More power from the 1200 8V

[rosso corsa]

DAES Mototec in Germany has some goodies for the 8V intended to increase low and midrange torque, including PC: http://contentmanager.brainst.com/8118/pro...e.php3?seite=11 . See www.daes-mototec.de

I would consider low and midrange torque more useful than top range power for normal road use.

[pete roper]

So Mr Roper.... a rather negative response was not what I was looking for.

My enquiry was in search of a POSITIVE response and constructive assistance.

 

I gather from your opening line "Yeah Wow Great" that you think the enquiry is some sort of fanciful flight of imagination.

 

Lots of things in life come down to attitude don't they!

 

No, I just think that you haven't thought this through and are about to embark on something impractical and un-neccessary. Let's outline a few reasons why shall we?

 

What will more power achive? A higher top speed? No. It won't. There is only ONE set of gearing for the 8V gearbox which is substantially different to the 4V gearbox. This is limited by the maximum RPM the motor can stand AT THIS TIME which is set a a fairly conservative but wise 8,500RPM. This gives you a top speed of 235KPH and even with the stock, shitty, map this is pretty much achievable 'On the Flat'. To get this 'More Power' you are going to need to play with a LOT of things but probably the most limiting factor is going to be airbox capacity. Yes, a larger airbox would be GREAT. Problem is there isn't room for one. I've owned both 4V and 8V grisos and they are essentially identical here. There is, unfortunately, no room for a bigger airbox.

 

'Hotter' cams? Why? The 4VPC configuration gives you a much larger valve area. On a slow reving twin increasing lift and duration will achieve little in the way of improving VE but WILL require heavier springs and will produce greater power LOSSES in the valvetrain as well as higher wear rates of components. Heavier springs may also require stronger, more expensive valves. There is also the Sword of Damaclese in the form of the dubious tappet design to take into account. will it actually handle higher spring pressures?

 

OK, so 'Power' is Torque x Revs. So you raise the rev limiter and fit stronger rods. Fine. Is the oil pump going to cavitate? Are the cooling jets that prevent the pistons from melting still going to do their job if you increase the MEPS over what it is at 8.500RPM?

 

If you do achieve 130HP will the clutch take it? Will the gearbox take it and remain reliable, (My guess is actually that it probably would be acceptably reliable even with heavy handed use.) will the CARC gears hold up? (Once again I think they would.) would the driveshaft hold up? (Hmmmm. That would be my biggest concern, small trunnions, silentblock bonded shaft?)

 

It's not that I don't think that any of what you are saying is unachievable. Just that it is HIGHLY unlikely to be achievable without HUGE expense and greatly diminishing reliability and for what? Bragging rights? It'll still be an enormously heavy, stupendously long wheelbased, shaft drive, air cooled motorbike. It'll just be that it will no longer be reliable and will STILL be cut to pieces by anybody with any riding tallent on any true 'Sportsbike' over 600cc.

 

Don't get me wrong. I think the bike is great as it is but honestly the mapping is crap. THAT is where to start and as I said in my first post 105-110HP should be fairly easily and reliably achievable. The BIGGEST gains though are going to be made by getting something organized to sort the fueling and ignition and improve the breathing both in and out. The restrictions AREN'T in the head so much as in the airbox and pipe and those cannot be sorted until we have a decent map modifier. Then we can look at turning it into what it should be, an absolute stump-puller from 2,750 through to where the cams come in at about 4,800 and then getting the mixture right above that point without leaning it out so much we start blowing holes in pistons or loosing the heads off valves.

 

The 8V Griso is a superb ROAD bike but it is not and never will be, a true 'Sports' bike and neither will any contemporary Guzzi with the current motive package. You can dress it up in any clothes you like and I KNOW a lot of people are dying for an MGS-01 lookalike for the street and I would dearly love to see one too but it will NEVER be competitive in the true 'Sportsbike' market for the reasons listed two paragraphs above. This isn't me being negative. It is simply the laws of physics and the rules of engineering. For a fraction of the cost of building this unreliable munter you could have a bike from any number of manufacturers that will do everything you want AND have lots of dosh left over for other projects. Common sense and practicality to me, not negativity. And if I wanted to try and do such a thing money would be no object for me either so it isn't a 'Sour Grapes' thing.

 

Pete

[belfastguzzi]

Here is a privately owned one for sale- not sure if Robin has found a buyer yet:

 

MGS01 ad

I read somewhere that it has gone to Europe (mainland), maybe Belgium, or further north? Can't remember exactly.

[GuzziMoto]

First off, Pete it is great to hear from you again. It has been too long.

Second, I think if you want to build ANY bike into something more then what it is then more power to you. But if you post what you want to do with out thinking it thru and ignore the realities of what you are doing, don't be surprised (much less angry) when someone with more knowledge then you post opinions that don't agree with your plans.

Lastly, I don't think there is as much room for improvement in the new 8V motor as there was in the old motor. In order to get your 125-130 hp (if it can make it) you may have to give up a lot of streetability. You can probably make the most improvement with getting the fueling right, but that is hard to do until the PCV comes out. Other improvements are going to be harder to get, Most will either be small and/or come at the expense of streetability. This is not to say it can't be done or that you shouldn't do it. It is just that it is more like trying to get big improvements out of a 1098 Ducati then an air-cooled two valve Ducati. The less refined a motor is the easier it is to improve upon. The 8V Guzzi motor is much closer to the edge of what it can do then the previous 4V motors.

[pete roper]

The 8V Guzzi motor is much closer to the edge of what it can do then the previous 4V motors.

 

 

Quite so. And perhaps in ten years or so time the factory, and probably other, independent outfits may well of got it lighter, stronger and reliable enough to produce the sorts of HP figures that the Bavarian twins are producing in their final itteration before they go to the preposterous new DOHC design.

 

There are LOTS of places where the new package can be improved. Putting it on a SERIOUS diet would be the obvious one . Knocking 3 inches off the wheelbase would be the next!! Getting the fueling right would be the obvious place to start, currently it is just absurdly rich at WFO and in the closed loop area, yes, there is cooling to consider but if it needs that much evaporative cooling then there is something fundamentally flawed in the piston design!

 

Pete

[Greg Field]

Let's not give up before we've begun. I'd bet there's plenty of power to be had in that motor. If you want someone to put in some flow-bench and development time, send the sumbitch to me. I can't wait to try. For all the added tech in that motor, it oughta be putting out at least 110 at the rear wheel . . .

[pete roper]

Let's not give up before we've begun. I'd bet there's plenty of power to be had in that motor. If you want someone to put in some flow-bench and development time, send the sumbitch to me. I can't wait to try. For all the added tech in that motor, it oughta be putting out at least 110 at the rear wheel . . .

 

Agreed Greg, but most of that will come from mapping and freeing up the breathing. There is no room for a larger airbox and I don't think that pods will help much. Judicious experimentation with opeing up the airbox, (I'll be consulting Phil Arnold on that!) and getting a decent map modifier are the main things. Yes, port work will deliver a bit more but that is NOT the first thing to attack and we have to find out, (Probably through destruction testing ) exactly how lean we can make it and still keep reliability.

 

The current fueling, at least at WFO, would indicate that opening up the airbox top and/or fitting a 'Flat' BMC/K7N type 'Filter' would give us probably another 4 or 5 horses right there, even with the current map. the problem is that at anything other than WFO it will go lean as crazy and detonate it's head off, run too hot on a steady cruising throttle etc. This is the shit with FI, you are now working in three dimensions rather than the two that you do with a carb. we NEED a map modifier and some way of influencing the closed loop running or probably better yet pissing it off all together, to get most of what we can out of the motor.

 

As I said before, I don't think outright power is the issue. what that motor needs to be able to do is pull like a 14 year old with his first stick book, and it CAN, all the ingredients are there, they have just been pacified by those who want to save us from ourselves!!!!!

 

Pete

[Greg Field]

The airbox and filter on that thing are bigger than on an Aprilia Mille. I'm not at all certain they are the root of the problem.

[Paul Minnaert]

I read somewhere that it has gone to Europe (mainland), maybe Belgium, or further north? Can't remember exactly.

 

It's in the Netherlands. I know the guy.

[Skeeve]

The airbox and filter on that thing are bigger than on an Aprilia Mille. I'm not at all certain they are the root of the problem.

 

Does the new QV Griso use the same [or essentially same] box & filter as the old 2v Griso? 'Cause if so, I saw the latter on ebay, and it's a wonder of fitting an airbox into a long, shallow volume, but w/ all the kinks & twists and the small volume that the intake bells pull from, likely to prove somewhat restrictive as Pete suggests.

 

Don't forget the experience when they were developing the MGS01: power increased linearly w/ airbox volume, which led to the oddball fuel tank shape as they kept sacrificing fuel volume for airbox volume!

 

Now, as to how to achieve the large airbox volume w/ the QV motor, it's easy: mount the puppy in a Tonti frame so you can get the shock(s) out of the way of where the airbox needs to be, beef up the frame tube diameter to improve rigidity so it can take the added power, wrap the whole thing in a V7 Special retro theme and laugh all the way to the bank...

 

Too bad Piaggio has NIH syndrome so bad...

[Guzzisport]

It is very interesting to see SOME comments in this thread that would be more fitting on a BMW or Harley forum.

 

Thank god Brough, Taglioni, Honda, Britten, the Dynotec guys, and of course Giulio Carcano didn't think like this.

[Greg Field]

It is very interesting to see SOME comments in this thread that would be more fitting on a BMW or Harley forum.

 

Thank god Brough, Taglioni, Honda, Britten, the Dynotec guys, and of course Giulio Carcano didn't think like this.

 

Any progress?

[Kiwi_Roy]

Well, I had a green V11 Sport and I had a Griso for a while, what more could I ask for?

Perhaps the V8 racer, it would be fun to roll up for coffee on that.

Edited August 30 by Kiwi_Roy

[pete roper]

Interesting to revisit this after so many years. I’ve learnt so much about the 8V since those long gone days and the fact is that opportunities for extracting more power out of it are few and far between.

A stock 8V makes, on the Dyno I used for years, which was run by a bloke who liked it calibrated pessimistically in the interest of being honest, made 96RWHP. Screwing around with air filters etc. achieved nothing apart from rapid throttlebody wear and the stock airbox and filter work fine although removing the snorkel from Grisos and Stelvios will give a small lift in bottom end torque. With decent mapping and the right pipe, with a dB killer installed you will be able to keep the delightful flat torque curve and lift the RWHP to about 100 +/- three or so depending on state of engine, atmospheric conditions or whatever.

You can increase the maximum hp if you use the right pipe and remove the dB killer and map for it. Not by a lot and the most you are likely to be able to get is 108-110 but in doing so you will sacrifice bottom end and midrange. 
 

Those limitations are imposed by the head design and there really isn’t a lot that can be done about that. Yes, there are people claiming much higher numbers than those. The laws of physics though don’t change. The fact is any 8V Guzzi is a big, heavy and ultimately not very powerful, (By contemporary standards.) motorbike. As I’ve said before. Love them for what they are. Not what they’re not. If you want *More*? Buy a Tuono!

[GuzziMoto]

On 8/30/2024 at 6:17 PM, Kiwi_Roy said:

Well, I had a green V11 Sport and I had a Griso for a while, what more could I ask for?

Perhaps the V8 racer, it would be fun to roll up for coffee on that.

If Guzzi made a modern V8 version of their V8 GP bike I would for sure buy one, as long as I financially could afford it. If for no reason other then how cool it would sound.