i have a 98 gsr swap in my eg hatch and it is killing me on gas because i have to go 5mph over what the speed limit says, since my speedometer is off. does anyone have a solution to fixing this issue. thank you

 

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Your speedo has no impact on your gas mileage... and why do you have to go 5mph over? If you know your speedo is reading 5mph faster, then you're going the speed limit.

As for a fix, are you running a different tire size than stock? Also, speedos typically read a little high as a safety feature. But if the speed reading is off because of a tire size issue (or speed sending issue) then your MPG calculations will be off as well.

I guess I'm just confused because what you posted really doesn't make sense

 

I think he believes that since his car thinks it's going faster than it really is, this somehow really affects his average mpg rating in the real world.

Don't worry SnatchBack, it doesn't matter if your gauges are off, the car still works the same way if they are correct, incorrect, or not even functional :-) If you actually are filling up for than usual it might have something to do with the full motor swap lol

 

yea i was thinking what johnny was saying, i just thought that i had to drive 5mph faster that it was affecting my average gas mileage. and the point of this is maily to find a answer on if there is a way to fix this issue or not.

 

Well, I personally have no experience with Civics, but on my '93 Integra I popped the cluster apart, took the glass off removed the speedometer needle, plugged in the cluster- took it for a drive down the road, and reattached the needle while at the correct speed.

However I would set it a little off- your speedometer is a little off from the factory to be more on the safe side as RJR said.. If you're really going 48mph, set it at 50mph..

 

What size tiers are you running?94

 

195/50/15 neogens

 

thank you proton, that is a good point i will try and do that. only thing is its a bitch to get off my dashboard. 94 e.g. lol

 

Stock tire size is 175/70R13, [if I remember], so now the question is what is the overall diameter of your tire compared to the stock tire? 94

 

lol that is the question... hmmm ill ask one of the techs to help me at honda when i go into work tomorrow

 

this is a simple calculation
175/70R13
195/50/15

13 inches + (175mm*.70)=17.82 inches
15 inches + (195*.50)=18.84 inches

Difference of 1.02 inches bigger with the current tires.

Now tire manufacturers don't exactly use the same way to measure. So your probably are closer to being exactly the same then you think. Have you tested your speed with GPS or someone driving next to you?

The other way to fix is buy the correct tire combination. If you wanted to keep the width 195 you could have gone with a 35 series tire. There are plenty of websites with calculators to figure this out for you.

 

they don't make a 195/35/15 I'm not that worried about it, just want to fix it.
and yes checked by gps

 

You may not find the tire you want in a 195. You need to see what other combinations could result in the correct size. probably a smaller width and a little more thicker tire. Tire shops are good at finding the right combination for the rim you want to use. Getting the correct tire combination is the correct way to fix this.