4v Vs 8v

[Sheepdog]

I have one of the early California Vintage models and had to do a little sorting to get the fuel mapping right.  Between updated Guzzi programming, some help from GuzziTech, and the motor breaking in, I don't think I have ever had a bike with a more pleasant personality. It does pretty well down low and  starts running out of steam at 7,000 rpms, but in between those extremes it is pure bliss. I waited a long time to pull the trigger, but I had a fascination for 2-valve Big Blocks that went back to "Magnum Force". When I finally bought my Vintage and got it running well, I concluded that it was the most satisfying machine that I've owned...even better than my revered Norton Commando. I must admit that I have not sampled a 4-valve example, but I feel I'm still on my honeymoon with my Vintage. For me, it is all I want.

[Kev m]

Yeah Moto that was the source.

But you're right, the stock mapping doesn't mean as much anymore.

I would be curious to see what a remapped 2V Dyno looks like. Sadly I never did brought my B11 back to FBF for a comparative dyno run after the Guzzitech reflash. But the OEM map run was impressive.

[Huzo]

Personally I wouldn't know a Tonti frame if it fell on my head, there's a lot I don't know about other Guzzies, but I've gained a bit of knowledge about mine. Moto made a good point for me, when he mentioned heavier flywheels, I just remembered a short ride on what I think was a T3 years ago and can recall the massive flywheel effect with accentuated tilt from torque reaction, I reckon it made you feel more connected to the engine and there seemed to me to be a constant reminder of the milling around under the tank. Marvellous....BTW is my '79 Le Mans a Tonti frame ?

[boatdetective]

With the 8V, you WILL find the rev limiter.

I think there's something to this. On my 2V 1200sport- I'm never up in that range. Just as Kev said- I'm in the 3500-5500 zone.

However, my Aprilia Shiver is another story. When you hit it on that bike, you naturally hold onto the gear (why wouldn't you- it just keeps pulling). As a result, going up over 6000 is SOP. Is the top end rush worth it?  Ummm...well...hell yes!

[Moto]

BTW is my '79 Le Mans a Tonti frame ?

Yes.

[rdbandkab]

You can keep the 8v,  I would take another 4v any day.
Another thread reminded me of the wonderful sounds coming out of our 06 Breva 1100.   (especially that clutch rattle...we loved that!)
We had a stock engine with a Mistral carbon oval and Mistral cross-over.  She wasn't loud...just perfect.

[Trogladyte]

There are some interesting opinions in this thread. I find the two motors quite different, and for my style of riding the 8v is by far the  most satisfying.

The 8v Griso feels like two different bikes. For most day to day riding, below about 5.5k rpm, it feels like a traditional big twin. There is oodles of torque, and the motor feels very muscular.

But there's another side to the 8v.  If you keep going up the rev range, the lump spins up readily and the bike feels like it picks up its skirts and buggers off very sharpish indeed. It delivers a real kick in the seat of the pants and surges with power. It doesn't last long, as you hit the red line very swiftly, and you need to change up.

If you keep the motor in this range, dancing on the gear change, the bike feels more like a sporty multi than a big twin torque monster. And some sports bike riders who expect the bike to perform like a Harley or a BMW boxer get a bit of a shock! 

[Kev m]

There are some interesting opinions in this thread. I find the two motors quite different, and for my style of riding the 8v is by far the  most satisfying.

The 8v Griso feels like two different bikes. For most day to day riding, below about 5.5k rpm, it feels like a traditional big twin. There is oodles of torque, and the motor feels very muscular.

But there's another side to the 8v.  If you keep going up the rev range, the lump spins up readily and the bike feels like it picks up its skirts and buggers off very sharpish indeed. It delivers a real kick in the seat of the pants and surges with power. It doesn't last long, as you hit the red line very swiftly, and you need to change up.

If you keep the motor in this range, dancing on the gear change, the bike feels more like a sporty multi than a big twin torque monster. And some sports bike riders who expect the bike to perform like a Harley or a BMW boxer get a bit of a shock!

Conversely that might also explain why some of us prefer the 2V motor and have no interest in the 4V.

[Cool Runnings]

You can keep the 8v,  I would take another 4v any day.
Another thread reminded me of the wonderful sounds coming out of our 06 Breva 1100.   (especially that clutch rattle...we loved that!)
We had a stock engine with a Mistral carbon oval and Mistral cross-over.  She wasn't loud...just perfect.

Kinda like fine wine, eh.

[Trogladyte]

Conversely that might also explain why some of us prefer the 2V motor and have no interest in the 4V.

Yes, I suppose it does.

Personally I love both of the motors, and think they are both really interesting, and have considerable charm and character. I found the 1100 4v motor very good indeed. It reminded me of bikes like the T3, although it was more free revving, I guess because of its lighter flywheel.

The 1200 8v motor was very similar at lower revs, but had a whole new side to it if you let it spin.

It's fascinating. They are different beasts - yet closely related. What's not to love?     

[beetle]

Yep, the 8V likes to rev. Don't confuse that with needing to rev. The old kick in the pants at 5500 was a result of the ECU trimming the sub 5000 area to meet emissions. Some folks using my maps have complained about the lack of kick at 5500. That's because the power delivery is linear. There's more torque down low and that results in seamless transition to the top end.

[oldbike54]

 And some sports bike riders who expect the bike to perform like a Harley or a BMW boxer get a bit of a shock!

 I'm trying to understand this statement . Boxers and HD motors act nothing alike . Did I miss something ?

 Dusty

[ohiorider]

Yep, the 8V likes to rev. Don't confuse that with needing to rev. The old kick in the pants at 5500 was a result of the ECU trimming the sub 5000 area to meet emissions. Some folks using my maps have complained about the lack of kick at 5500. That's because the power delivery is linear. There's more torque down low and that results in seamless transition to the top end.

Reminds me of the first generation V Max with V-Boost.  I recall reading reports of V Max bikes with V Boost disabled, where the riders complained that 'it just didn't have that kick at 5500 rpm.'  However, when the two bikes (with and without V Boost)  were compared on the drag strip, they ran about the same.  What was missing was that kick in the a** vs a linear power delivery.

[ohiorider]

Regardless of the back and forth on this thread, I would love to own a silver 1200 Sport with a roller version of the 1151 engine.  I'd probably keep my 2v Sport, since I believe it would be like riding two different bikes.  I only say this because I previously owned a fine-running Griso 8vSE, and I think I understand the differences in power delivery between the two and four valve per head engines.

NOTE: I am truly going to be pi**ed if Guzzi does not continue the CARC lineup.  Not for me, so much, but for you 'youngsters' coming up who will have missed a really fine generation of Moto Guzzis.

[Kev m]

I'm trying to understand this statement . Boxers and HD motors act nothing alike . Did I miss something ?

 Dusty

Linear delivery of power?

[rdbandkab]

I want this (with the shotgun pipes),  but with the side bags still usable!!



 

[lucian]

Yep, the 8V likes to rev. Don't confuse that with needing to rev. The old kick in the pants at 5500 was a result of the ECU trimming the sub 5000 area to meet emissions. Some folks using my maps have complained about the lack of kick at 5500. That's because the power delivery is linear. There's more torque down low and that results in seamless transition to the top end.

Beetle maps RULE the 8v world!   lamdas off, co plus 5  = happy camper

[Trogladyte]

I'm trying to understand this statement . Boxers and HD motors act nothing alike . Did I miss something ?

 Dusty

Sorry - I wasn't being very precise or scientific - just being a bit facetious in fact. I just meant that the Griso 8v is quicker than a lot of other big twins, and can be rather quicker than people expect it to be.

[oldbike54]

Sorry - I wasn't being very precise or scientific - just being a bit facetious in fact. I just meant that the Griso 8v is quicker than a lot of other big twins, and can be rather quicker than people expect it to be.

 We don't allow anyone to be facetious ... oh hell , even I can't keep a straight face making that statement . OK , where have my emos gone , again .

 Dusty

[canuguzzi]

If you long for a 4V Norge ( don't know who owns it)


http://sfbay.craigslist.org/eby/mcy/5448829757.html

MG says the 2nd gen Norge's are 8V BTW.

[pete roper]

For those who are interested in simple, traditional looking, but less than modern performance motorbike options Guzzi are making the V9 series and already have the V7's which are a great little bike within their limitations as long as you don't obsess about the power/swept volume issue. For those who want a fat-ass cruiser they make the Cali 1400.

What will end up missing from the lineup if they knock the 1200's on the head is something with a little more get up and go coupled with a modern rolling chassis. That would be a shame.

The early dyno charts say nothing. They are essentially like comparing the performance of a car with a 1960's engine and one with a Y2K engine and so very much is dependent on the tune and the map.

As Mark has explained the early maps, especially the GRS8V-01/2 were beyond dreadful. Even the factory accepted that and clandestinely released the 68S which remains the best of the factory maps. The GRS8V-03 map. The last factory iteration, seemed to manage to eradicate the 'Step' in the midrange but mainly by just making the power delivery *Soggier* in the open loop area.

Early solutions like Power Commanders, apart from being a kludgy plug in, were almost invariably used, (And in many cases still are.) by people who give zero thought to the design peculiarities of the 8V and even the main maps produced are all stupid rich because of this. Rexxer Pro allows full adjustability but most people using Rexxer are just using their 'Off the Peg' maps which are fairly crude.

The other option is DIY with Guzzidiag, Reader, Writer and a programme like Tunerpro. This is true not only for the 8V but any of the bikes using the W5AM or 15M/RC. The only caveat with this is of course you have to understand how the motors differ and why their pumping characteristics have little in common and its NOT simply a matter of valve area as many seem to think. It's also the reason why the Guzzi 8V is thirsty if you thrash it!

At the end of the day if you prefer the 2VPC motor for whatever reason? That's fine, but it's not coming back so get over it. If you want a 2VBB you'll be buying second hand. If you are worried about the 8V being unreliable? Buy a post mid-2012 model with a roller top end or, as suggested elsewhere, factor in the cost of the top end swap into the asking price and risk the fact there may be other damage. (Three of the bikes I've rollerised have had subsequent problems, only one of those was really inexplicable. I've done a LOT of conversions now, I have a corner of the workshop we call 8 valve-aggedon! The attrition rate is not high but it is worrying.

Oh, and one final point to counteract the argument that 'Nobody asks for less power'? This isn't true! My mate Dave who bought the 'Melted Munter' from up the hill found the Beetlemap too aggressive so Mark is developing a kinder, gentler, *Training Wheels* map for him to use to get him up to speed, (It's still too rich at the moment.). Dave is coming off a MkIII LeMans with half the HP and torque and stodgy old Carbs, he's finding it a bit of a challenge. That's fine. Challenges are to be met.

Pete

[MotoG5]

With the 8V, you WILL find the rev limiter.

Yep! Yes Sir! You Will. Kind of like other experiences in life you will want to do it again. And again.

[oldbike54]

 Pete says "Challenges are to be met" .  :1:

 Oh , welcome home Pete 


  Dusty

[tazio]

YES! Welcome Home Mr.Pete !!!!!

[ohiorider]

YES! Welcome Home Mr.Pete !!!!!

Yowzah!  Good to hear from you, Pete!

Bob

[pete roper]

Since you've done it, what happens between 8000 and 9000? I mean is there something to be gained past the 8500 limit I think you put into the last map? Is that a forbidden zone at which point you should have a well stocked shelf of parts just in case?

It's not somewhere I go very often now Mark has raised the limit to 8,750 as 8,500 or even 8,250 but I do go there and so far nothing has escaped out of my new engine, (Shrug?)

It's probably more important if you really are chasing peak power or ride in such a way that you may want to hold a gear between corners when pushing hard rather than changing up.

Some things to remember. I have no interest in outright power, my G12 makes plenty. People ask me "How much?" I say "About 100". My *Guestimate* is probably, on the same dyno we usually use, 102-103 at the rear wheel BUT the torque all the way from 3,000 to 7,500 is MONSTROUS! It has to be in the mid eighties ft-lbs. we'll find out soon enough. Note though that my bike is dead stock (Roller top end.) apart from a Mistral Hi-Pipe with the butt plug in and no snorkel on the air box simply because it allows room for the logging gear and that's what Mark builds the maps for! I like quiet, I also like the bottom end strength offered by this system. If you run the same system with the butt plug out? Mark has done a lot of work on that and I'd guess you get a few more ponies at the top, (2? 3?) maybe more, I really don't know, but you will loose out a bit in the bottom end in particularly. Whether you'd really notice it I have no idea.

Note ALL roller bikes use the same cams. Griso, Norge, Cali, 8V Sport when rollerised, Stelvio? All the same. Differences between roller bikes, apart from stock pipes, air boxes etc. are negligible but those changes make a BIG difference with the 8V.

Another thing notable about the 8V is that it's single plate clutch assembly is a heavier than the last of the twin plates, especially at the flywheel periphery. I love that. So far AFAIK there are no 'Lightweight' aftermarket offerings available.

To change the subject a bit but if you are looking for shit to spend money on? Brakes and suspension. And there the sky's the limit.

Pete

[beetle]

The Mistral and Agostini roller maps I built have an 8750 rev limit. The custom map in my Griso goes to 9000. I hit the limit frequently still accelerating. I don't sit there bouncing off the rev limiter though.

[keener]

i have the Griso 1100 2vpc  love the bike and its a keeper, that being said i think the best future for Guzzi still resides in the 4VPC big block engine ...and now that  top end issues issues have been solved and great maps created thanks to Beetle , hopefully the  8v can move forward to where it was meant to be.
i look forward to  development of the engine via Guzzi in the future , hopefully they are on that track because the competition is and will continue to do so.
the V7/V9  are important as well as the 1400 series  bikes, but Guzzi needs performance based models with modern engines and suspension to truly compete with the other mfg or at the very least to show that they are in the hunt.
It is totally within their capacity to do so.
 

[bpreynolds]

So many good points in this thread, I struggle to find anything remotely new I could add to it.  Let me think.  Hmm.  Nope, the only thing different or new I could add here to what has been stated is to say the later V7 engine is the best of the bunch.   Wait, we weren't talking about that one?  :1:

[Huzo]

Good to see Peter Roper giving some thoughts based on real rider feel and meshing in nicely with some solid factual knowledge. Like Kev, I flinch a bit when I read things like "a bit of a dip in the torque at blah rpm but a good linear power delivery", remember ,POWER is Torque x RPM , so you will not get "linear" power with non linear torque, best example of linear torque and power is an electric motor. My old mate Issac Newton from Cambridge, told me the other day while we're were enjoying an apple under an old oak tree. Power is force x times distance / time , (or in English), work done is force x distance, and the rate of doing that work is force distance / time, that is what POWER is, you don't "make" power, is a numerical value given to a calculated figure of the rate at which you have done that work.  Having said that I'm convinced that we each know what we all mean so I'll move on ....I am in two minds as to whether to remove the snorkel from my Norge, the bike used to "ping" at low rpm/ high throttle settings on warm days > 35 deg C, the problem was of course lean mixture at that combination and has been fixed by some map manipulation by a genius in Melbourne, the bike now settles out at 5.8 L/100 k where before it would have been closer to 5.1L/100 k at the same conditions. Does anyone know if removing the snorkel will lean it up a fraction without re introducing the dreaded " ping".