I drove out to Charlottesville Va last week to pick up a friends brother, he didnt believe me when i told him the fits slow, so i showed him...

i was in third gear and we were watching the rpms slowly creep up, when it hit 6,500 it then dropped to 6,000 then crept back
up to 7,000 where i shifted (obviously) and the whole time my foot was jammed to the floor, i tried it again and it did the same thing.
i NEVER ride at high rpms (especially in 3rd) so i never noticed this, has anyone else noticed this??



and dont worry, it was an empty highway

 

That is strange.

The RPM changing like that makes me think of either the Rev limiter kicking, which doesn't make sense if you go past it immediately afterwards. Or the car shifting itself, which wouldn't make sense if you had a manual, unless your paddle shifting an auto.

If you are paddle shifting an auto, it's possible the car auto shifted from 3rd to 4th when it hit the redline.

 

^^^ like he said

 

That's interesting. I drive an MT and listen in on the paddle talk, so in sport mode it will up-shift if you push it to the limit?

 

it does it on down-shift so it just might... auto shift when riding it at red line or just the rev limiter kickin in...

 

sadly i do have an auto. i was in sport and it definitely didnt upshift because it would have dropped more than 500 rpm

 

Well, seems like it doesn't shift from 3rd to 4th in sport mode.

Which goes to the issue, why does it do that?

If you bounce of the limiter, you shouldn't be able to go past your bounce (ie, if it bounced at 6500, you can't get to 7000). Of course, the other thing is... shouldn't it bounce a little higher (than 6500) anyway?

Another possibility... it was a shift change, but not from 3rd to 4th, but only from 2nd to 3rd. This has to be in Sport mode, because, if I'm not mistaken, it would upshift earlier in Drive mode. It's possible the OP is mistaking being in 3rd, when he's only in 2nd.

Now, what the OP needs to do... list the speeds this is happening.

In an M/T (for me)

1st can rev bounce at 30 mph.
2nd can rev bounce past 45 mph (I didn't actually hit the bounce, but it was about 6500 rpm at 45-50).
I didn't really push it much after that, seeing as I was well into highway speeds the moment I put it into 3rd.

Now, if auto has taller gears in general and if you are redlining at about 50-60 mph, then I think you might only be in 2nd gear.

 

When my car was stock I remember 2nd was good to 58MPH 3rd 80 MPH 4th 105 MPH and 5th 110 to 115MPH... The limiter kicked in at 6800 RPM.... The limiter activates at 7200 now and gets to it a lot faster but it was costly getting it that way.

 

I too have noticed this at WOT. I figured it was the i-vtec design and keeping the tq up but who knows...if feels like the rpm aren't being dropped so much but are just kind of holding. I've noticed it only on the freeway with the gas to the floor for long periods of time. Top end of 4th does the same thing . My TSX also has i-vtec but it's dohc and I have never seen this characteristic in it before. I don't know if its some how a characteristic of only the i-vtec sohc engines or not.

I've search this occurrence but haven't had much luck. This is the only thing I can find that sort of explains it.

"This implementation uses the so-called "economy cams" on one of the two intake valves of each cylinder. The "economy cams" are designed to delay the closure of the intake valve they act upon, and are activated at low rpms and under light loads. When the "economy cams" are activated, one of the two intake valves in each cylinder closes well after the piston has started moving upwards in the compression stroke. That way, a part of the mixture that has entered the combustion chamber is forced out again, into the intake manifold. That way, the engine "emulates" a lower displacement than its actual one (its operation is also similar to an Atkinson cycle engine, with uneven compression and combustion strokes), which reduces fuel consumption and increases its efficiency. During the operation with the "economy cams", the (by-wire) throttle butterfly is kept fully open, in order to reduce pumping losses. According to Honda, this measure alone can reduce pumping losses by 16%. In higher rpms and under heavier loads, the engine switches back into its "normal cams", and it operates like a regular 4 stroke Otto cycle engine."

 

re commitedtobefit08

Uh, the "economy cam" is for low rpm and low engine loads.... 6k is, as far as I'm concerned, not low rpm.

Is yours also an auto?

 

Yea I was more referring back to this...I didn't know if the rpm hold/drop was something to do with the engine mapping in "normal cams mode".

"In higher rpms and under heavier loads, the engine switches back into its "normal cams", and it operates like a regular 4 stroke Otto cycle engine."
Like I said ...I hadn't had any real luck explaining this occurrence.

Yes mine is also an auto.

 

I've been trying to get the low-down on the i-vtec engine since I bought my FIT.
I think you've found 'part' of the answer - the "i" in i-vtec is the "intelligence" part.

I've bookmarked the following links, some might have seen before, that have shed some light for me.

Honda L-Series SOHC i-VTEC Engines for the new GD Honda Fit/Jazz

YouTube - ‪i-VTEC Technology‬‎

YouTube - ‪Nice clip showing how VTEC works‬‎

Not sure I understand the RPM drop, however, nor if these links explain it. If your foot is in it - your foot is in it. AT and MT can perform differently, however, in that the AT can drop RPM on command from the ECU.

 

From what I've seen mentioned on the forum and maybe a couple of other places, i-VTEC "activates" at a lower rpm, some some claim around 5400 rpm. I think even one poster thought it was as low as 3500.

 

Nah it's definetly around 5400 rpm. Its weird though ...like the OP mentioned it will be roaring in i-vtec (5400k-6800k) climbing climbing ....then kind of hesitates and holds and dips (around 6.5K) then continues to climb..then shifts at 6800K. It's an odd sound and feeling very noticeable but it does seem to help the performance because its keeping the engine in higher rpm (close to peak hp) for that hesitation moment.
That's odd you MT guys have never noticed this. I would think it would be a characteristic of all Fits mt & at

 

I think that it's a characteristic of the AT. Fuel economy.

Would sure be nice if every one would sig their ride - yr,model,transmission. It sure helps to understand what folks are referring to.

 

It will only upshift in sport mode if the paddles are not engaged. If the paddles are engaged it will bounce of the rev limiter.

 

Updated mine for ya.

 

I've only bounced off the rev limiter in 1st gear, came close in 2nd. There's no real clear area that I would dare to try and bounce off 3rd. Even on the highway, it's close the fastest I've gone in the Fit, period.

One of these days, if the highway is clear enough, I'll try to ride out 3rd to see.

 

It's an automatic thing, kind of like an allison transmission on big rigs which is that it acts as if it has a dual stage in other words a low/high per gear that's why you get some rpm drop as if its winding up again. On mine you can only notice it when your at about 70-80% throttle but it is definetly not the engine.

 

I have experienced this too. hit 6500 drop to 6000 then continue to 6800 and shift. Could be the transmission/stator locking/unlocking before the shift?