No redline on Tach?? - Jeep Compass Forum
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post #1 of 7 Old 02-09-2018, 01:43 PM Thread Starter
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No redline on Tach??

I just purchased a 2012 Compass manual shift, and noticed there is no redline on the tach. Does this mean there is no high point to revving the engine or downshifting up hills, or passing? I've never seen a manual shift car that had no redline! I also HATE HATE HATE the hill assist; is there a way to disengage it?
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post #2 of 7 Old 02-09-2018, 04:54 PM
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Don't be silly, obviously there is a safe limit and you will find the ECU will not allow you to rev past that point and common sense tells you that you should never downshift to a gear that will put you into ridiculously high RPMs.

Its not like its an exact science, you can't pinpoint "well, at 6999.9 RPMs everything is fine but at 7000 it instantly blows up". Manufactures set a limit at some point and its usually well below the true physical limit but they pick their number with longevity in mind. Your responsibility as a driver of a manual transmission vehicle is to use your common sense to keep the engine within its normal working RPM range. Its a simple given that "no, you can't shift into first or second gear while going 80 MPH, your stupid engine will be damaged or blow up!"

Read the owner's manual, it will tell you exactly what the recommended shift points are and probably will also mention the top limit of the RPMs.
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post #3 of 7 Old 02-09-2018, 06:44 PM Thread Starter
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This information is NOT in the owners manual. In fact, there are no details about the manual shift model in the owner's manual. I have owned manual shift cars since 1974, so I am well aware of RPMs. I have never seen a car without the redline - some have a wider range than others. I am trying to find out what the safe upper limit is for RPM's, since there is no indication on the tachometer. Your condescending reply was not helpful in the least.
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post #4 of 7 Old 02-11-2018, 06:34 PM
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Well I'm sorry it just seemed like a goofy question. If you've been driving manual transmission cars since '74 then you could have noticed a pattern by now. Basically all gas engines in normal cars peak somewhere between 4500 and 6500 RPMs, or a bit higher for some wound up imports. That hasn't really changed in the last... ever.

I'm googling through pictures of 2012 Compass instrument clusters and they all seem to show a red line at about 6400 RPM. I don't know if you have some aftermarket gauge inserts on yours from some previous owner or what, but it probably didn't start out life that way. Its irrelevant anyways, because as mentioned before the ECU is not going to let you rev it past a certain point and common sense says you should not downshift into a range that will put the needle higher than the gauge reads.

Not just common sense, the owner's manual spells it out too. Despite what you say, it does talk about the manual transmission on pages 298-300. On page 300 there is a table of recommended shift points as well as a warning about improper downshifting. So...

I don't wake up in the mornings looking to go online and act like a [email protected]$$ any more than you wake up in the morning and want to think of weird questions to post but in this case I have to say I feel justified in saying it is a silly question. Sorry my responses are not sugar coated enough.
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post #5 of 7 Old 02-12-2018, 01:23 PM Thread Starter
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Ha - I do not have the actual Owner's Manual, which I only discovered after you mentioned the number of pages in the OM. Instead, I have the User Guide with a grand total of 98 pages, and it literally has nothing about Tachometer or manual transmission, but there are 35 pages on the electronics. As for the redline, I must plead aging eyes - I put on my readers and low and behold there it is. I did not mean to come off as bi***y; I thought perhaps "new" cars had governors or other types of safety features to protect the engine because I couldn't see the red tick marks. I drove my Saab 9000 Aero for 20 years, and only recently retired it, so I am completely unfamiliar with new technology and mistakenly assumed that upgrades must have happened to protect the engine. There are so few manual shift vehicles available in the US now, and I really do not want a Subaru.
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post #6 of 7 Old 02-12-2018, 02:05 PM
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No worries, and I truly do apologize for my ornery responses I am often needlessly abrasive in my posts, especially if its in the morning before my coffee, but its something I actively try to work on (used to be even worse than I am now!)
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post #7 of 7 Old 02-21-2018, 09:50 PM
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My experience(s) with my 2008 Compass 2.4L w/CVT is that anywhere from 3800-4000 RPM is the engine's happy torque/pulling zone (using the Tiptronic-like manual shift feature). Anything above that, and the engine just works harder and makes more noise without any appreciable acceleration.

I got the following from a CarAndDriver review page, and it seems to concur with my assessment:

DISPLACEMENT: 144 cu in, 2360 cc
POWER: 172 hp @ 6000 rpm
TORQUE: 165 lb-ft @ 4400 rpm

UPDATE: I looked at the tach on my 2008 Compass 2.4L CVT, and there is a striped/broken red-line mark at about 6400 RPM, and solid red soon after that.

-CSM

Last edited by CompassSportMan; 02-22-2018 at 06:05 PM.
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