Accelerating slowly is not good for fuel economy... mashing the pedal all the way down isn't good either, but slow acceleration kills fuel economy too...

 

It doesn't matter...it was about using the clutch, not getting the best MPG. I know all the theories about accelerating and how it affects fuel economy, as there is plenty of evidence to suggest that accelerating more briskly is more efficient than what is preached to us.

I could have said, "Let's say I tell you to accelerate slowly to keep from spilling your coffee..."

I was trying to make a point that when going slowly, it's easy and quite acceptable to engage the clutch nice 'n' easy. For cripes sake, you want a slow, steady, nice ride...enjoy your nice delicate clutch movements. It ain't like anything terrible is beating the clutch down, but...

...under hard accelaration, if your goal is to have a sweet and precious/delicate clutch engagement, the clutch will have to be engaged slowly, and while you might not thud into gear, the clutch absorbed a helluva lot of friction to mask the thud. The thud energy went somewhere, and that 'somewhere' is into friction and clutch wear.

 

heres a video of me taking off..

can u tell me what im doing wrong i know its SOMETHING

http://break.com/index/the-differenc...hird-gear.html

 

Ouch. First gear = SUDDEN deceleration!

 

I've always double-clutched on my downshifts (I know, waste of time, but it's a habit I learned on the track), but I'd like to master rev-matching. Do you simply hold the throttle at the desired RPM, or do you blip it and engage the clutch as the revs hit the right spot?

For instance, if I'm downshifting from 5-4 and want to engage at 4.5k RPM, would I hold the throttle at 4.5k or blip it and simply engage when the revs fall back to 4.5?

 

man thanks for the info! i keep holding my clutch down on uphills, iono why X_X

 

I blip.

"...hold the throttle at the desired RPM..." implies a significant lag time between gears. I just see rev matching as a blip you do as the shifter passes from one gear down to the next (which you know you've done right if when you engage the gear below the rpms pick up right where you left 'em.

That's just how I do it.

 

WTF since when if holding clutch and giving gas good??
Doesn't that burn your clutch?? Its cool if your racing, but to downshift like that all the time... sounds a bit stupid!!

 

Any time you have the clutch partially engaged/disengaged, you are wearing the crap out of it, especially under hard accel and higher engine speeds - think Disc Sander. With the engine spun up, having the clutch in contact but not fully engaged is just another form of slipping the clutch, which I think everyone agrees destroys its life at low speeds, because you can't avoid smelling it. Now add to that a very fast spinning fine abrasive surface, like a disc sander, you don't have to press too hard to remove a lot of material.

Honestly IMHO the Nissan OEM Value-crap clutch is a POS that can't handle the VQ motor in our cars driven hard, BUT, with a decent clutch, like the JWT I use, it's ON then OFF, quick as you can, there's no "THUD". Lengthening out the time ("engaged slowly") will fry your clutch as fast or faster than slipping it starting out from a stop. The OEM clutch just cannot handle really being driven hard, it's underspec'd for clamping force to save them potential transmission problems and make the clutch more girly-girl friendly.

That THUD you hear is probably the sound of the massive OEM dual-mass 32 lb flywheel slamming into the clutch plate, another item I use as an ornament today, running a 12-lb JWT FW instead. That's the one a dealer will try to charge you $1100 for a replacement and tell you it cannot be resurfaced...

I have >10k additional miles on the JWT than I got out of the OEM clutch total (just 30k), and it's still as solid as ever. With 200 ft-lbs of torque after about 1800 rpm to redline, the car is setup great to kill a weak clutch if you misuse it or abuse it. It's designed for that person who thinks going above 4k on the tach is "pushing it"...

As far as " accelerating more briskly is more efficient" you must not have the NAV with instantaneous MPG or you would not say that. It's common sense that it takes more energy to accelerate a given body of mass at a higher rate - faster rate of change of acceleration, more energy required.

Under brisk acceleration the MPG drops to about 5 MPG, under steady and gentle acceleration at any speed, it's hardly ever worse than 20 MPG, and over 30 MPG when you're just cruising in 5th or 6th gear above 50 mph. If you push a little, it hardly moves, but if you're not smooth with the throttle, easy on and easy off, the MPG takes at least a ~5 MPG hit on average.

That's why some people see 17-18 around town vs. 20-21, and 25 at best FWY instead of closer to 30 MPG. I occasionally drive the car hard and I still see 20 MPG a tank all 2-lane backroads, no FWY, with plenty of stop signs and lights. If I'm "brisk" away from those stops, MPG suffers easily 25%.

 

As for MPG, I tried the slow and steady and the brisk and steady styles. The slow ans steady gives me a much better econ on my trip computer in my work truck.

 

Yep. It makes the difference between 10-12 vs. 14-16 mpg in my Dodge, it's not the biggest truck on the road (1500 Quad Cab) but that HEMI is thirsty when you put your foot into it - 8, 10 mpg. When I load it up, firewood for example, it rides better, and if I'm smooth, I get my best fwy mpg. Still better than my old Chevy Cheyenne, '72 3/4 ton 4x4, 350 with only 210-220 hp, it emptied the main and saddles at an amazing rate

 

There are studies that show slightly brisk accel up to cruising speed is better than slower options.

Also, read my post again. No where do I encourage riding the clutch.

As a rule, slower is better, but there is a point where something slightly more brisk than very slow is actually MORE efficient.

 

If anyone wants a lesson in MT step into my G.

 

thx for the info...

here's a simple ? for you. i've heard different things about the clutch. should i push the clutch ALL the way down to the floor or just enough so that it engages (i think it would be slightly more than half way) for shifting?

thx in advance...

 

Thread title should be "How to drive a manual transmission for idiots"


And to the above question, its safer to push it in all the way. If you push it in just enough, it could cause premature engaging when you are letting it out and cause you to grind the gears. However, if you know how to put the shifter in gear you will be fine.