New exhausts...

[AlmostThere]

Hey all,

Just recently started riding with earplugs in in a bid to reduce the noise inside the helmet at higher speeds. They've made a big difference and even with all the vents open noise is now MUCH reduced. However, it also blocks out much of the sound from the standard exhaust silencers.

I had been half looking at getting new cans and I was going to try 450mm Hawk oval exhausts (made by PipeWerx) but they currently have a lead time of four weeks. Ride time is scarce as it is and I didn't wish to wait that long before enjoying the sound of a V-twin again (half the reason I bought a Firestorm) so I took a bit of a punt (this was Friday and I wanted them for the weekend) and bought a set of high mount cans from Black Widow.

TBH, I wasn't expecting much as they are cheap but they've been fine so far. How well they last with time is another thing but they have a two year warranty so if I get that long out of them I won't be complaining.


-ive:

The clamps aren't great; M6 bolts aren't up to the job of clamping tight enough and I've had to replace them (the bolts, not the clamps) as they were bending trying to get things tight enough. One of the four joins blows ever so slightly but they are all dry, I could use the exhaust paste supplied but I'll grab some better clamps first.

In fact, the supplied hardware/fixings are all a bit cheap and soft with head sizes that are never a tight fit with tool size.

The heat shields aren't anything fancy and a bit thin.

PITA trying to get everything lined up and tightened (doesn't help that the link pipes do not attach to the rear footrests like the original Honda items).


+ive:

Exhaust hangers are nice thick aluminium.

The pipework (link and cans) look to be decent quality (certianly better than I expected for the money)

Black Widow branding on the cans comes off super easy (sort of a metal foil sticker)

Sounds nice (these are 400mm cans, and I've yet to try them with the baffles out). When cruising there's a nice gentle grumble, lovely subtle pops on the overrun and plenty loud enough when you're asking the engine to work.























Think my fuel economy has gone down though....not sure why

[sirch345]

It looks like you have now got them lined up and nice and level with each other
That is one thing that stands out like a sore thumb to me if both cans are not level with each other, but then I'm a fussy so-and-so

Good feed-back on your purchase,

Chris.

[MacV2]

The Black Widdow cans are allways a pita to fit right... Get some Milakor clamps they come in full marine grade SS.

[tony.mon]

The Black Widdow cans are allways a pita to fit right... Get some Milakor clamps they come in full marine grade SS.

But get the Mikalor ones with stainless bolts, too. They do some cheaper ones with ordinary steel bolts on stainless clamps- you can do them up tighter than the all stainless ones, but they rust solid in a season.

[AlmostThere]

Appreciate your comments guys

The Mikalor clamps (ordered the W5 version, full marine grade 316 S/S) were fitted on Saturday...then promptly removed.

I checked the max torque setting listed by Mikalor (12N-m and 16N-m for the two sizes I required; both on M7 bolts) and compared these to the original Black Widow M6 clamps/my bolts combo I had already installed; they were all around 25N-m (here or there) on the torque wrench, so no wonder I was bending the original bolts (Mikalor state 10N-m max on their M6 clamps/bolts). Not sure what grade of bolts I used as a replacement but they were holding that torque like a trooper, all but one rolled straight and true when I removed them, threads were sound.

Fitted the Mikalor ones and tighted to spec...pipes/cans were barely tight. So I tightened the bolts a little more (i.e. over and above that stated by Mikalor), the first lasted about two turns before stripping the threads, the second a little more. The captive nuts on the clamps were servicable but I'd have to run a chaser through (which I don't have). Doubt these weakened ones would hold the 25N-m ish I need, the other two (non-threaded) ones might.

So I ended up going full circle, MIkalor's off, old ones back on. Still have that one joint (link pipe to can) blowing slightly so I'll have to address that at some point but I reckon some fiddling will remedy it before the exhaust paste comes out.

Whilst I was about the vacinity I removed the baffles. Yes, things are probably now on the loud side but what a difference removing them makes to how the engine behaves. Throttle response is up (especially noticable when rev matching on the downshifts) and there is a very noticable increase in pull and top end. The baffles must truly clog things up if there is a night and day difference like that.

[tony.mon]

What you can do is to extend the slots cut into the outer section of each link pipe to allow the metal to deform slightly more. You'd need new graphite seals, and make sure you position the seals so as to prevent leaks.
That way you can tighten them enough.

Another option is to compress the gasket using ordinary steel bolts, then remove those and replace with the stainless ones, they'll then nip up securely.

The ordinary steel ones can be tightened a fair bit more than stainless.

[AlmostThere]

Thanks for the advice tony.mon

The Honda downpipes to Black Widow (BW) link pipes seal perfectly (even although it does away with the seals (which I guess are the graphite ones you mention)). The issue is (was?) one of the BW link pipes to one of the BW cans. These are a sleeve fit (and not a very tight one!) with no gasket, which is why I assume they include exhaust paste.

There were slots (four of them) already cut in the end of the can flange where it sleeves over the link pipe. I have probably voided the warranty but I cut four more about half the length of the original slots. Seal was sound when I refitted the can and after a quick run it's still not blowing so fingers crossed that's fixed it.

I'd also like to give an update on the exhast itself:

With the baffles out the bike is too loud IMO. Without earplugs and around city streets it feels like you are doing yourself and everyone around you no favours at all. People look not because it's a nice sound but simply to see what's making all the racket! With earplugs it's a far better experience and I can hear the exhaust note clearly at all speeds.

The baffles are back in and whilst there is a surprising drop in engine livliness it's probably the better option if you still possess some morals. I might swap out the BW links/cans for the standard setup as I reckon they probably out perform the baffled BW setup.

[rktdoc]

Thank you for your honest review!
I had been planning to order black widow system, but very hard to find many reviews on them especially on our bikes.
I wasn't sure about them but now I know.
I would definitely not consider this a high mount more akin to the arrow mid mounts.
Curious do these use a straight through perforated core, or are they a spiral fluted core like the Jardine street?

[AlmostThere]

Glad my comments could help

Yeah, mid mount is probably the more correct term, they are certainly not as high mounted as some systems. To answer you question, I'm not 100% sure. The bike is not kept at home so I can't check right now. I will get a chance at the weekend and will let you know.

In fact, you have good timing. I had the bike on the dyno on Wednesday to satisfy my curiosity in power difference between the standard and the Black Widow cans/link pipes.

These are wheel figures:

Stock ...................... 97.75 hp @ 8661 rpm .......... 66.60 ft/lbs @ 6531 rpm
BW (with baffles) ...... 100.80 hp @ 8750 rpm .......... 67.81 ft/lbs @ 5692 rpm
BW (no baffles) ........ 101.59 hp @ 8776 rpm .......... 67.67 ft/lbs @ 5669 rpm

(I had to use dots as it won't let me use spaces)

Power loss figure...well, take your pick, from the brief look I had online they range widely from 5 (%) up to and into the 20's. The guy who runs the shop (racer, tunes/builds race bikes) was also doing the dyno runs and he said a figure of around 12% is what he uses. This seems reasonable given that the most common numbers I read about was a generic 10% for engine/transmission/ancillary loss, and further 5% for the chain/tyre, so 15% in total.

So, if we take the overall loss as 12% then the bike runs a decent 109/110 hp at the flywheel with stock cans and 113/114 hp with the BW cans with no baffles. A 3 to 4 hp gain in peak hp is fair, but this only tells half the story (see graph below).

Slight aside but when the bike gets strapped the rear tyre is pressed firmly enough on the drum of the dyno that it leaves a 3" wide strip on the tyre where it's been running and manages to build up a surprising amount of heat in the rubber too. I should have asked what gear he was in for the pulls but I saw over 140mph on the monitor near redline so I'm guessing 5th, maybe

Here is a printout of the run for stock vs BW with no baffles (click on it to make it bigger). I have another with all three variables but it's difficult enough to read the faint lines (and my poor camera work) with just two being shown.



Now, whilst the 3 to 4 hp gains were decent for peak gains it's the power and torque figues below 6,500 rpm that really shines through. Not only is the flatspot around 4,000 rpm gone, it's about 8 hp and 12 ft/lbs higher at this point. The torque curve isn't so much of a curve but a plateau; 64 ft/lbs from 3,500 rpm, peaks at 68 and is still putting out 62 ft/lbs at 8,500 rpm, a full 5,000 rpm later. Peak torque is reached about 900 rpm lower in the rev range than stock. The curve for hp has also smoothed out and it too shows some nice gains lower down, roughly 6-8 hp fading out at 6,500 rpm then picking up to a steady 3-4 hp until redline.

The only thing than was concerning me a little was the AFR leaning out for the first 1,000 rpm or so with the BW cans fitted. I spoke with him about it and he suggested I needn't be worried, saying that going from near zero throttle to 100% wide open can lean it out a little. He said he could put bigger pilot jets in but wasn't sure that would cure it. The rest of the rpm has plenty fuel, maybe a little too much as I think we about gassed ourselves in that little dyno room. If anyone has some more info on why this is happening and are in a sharing mood I'd appreciate the feedback.

I was surprised the baffles flowed as well as they did. There is some seperation between baffles in and out below 5,500 rpm but after that they trace each other in hp and torque remarkably well. In terms of noise, stock cans really are on the quest side (especially now that I've been riding with the BW cans on for a while now), baffles in it's acceptable but with no baffles it's quite loud. When doing the pulls with no baffles you could not just hear it (through the ear defenders) but feel it in your chest in the higher rpm. I think my multimeter can measure dB so I will try and get some number for you as well if you want. I doubt it'll be accurate but if I measure the dB of the horn it'll give a relative difference at least.

Not sure if I've already posted somewhere but the cans are 400mm long.

[tony.mon]

Well done, it's good to see someone posting empirical measured data instead of just how it feels or compared to their mate's car!
As regards the fuelling, almost anything done to VTR's that allows the engine to breath better results in richer running.

I can only make an educated guess, but I think that the increased air flow lifts more fuel through the main jets. The carbs in these are so large they don't always follow the usual carb tuning rules.

You can try going down one size on each main jet, (note that they aren't both the same size) and see how that goes.
The initial dip is likely to be slide lift, controlled by the vacuum above each slide.
Dynojet kits can help, as can drilling extra small holes in the base of the slide which reduces the vacuum slightly across all revs, but you could also try fitting new standard slide springs.
The manual gives a free length limit, and it wouldn't surprise me if they have shortened slightly due to hear and working cycles.

But to be honest it makes very little difference to the way the bike runs, power or fuel consumption, so it depends how much work you want to do for not much gain.

Let us know if you do anything more

[sirch345]

Well done, it's good to see someone posting empirical measured data instead of just how it feels or compared to their mate's car!

I thought the same thing

A great explanation of what went on at the Dyno with all three variations.

Well done "AlmostThere" for taking the time to write-up a such a comprehensive report

Chris.

[fabiostar]

nice looking pipes for not crazy money...... what are these baffle things you talk off

[tony.mon]

Slightly off topic, but I recently changed helmet from my old comfortable HJC carbon to a Shark carbon one.
After half a dozen rides the new one is starting to feel less tight, but I found I now need to ride with earplugs.
I didn't need to do that with the HJC.
The Akra baffle is still in.

It's easy to forget that a comparison of cans is only realistic when all other factors are the same- route, whether you're on your own or with friends, any gear or helmet changes and the weather also affects things- you ride differently and background road noise is different.

A Dyno is the best way to compare, every time- but even then, correction factors for temperature and pressure can make any differences seem bigger or smaller.

[AlmostThere]

So much for getting back to you guys by the weekend, apologies for the delay.

Appreciate the comments

Thanks for the info tony.mon. I asked around and it seems that going from almost no throttle to wide open does lean out the mixture...on a dyno. I was given the same explanation by two places who said the following: when you have those huge fans blasting air at the bike some ends up pressurising the air box, like a ram air effect, so when you go wide open throttle this air is pushed into the carbs/engine initialy leaning out the mixture in the lower rpm range. The bike 'catches up' after a little bit and settles down. Was also told it happens a lot less on fuel injected bikes.

Now, I don't know enough about it to say weather or not if any or how much of that is true, but it seems to make sense. If true, I do wonder how accurate the dyno is at representing engine performance low down in the rpm range if the bike is getting a free ram air effect

That aside, here are some pictures:


For member rktdoc

[tony.mon]

Back when I had a Storm I fitted llambda sensors in the two downpipes and a little electronic display that showed me the actual fuel to air ratio while I was riding.

It responded the same way on the road as on the Dyno.

You can lessen the effect by fitting different slide springs, or drilling of filling tiny holes in the bottom of the slides, which affect the speed at which the slide responds to sudden full opening.
But remember that these are CV carbs, and there's no direct connection between throttle and carb slides. Opening the throttle fully won't give you full slide opening at first.

Try taking the tank off and the airbox top and looking into the carbs as you start it and blip the throttle.