[medik418]

I just finished putting new tires on the RZR and went to 26 inch tires. I just finished the first part of a video logging acceleration times with everything stock and am going to log changes to each change I make to see exactly what difference some of these things make. Today after putting the 26 in tires on, I took it out for a top speed run to see what if any difference it made. The top speed stayed the same. The thing fell flat at 55 with the rev limiter banging its head against a wall. Yesterday with the shorter tires, same thing 55 with the rev limiter banging.
Is the rev limiter tied into the speed sensor? I would think that if the top speed went down, the rpm would as well. I would also think that if i can hit the rev limiter with larger tires, the top speed would go up.

Anyone have anything. This afternoon, I hope to get the times again to compare and will post the video tonight. :think:

 

[Vinman]

If your hitting the limiter with the taller tires your top speed DID increase.
The speedo is now reading a bit slow due to the taller tire. No matter what size tire you run, if you hit the rev limiter the speedo will always read the same (unless you somehow recalibrate it). Use a GPS to accurately measure your speeds.
Make sense?

Vince

 

[Guest]

Vinman is correct..changing the diameter of tires will throw off the speedo...
ASSuming your machine is stock...is that normal for the Std stock RZRs to 1..pull to the Rev limter and 2...at only 55 mph?
I've never had a stock Polaris that would pull to the rev limter in high range on flat ground...usually the clutching is set up so that it is loaded enough that it will keep the engine just off the hard rev limiter all day long..my RZR4 was no different when stock...I could hold it to the floor in high for 10 minutes..and it never would hit the hard limiter..granted that rev limter is what 100 rpm higher on the "s" motor..my point is I find it odd you are hitting the rev limiter at all on a stock machine,if it is stock..unless maybe you are slipping the belt or the clutches are not shifting out properly?

 

[medik418]

I'll post the video tonight of the first runs. The rev limiter hits right at 6350 rpm. I did take the GPS out a few minutes ago and it tops out at 53.2 mph with the bigger tires. Don't know what it was before the swap. The speedo does show closer to 54 mph than 55 so I guess that's what the speed sensor is reading. Fny thoough, the speedo is off around 4-5 mph from stopped to about 45 then it shows really close to the speedometer. Not that it matters, just thought it odd.
I've been hitting the rev limiter for quite a while on hard pack and sand and as far as I know the engine is stone stock. I bought it with 30 hours on it but I'm sure the seller would have mentioned any improvements he may have done.
I'm wondering about the belt thing myself. I'll pick one up this afternoon. I started making a video showing stock runs timed at 20,30,40,and 50mph as a baseline so I could show what improvements if any some simple mods would do. First the bigger tires, then the clutch spacer removed, then with one of Dale's clutches. Does Polaris sell a higher performance belt than the one that would be in there right now?
Eventually, when the tooth fairy comes by, I want to get that monster clutch Dale sells but Maw might notice that hole in the bank accont. (winter project)

 

[Guest]

I'll post the video tonight of the first runs. The rev limiter hits right at 6350 rpm. I did take the GPS out a few minutes ago and it tops out at 53.2 mph with the bigger tires. Don't know what it was before the swap. The speedo does show closer to 54 mph than 55 so I guess that's what the speed sensor is reading. Fny thoough, the speedo is off around 4-5 mph from stopped to about 45 then it shows really close to the speedometer. Not that it matters, just thought it odd.
I've been hitting the rev limiter for quite a while on hard pack and sand and as far as I know the engine is stone stock. I bought it with 30 hours on it but I'm sure the seller would have mentioned any improvements he may have done.
I'm wondering about the belt thing myself. I'll pick one up this afternoon. I started making a video showing stock runs timed at 20,30,40,and 50mph as a baseline so I could show what improvements if any some simple mods would do. First the bigger tires, then the clutch spacer removed, then with one of Dale's clutches. Does Polaris sell a higher performance belt than the one that would be in there right now?
Eventually, when the tooth fairy comes by, I want to get that monster clutch Dale sells but Maw might notice that hole in the bank accont. (winter project)

OEM belt is as good as it gets IMO...
Since you bought the machine used I would check..that it has the stock clutching..someone may have added a clutch kit..
Also make sure it has an OEM belt..and check the condition..either way if it is due a new belt you can save the old one for a spare if it is decent...ALWAYS carry a spare and know how to change it IMO...a few things can leave you stranded..most of them can be rigged..a belt failure can't be rigged very easily..if at all.

Maybe someone with a STD RZR will chime in..just odd to me you are hitting the limiter on a stock machine in high...IIRC the hard limiter is 6500 on the STD....but also the Tachs aren't known for being real accurate..oddly(for you seeing 6350) though from what I have seen they tend to read high..unless it is a transient condidtion,ie they are slow to react...but at steady RPMS tend to read high IMO..

 

[medik418]

Here is the video from yesterday. Its not finished by any means but you can hear the rev limiter kick in each run.

 

[Guest]

Obviously coudn't read the tach...but it looked like just over 50 mph when the limiter was kicking in...hopefully a STD rzr owner will chime in...but I'd say something isn't right..seems to get there plenty quick...makes me think maybe you have a clutch kit installed...maybe for larger tires? What RPM does the clutch engage? It is possible to have a clutch kit to improve acceleration without loosing top end..but it just depends on what it is set up for and whether the clutches are shifting all the way out..

 

[Riddler6.7]

I am able to hit the rev limiter in my regular rzr. Never had a problem since it was all stock, even now with 26" terracross tires and itp wheels. My tack will read btwn 6300-6500 when it starts to bang off the rev limiter.

It is obviously easier on a slight down hill but is achievable on long strait flat ground as well. Yours does seem to get there a little quicker then mine, however i cant remember the last time i tried it out on pavement...

 

[Guest]

I am able to hit the rev limiter in my regular rzr. Never had a problem since it was all stock, even now with 26" terracross tires and itp wheels. My tack will read btwn 6300-6500 when it starts to bang off the rev limiter.

It is obviously easier on a slight down hill but is achievable on long strait flat ground as well. Yours does seem to get there a little quicker then mine, however i cant remember the last time i tried it out on pavement...

Maybe normal then....I've just never had a Polaris that would...even my 850 Sportsman..70hp..it would run 10 miles at WOT @ 75mph or so and never bang the limiter...I've never owned a STD RZR though.

 

[medik418]

Today i held the throttle pinned and the limiter held the engine firm at 6350 rpm. I noticed that too

 

[medik418]

Obviously coudn't read the tach...but it looked like just over 50 mph when the limiter was kicking in...hopefully a STD rzr owner will chime in...but I'd say something isn't right..seems to get there plenty quick...makes me think maybe you have a clutch kit installed...maybe for larger tires? What RPM does the clutch engage? It is possible to have a clutch kit to improve acceleration without loosing top end..but it just depends on what it is set up for and whether the clutches are shifting all the way out..

That was the camera angle. It kicked in at 55 mph every run

 

[Guest]

Today i held the throttle pinned and the limiter held the engine firm at 6350 rpm. I noticed that too

Well...the rev limiter is supposed to be at 6500..according to the EFI secion of the service manual..
"To prevent engine over-speed and possible failure, a revlimiting
feature is programmed into the ECU. If the maximum
RPM limit (6500, RZR), (6600, RZR S) is exceeded, the ECU
suppresses the injection signals, cutting off the fuel flow. This
process repeats it self in rapid succession, limiting operation to
the preset maximum"

But in the specs section it says max operating RPM 6500+/- 200...so who knows..400 RPM is a pretty wide range IMO..guess it is what it is..
In anycase I think your machine is running to 55 pretty darn good..just not used to seeing a stock machine bang the limiter so easy like that...maybe you got a strong one

 

[Riddler6.7]

actually there is a soft limit which is at 6375 for rzr and 6550 for rzr s at which timing suppression occurs, then the hard limit comes at 6500 &6600

sect 4.11 of the 2009 service manual...

 

[Guest]

Yes that is why I said "hard" limiter ...you don't hear/feel the soft limiter...hence the "soft",it is subtle power reduction...in the vid that is the "hard" limiter...
The soft limiter is another reason it was odd to me for a stock machine to hit the hard limiter in high.

 

[medik418]

Finished the new belt and removed the clutch spacer then ran it after a little warm up time for the belt.

 

[Guest]

Good info..
I saw your other thread..it does look like you have stock clutching. Like I said I've never ran a stock STD RZR top speed..just never had a Polaris that was set up where it would hit the limiter..guess the set up the Std RZR different than the ATVs