Grand Vitara ECU re mappable? More bottom end power

[Jay18]

Yer the current air box is in the front corner of the engine bay, so I was thinking of making a heat shield with a cone filter inside, then just a piece of aluminium pipe with the AIT sensor in just between the MAF sensor and the cone filter, maybe run some big silicone hoses towards the sealed off corner for the intake from behind the front bumper so it has fresh clean cool air

[ScottieJ]

I would honestly just keep the original airbox and filter, no aftermarket air filter will filter better than the original and again aftermarket air filters that "flow" better won't really give any significant power gains. You could spend loads of time trying to make a set up for it that is no better or even worse than the original. Tbh the original set up draws air from inside the wing so a different set up probably won't lower the intake temp anyway. The original set up is a good design I think.

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Even for maybe 5bhp if you are lucky in something like a GV I don't really think is worth the effort.

[Rhinoman]

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?

VTEC won't make any difference as far as a CAI is concerned.
A factory air box doesn't usually give that much restriction these days, while you're logging data do a comparison of MAP v Baro at full load to see what difference you get. I'm not a fan of cone filters I would just try to feed cold air, if its needed, into the stock box.

[Jay18]

I think I'll go for the cat back and see how that goes, would be nice to gain some power but I'm not expecting huge gains, it's more for the fact stainless lasts longer and it's about the same price for a custom cat back as it is for one section of stock exhaust

I may look into cams depending on what the costs are but will see, can't seem to find a company in the UK that makes it sells performace cams for the J20a

I've thought about porting and blueprinting as well but not sure whether there are much gains?

[Anton]

The problem you face (imo) is that you are looking for low down torque, and most of the mods people do are designed to gain high end HP, because HP is the holy grail of the ricer/wannabee tuner.

HP is great, but torque is what truly matters in a 4x4. Yes, more torque can come from more HP (HP and torque are mathematically linked via RPM in a similar way to volts, amps and watts) but truthfully it's not easy to gain torque down low.

Your cat back is probably a good idea, as it should increase not just flow but also scavenging as the gas will flow more freely, but as the standard exhaust probably isn't very restrictive at low RPM I'd say that you shouldn't expect huge gains.

The only way to make huge gains in torque that would really revolutionise the way you tow would be a turbo that is small enough to spool up at lower RPM's, a supercharger, NOS, diesel or a bigger petrol engine.

I'm certainly not saying you shouldn't go for the catback, because it should see you small gains in torque, MPG's, HP, and probably sound great too.

What I am suggesting is that you be realistic with your expectations, and don't be overcome with dissapointment if it's not a vast improvement.

All the best and don't forget to post up pics, you know how much we like our pics.

[Rhinoman]

the standard exhaust probably isn't very restrictive at low RPM I'd say that you shouldn't expect huge gains.

Its more a case of the exhaust being restrictive under high load rather than low RPM.

[Anton]

the standard exhaust probably isn't very restrictive at low RPM I'd say that you shouldn't expect huge gains.

Its more a case of the exhaust being restrictive under high load rather than low RPM.

Yes, that's what I was trying to say - the engine is probably breathing just fine at the lower parts of the RPM band already.

The same is true of the intake manifold, which is why port matching, blueprinting and flowing etc probably won't have significant impacts on low end torque. They're all strategies for gaining HP up top of the RPM band where the engine is having more difficulties shifting gasses around in a timely manner.

I wouldn't spend the money, personally. I'd save it and put it towards an engine swap if more torque was a serious concern.

[Jay18]

I'm not too bothered about it really, would be nice to have some more power as well, usually you have to gain a lot of HP to gain a bit more torque right?

Would love to turbo it but need a good few grand for a decent setup so will see how work goes next year, I want to keep the car a few years and then I'd like to upgrade to maybe a 2.4 GV SZ5, the J24b is a 169 hp engine with 166 lb-ft torque so it should be capable of towing a bigger caravan with ease

But for now a little bit more power would be good in the one I've got, ive pretty much got it how I want it, just a few little bits of like to do

When I get my cat-back I'll post some pics for everyone to see, not is due in March I think so I'll try and get it done before then incase they fail it on a leaky exhaust or corroded tail pipe

[dan_2k_uk]

I refer back to my previous post about refitting the standard size wheels/tyres while towing......

[Jay18]

There isn't much diefference in size really, just gone from a 65 profile to a 70 profile