My brother owned a 98 altima 5spd. It got totaled last year. I used a for a highway trip once. I posted a thread on GS about it but here is the text.
I had to make an emergency trip to TN tuesday. My saturn needed some maintenance and the tires mounted so I borrowed my brothers altima. Specs for the car are
1998 altima GXE
145k
fresh tune up including synthetic oil and ntk o2 sensors
5 speed
new yokohama trz's at 46psi
HAI (still being tweeked)
aluminum foil on the o2 sensors
cold front on the radiator
scangauge 2
Best tank
653.6 miles 18.10 gallons 36.1mpg target cruise speed was 65-67mph.
current tank scangauge reading is 32.3 should be within 3% using cruise control at 74mph.
numbers were taken using a full top off. I mean it won't hold anymore! The listed capacity of the tank is actually 16 gallons LOL.
After lots of tank to tank testing the HAI simply doesn't work in this car. After about 50 miles the ECU will adjust fuel and timing to negate any improvements. I WAI in the winter months might show some gains. Its a shame because it was a neat HAI. Here's a pic
