anyone read/speak italian? GPR sent me this dyno report

[RoninJames]

So I emailed a guy selling GPR exhausts for the rc390 on ebay in italy asking if there was any dyno testing results i could see and he sent me this.
i dont speak italian but you can see the claims.
what do you guys think?

http://www.gpr.it/gpr//prodotti/1302/pdf_banco_prova_1302_713317331.pdf

 

[Ryanthegreat1]

So no power gains and a lot more noise. I think that is exactly what Formula390 was finding with his exhaust testing.

Also with how rough that power curve is it looks like they did no tuning.

 

[cjwell]

Exactly! Bunch of noise and no gains but even with tuning it won't make gains like a proper full length system......

 

[guzz46]

Using google translate, the thick line is reference, which I assume means the standard exhaust, and the thin line is comparison, which I assume means the Powercone, in which case they are both more or less the same, where Formula390 said his clone made I think 3hp less than standard, so going by this graph the Powercone won't gain you any power, but it won't lose you any power either, but it will lose you 7lbs of weight, and it will sound louder and better too, all while retaining the same position as the standard exhaust.

 

[RoninJames]

going by this graph the Powercone won't lose you any power, but it will lose you 7lbs of weight, and it will sound louder and better too.

thats a decent point guzz

 

[Formula390]

So no power gains and a lot more noise. I think that is exactly what Formula390 was finding with his exhaust testing.

Also with how rough that power curve is it looks like they did no tuning.

Yup, near same results. Tho they only lost 0.4HP according to their chart as opposed to the 0.5HP my design did. I'm surprised they did as well as they did. My test showed 3HP down for them vs the Akropovic map... but considering that's also what I picked up from bone stock, and the order of my tests, it's difficult to compare exactly... but, yes, that's what I would expect to see in general. We don't see any data there on if they had the baffles/DB Killer installed. My PowerClone test didn't use a catalytic converter or any of their two baffles/DB Killer, as at the time I had no means of verifying the exact design or measuremnts of those parts, but as it was report was reported to me the owners stated that it made more power without them in, than with... It could be that discrepency between the two tests of my clone vs theirs, with the use of the CAT and baffles, made up the difference with the additional backpressure my clone lacked. Of course, that then also reduces the desired additional sound. It WILL be a weight savings, that's for sure, and we all know 7# == 1 "free" HP for acceleration.

I am VERY annoyed at their use of the same colors for Torque and HP make comparison difficult and misleading, at least with MY eyes... so I have to go off the text.

Riferimento = Reference = 45.8 HP and 35Nm (25.8 foot pounds) Torque
Confronto = Comparison = 45.4 HP and 36Nm (26.5 foot pounds) Torque

So, that means the thick / bold line is presumably stock, and the thinner line is with their exhaust... in some unknown state of with baffles/DB Killer, or the CAT... but anecdotal evidence would lead one to believe that with the addition of the cat and baffles/db killer, is what made the extra 2.5HP difference between the two tests. That's contrary to reported "butt dyno' results, but... well... as we previously touched on.. placebo is a wondrous thing! Right up until when the guy with the bone stock quieter exhaust zips right clean past you. LOL

 

[Formula390]

going by this graph the Powercone won't gain you any power, but it won't lose you any power either, but it will lose you 7lbs of weight, and it will sound louder and better too

thats a decent point guzz

I wouldn't agree with that conclusion. Look at the power. Yes, you get a little bit down low in the RPMs... but that's NOT where we ride power wise. Or at least not where I do on the 390. You keep in the power by staying above 8k RPM. Look at their chart tho. Now that's showing KPH, not RPM, but we know what the RPMs are going to also look like where it's going to shut down at ~10k RPM and crossover for torque and HP is at 5,400. So, that puts 5,400RPM at ~65KPH, and redline at 10k at 120KPH. OK, so where does that put 8K RPM then... simple. we just need to convert the speed to RPM. 10000 / 120 = 83.333. So 8000 / 83.333 == 96KPH. That looks dead on where we'd expect to see 8k RPM on that dyno. So, what are the lines doing there... Well, from 8kRPM to 105KPH (aka 8750RPM) we hold stead... but from 8750 to redline, we are consistenly down 0.4HP for that full rev range of 1250RPM, where our peak power is. So, given that stark empirical evidence to the contrary of "won't lose you any power either" I guess it then comes down to what percentage of power one is willing to pay to give away to noise. Additionally, it seems to be that pulling the DB Killer will cost more in terms of lost HP to noise, as will pulling the cat. What it means is, best case, you will be down 1% power.. and more than likely will be down even more than that.

I do have to say, I'm kind of surprised GPR released the dyno data showing the results, when their promotional material states it will deliver a "Power gain" when empirically, it clearly does not.

 

[guzz46]

I can only speak for myself, but personally I wouldn't care about the loss of 0.4hp above 8k for an exhaust that knocks 7lbs off the bike and gives a 4% increase in torque as well, all while keeping the stock location, the improvement in the bikes handling was worth it for me alone.

 

[Formula390]

I can only speak for myself, but personally I wouldn't care about the loss of 0.4hp above 8k for an exhaust that knocks 7lbs off the bike and gives a 4% increase in torque as well, all while keeping the stock location, the improvement in the bikes handling was worth it for me alone.

Uhmmmmm. 4% increase in torque??? Is this some form of Kiwi Math I'm unaware of??? 36 / 35 == 1.0285 - 1 == .0285 * 100 == 2.85%.

Improved handling? from 7# of sprung mass. Really. Really! Really???

 

[guzz46]

Yes, it improved the handling, the bike responds quicker to changes in direction, eg... Making line adjustments when fully lent over, and even at 2.85% its still a bigger gain in torque than the very small loss in peak HP, add in the weight loss and overall its a performance improvement all round in my opinion.

 

[Okavic]

If anyones still willing to answer on this thread, but if i picked up this exhaust and kept both baffles in, would i need to do a remap, or could i get away with the stock map. Since im at 2000