Griso GT-Rx R/S Griso 8V pipe

[Penis Rotor]

Mine arrived today and I'll try to get it fitted sometime today or tomorrow. I can tell it is going to be ear-bleedingly loud and my guess is it will screw up the fueling unless I fit some sort of baffle in it.

This probably won't be a problem as long as you a.) Like really loud pipes, (I don't.) and b.) get a map modifier for it a-la 'New PC when it comes on line or get the 'pooter re-programmed.

Personally I'm not really after a lot more performance so I'll probably experiment with some sort of DB killer insert but it's a nice bit o' welding!!!!

Pete

 

[muz64]

Hey! Great news Pete. I thought you were going for the super dooper expensive German pipe?

Give your bike a wash and I'll come out with my good camera and take a few pics of it.

Cheers,
Murray

 

[Penis Rotor]

In a lot of ways I would of preffered the Bos system and still think it is by far the sexiest sytem out there but it is very expensive and requires a lot of buggering about to fit.

Todd's pipe is a fairly simple fit and is a lot cheaper. Despite Jude's comment that the bend on the pipe made it look like a part that had dropped off the Tin Man from the Wizard of Oz because it is welded in segments I actually quite like the fact it is obviously *assembled*. Fit and finish is good, the welds are nice. The biggest issue I had with fitting was the fact that the 'Y' piece is made out of what must be Imperial pipe and the Griso headers are of course metric. This means that the pipe won't clamp down onto the headers sufficiently to exclude air which on a bike with an O2 sensor is pretty important. The cure was simple enough, I simply cut some 6 thou shimstock into strips and wrapped them round the end of the headers and everything was peachy. What I would suggest is that if the pipe constructor has a flaring machine they stretch the arms of the 'Y' so that the original Guzzi exhaust gaskets, which appear to be a sort of Kingerlite tube, can be utilized on these joints as they are very effective at sealing.

Unfortunately the db arrestor I wanted didn't come in the box but Todd is sending me one separately. This is good as without it the pipe is incredibly loud. The blokes who work in the workshop I have space in described it as Awesome! Unforunately I can't really comment as in the last two weeks I have suddenly experienced sudden onset hearing loss and am now really quite deaf!

Initial impressions, and I've only done a few Km, are that it works OK but that torque is down below the 5,500 point where the 'Rush' begins but when you hit that point in second gear with the throttle WFO it goes seriously spastic! Unfortunately it also seems to run out of puff a bit earlier too. The long and the short of it is that once have played about with the db arrestor and have that installed, (I'm not a huge fan of loud bikes.) I'd like to get the bike to perform as well as it does with the original pipe with map #2 in which is really pretty damn well. I'm not really chasing more speed, for heavens saked the bike will do an indicated 230kph! but if it can be fitted with a fueling modifier, either a new map into the computer or a Power Commander of some sort I'm sure that the issues with fueling and performance at the BOTTOM end can be addressed as I'm certain that it CAN be made into a torque monster just as the earlier 4VPC models can. That is my ultimate goal, more torque and a nice linear build up of power with no dips or steps. I don't need it to go any faster than it does!!!

The RH exit pipe does show off the wheel very nicely. It'll show off the wire wheels I'll be getting as soon as they're available even better :laugh: and with the money I've saved using Todd's pipe over the Bos system I'll likely be able to afford 'em without having to eat snails and roadkill for a year!!!!

Pete

PS, Murray, if I get a chance I'll nip into town tomorrow and drop in at your work so you can have a gurn at it. I might even wash it first .

 

[uncle]

Having a removable baffle is nice... I put a Termi on my G11 and it is LOUD with the baffle out - and much more civilized with it in. I usually leave the baffle in but I really like being able to match the sound with my mood.

The Termi is much slimmer than the stock and does show off the rear wheel a little better - (not as much as the RS/exhaust of course) -

 

[GTM®]

Thanks for the words Pete, and thanks on the design, one that I think most compliments the design of the bike. Price does nice welds, eh?

Sorry for the oversight on the db-killer, on it's way this week.

Your 8V is the second ever to get mated to a GT-Rx R/S, and I appreciate the input. Still waiting for someone here in the U.S. to give it a go. On all of the OEM 'Y' pipes, the distances/diameters vary, so we're trying to catch the happy medium. Yes we're dealing with standard vs. metric pipe, but they can swaged as needed. We'll make the next a tad smaller on the inlets.

Sound, Righteous IMO, is softened immensely with the db-killer, though still quite awesome(!). Hell, if you're going deaf, does it matter? :huh: Sorry, couldn't resist.

I hope to get a 8V on the dyno soon, as the pipe design (reverse cone meg) is one for top end power, so hearing it runs out of steam sooner, is likely the result of it pulling better from the mid (hopefully the "dip" is gone). Low speed fueling (on the 02 sensor) is where my curiousity lies.

When the PCV is available, all will be well.

Keep me updated as you go Pete.

Who's next?

 

[Papasloan]

Pete,
Good idea on using the stock gasket and clamps. I'll look in to it. I have an 1100 crossover in the garage. The First 1200 I did had the same numbers on the crossover as the 1100 crossover. I assumed it was the same . The outlet diameter on the 1100 was 49mm the outlet on the 1200 was 50mm with the same crossover number. Diff had to be in the gasket.
I like the look of the slip fitting without the gasket. I can adjust the swage a little to make them tighter. Just not sure of the actual diameter. I'm sure they vary slightly.
Can you give me an actual dimension on the outlet from your bike?
Thanks for the kudos on the welds.
Price

 

[Belfastguzzi]

Hi Pete
I had the opposite problem, which is why your Y piece is made wider no doubt. I don't think that I put pics here as I didn't want to air the issue 'til it got sorted.
I couldn't get the 2 pieces together no matter what – I heated the Y till it was red hot, I cut an extra slot and I hammered and hammered, but a 50mm OD header pipe won't go into a sub-49mm ID tube.

I didn't know about the pipe expander tool, so what I did was grind and file the header pipes down in order to get them in. They're pretty thin now.

I would have liked to have used the gaskets too, but there's obviously no way, as the Y piece end tube would have to be hugely bigger than it is. The fact that everything is rigidly solid from barrel clamp back to the rear hanger bothers me a bit. Apart from stress, it means that there is a lot of vibration at the right side footrest bracket. A pillion found it too uncomfortable to use because the footrest buzzes so much.

My biggest performance issue was at low revs from start when pulling away and when decelerating. There's a lot of stuttering and surging and the engine would cut out when crossing roads, going through roundabouts, coming to bottom of hills etc. Have you not had that problem?



The Y piece with an extra slot cut in it and after being heated and forced open a bit by having a cone hammered in the end.
The Griso header pipe still wouldn't fit, so I ground it down to a smaller OD –>

 

[Belfastguzzi]

An end insert is a must, unless you live in somewhere like, oh, say, the Australian outback. The open pipe makes a great sound, but is too fiercely loud for riding near people and livestock or in traffic. I could literally see babies in prams starting in alarm or being woken. That's just embarrassing and anti social. I also found it fatiguing and was constantly aware of the high level of sound every second throughout a ride. i was never able to forget about it.

I'd like a removable baffle as it would be enjoyable to have the full-volume blast – on some special occasions, but take the violent edge off the sound for most everyday riding.

All things considered, I do think that Guzzi did a good job with their can. It does drive smoothly and does actually sound good (in a soft, quiet sort of way) and has a nice bass and a range of sound that isn't present with the open pipe.
However the RX looks way better and the Guzzi double barrel can is much too heavy.

The RX is a bit fluffy around the 4k area (sitting in traffic at 4k to 4,500 rpm can be a minor headache) but it does pull better up the revs. I don't have as much dip as I had with the stock pipe.
I could have done without the mismatched fitting hassle and without the shenanigans at low revs from idle (and without the unforeseen extra cost of tax being charged on top of tax before I could retrieve it from customs) but that all aside, I'm delighted with the thing.

 

[GTM®]

Belfastguzzi wrote:

The RX is a bit fluffy around the 4k area (sitting in traffic at 4k to 4,500 rpm can be a minor headache) but it does pull better up the revs. I don't have as much dip as I had with the stock pipe.
I could have done without the mismatched fitting hassle and without the shenanigans at low revs from idle... but that all aside, I'm delighted with the thing.

Define "fluffy" for me. :side:

NOW, NOW... I was reluctant to send these, as the "fitting issue" was due to the fact we hadn't even seen an 8V yet when we built it, so you were the first as you know. We based it solely on the info supplied to us (by you) on the part no. stamped on the 'Y-pipe' -- not having any real dimensions to work from.
We've only since delivered one more (Pete Roper), but we're getting closer to perfecting it now with both your feedback.
Low revs issue is likely a fueling related and that I don't yet have control of, but hopefully within the next few months.
Glad you like it otherwise.

EDIT: I just noticed all of the pics you posted above, see my words above, and also for the record we offered to send you a revised Y-pipe in exchange. So, everyone will not have this problem.

 

[GTM®]

Also for the record, I've been running this pipe design (shown below) with no "db-killer" for close to two years now, and in fact have also *never* exceeded the strict db limit at Laguna Seca Raceway as an instructor. A good deal of sound feeds back to the rider, so it's not as loud as you guys seem to make it sound. Have a buddy ride it near you, and you will see just how loud it's not under normal operation. Now at full-tilt, that's another story.

 

[Penis Rotor]

Todd, I don't think BFG is complaining, just doing same as me, listing it as he sees it.

On the poor running issue? Have you got the second map installed yet? If not this may be a fairly substantial contributor to the overall problem. I took mine into Canberra today and once it was up to proper operating temperature most of the issues I'd noticed yesterday when cold were very much diminished, almost to the point of invisibility. Mine sees to run fine with the pipe on, not perfectly but a lot better than my 1100 ran with the Lavizzarri with the baffles out!!!

The pipe size issue is a pain but its hardly Todd and Price's fault that the Guzzi/Lafranconni quality control is completely shitty :laugh: .

It IS ear bleedingly loud, far too loud for me, which is why I'm going to need some sort of baffle. the CRITCAL thing is going to be that while it muffles NOISE it mustn't hinder the flow of gas too much. I'm sure that one of the reasons for the 'Piggy-back' design of the original muffler is to allow for a LARGE aperture, (In the form of the two orrifices.) to flow gas. that will have to be maintained if performance isn't to suffer.

My idea is to use a fairly long tube that will fit down the inside of the Rx-RS with an orrifice of considerably smaller size in the end nearest the engine but still keeping a nice large aperture at the atmosphere end and then experiment by grinding slots or drilling holes into the length of the pipe until a happy medium is found between restriction of gas flow and undue noise. As long as there is good clearance betwixt the poter pipe and the inner this shouldn't hinder gas flow too much but hopefully will do a lot to help the racket. This will work within reason but until we get a proper map modifier it is going to be very hit and miss.

Todd, when the db killer arries I might take mine off to the dyno and do a couple of runs with an EGA stuck up its arse. At leat this way when the new PCV or whatever arrives you should be a bit ahead in the game in finding out what needs changine where.

pete

 

[Belfastguzzi]

No I haven't got the map installed yet. It may be after the New Year before I get the time for that.
From what you have said before, I hope that the new map will make a good difference as it enrichens the bottom rev range.
It could help the 'fluffy' area too, which manifests itself in stuttery, surging behaviour - the bike won't run steady and smooth at those revs: and it's just particularly noticeable because it's the natural engine rev area the bike sits at in the traffic conditions that I'm riding in.

As for discussing the issue: :unsure: I thought that is what a tech. forum is for? :huh:
In fact I didn't raise the matter publicly at the time when I was trying to sort it and when I would have liked to have asked for wider advice on various issues. I'm now just contributing to this thread as time has moved on and the subject has come up. As I said privately at the time, I fitted the new pipe immediately before going on holiday and actually came home in the middle of my holiday in order to change the pipe because of the changed behaviour of the bike. If I wanted to complain – that is when I would have done it!

I don't think that I was complaining or blaming anyone in my post?

I also didn't supply information about pipe sizes. I just gave the part number of the MG y piece when asked for it. :blink:

I don't understand why mentioning the noise is perceived as some form of attack. It IS 'THE' defining characteristic of the pipe, well before anyone sees the visual construction. If the noise level is imaginary, then I don't know why it is the first and only time in my many long years of having bikes that I have had a stream of complaints about noise! High speed noise isn't an issue at all. It's low speed and bottom half of the rev range where the social aspect is an issue.

Oh well – I'll just keep an eye on what Pete has to report from time to time.

 

[GTM®]

BFG, didn't take it as an attack, I just noticed that some very pertinent information regarding fitment was missing on your post.
All Technical posts are welcome, but are subject to "rebuttal of facts" as needed.

Sound, not noise, is subjective... so I suppose if one never owned say a Harvey Doodleson with open pipes, then "noise" is relative. These words are from the land of HD noise. My name is Rx, and I support that message.

I'll be anxious to get the 8V on the dyno to see where power/fueling lies. Hopefully, this will be about the time the PCV is out.
Pete, please do keep me posted.

 

[Penis Rotor]

OK, a bit more feedback.

I am becomming more and more convinced that a problem with the Guzzi maps is that the temperature compensation is up the creek. This was noticeable on the bike with the original pipe but seems to be exacerbated with the new pipe.

In the morning yesterday when the ambient temperature was in the low twenties the bike was running superbly. In the afternoon though I took it into Canberra with me for a doctor's appointment and by then the temperature was in the mid thirties. In traffic I started to get a bit of popping on the over-run, something that in similar conditions it would do with the factory pipe but of course the 'pops' are much more noticeable in what is essentially a hollow pipe! Now it may be that a bit of air is leaking in at the 'Y' pipe join but I don't think so and the whole engine *feels* leaner. I think that the ECU is simply leaning it out too much as the temperature increases. I'm tempted to try fitting an appropriate resistor to the ATS plug for say the eqivalent of 22*C and seeing if that cures the problem. the ATS is after all very easily accessible.

When hot I found that the engine did surge a little bit at idle. Once moving there was no issue. Interestingly Nick in Japan was complaining that his bike, with I believe the stock pipe, was doing the surging and stalling at idle thing. The new map cured it instantly.

All the people who have seen the pipe love it BTW. Most of 'em love the sound too but I'd have to agree with BFG about its presence in urban areas. It is simply too loud, you can see people glancing disapprovingly at you as you ride past. I also find so much noise tiring ona ride of any length. That isn't to say others will neccessarily feel the same but I'm a crotchety old middle aged deafy who prefers something a bit more muted.

Pete

 

[double.d]

I might weigh in here with my 2 bob's worth of noise. I have always agreed with Pete about the noise level comming from the open Lavizzari's, but i wear ear plugs and like noise so that is where we differ. recently i had my bike at the dealer for an unrelated matter and he had to take it for a test ride. i told him to be heavy on the throttle cause i wanted to hear how loud it is. Well i was surprised that it was a lot quieter than i expected, much quieter than when i am riding it. On another occasion i have followed my bike on another std equiped mufflered bike and have not been able to hear the Lavizzari's under acceleration.

Pete & co, try this experiment, get someone to ride your bike while you stand on the side of the road and listen. Your perceptions may change .