How did guzzi develop the BHP with air cooling and pushrods?

[Grim]

Engineering wise, it is said that there are specific reasons that Indian can almost double Harley Davidson's bhp when it comes to the 1200 v-twin; those being Harley's marketing department insisting on pushrods and air cooling, necessitating a long stroke undersquare design to allow for slow valve train and maximum surface area for cooling.

Indian use an oversquare, 4v, ohc, water cooled design to reach 100 odd bhp from the same displacement, and people make a big deal about it.

So how does the air cooled pushrod engine in a Guzzi do almost the same thing? It's oversquare, but not by as much as the Indian 1200, and it's a narrower angle than a Harley, but it still has pushrods, and is also air-cooled (albeit better air-cooled).

Could Harley not just follow suit or is it that pesky rear cylinder?

 

PS I am not an engine expert (and it shows) just interested, so if I got some terms wrong I apologize.

[pete roper]

Swept volume means very, very little when comparing different engine designs.

[Scud]

Becuase Guzzis are made with red wine and Harleys are made with beer. Wine has a higher alcohol content, so it burns more efficiently. The tannins in the red wine also account for Guzzis having more character. My Scura, for example, has hints of blackberry and chocolate.

[GuzziMoto]

I don't think HD is chasing HP. They are after torque, it seems. And feel. HD has built some pretty powerful engines. Obviously there was the V Rod engine. But they also built a 1200 air cooled engine for the Buell that made 101 HP (mine put out about 80 HP at the rear tire, more than the wife's V11, and over 70 ft/lbs of torque). That was a seriously sweet motor. Not like a V11 motor, it was much more of a stump puller that would still rev while the V11 motor is more of a mid-range motor.

Certainly HD could build a more modern engine, but really they seem to be doing fine where they are. And the Live Wire is seriously fast. In the end, there is more than one way to make a nice engine.

I just wish HD hadn't killed off Buell.

[LowRyter]

Harleys rev to 5k and Guzzis go to 7k+.    Wanna make a 500cc engine make power like 1000cc?  Double the revs.  Looks at those F1 motors in the '90s that revved to 18k.  

[docc]

Good point about the revs. As much as pushrods and air cooling, isn’t the low revving motor part of the cruiser purpose statement?

When I demo rode the new big Indian, I kept hitting the rev limiter (no tach). Finally, I figured out to put it in sixth and “lug” it. It was, then, perfectly at ease. 

[Grim]

8 minutes ago, LowRyter said:

Harleys rev to 5k and Guzzis go to 7k+.    Wanna make a 500cc engine make power like 1000cc?  Double the revs.  Looks at those F1 motors in the '90s that revved to 18k.  

 

Thanks, from what I was reading/watching I get this part, I was interested in the hows and whys of completing this task.

If you wanted power "in the old days" you went with torque, your lubrication is crap and you don't want to rev high and blow up, so your cylinder is long and thin, the combusting gas exerts it's force all at once on the piston, the lever is long and you get a big slug of torque.

But an oversquare cylinder needs revs to make power, but it's harder to cool with air, and it's hard to rev fast with pushrods 'cos your valves might start to float.

So is a guzzi engine kind of on the edge of what is possible with the design?

 

25 minutes ago, GuzziMoto said:

I don't think HD is chasing HP. They are after torque, it seems. And feel. HD has built some pretty powerful engines. Obviously there was the V Rod engine. But they also built a 1200 air cooled engine for the Buell that made 101 HP (mine put out about 80 HP at the rear tire, more than the wife's V11, and over 70 ft/lbs of torque). That was a seriously sweet motor. Not like a V11 motor, it was much more of a stump puller that would still rev while the V11 motor is more of a mid-range motor.

Yeah I get this bit, they want to sell yesterdays tech at tomorrows prices and it works! 
I was really interested in how the Guzzi engine manages to make decent power, when by some accounts it is hamstrung by it's own design. 

So to get decent power from a C1100 v-twin, it seems manufactureres tend to make it oversquare, which usually requires water cooling / multi-valves and OHC, Guzzi just didn't seem to go down that road, which I love.

[motortouring]

We need a TURBO-CHARGER or COMPRESSOR :-)

 

[GuzziMoto]

For a production air cooled push rod V twin a Guzzi big block makes good power. The newer 8V CARC engines make better power, but they seem to less fuel efficient. The older 4V engines like from the Daytona and Centuaro have their own issues but they make good power. All three are big block Guzzi's, but each of the three has a different character.

Being oversquare is only one aspect of engine design. If you make an engine oversquare but you don't have the flow past the valves to support the oversquare aspect you could make less power, not more. Being oversquare alone does not make more power. Being water cooled alone doesn't make more power. Although you can make more power by adding a turbo or compressor alone.....

But then you need to be able to shed the extra heat.

I do like how Guzzi's respond well to old school hot rodding. Cleaning up the ports, adding more compression and squish, things like that, can make a noticeable difference in power output of a Guzzi engine. Trying to get more power out of a modern sportbike engine is pretty hard in comparison.

[Scud]

1 hour ago, GuzziMoto said:

The newer 8V CARC engines make better power, but they seem to less fuel efficient.

My Stelvio is very efficient. I got close to 50MPG on a 400 mile ride recently, and I was not being gentle. However, a carbon Mistral slip-on fuel injection trim module are the way. So I will try to be less efficient.

Interestingly, the FI Trim Module (from MG Cycle), claims to work with Mistrals on Stelvio, V11, and several other Guzzis. I have the Moto Guzzi Titanium Race exhaust on my Scura, but have not messed with the ECU. I think I will try this plug-and-play module on the Scura. I assume the MG race exhaust is similar to the Mistrals.

[footgoose]

7 hours ago, GuzziMoto said:

I don't think HD is chasing HP. They are after torque, it seems. And feel. HD has built some pretty powerful engines. Obviously there was the V Rod engine. But they also built a 1200 air cooled engine for the Buell that made 101 HP (mine put out about 80 HP at the rear tire, more than the wife's V11, and over 70 ft/lbs of torque). That was a seriously sweet motor. Not like a V11 motor, it was much more of a stump puller that would still rev while the V11 motor is more of a mid-range motor.

Certainly HD could build a more modern engine, but really they seem to be doing fine where they are. And the Live Wire is seriously fast. In the end, there is more than one way to make a nice engine.

I just wish HD hadn't killed off Buell.

I'm with you on all this. Several HD's have come and gone in my garage and honestly they were more dependable, required less maintenance, and easier to work on than my Italians, and an endless support system and aftermarket. The torque was thrilling. Twisty roads.... not so much. (Except for my buddy's Buell XB9r)

[pete roper]

3 hours ago, Scud said:

My Stelvio is very efficient. I got close to 50MPG on a 400 mile ride recently, and I was not being gentle. However, a carbon Mistral slip-on fuel injection trim module are the way. So I will try to be less efficient.

Interestingly, the FI Trim Module (from MG Cycle), claims to work with Mistrals on Stelvio, V11, and several other Guzzis. I have the Moto Guzzi Titanium Race exhaust on my Scura, but have not messed with the ECU. I think I will try this plug-and-play module on the Scura. I assume the MG race exhaust is similar to the Mistrals.

So is the Mistral POS an air temperature sensor spoofer or a lambda sensor spoofer. Both are awful and both have issues. Given the fact the W5AM ecu is an open book using these crappy *solutions* is madness.

[po18guy]

The V11 combustion chamber and piston are very similar to the 1964 Chrysler 426 Hemi. Advantage to the car engine for liquid cooling. Disadvantage for iron which tends to hold hot spots more than aluminum. At Guzzi's claim of 91 BHP, size-for-size, it would make 600 BHP in 7.0 litres, whereas Chrylser's 426 made a 'claimed' 425 gross HP. Some sources claimed that it made more like 550 BHP, but those were claims only.

[LowRyter]

15 minutes ago, po18guy said:

The V11 combustion chamber and piston are very similar to the 1964 Chrysler 426 Hemi. Advantage to the car engine for liquid cooling. Disadvantage for iron which tends to hold hot spots more than aluminum. At Guzzi's claim of 91 BHP, size-for-size, it would make 600 BHP in 7.0 litres, whereas Chrylser's 426 made a 'claimed' 425 gross HP. Some sources claimed that it made more like 550 BHP, but those were claims only.

funny, I just did a google today  MOPAR (gen 1 & 2, not the new ones) 55 degree valve angle and Guzzi 56 degrees.

well said

[pete roper]

Volumetric efficiency

Thermal efficiency.

Mechanical efficiency.

Improve any or all of those and you'll get more power.