't actually draw in cold air, if you measure the increase in air temperature over ambient then you can calculate the potential gains. I would do the exhaust, you should get a small gain and if the existing item is shot then its a good time to do it.

[Anton]

I have to agree about the CAI. Mighty Car Mods did a video recently where they checked out the gains of a CAI on a Honda S2000, and it did give a small increase - but only small, and that's a very highly tuned engine right from factory.

The guy doing the dyno runs mentioned that most CAI's he's seen tend to actually decrease power for many reasons (can't remember what they were, although the video is on youtube if you're interested).

Also, be careful with your exhaust - if you fit a bigger diameter exhaust while you're doing the catback, you could find that because of the lessened "scavenger effect" at lower rpms, you loose low down torque - the opposite of what you're trying to do! Bigger exhausts can offer more power up high, but often do so at the expense of low end torque.

Keep that in mind when choosing a new exhaust - go de-cat or whatever, but think hard before getting a larger diameter exhaust.

[dan_2k_uk]

Swap back to the slightly smaller standard size tyres while towing

Bingo... more torque!

[Rhinoman]

The guy doing the dyno runs mentioned that most CAI's he's seen tend to actually decrease power for many reasons (can't remember what they were, although the video is on youtube if you're interested).

Mainly because they are inside the engine bay drawing in warm air, for the same reason a dyno is a useless place to try and test a CAI because you get very little in the way of cold air. Any decrease in air temp gives the same increase in power but you have to remember to calculate using degs K not degs C.

[Anton]

They were using an industrial fan to draw air from outside the garage and blow it directly at the front of the car to simulate the car running down the road at motorway speeds.

Having said that, they're in Australia, so there's very little in the way of cold air to be had in or out of a garage, with or without a squillion cfm fan...

[Jay18]

If I do a cold air intake is make a heat shield so it draws the air in from the inside of the wing like the standard air box does, but with less restriction

I'll try a stainless cat back exhaust but I don't want loads of noise, I just want it to have some grunt when I accelerate, otherwise the neighbours will hate me and it'll do my head in on long journeys haha

I'll be keeping the cat as it's less work and not sure if it will pass emissions with de-cat? Plus I wouldn't know what to do about the second lambda sensor that tweaks the emissions after the cat

Would like it to have a nice tip as well, maybe a mini jap cannon, or just a nice looking tip with the silencers hidden

I think the other thing with moog's s2000 is that it's Vtec, so that would effect the performance of a CAI wouldn't it? Or just the fact that the factory box has loads of restriction?

I have a obd2 wifi plug that works with an app on my iPad, not sure if it records data but I could probably set it up on my trip down to kettering and see what it shows for intake temp

[Anton]

If you do go for a CAI, I'd suggest you make one yourself. They're hardly rocket science, and it gives you the chance to route the intake somewhere away from the radiator, engine block, exhaust etc.

And then if you find it's done nothing but made your car noisier and/or slower, you won't be too out of pocket by going back to stock.