33mpg VX, A/C on, highway miles going 80mph
 

I've got a 92 vx, its been tuned up to oem specs with a new o2 sensor. Have a cali ecu L00. Right now getting about 33mpg all highway miles. 80mph w/ ac on. Does this sound right or should I be getting more? Whats everyone getting using their a/c?

Wow whats your rpms at? 3,000? I run about 55mph and get 55mpg. But yes that does sound about right.

its a little low... but not really bad. whats your tire pressure like?

RPM at that speed should be around 2700RPM. 33MPG seems a little low, but if you are running the A/C on high than it could be normal. Do you keep it in 5th gear while driving at 80mph? I don't use my A/C enough to give you numbers, but I think if you have it on low (1 or 2 fan settting) it shouldn't effect the numbers too much, but I suppose at higher speeds it could have more of an impact as its sapping some much needed power at those speeds.

I agree with notjared, I would expect 10-20% better than that. Its a little hard to compare because you have one of the few Cali versions here. If it runs and idles ok otherwise, I don't think I would worry about it. But check those tires.

Yea, I have 15" 99 SI rims right now and the previous owner put power windows on it so its a little bit heavier. my rpm at 80mph is around 2700 rpm. I also have to downshift when the a/c is on going on slight uphill.

hmm....downshifting to go up a slight hill? thats not right. what is the tire pressure????

fyi the si wheels are maybe 1 lb. lighter than steelies. and the power windows wouldnt effect your mpg on the highway by any noticeable measure.

I could stay on 5th gear no problems without the a/c on. If it's on I need to downshift.

that is weird... was the unit ever replaced?

no, but I think its a product of the a/c compressor taking up power from the motor not necessarily a/c unit being defective. After all we do have a dinky 1.5l with tallest gearing ever :p