EricUSC

I've been driving a completely stock '97 Civic EX (w/ SOHC VTEC) for 6 years, 40,000 miles and have been constantly getting around 35 mpg doing mostly freeway driving. I recently got the following parts installed and since then, I started getting around 28 mpg doing the same kind of driving:

ITR 5 lug conversion
15" ITR wheels w/ 195/55/15 Bridgestone Potenza RE010 tires
Mugen Sports Suspension System

Camber was set at 0 in the front and -1 in the back, which are factory 96-00 Civic settings. My engine is still bone stock.

Does the engine really have to work this much harder when I have 15" wheels (instead of 14"), sportier tires, stiffer suspension setup, and heavier brakes? Is this normal or do you think that one of these parts may have some kind of problem? If so, what could be the problem?

SkyeC

I was going to say your toe was way whacked out, but it looks like you got an alignment...

There's no way adding that **** would kill your mpg like that.

Maybe you're just flooring it through corners more often now.

EricUSC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SkyeC &raquo;</TD></TR><TR><TD CLASS="quote">I was going to say your toe was way whacked out, but it looks like you got an alignment...

There's no way adding that **** would kill your mpg like that.

Maybe you're just flooring it through corners more often now. </TD></TR></TABLE>

My driving habits haven't changed. But the steering is a lot stiffer and it seems that there is more rolling resistance in this setup. I would expect a slight decrease in fuel economy, but going from 35 to 28 mpg is a bit much, isn't it?

SpooN Man

It could be the increase in unsprung weight

tonyxcom

Do you have your tires inflated properly?

And I am sure the weight difference can be felt with a stock motor.

NonovUrbizniz

the difference between my stock wheels and my borbet 15"er's is pretty noticable... when I went for the borbets to heliums it was UNREAL how much more power my car had... It also got better milage when I switched them... not that much but 2-3 mpg.

Solo2Vtec

Its heavier what else do you want to hear.

EricUSC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tonyXcom &raquo;</TD></TR><TR><TD CLASS="quote">Do you have your tires inflated properly?

And I am sure the weight difference can be felt with a stock motor.</TD></TR></TABLE>

The tires are inflated properly 35 front/32 rear.

Is it possible that the hubs need to be greased? Could improperly lubricated hubs cause fuel economy to go down? My conversion did come off of a race car, so who knows what these parts have been through.

Also, right after I got my conversion installed, the front brakes were set too tight and the pads basically clamped to the rotors after driving 15 miles. I had to get my car towed back to the shop to get the brakes re-adjusted. Could those 15 miles have caused engine damage?

TrboInteg

It's possible that one or more of your brake calipers is dragging. You would feel the resistance and it would decrease gas mileage. And if the brake pads are in decent shape, they don't make much of a sound. You might want to check that out.

migs

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Solo2Vtec &raquo;</TD></TR><TR><TD CLASS="quote">Its heavier what else do you want to hear. </TD></TR></TABLE>

boostn5Ghaba

It's true, it's heavier

kommon_sense

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EricUSC &raquo;</TD></TR><TR><TD CLASS="quote">

My driving habits haven't changed. But the steering is a lot stiffer and it seems that there is more rolling resistance in this setup. I would expect a slight decrease in fuel economy, but going from 35 to 28 mpg is a bit much, isn't it?</TD></TR></TABLE>

I think that you answered your question. more rolling resistance. Why? I do not know, but resistance in the drive train will impact mileage. Could be the brakes. Could be the wheel bearings, etc...

Nextelbuddy

is that sort of like when you get a lightened flywheel you free up more hp because they say that for every certain amount of lbs you take away from the flywheel thats equivalent to taking so much lbs from your car or so many people out of your car for weight?

NonovUrbizniz

I had draggin brakes and you couldn't feel it AT ALL... until you rolled to a stop and it take your foot off the brake... it would stop on it's own... but only when you were going REALLY slow...

the best way to tell if you have draggin brakes is DRAMATICALLY higher temps around the brake area... mine got so hot that the center caps on my wheels melted.

no it won't cause engine damage...

there is no way to "adjust" the brakes so they clamp all the time (other than improperly adjusting the booster but then your brake lights will ALWAYS be on.) there is a GOOD chance that if these were on a race car just about ALL of the parts are worn excessively...

however a LARGE part of the loss in gas milage can be attributed directly to the DRAMATIC increase in rotating mass... it's not just more unsprung mass... it's rotating as well.. this is the worst kind of weight and creates the most parasitic loss. so this could just as easily explain your problems.

check the heat of both wheels after you drive for a while... if one of them or both are REALLY hot then you probobly need to replace the calipers.

also excessive brake dust is a good indicator that the pads are always in contact with the rotor.

kommon_sense

I'm not buying that the 20% reduction in gas mileage is because he got bigger/heavier brakes... If you believe that then all of those people with those lightweight spoon wheels must be getting like 40mpg...

Neptune

The former owner of my car claimed 30+ mpg city. I have found I get 20-25 mpg city. It should be higher, because I usually drive very conservativly and highway I seem to get 35+ mpg. Maybe its the engine slowly wearing down? I dunno. My EX has 60k

Gr8Wyt3

its heavier and its a bigger rotational mass, so what do u expect. you have wider and larger wheels/tires now, the engine has to work a lot more

NonovUrbizniz

like I said I went from borbet type t's to heliums and my milage went from around 300 mi. per tank to as much as 340... usually both to about 10 gals. I don't keep records so I'm guestimating but it did improve quite a bit and I get on it more often now.

however like I said... check your brakes... they shouldn't be able to adjust out dragging calipers... it means that the piston is scored or there is debri in there causing the piston not to retract... this would DEFINATELY have an affect on mpg.

Jack your car up and leave it out of gear... do the wheels spin freely or is there considerable drag... with a good spin they should at least spin once on there own...

If they're sticking then maybe your hubs need to be replaced or the caliper is dragging...

that's the most I can offer...

EricUSC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">
there is no way to "adjust" the brakes so they clamp all the time (other than improperly adjusting the booster but then your brake lights will ALWAYS be on.) there is a GOOD chance that if these were on a race car just about ALL of the parts are worn excessively...
</TD></TR></TABLE>

The mechanic adjusted the FRONT brakes from some kind of screw from where the pedals are located (from inside the car). Does anybody know what that screw is for and what it does? After I had my car towed back to the shop, he adjusted it really loose to the point where the brakes feel kind of spongy. I have an ITR master cylinder/booster, and have heard that the braking should feel very direct with that setup. The mechanic said that the rear brakes couldn't be adjusted and that everything in the back should automatically settle in. The mechanic said that the reason the brakes started to drag was because the booster was breaking in.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">
also excessive brake dust is a good indicator that the pads are always in contact with the rotor.</TD></TR></TABLE>

I have driven for around 500 miles since I got the 5 lugs, and I don't have much brake dust on the wheels.

I just IM'ed somebody who got a 5 lug and a D-Series engine, and he told me that he didn't notice a difference in gas mileage after the conversion. I would think the gas mileage may decrease slightly w/ the 5 lug conversion, but going from 35 mpg to 28 mpg is pretty big. I mean, ITR rotors are heavier, but not that much heavier than Civic rotors. I'm starting to think there may be something with the 5 lugs that is causing this decrease in fuel economy (at least I hope so).

I'm going to see the mechanic next week. I'm going to ask him to inspect the calipers and the hubs. Is there anything else I should ask him to look at?

Also, I added Mugen dampers and springs to my car at the same time that the 5 lugs were installed. Could new dampers and springs reduce fuel economy?

Greg L

i experienced some weird crap like this to, i got like 31mpg and then after my car got aligned, its been up to 38mpg, strange how little stuff can effect your gas mileage that much.

NonovUrbizniz

what he adjusted was the adjusting nut (he should have had a 17mm open-end wrench to do it (if you were watching)) on the booster... apparently it was overtightened which does draw in the brake pedal and apply light pressure but usually the brake lights will stay on (however this would NOT be the case if the brake light switch adjuster screw was loose or out... IE.. if the pedal had to travel further to trigger the light then to trigger the brakes.) If all he adjusted was the screw then there should be no impact on the brakes at all.

the best bet is just to jack up the car... for this kind of dramatic loss there should be something big... like one or both of the wheels don't spin easily at all.. that could mean still dragging brakes (probobly the calipers then) or bad hubs.

also I believe you said the alignment was done correct? if not that could be it right there... check your tire pressure and make sure it's aligned... if it's as far out as it would have to be to drop your milage like that you should see minor differences in the inside vs. outside tread... if you can get a tread depth guage or have one it should give you a decent idea... but of course the best is to have a reputable shop align your car.

other than that I can't really think of anything...

oh wait... did you notice a significant difference in drivability.. ie does it take more pedal to get just as far... I know it's hard to *** dyno but.. it should be a noticable loss in power if the mpg issue is to be attribute to the hub swap alone.

If there is not much power loss then it's probobly just the alignment because hubs or brakes putting that much drag on your car would also make you notice a significant drop in usable power... (like when you switch on ac (if you have it)).

Hope this helps... don't give up.

beeboyee

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpooN Man &raquo;</TD></TR><TR><TD CLASS="quote">It could be the increase in unsprung weight </TD></TR></TABLE>

i support spoon man!

EricUSC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">
also I believe you said the alignment was done correct? if not that could be it right there... check your tire pressure and make sure it's aligned... if it's as far out as it would have to be to drop your milage like that you should see minor differences in the inside vs. outside tread... if you can get a tread depth guage or have one it should give you a decent idea... but of course the best is to have a reputable shop align your car.

other than that I can't really think of anything...

oh wait... did you notice a significant difference in drivability.. ie does it take more pedal to get just as far... I know it's hard to *** dyno but.. it should be a noticable loss in power if the mpg issue is to be attribute to the hub swap alone.

If there is not much power loss then it's probobly just the alignment because hubs or brakes putting that much drag on your car would also make you notice a significant drop in usable power... (like when you switch on ac (if you have it)).
</TD></TR></TABLE>

I did not notice a significant drop in usable power. It could possibly be the alignment. I didn't actually have a computerized printout for the alignment job. The parts were used on a race car before, and the owner of that car told me that he had the knuckles professionally bent to make a lot of negative camber. When these parts were installed on my car, the same guy came to the shop to bend it back to 0 camber. I'm not sure if any of you are familiar with this kind of camber adjustment. The mechanic told me that they use this kind of camber adjustment for track cars that need lots of negative camber and for extremely lowered cars that cannot be corrected with camber kits. I watched the guy do the camber adjustment. The guy first made some measurements, drove one wheel on his tool, made camber adjustments, and measured again. He did this for each wheel. I was told that this guy as been doing this stuff for 15 years. Has anybody heard of this kind of camber adjustment and what is it called so I won't have to describe what he did every time I bring it up?

I asked him to set the front camber to 0 and the rear camber to -1. But when I mentioned toe-in, toe-out, and caster, the guys at the shop just told me, "don't worry, he's the expert." Is it the camber, caster, or toe that affects fuel economy? Does anybody know if this kind of alignment does anything about caster or toe, because I have no computerized printout to prove that caster or toe was adjusted?

NonovUrbizniz, thank you very much for your detailed responses. You have been very helpful.

NonovUrbizniz

No problem...

I don't know what he did... however if he knew about the camber stuff that the race dude did and how to correct it without looking like he was bsing it sounds like he did a good job aligning it...

if the wheels spin freely by hand when off the ground and you double check the alignment it's almost definately just a HUGE increase in rotating mass...

other than that I really cant think of anything. unless its something unrelated that just happened to go wrong/get messed up during the swap over.

EricUSC

One more thing. Ever since I got the 5 lugs, my driveway has a bunch of black tire tread marks. My driveway didn't have that before. Are these marks an indication of bad alignment? I have a feeling that caster and toe may not have been adjusted.