I read about an e prom (computer mod) resistor install, that tricks the computer into thinking that there is a mass of cold air coming into the (mass air) sensor!  Does anyone know if this mod is worthwhile?  brick

haven't heard any specifics on that mod for a Grand Vitara... there are some things you can do before going that route. In 2002 the Grand Vitara went from 155hp to 165hp and the only difference was the diameter of the exhuast from the catalytic converter back. You'll loose a little torque bolting on a 2002+ exhaust but you'll gain the 10hp. Add a better air intake / filter to the mix and you'll probably stand to gain 15+ hp without breaking the bank... any mod you do from then on will only benefit from the improved airflow

... wait a sec, after posting the above i did a search to find out the torque difference between the 2002 and a 2000 GV. I know the gain in horsepower is entirely due to the larger diameter exhaust and I've been told that it lost some torque in the process... but when i compared their specs it looks like the 2002 actually had 2lbs more torque! Can anyone explain that to me?

2000 specs: http://www.nctd.com/review-final.cfm?Vehicle=2000_Suzuki_Vitara&ReviewID=720

2002 specs: http://www.nctd.com/printversion-review.cfm?Vehicle=2002_Suzuki_Vitara&ReviewID=1173

I would assume only 1 thing...

Back pressure
If everything is exactly the same, including the mass air sensor, and the way the amount of fuel the o/2 sensors pick up for the fuel injection

that's all I can think of

I read about an e prom (computer mod) resistor install, that tricks the computer into thinking that there is a mass of cold air coming into the (mass air) sensor!  Does anyone know if this mod is worthwhile?  brick

This is a scam - you see them advertised for just about every car with FI.  All it does is make the ECM overfuel.  Too much fuel (or not enough air) does not increase performance, but it does increase fuel consumption.

The only ways to increase performance are to get more air in , and to reduce losses (e.g. the exhaust).

Only way so far to mod the Air Fuels right now is with a piggy back.

Im gonna dyno the truck soon with the wide band and so forth

... wait a sec, after posting the above i did a search to find out the torque difference between the 2002 and a 2000 GV. I know the gain in horsepower is entirely due to the larger diameter exhaust and I've been told that it lost some torque in the process... but when i compared their specs it looks like the 2002 actually had 2lbs more torque! Can anyone explain that to me?

2000 specs: http://www.nctd.com/review-final.cfm?Vehicle=2000_Suzuki_Vitara&ReviewID=720

2002 specs: http://www.nctd.com/printversion-review.cfm?Vehicle=2002_Suzuki_Vitara&ReviewID=1173

I thought I had posted an answer to this, but it's not visible, so I'll try again.

I believe this is because the torque curve is peaking at very high rpm.  If they showed the curves, I would expect there to be a reduction at lower rpm, which is where you want the maximum torque, especially for off-roading.  The mod to the exhaust is to improve top speed, at the expense of flexibility.  Great for the highway, but not for the rough stuff.

Naughty to reply to my own post, but this link shows what can be done with a GM diesel and the right gearing and some other mods.  (It runs on biodiesel, and that 60 mpg is Imperial, it is equivalent to 50 mpg US.)  Ok, you won't get that hauling a 4x4, but 45 US ought to be possible.

Check the torque, and the revs at which it is generated!

http://www.trident-vehicles.co.uk/index.php?option=com_content&task=view&id=30&Itemid=41

Quote from: ngrover on October 19, 2006, 07:57:59 PM

... wait a sec, after posting the above i did a search to find out the torque difference between the 2002 and a 2000 GV. I know the gain in horsepower is entirely due to the larger diameter exhaust and I've been told that it lost some torque in the process... but when i compared their specs it looks like the 2002 actually had 2lbs more torque! Can anyone explain that to me?

2000 specs: http://www.nctd.com/review-final.cfm?Vehicle=2000_Suzuki_Vitara&ReviewID=720

2002 specs: http://www.nctd.com/printversion-review.cfm?Vehicle=2002_Suzuki_Vitara&ReviewID=1173

I thought I had posted an answer to this, but it's not visible, so I'll try again.

I believe this is because the torque curve is peaking at very high rpm.  If they showed the curves, I would expect there to be a reduction at lower rpm, which is where you want the maximum torque, especially for off-roading.  The mod to the exhaust is to improve top speed, at the expense of flexibility.  Great for the highway, but not for the rough stuff.

I would think you're right.... but based on the links i provided, the max torque rating for both configurations was listed at 4000 rpm.