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Loss of low end torque with slip on.


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33 minutes ago, Sulli said:

Maybe this is the route to go.  What was the cost?

 

$264 , they are in Seattle area so you could take a road trip and save on shipping.  They are a Vendor on this board and have been tuning this engine for many years.

https://www.tenere700.net/forum/25-2-wheel-dynoworks/

 


This product is intended for closed-course competition use only. Use of this product for any other purpose is strictly prohibited. By purchasing this product, you acknowledge that the product and/or service being purchased is...

 

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43 minutes ago, Cruizin said:

$264 , they are in Seattle area so you could take a road trip and save on shipping.  They are a Vendor on this board and have been tuning this engine for many years.

https://www.tenere700.net/forum/25-2-wheel-dynoworks/

 


This product is intended for closed-course competition use only. Use of this product for any other purpose is strictly prohibited. By purchasing this product, you acknowledge that the product and/or service being purchased is...

 

Is it a standard generic tune?  Focused for off road or road?  Or is the tune for specific mods?

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On 6/23/2022 at 3:11 PM, Sulli said:

I ran the exhaust with the disk db killer/flow restrictor, then with the addition of the bolt in db killer, then, without any.  I cannot say other than noise, that there was any dicernable difference.  Then I pulled the the exhaust and replaced the OEM.  The difference was night and day.  With the OEM, the low end pull throughout the gears, is crisper and sronger.  Not satisfied with just my opinion, I recruited a long time riding buddy, proceeded to pull the OEM, installed the huzar and had my buddy ride with the same configurations as above.  I then pulled the exhaust and had them ride the OEM.  They were 100%  sure the OEM achieved better power throughout the gears low down in the rev range.  So the stock is back on and here to stay.  As I mentioned before, I do a lot of offroad riding and one of the sweetest parts of the T7 is that crisp low down torque througout the gear range, its where my bike lives when I am off road, and I would not trade that for anything.

 

Any way you can try another exhaust, same brand or otherwise?

 

My experience with exhausts has always been more oomph right of idle in first gear. But no increase anywhere else. Dynos do not measure right from idle, and the engine is run at a steady increase in high gears. This doesn't reflect the acceleration of the engine in actual riding. This is why the graph never communicates the feeling the rider gets.

Additionally I've found the noise bungs to always affect the performance. Different bikes/exhausts have different results but generally they always brought the performance back down to the OEM exhaust, and sometimes made it worse.

 

 

To clarify, four strokes don't benefit, and are negatively impacted from back pressure. The back pressure idea comes from the exhaust tuning in some two strokes that does increase performance. In a two stroke the exhaust and compression stroke are the same. So by having a bit of back pressure you can prevent the fresh intake charge from escaping out the exhaust, and effectively increase the compression ratio.

 

Also while like most new bikes the T7 does run lean (particularly at low throttle and rpm), it's not that lean. In any case it's fuel injected and can compensate for the changes caused by intake and exhaust modifications. While re-tuning is a great idea it's not going to be the cause of your problem. This is just a myth carried over from most carburetor bikes that can't compensate for intake or exhaust changes. (or air temperature, altitude and other factors).

 

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2 hours ago, Sulli said:

Is it a standard generic tune?  Focused for off road or road?  Or is the tune for specific mods?

Call them on Tuesday, i dont work there. I have them tune all of my bikes because of the factory lean/exhaust even leaner issue. I do it for engine safety, but in this case it also lowered the temp for the fan to kick on, which helps greatly on the trails during summer months in the rockies, also got low end boost and a few hp over stock. 

 

Have you not wandered into their section here on the forum. They have tuned hundreds of our bikes, thousands from the MT07 forum. Nels is Legend. 

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4 hours ago, Hogan said:

Any way you can try another exhaust, same brand or otherwise?

 

My experience with exhausts has always been more oomph right of idle in first gear. But no increase anywhere else. Dynos do not measure right from idle, and the engine is run at a steady increase in high gears. This doesn't reflect the acceleration of the engine in actual riding. This is why the graph never communicates the feeling the rider gets.

Additionally I've found the noise bungs to always affect the performance. Different bikes/exhausts have different results but generally they always brought the performance back down to the OEM exhaust, and sometimes made it worse.

 

 

To clarify, four strokes don't benefit, and are negatively impacted from back pressure. The back pressure idea comes from the exhaust tuning in some two strokes that does increase performance. In a two stroke the exhaust and compression stroke are the same. So by having a bit of back pressure you can prevent the fresh intake charge from escaping out the exhaust, and effectively increase the compression ratio.

 

Also while like most new bikes the T7 does run lean (particularly at low throttle and rpm), it's not that lean. In any case it's fuel injected and can compensate for the changes caused by intake and exhaust modifications. While re-tuning is a great idea it's not going to be the cause of your problem. This is just a myth carried over from most carburetor bikes that can't compensate for intake or exhaust changes. (or air temperature, altitude and other factors).

 

 

At the risk of opening up a can of worms, the whole "back pressure" thing is a misnomer. The relevant properties of exhaust (and intake) as it relates to power levels and area under the curve are velocity and pressure. As I'm sure you know, exhaust flow is not a smooth linear event, but a lot of pulses stacked up on top of each other. This effect is reduced when you're dealing with a forced induction situation like superchargers and turbochargers, but when dealing with normally aspirated internal combustion engines it's relevant just as much now with fuel injection as it was in the days of carburetors. Method of fueling does not change the need to maintain escape velocity for spent intake charge,  nor the properties induced by cam timing and ignition timing.

 

In the most general of senses, your engine is going to produce X number of HPs/torques in normally aspirated form, that being directly proportionate to bore, stroke. cam profile, ignition timing, and volumetric efficiency. You can tweak and tune, but the gains/losses are generally fairly minimal unless you start changing a lot more than just the exhaust. On an otherwise stock engine, opening up the exhaust  more often than not shifts the existing power output up in the powerband, and opening up the intake shifts it down in the powerband.  This is due to the escape velocity of a spent intake charge needing to be maintained to adequately clear the combustion chamber so more fresh air and fuel can make its way in, and the more fresh air and fuel you have in there when it goes boom, the bigger the boom. The powerband shift comes from the peak escape velocity being attained at higher or lower piston speeds, depending on which side of the flow path you alter.

 

As a couple gents named Bernoulli and Venturi once described, the pressure of a fluid in motion is reduced when you increase velocity, and you can increase velocity by constricting its path. This is why airplanes fly, why your air compressor driven vacuum pump works, and why people put those fun looking "trumpet" looking tubes on the intakes of hotrods. In this context, less pressure and higher velocity on the exhaust side of an internal combustion engine scavenge more spent exhaust gas and make more room for fresh air and fuel for any given cam profile, and while the effect is far more noticeable on 2 stroke engines than it is on 4 stroke, it's still entirely relevant as they're both just pumping air. It's also a bit more important on poly-cylindered engines than it is on thumpers. The only impact you'll see by changing one side of the flow (intake or exhaust) is shifting the powerband around a little bit. Change both and you might get some small gains and a bit more area under the curve.

 

The engineers designing these engines have access to and the skills to use some heavy duty CFD/Computational Fluid Dynamics software, and there's a reason things are what they are from the factory. Emissions is a part of it yes, so a slight enrichment is due (in my opinion), but they know that numbers sell machines. They have zero motivation to cheat anyone out of peak power numbers on machines they get paid to design. Personally I prefer more usable area under the curve in a usable RPM range than I do peak dyno-queen numbers.

 

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37 minutes ago, nihil said:

 

At the risk of opening up a can of worms, the whole "back pressure" thing is a misnomer. The relevant properties of exhaust (and intake) as it relates to power levels and area under the curve are velocity and pressure. As I'm sure you know, exhaust flow is not a smooth linear event, but a lot of pulses stacked up on top of each other. This effect is reduced when you're dealing with a forced induction situation like superchargers and turbochargers, but when dealing with normally aspirated internal combustion engines it's relevant just as much now with fuel injection as it was in the days of carburetors. Method of fueling does not change the need to maintain escape velocity for spent intake charge,  nor the properties induced by cam timing and ignition timing.

 

In the most general of senses, your engine is going to produce X number of HPs/torques in normally aspirated form, that being directly proportionate to bore, stroke. cam profile, ignition timing, and volumetric efficiency. You can tweak and tune, but the gains/losses are generally fairly minimal unless you start changing a lot more than just the exhaust. On an otherwise stock engine, opening up the exhaust  more often than not shifts the existing power output up in the powerband, and opening up the intake shifts it down in the powerband.  This is due to the escape velocity of a spent intake charge needing to be maintained to adequately clear the combustion chamber so more fresh air and fuel can make its way in, and the more fresh air and fuel you have in there when it goes boom, the bigger the boom. The powerband shift comes from the peak escape velocity being attained at higher or lower piston speeds, depending on which side of the flow path you alter.

 

As a couple gents named Bernoulli and Venturi once described, the pressure of a fluid in motion is reduced when you increase velocity, and you can increase velocity by constricting its path. This is why airplanes fly, why your air compressor driven vacuum pump works, and why people put those fun looking "trumpet" looking tubes on the intakes of hotrods. In this context, less pressure and higher velocity on the exhaust side of an internal combustion engine scavenge more spent exhaust gas and make more room for fresh air and fuel for any given cam profile, and while the effect is far more noticeable on 2 stroke engines than it is on 4 stroke, it's still entirely relevant as they're both just pumping air. It's also a bit more important on poly-cylindered engines than it is on thumpers. The only impact you'll see by changing one side of the flow (intake or exhaust) is shifting the powerband around a little bit. Change both and you might get some small gains and a bit more area under the curve.

 

The engineers designing these engines have access to and the skills to use some heavy duty CFD/Computational Fluid Dynamics software, and there's a reason things are what they are from the factory. Emissions is a part of it yes, so a slight enrichment is due (in my opinion), but they know that numbers sell machines. They have zero motivation to cheat anyone out of peak power numbers on machines they get paid to design. Personally I prefer more usable area under the curve in a usable RPM range than I do peak dyno-queen numbers.

 

MT10 Tune produces 15 kick kick ya in the arse hp and a bunch use useable tq. Some bikes, it's much less hp gain but again, I have nels tune my bikes for a variety of reasons. On my old FJ-09, it was limited to 110 MPH without a tune.  On the Tenere 700 I got some hp and TQ, and am getting the most out of my Wings exhaust and Foam airfilter with a matched tune for that exact setup.  Many cars are same way, hardly any benefit to exhaust change only but add a matched tune and power is gained, safely if done correctly.  Again, to me the biggest thing I was looking for from my T7 tune was to drop the temp where the fan kicks on from 215F down to 200F.  215F temp is fine for street, but I found it way to hot on the trail in the rockies here in the summer. I also enjoy no longer having that annoying factory deceleration fuel cut off.  

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7 minutes ago, Cruizin said:

MT10 Tune produces 15 kick kick ya in the arse hp and a bunch use useable tq. Some bikes, it's much less hp gain but again, I have nels tune my bikes for a variety of reasons. On my old FJ-09, it was limited to 110 MPH without a tune.  On the Tenere 700 I got some hp and TQ, and am getting the most out of my Wings exhaust and Foam airfilter with a matched tune for that exact setup.  Many cars are same way, hardly any benefit to exhaust change only but add a matched tune and power is gained, safely if done correctly.  Again, to me the biggest thing I was looking for from my T7 tune was to drop the temp where the fan kicks on from 215F down to 200F.  215F temp is fine for street, but I found it way to hot on the trail in the rockies here in the summer. I also enjoy no longer having that annoying factory deceleration fuel cut off.  

To be fair, I'd wager those gains come from ignition timing changes. Manufacturers do pull timing quite a bit by default to account for variation in fuel quality, where a tune will generally specify higher octane fuel to avoid risk of knock/pre-ignition/detonation. You should be able to realize similar gains with just an ignition map change both with stock intake/exhaust and with aftermarket. The same powerband shift applies.

Side note, do I read correctly that the 2022+ has a different ECU and is less tunable?

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2 minutes ago, nihil said:

To be fair, I'd wager those gains come from ignition timing changes.

 

Moreso on the T7, where I assume the slugging low end is mostly about increasing traction & rideability off road.

I've always though that this is a bike that would beneft from having a simple A-B riding mode option.

 

50 minutes ago, nihil said:

 

At the risk of opening up a can of worms, the whole "back pressure" thing is a misnomer.

 

We haven't even mentioned scavenging yet 😉

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3 minutes ago, Hogan said:

 

We haven't even mentioned scavenging yet 😉

 

That's because 2-smokes are the devils cycle. 🤘

 

Same principles apply though, they just rely on it a lot more heavily to tailor the output curve.

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13 minutes ago, Hogan said:

A-B riding mode option

A-B riding mode options are the devil's cycle.

We are all tattooed in our cradles with the beliefs of our tribe

~Oliver Wendell Holmes~

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3 hours ago, Hogan said:

 

 

Moreso on the T7, where I assume the slugging low end is mostly about increasing traction & rideability off road.

I've always though that this is a bike that would beneft from having a simple A-B riding mode option.

 

 

We haven't even mentioned scavenging yet 😉

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