jwhert

i didnt read all the posts, someone mightve said this, but doesnt it say what speed to get into 6th at in the owners manula, or rpm maybe, not speed

98camaroLS1M6

iTrader: (35)

In my manual it says to shift into 6th for best mpg, obviously shift to fifth or four if you need to accelerate more quickly. Some Cammed engines don't like low rpm so maybe keeps at least 1800rpms on highway. My 236/236 doesn't mine shifting into 6th at 55mph at all. It all comes down to preference and how your engine feels at lower rpms, if it feels like its bogging downshift to fifth.

GETGONE

iTrader: (5)

LOL...most of you guys crack me up. I put it in 6th at 40mph on my stock M6/3.42 car. If I want to accelerate, I'll downshift but just crusing I leave it in 6th all the time above 40mph. I can run the car hard through 1st and 2nd to redline then drop it in 6th can cruise. I still get 21-24mpg depending how hard I get on it taking off. That's the same or slightly better mileage than I get with my 4 banger 5 speed regular cab Sonoma. I've gotten 27mpg on the highway with it a couple times. If you keep it out of the higher RPM's when cruising it has a huge impact on your mpg. I'd much rather be driving my SS than my Sonoma considering I can get the same or better mileage!

1995vert

I have a M6 with 3.42's and I drive 80 mph at about 17-1800 rpm. Get 27 mpg and have the top down to enjoy the sun....

WERD.....(WTF was that?)

Adnectere

It seems as if some interesting things happen. There seem to be two schools of thought - one that says to shift without bogging, the other that says its fine to be in 6th no matter what. In fact, I'd say that most guys who are in the second camp brag about using the higher gear at ever lower rpms. And btw we all know that even though 4-6 are technically overdrive gears, 6th gear is blatantly a highway-only gear.

Here's something in addition to our previous poster on pumping losses for a little technical juice. I'm not sure how heat and time losses affect matters. This is from Taylor's #1 book p 474 (I know most of you guys have it ) "For spark-ignition engines...performance maps nearly always show best fuel economy in the range 1000-1400 ft/min." So if your motor is a LS1, it has bore x stroke of 3.9 x 3.62 in. That means that your best fuel economy (if Taylor's generalization holds) would be from 1000-1400 ft/min or 1657-2320 rpms.

Is it any wonder why on the highway in 6th gear your motor is designed to turn ~1500 rpms?

DriverJ

60+ is almost always 6th for me, unless I wanna hear it roar, or I'm accelerating. ..

hotrod_bljak

iTrader: (3)

Like everyone else is saying. I drive in 6th at 60 and above. Anything under I stay in 5th. I hope you found your answer.

jwhert

i was doing 63ish down the interstate in 6th and got worse gas mileage than i was doing 70 in 6th, so i wouldnt suggest using 6th under 65 or so, but then i dont know what mileage u would get in 5th at 63, so just go 70 in 6th

redhead

Sixth, fifty and up ,and plenty of power.

KipMaslonka

iTrader: (9)

im the same as getgone, about 40mph i shift into 6th as long as im only interested in maintaining speed. if im ever accelerating at all i downshift, but with the sole purpose of maintaining speed 40+=6th gear.

one thing that makes me think this was the skip shift (before i did the !cags mod): the cpu wants you to shift into 4th to bring it down to like 700ish rpm. so it must not be harmful to have it run down at 700rpm as long as its not under the load from acceleration, if the output torque is as low as it is in 6th right?

Venkman

iTrader: (4)

I cant believe some of you guys use fifth for highway driving between 55-65. Always 6th for me.

Wesmanw02

iTrader: (4)

Definitely 6th gear. Why turn the extra RPM's if you don't have to?? The LS1 is more than happy enough running in the 1200-1500 RPM range on flat, level highway.

BuffJoeyD

iTrader: (2)

It must depend on the car. @ 900-1300 my car runs fine in 6th I use it in town. I can pass people without downshifting or giving the car more then 35% throttle. - 370 Lq9 , 224/224 cam Mac headers - But the car really only weights about 3200-3300 on the road. I think with a full stereo / interior - It would bog much sooner.

sdm1234

iTrader: (8)

haha now THAT cracks me up. 6th gear at 40mph? Do you realize how bad that is for the injectors? Those things will coat themselves in no time if you keep that up. That is definitely not recommended and I don't care how good your gas mileage is. I've had my once-stock car up around 23-25mpg at every fill-up just with backroad driving, and breaking the tires loose at just about every intersection. Just because you skip 4 gears at a time, that doesn't mean you're skipping that much more load on the engine. You're unknowingly damaging your motor's internals with those driving habits. Doing all these little shortcuts are useless and only put more stress on the less-obvious parts of the vehicle. Stick to what the manual says; it's written that way for a reason.

Wesmanw02

iTrader: (4)

Ok maybe I'm missing something but how do you figure that?? How does driving at a low RPM damage the injectors and engine internals?? I could see how bogging the engine (like flooring it to accelerate at a low RPM in 6th) is rough on it, but if you're just cruising along at 40MPH in 6th gear at 1/8 throttle, how is that bad for anything?? There's no harm in that at all, so long as the engine isn't bogging/struggling.

GETGONE

iTrader: (5)

According to your philosophy, the car idling at 800rpm or so is bad for it then? Oh..and I dont' skip 4 gears..I skip 5. I'll full throttle to 40-45mph in first then drop it in 6th and cruise along. 18K miles and not a hiccup yet. No oil use, no heistation, just great power and mileage. I'm not trying to skip any load. I get it up to speed and then cruise in 6th. If/when something breaks or goes wrong I'll be sure you're the first to know ok?

orangeapeel

iTrader: (18)

With the cam I run! I put that bitch in 6th anytime I can stand to do so.

orangeapeel

iTrader: (18)

You definitely dont want to run too low RPM's under a load though. It causes some crank stress if I am not mistaken.

Tobynine9

iTrader: (17)

I match revs and downshift to 5th if speed drops below 60 mph. I do lots of driving in traffic and don't like waiting on the engine to build revs and speed from 1300 rpm in 6th.

KENS_SS_4

I cruise in the two over drive gears (5th & 6th) when ever possible. I will cruise in 6th gear often lower then the 55-62 mentioned in the first post. I use the best gear for accelerating based on the conditions and needs of the moment.

I have averaged 21 miles per gallon over the past four years (with 30K miles of records). I drive my car like a sports car, no need to granny it for mileage. I make great time where ever I go. I don't speed up for a red light just to slam on my brakes. I look as far ahead as possible. "Vision and control, speed is a byproduct" (Gone in 60 seconds).

These engines make great low end torque. They were designed for trucks! GM was going to **** can the whole Corvette program in the mid 90's. The Corvette guys spoke up and pionted out to the GM brass that every new inovation that they were working on for the new C5 was crossing over into all the future cars and trucks. So the brass gave them their jobs for a while with the clear under standing that the LS1 better be a great truck engine design. That is why the 5.3 is basicly just a cast iron version of the LS1. That is also why these engines are so bullet proof. That is also why they cruise easily at such low low low RPM's.