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Big disappointment from Triumph

13K views 60 replies 20 participants last post by  mpak 
#1 ·
Its almost 10 days that i have installed vance and hines high exhaust from scrambler inspiration kit. I had a feeling that something was wrong except from the heat on my right leg and removal of passengers foot pegs. Today i went to the dyno and dynoed the bike. Result is that the bike is underpowered and without that torquey think at low rpm. It totaled at 50,97 HP which is 2 horses less than the original according cycle worlds dyno. Bike is also reflashed from Triumph because as they say it is racing "ha ha" of road exhaust and needs to reprogram ecu (probably to underpowered it). After paying almost 1300 euros for the exhaust i will not accept a compromise of loosing money and comfort and not gaining at least something more at responsiveness and power.
Probably i will sell the exhaust which is brand new to someone that want to spend some time how to upgrade this bike.
 
#6 ·
mpak - You are apparently confused about how a dyno works. Dyno results are subject to many variables, including air temperature, atmospheric pressure, physical differences between engines, dyno operating procedures, etc., just to name a few. The same bike could easily show a 2 HP difference between two runs on the same dyno; comparing runs of different bikes on different dynos is meaningless. If you had wanted to know the effect of changing your exhaust system, you should have made a dyno run with the stock exhaust, installed the new one, and dyno'ed the bike again, preferably on the same day. The only real value of a dyno is to make such before and after comparisons on the same dyno and bike.

With that said, an engine is basically an air pump. As Haggis noted, removing restriction from the exhaust (i.e. pump output) side will only increase power if the engine was being prevented from making maximum power due to exhaust restriction. On some specific bikes, that is undoubtedly the case, due to differences in their individual engines (e.g. tolerance stacking, etc.). In other words, if you dyno'ed a lot of bikes with and without a given exhaust, some would show a significant increase in power (e.g. typically 4 - 6 HP peak) others would not. Reducing the intake restriction as Haggis suggested may increase the amount of power your engine makes, but only if it is capable of using more air. Other modifications may be required for it to do so (e.g. porting the head, installing higher performance cams, etc.).

Decades ago, factory exhausts were typically built as inexpensively as possible and replacing them with a more carefully designed and built exhaust system would almost always produce measurable power improvements. However, modern OEM exhausts are very well designed and built and such gains are no longer assured. Moreover, the loss of some low-end torque is a natural consequence of reducing exhaust restriction (i.e. it "proves" the new exhaust is functioning as intended). These are all well known facts that you could have found by reading this or almost any other performance forum. Doing so might have saved you 1300 euros or you could just wait for a clear, cold day and dyno your bike again.
 
#7 ·
I would not put to much into that cycle world dyno you may have picked up hp with your changes but you wont ever know because you never put it on the dyno stock so you could compare. all most 51 hp maybe be good for what you have.
 
#12 ·
Dear mpak, be careful that feelings alone can be very deceptive. Riding your bike, maybe in a week or two you may change your mind. If you are so convinced about your sensations, having already spent eur 1300, I would switch to original exhaust again and dyno it. Make some acceleration tests and top speed tests (if possible) for both exhausts and record your findings.

IMHO changing exhaust is more of a sound and look mod, not about strong performance gains. Perhaps your expectations were too high?
 
#13 ·
Ok the facts. Open muffler, catalyst off,Ecu reflashed for better performance. The result is minus 1 hp from a total normal bike. Why I am the only one that finds that odd? i cannot agree that the bike maybe produce let's say 49hp normal and is on gain. X engine was 67hp , cycle worlds dyno 51hp declared 55hp , mine was the black sheep ?
 
#14 ·
You have no accurate control to compare the current dump run to. As others have said, put it in the dump stock and mod and then you will know the effect. Comparing the dump results to a magazine result on a sidemen dyno and different testing circumstances isn't sound science.

I'm not saying that you're wrong but you don't really know how much it changed!


Sent from my iPhone using Tapatalk
 
#21 ·
I've heard that they had vance and Hines help designing the oem exhausts,
That's why they're so good standard, it's triumphs accessory trap that sells you better looking parts, in the case of the exhaust I think the best you can hope for is a louder noise and lighter system.
That's where that v&h scrambler exhaust comes in.. As an off road system you've lost all the weight of the cat, and twin mufflers so your bike is much lighter for scrambling around
 
#26 ·
You do not need back pressure, exhaust gasses need velocity to flow best & scavenge, bore size is critical can't see them getting that wrong.
An exhaust designed specifically for that bike with decat should flow better, perhaps there was a problem with the remap, it should pull harder without the cat restriction, either way take it back to Triumph to check it out.
 
#23 ·
talk to dealer today and show him dyne results. He almost admit that something was wrong and we arranged a new flash of the ecu and redyno. It will be interesting to see what is the range of available ecu-maps on dealers and on what purposes.
 
#24 ·
I know it's been touched on but it's also very worth repeating. Comparing your run on a different machine, at a different elevation, most likely using a different correction, and with different fuel to a run published in a magazine is absolutely 100% ludicrous. The only thing that would tell you a gain or loss are before and after runs on the same machine.
 
#30 · (Edited)
I know I had to dyno before , I just couldn't fit my , dyno and dealers time.But I have another let's say reference point. https://youtu.be/Z03AarqtMio
Remus have a before and after dyno and they are both better from what I got.
Anyway I was at dealer today and reflash the bike with a map . They have 8 different maps for street twin depending on what set up it is. I think that's works because is more responsive and have 140km very easy. More on dyno after installing open air filter.
 
#34 ·
It's quite simple to see if there's a cat in the exhaust. Can you see through it or poke a stick through it? If it's off-road it won't have chamber baffles. But seriously, there is no cat in there.

Apart from the difference in Dynos, air temperature/density fluctuations, and dozens of other small factors, the effect of changing exhausts has a lot less effect than it used to.
The key thing I'd be looking for is improved pick-up and smooth delivery, and just ignore peak power. Unless you start changing compression ratios you won't get a load more power, and many of the 'improvement' charts I've seen from dynos have had a suspiciously linear constant increase of 4-5hp over the 'before' run, simply because the operator moves the temp sensor closer to the engine (so the dyno air temp compensation is fooled).

When I worked at a dyno shop every OEM exhaust was 'tuned' to have a huge power-gap at 6000-7000rpm where noise emission levels were measured, and this was achieved purely by tuning the exhaust. Replacing it with a race can removed this completely, but had little or no effect on the peak power. Changing jets and filter could give an extra 5hp on some sports bikes, but certainly not all.

Modern bikes are designed to be quiet at all RPM, so there is no 'hole' in the power that the race cans removed, hence you won't see some awesome power boost even if you did somehow get an extra 5hp at the peak.
Even back then lots of riders asked to have the changes removed because they could "no longer wheelie it off the throttle in first and second". The fact this was because there was no longer a surge of torque after the 7K rpm hole was irrelevant, but that's the thing with opinions, preferences, and perceptions.

If you're happy with the look and sound, don't stress over it. Look at the charts at 1:16 of that Remus video to see that all that money on slip-ons made bugger all difference to power.

Re the multiple tunes, check the description text for the reason each is there. I remember it often used to be to do with things like the air injection systems for the US market or altitude related for places like Utah, so just find one that gives best A/F balance at the RPM/throttle points you want it, and go for it.
 
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