noah89

When you look in the rearview mirror and you see two big black snakes chasing you, then and only then are you using the clutch correctly from a standstill.

AU N EGL

What are you doing in 5th gear at 37mph? Depending on your rear gearing 37mph is 3rd or 2nd gear.

Other wise yes the engine was just lugging along which I dont think is too good for your cars engine and drive train.

Crimsonnaire

iTrader: (1)

I can shift into 5th at 35mph and 1000 RPM without hearing any engine growl. At 10mph, I shift to 2nd. At 18mph, to 3rd. At 28mph, to 4th. At 35+, to 5th and usually cruise at around 1500 RPM. All this without growling and vibration. The engine sound is of course at a lower pitch at 1000 RPM than at 1500+ RPM, but no growls or vibration.

I've read where people detect lugging in 5th at 1500 RPM, but I can't see how. There simply isn't any growling and shuttering to indicate this. At least not for me.

I don't know what rear end/gear ratios I have, though. But I'm assuming it's all stock.

clubber

All this talk of how low of RPM's you can go and be OK isn't good. Quit it. 1000 RPM in 5th isnt desirable. Yea you may get by with it for a good long time but in general don't shift before 2K RPM. Just like bouncing off the rev limiter all the time isn't good, neither is lugging all the time. Middle of the tach is good. Now I'm sure some will argue but stay a little farther from the bottom of the scale when you can. OK rant all done.

Crimsonnaire

iTrader: (1)

Well, I have no problem shifting after 2k RPM. But judging from this specification, how is anyone supposed to skip shift without lugging the engine?

Amoretti

iTrader: (4)

Hit the gas in first so that you build up enough inertia to not stress out the car when shifting into fourth. I do it all of the time with no problem.

And also, (thought it was appropriate for this thread) I have a friend (with an S10) who preaches that in order to obtain maximul fuel efficiency, one must constantly lug the engine through every gear while flooring it. So that is what he does, 24/7.

EDIT: I would also recommend finding something else to worry about. If shifting early is the pinnacle of your worries, I truly envy you.

jmmullin

iTrader: (2)

i call that 'bogging' but have heard lugging too.... bad for gas mileage. but so is a v8; mehh.

clubber

Oh, My Ls1 is in an RX-7 so I never had the skip shift problem. Sorry about that.

Crimsonnaire

iTrader: (1)

What RPM do you go up to in 1st before going into 4th? I've been shifting at 2k RPM, but always compensating by giving little gas for the RPM to go up in 4th before full acceleration. Here, the difference between a smooth-but-slow acceleration and lugging is the amount of gas you give--at least in my experience. So why do I believe that a low throttle at a low RPM isn't lugging? This is because you're not putting more gas into the combustion chambers than there is volume per down stroke of the pistons as allowed by the gear ratio resistance/load. But I've only recently learned that this actually decreases the gas mileage, as I'll explain in the next paragraph.

I had an interesting read from the operater's manual yesterday. I went to manual transmission operation page, and there was a chart showing the recommended speeds to shift for best gas efficiency. The chart shows 15mph to shift into 2nd, 25 into 3rd, 40 into 4th, 45-50 into 5th, and 55+ into 6th. After speaking to another tech at a Pontiac dealership, I was told that it's a case of the RPM vs gear ratio. If you accelerate under a low RPM with the same amount of gas, you'd be using more gas to push the car than under a lower gear of the same RPM. In other words, you have more momentum against the gas that would be pushing more efficiently under either a higher RPM or lower gear. So it's an issue of minimizing the acceleration time to reach the cruise speed. But wouldn't the more RPM used by this equate to the lost gas under less RPM? That's what I thought, but apparently not the case.

This leads me to a question I've been wondering for some time. If you travel on the freeway in 6th gear and it takes 20 minutes to get to point B at 1500 RPM, would you save or use more gas if you go at 2500 RPM and get there in 12mins? So in essence, does the faster travel time cancel out the lower RPM?

And before someone complains about the 1500 RPM in 6th, this is the unavoidable result of shifting under the recommended speeds from the manual. I tested this yesterday on the freeway. I went up to 60 in 5th and then shifted to 6th. Once I went into 6th, the RPM dropped to around 1500.

melchoir

iTrader: (4)

1500 in 6th is fine. I have no problems with 1200rpm in 6th, but I also live in flat *** Florida.