mililani

Hi folks,

Lately I've been thinking that my 2001 Civic may have some weird engine compression or fuel injection problems. I could have sworn that my car could run 65 mph under 2.5k RPM's. Nowadays, it seems that I need to go over 2.8k RPM's to maintain that. In terms of gas mileage, it's a pretty severe difference. I can maintain 44 mpg at 60 mph, but if I go up to 65 mph (which is over 2.8k RPM's), my gas mileage drops to 38 mpg. I don't ever remember it going that low when I did long distance commutes 2 years ago for work--and, I was going around 65 mph.

So, I'm just wondering if I could get some help from this forum. Can you guys drive 60 mph and 65 mph, and let me know how high your RPM's were? That would give me a good idea if I have some sort of efficiency problem with my engine.

Much thanks

MindBomber

Pretty sure I'm right at 2500 at 60mph, will confirm tomorrow.

Balzdpr

By time i get to 60 the tranny has already switched into 4th. Im certain...cant quite remember... but im sure im somewhere around 2500 or 2800 maybe closer to 2500. However, when I rail it to 70 im just under 3000 I can fluctuate the rpm between 2900 and 3100 on my own by balancing the gas pedal finely. I can keep it under 3000. I only notice a significant fuel over consumption when i am at rpm's higher than 3000. I have tested the limits of the motors ability to hold strong at high rpm's by keeping it in 3rd gear while I floor it until I reach 50 or 55. There is a **** load more power in 3rd gear but it is more noticeable between 40 and 45.

MandM

My D17A2 5-Speed is right around 2900 rpm @ 60 mph.

scooty

The only scenarios under which your RPM would have changed from what it used to run at, are:

1) You have a manual transmission and the clutch is slipping, a lot.
2) You have an automatic and something is wrong with the torque converter or some of the clutch packs are slipping.

It has nothing to do with compression. At highway speeds, the transmission is supposed to be locked to the drive wheels so the RPM is always the same for a given speed and gear.

Civicnoobie

I have to manually shift into 4th each time by putting it into OD. I keep it in D3 literally all the time, except for the times where im on a highway or freeway and gonna be shifting over 3000rpms then i put into D from a stop.

Youre probably wondering why i manually shift to 4th by putting it into OD right?

CountryCivic

My '04 ex auto does 70 mph at 2800, 65 at 2600 and 60 somewhere between 2400 and 2500.

TFMEX

I have a manual and I'm running
2900 @ 60
3100 @ 65

MindBomber

Automatic@2450

It would be good if those with a manual indicated if they have a d17a1 or a2, the a2 manual transmission has a shorter fourth gear than the a1.

TFMEX

I assume your referring to me and I have the EX VTEC so I BELIEVE its an a2???

MindBomber

In a way, yes. It would be helpful if everyone who posts in the thread were to include that information.

Canadian Si/American EX - D17a2
LX/DX/SE/VP - D17a1

Highway speed RPM ranges seems to be a common question, it would be a good topic to dive into.

pmjr0987

same, 2900 rpm at 60 w/a2 5-speed. vtec starts at 3250 rpm so basically anything over 64, 65 mph im in vtec getting 30 mpg or so... smh is there a way to raise vtec to 4k or something? i mean it comes on 2300-3200 depending on throttle input, why not make that 2300-4k so ur not in vtec coasting 80 mph on a flat road, seems like a waist. really 5th gear entirely seems like a waist. I started to really like my civic, but the highway rpm just seems nuts. i hear you can swap in an lx, or HX 5th gear for better highway mpg and rpm which might be a good option as most of the time around town im in 4th for anything under 45

n8marsh

03 lx manual, at 70 I'm exactly 3000

pmjr0987

dam you

n8marsh

Every time I drive on the highway at 70 and see that perfect match of 3k and 70 i try the damndest to figure out the ratio of my gear. Try to calculate wheel circumference. I like long drives.

MindBomber

1st: LX: 3.461, EX: 3.142
2nd: 1.869
3rd: 1.241
4th: 0.969
5th: LX: 0.710, EX: 0.756
Rev: 3.230

Final Reduction: LX: 4.111, EX: 4.411

MandM

D17A2 Manual 2900 @ 60.

mililani

Much thanks for all the replies! I forgot to mention I'm driving AT with no VTEC. Ok, so, it seems like I'm still around ballpark average. Odd. My wife's 2009 civic, which has more horsepower so it's not an apple to apple's comparison, hits 65 mph at 2k rpms on freeway. Her car averages 40-41 mpg at this speed on long drives. I guess it's about an equal tradeoff: 5-10% lower mileage for 5-10% more speed.

sdaidoji

iTrader: (1)

Mililani,

whatever the others' answers were, scotty is of the same opinion as me. read again in a quote here.
Your problem is not engine, it's on the clutch/trans.

Or you need desperately to inflate tires or you put tires too small OD.

pmjr0987

but the rpm to indicated mph would not change with smaller tires, the actually vehicle speed vs indicated will change unless he is only comparing gps to gps before and after that wouldnt be it

BlueEM2

iTrader: (1)

Manual A2 2900@60 3100@65

sdaidoji

iTrader: (1)

point taken

bg_008

2900 @ 65-70 01 Automatic LX with 215,000 miles

GolNat

iTrader: (7)

2950 @ 70mph. 01 Lx 151,000 miles, stick original clutch. 17inch rims with 205/40/17 tires.

MatthaiN

iTrader: (1)

I know this is a seventh gen Honda question... but dang I wish I had a longer geared tranny sometimes... My Si is at 3400 at 60 and 4000 at 70... I dont even go above 70...

Brandovibe

Mine is terrible. Manual trans car in 5th gear is screaming at around 4k at 80mph. I'm trying to figure out how to gear it taller. Do i change just 5th gear or the final drive? Which is easier?

johndeerebones

So, I am fine with my 32. Like said, slippage is the only change to this. Not compression. I am betting your SOTP is changing. With those kind of mileage numbers there is nothing wrong with your car....

I'll take 75 over 65 for a mileage tradeoff any day. Mine is an EX, so it is wound tight at 75, don't care. Its a Jap engine, high rpms are par for the course (when the difference between very little HP and more is a few hundred rpms they will do what they can to put the typical user in the power range when cruising). Used to 15 mpg so 30 and up is nice...

cja3455

Mine is 05 ex manual, 3000rpm at 65mph, 4000rpm at 85mph

mikey1

this is an old thread i see,

but for what its worth, my 05 auto at 70mph is around 2800rpm

johndeerebones

lol didn't even notice