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Discussion Starter · #1 ·
hi guys.
Got a question for you!
I have read that the 09+ daytonas, have 600rpm higher rev limit.
Also I think that i have read that many people increase the rev limit of 06-08 daytonas, through TuneECU or Tuneboy, by 600rpm.
Am I right?
What conciquences would this have on a 08 bike? Possible risk of damage? Reduce of reliability? More HP?
Just curious because i was playing with my tuneECU and noticed that the rev limiter can be changed.
 

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I would be careful in raising the revs, oil flow ports in the head are bigger among other technical refinements in the 09+ bikes...... are you racing is that why you would like to raise it?
 

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You'd have more range, but you're losing power after 12 k anyay, and decreased reliability, not much use.
 

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Adding onto this.. I was just playing around in tuneecu to shut off the exup. My bike is an 11, so the redline on the tach is 15,000rpm. The rev limiter cuts in right at an indicated 15k. According to tuneecu, my bikes fuel mapping only goes to 14k, and my rev-limiter is set at 13,750 rpm.



Confused yet?
 

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Adding onto this.. I was just playing around in tuneecu to shut off the exup. My bike is an 11, so the redline on the tach is 15,000rpm. The rev limiter cuts in right at an indicated 15k. According to tuneecu, my bikes fuel mapping only goes to 14k, and my rev-limiter is set at 13,750 rpm.

Confused yet?
Good observation, but: no not confused at all, it's just an inaccurate tach. Show me a vehicle with accurate gauges out the box, and I'll show you the tooth fairy. Trust the software.

I'm certain you know at least a few guys that swear their R1 does 200mph. "but the speedo said so!!!!!1111" Same idea. :smilielol5:
 

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Good observation, but: no not confused at all, it's just an inaccurate tach. Show me a vehicle with accurate gauges out the box, and I'll show you the tooth fairy. Trust the software.

I'm certain you know at least a few guys that swear their R1 does 200mph. "but the speedo said so!!!!!1111" Same idea. :smilielol5:
Oh I understand the tach being off, thats expected. But why does Triumph advertise it as spinning 15k? The 06-08 bikes redline at 14k, why did they raise the redline to 15k on 09+ if they actually didnt change the limiter?????

Its like people who say "my speedo goes up to 180...."
 

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Oh I understand the tach being off, thats expected. But why does Triumph advertise it as spinning 15k? The 06-08 bikes redline at 14k, why did they raise the redline to 15k on 09+ if they actually didnt change the limiter?????
The 06-08 bikes DON't redline at 14k. That's just what the tach says. It's the same concept as on the 09+ bikes. You're comparing the actual redline of your bike to the tach redline of the older bikes...
 

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wow, what was the rev-limiter set at on 06-08 then. RHC over 13?
 

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I have an 07 and I raised my rev limiter to 13,750 ish, up 400 or so RPM from stock.

Even though power (on a dyno chart) drops off a little in the upper echelon of the RPM range, the extra 400 RPM allows me to pull longer in first and second especially.

I can definitely notice the difference, it just keeps pulling a little bit longer. It'll also raise the top speed by a good 10-15 MPH (not that I'll have an area to go that fast)

HOWEVER...just to be safe, I richened the fuel mixture in the RPM range above the stock RPM limit to help eliminate against detonation. (I don't remember the exact amount off the top of my head). This probably hurt power production a little bit, but it's best to be conservative up in the higher RPM's. I also leaned out the A/F ratio in cruising RPM (up to 7500) /throttle position (up to 15%) up to 14.7 from 14.5. And I leaned out the ratio at idle (0% throttle position, up to 1500 RPM up to 14.8. This will help provide better fuel economy when sitting in traffic, light throttle around town driving and highway cruising. I've already noticed a 4MPG increase. No higher temps, no pinging, no rough idle.

I'd like to play around with the rev limiter on the dyno and see what sort of power and torque it makes in the few hundred RPM above the stock limit, in addition to the A/F ratio and ignition timing.

Oh, by the way, my bike is 100% stock, no aftermarket exhaust, nothing. TuneECU is the only way I'm going to extract extra power from the bike.
 

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My stock rev limit setting on my 2007 was 13,250rpm, but when Wayne replaced my head gasket and tuned the bike for the shorty exhaust we made, he raised it to 13,600rpm and tuned it that way. That extra RPM might not make more power, but I can pull a little longer and so the -1 front sprocket with this slightly higher RPM probably has my top speed close to where a completely stock geared bike with the lower RPM would be.
 

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Unless you are racing, not only is it unnecessary but it isnt a good idea.
 

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Unless you are racing, not only is it unnecessary but it isnt a good idea.
Why not? The argument sounds as if you shouldn't make any modifications to a bike or increase its HP if you arent racing it. Thats just how the logic makes it sound.

If you are a drag racer, the rev limiter is one of two very important tuning tools in addition to gearing. You want to be going through the traps just as you're about to hit the rev limiter. So, depending on how your bike is geared, if you have to shift right before the traps, you could increase the rev limiter, allowing you to go through the traps without having to make a time-eating shift. That's one argument I just made in your favor.

But on the other hand, why isn't it a good idea to do on the street? Remember, this thread isn't about the riding conditions of the street vs track, it's about the conditions of the bike itself. This isn't an argument about riding fast on the street. So, holding that constant, why isn't it a good idea (for the bike)?

It allows you to pull through a gear longer. I always felt like my bike had more power, it kept pulling hard all the way up to the rev limiter, do by increasing it by 3-400 RPM, I just extended the powerband.

I've never gotten my bike fast enough to test the top speed, and I don't know if it's aerodynamically limited, but increasing the rev limit could increase the top speed of the bike by up to 15 mph, even with only a 400 rpm increase.

The point im trying to make is that increasing the rev limit is a free way of extending the powerband of the bike. It's not going to make anyone ride any more dangerously than it would otherwise. And usually the bike is only at that RPM for a single second at the most, unless you are going for a top speed run. It's not going to destroy the engine if you raise the limit by 3-400 rpm and take advantage of it occasionally. There are lots of other things that will happen before the engine destroys itself, like not having enough power to rev that high, valve float, etc. The main reasons engines are damaged at high RPM's is not from throttling them that high, it's from missing a shift, or downshifting so they are spun higher than they should... And the rev limiter doesn't do anything to prevent that from happening.

and depending on what parts/mods you have, you might even have the capability to make a higher peak HP amount, depending on how those parts affect the powerband. If the rev limit kicks in before those parts are designed to increase the power, it defeats the purpose of those mods.
 

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I've never gotten my bike fast enough to test the top speed, and I don't know if it's aerodynamically limited, but increasing the rev limit could increase the top speed of the bike by up to 15 mph, even with only a 400 rpm increase.
Where are you getting 15mph? All other things equal or linear, and giving stock a generous top speed of 168mph... 168mph/13250rpm = x/13650rpm, x = 173mph. That sounds like 5mph at best...
 

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Where are you getting 15mph? All other things equal or linear, and giving stock a generous top speed of 168mph... 168mph/13250rpm = x/13650rpm, x = 173mph. That sounds like 5mph at best...
Honestly, that was just a guess..

So, I did a little calculating of my own.

Since I wasn't hooked up to a dyno to get an exact tach/speed reading in 6th gear, I got some sample speeds at different RPM's. For example, at 4000 RPM (approx) I was going 46 mph. At 5000, I was going 56 MPH, at 6000, I was going 65, and at 7000, I was going 76.

When I divided the speed by the RPM, I got about .10-.11 MPH per 1RPM. I averaged the sample size to get .11203677 MPH per 1 RPM. (Take a look at the spreadsheet)

I then multiplied that by the rev-limited RPM in multiple increments, starting out at 13000 and going all the way up to 14250, just to see.

At the factory limiter of 13250, you would have a factory top speed of 148 mph.
If you increased your rev limit to 13750, you would have a theoretical top speed of 154 MPH, which is about a gain of 6 MPH.

If you increased your rev limit to 14000, you would have a theoretical top speed of 157, a gain of about 9 MPH over the stock RPM limit.

And if you were feeling saucy and wanted to go to 14250, you would have a theoretical top speed of 160 MPH, a gain of 12 MPH over stock.

For someone like me, who only increased the rev limiter a few hundred RPM, it'll only increase the top speed by 6 MPH, (Which I'll never go that fast anyway).

But for someone who is in a top speed race, has a prepped motor, doesn't care about destroying it, and can't change the gearing, this is a quick and easy way to get an extra few MPH. It wasn't as drastic as I thought, but still, you could gain as much as 16 MPH theoretical top speed if you increased your rev limiter from 13000 (below stock) to 14250 (well above stock).

These tests were done with stock gearing, in 6th gear. I didn't check any other gears to see what the theoretical top speed would be by raising the rev limiter, but it would certainly be less of an increase than in 6th gear. Maybe 2-5 MPH in second or third gear. But even still, it pulls longer.

Oh, and based on my testing, there's no way a bike with stock gearing is going 168 MPH unless the gearing is changed. 150 sounds about right.

Enjoy the spreadsheet! If you happen to run your bike on the dyno, see if you can get some exact RPM to MPH comparisons. I was only able to make mine somewhat accurate by using a large sample size and averaging it.
 

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168 seems to be the average "indicated" speed people see when redlined in 6th. It's not realistic due to the overly optimistic speedometer and some frictional losses at that velocity, but it's what people see. And I thought you said 400rpm, which would be closer 5mph.

Anyways, for everyone, I came across this article a while back which is interesting. It shows some of the math behind the actual driving force in a given gear, and why it might still be better to stay in a lower gear, even when you're beyond the engine's peak hp rpm.

http://www.sportrider.com/tech/146_0402_art/index.html
 

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168 seems to be the average "indicated" speed people see when redlined in 6th. It's not realistic due to the overly optimistic speedometer and some frictional losses at that velocity, but it's what people see. And I thought you said 400rpm, which would be closer 5mph.

Anyways, for everyone, I came across this article a while back which is interesting. It shows some of the math behind the actual driving force in a given gear, and why it might still be better to stay in a lower gear, even when you're beyond the engine's peak hp rpm.

http://www.sportrider.com/tech/146_0402_art/index.html
Interesting article, ill take a look!

The dealer said that the speedos are supposed to come from the factory " + / - 5%" which is a load of crap.

I recalibrated my speedometer, having to reduce the reading by 7.9%, almost 8%. If it allowed me to adjust to the hundredth, I would have made it 7.95% slower.

When you account for the adjustment in speedometer readings, it takes you down into the 150 range.
 
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