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View Full Version : Big block gas engines, are they worth it?


tacoma200
09-13-2006, 10:23 AM
Just wondering how much extra fuel that the big blocks such as the 31/35 hp engines are using in your experience. Does the extra power and torque needed probably a small percentage of the time justify the added weight, expensive and fuel cost under normal conditions. Love to have a big block but thats alot of extra money and I'm not sure about the reliability of the Vanguards or the fuel consumption.

luckylawnboy
09-13-2006, 10:29 AM
I have one on my XS lazer and it uses less fuel than my 25 hp kaw. on my deeres. It has so much power in reserve that the governer is never opened all the way compared to the Kaw. is always open and bogging alot.

noseha
09-13-2006, 11:11 AM
I Like My Late 3/4 Or 1ton's 80's Ford With The 351/400m For The Work Truck Money!!!!!!!!

Willofalltrades
09-13-2006, 12:14 PM
I Like My Late 3/4 Or 1ton's 80's Ford With The 351/400m For The Work Truck Money!!!!!!!!

What a sence of humor! lol I can see the uses of a big block (on a mower).

J&R Landscaping
09-13-2006, 03:07 PM
The vanguard engines are very durable engines and I never did anything to mine other then standard oil changes, fuel filters, and spark plugs. Other then that, it needed 1 pull cord but that was it. It was a great engine and gave plenty of power to my hydros and the deck. (it was on a 52" bobcat hydro wb) I like the kawasaki engines as well.

TAZ
09-13-2006, 03:13 PM
I got one on my lazer XS 60. I am running a mulch kit. That consumes some power in thick grass so I am glad I have it in that regard. Without comparing the same mower with the same deck with 2 different motors on them all your going to get is opinions. Some of the guys here may have that setup but I don't. That being said though I have not been surprised by the fule consumption.

-TAZ

Green King
09-13-2006, 04:51 PM
There is a lot of Encore guys here that are using the generac v-twins and like them alot they say they are easy on gas. I have a vanguard diesel and have never had any problems.

tacoma200
09-13-2006, 05:21 PM
Well you read many post about guys wanting more power. My Lazer with the 27 Kohler/60" cut seems fairly powerful in most conditions but of course you can bog it down if you cut heavy and fast enough. Of course with the big pump/motors the Hustler Super Z can really leave you wanting more (alot more) on hills. If Exmark had had the decks fixed I would have probably got a XS but I notice Scag offers the big blocks also on the Turf Tiger. The problem with Exmark (other than the new deck which I hear is going to be fixed) is that you have to go to a larger mower frame to get above 30 hp. Some of the heavy lawns I do I probably should have gotten a big block but I would sure loose money on a trade. Does the Sabre Toothed Tiger have a larger frame than the Turf Tiger?

rodfather
09-13-2006, 06:39 PM
I have a 35 hp Briggs & Scrapiron on my Ferris 4000...it just loves fuel I can tell ya.

dvmcmrhp52
09-13-2006, 06:58 PM
The 31 on a 60" deck can certainly outperform the 23 horse with the same 60" deck, but obviously there is a fuel cost to consider.
Unless cutting acreage with it the big blocks really aren't necessary.

The XS with the 31 horse briggs is a great machine, however it is too heavy for smaller lawns. Wide open is the place for the big blocks..............

rodfather
09-13-2006, 07:02 PM
Wide open is the place for the big blocks..............

Exactly...good point Dave. BTW, we have to wear ear protection with that puppy cause it is LOUD to say the least.

dvmcmrhp52
09-13-2006, 07:08 PM
Exactly...good point Dave. BTW, we have to wear ear protection with that puppy cause it is LOUD to say the least.


Ya, they are loud, however they're not much louder than the 23 horse motors on the Lazer HP's due to the routing of the exhaust. There's a big difference even between the 23 horse motor on the Lazer versus the 23 horse Lazer HP simply because of that exhaust routing.

rodfather
09-13-2006, 08:55 PM
Ya, they are loud, however they're not much louder than the 23 horse motors on the Lazer HP's due to the routing of the exhaust. There's a big difference even between the 23 horse motor on the Lazer versus the 23 horse Lazer HP simply because of that exhaust routing.

Dave I swear to ya my 35 Briggs full throttle sounds like my friend's 182 Cessna on takeoff...no lie :laugh:

green acres lawns
09-13-2006, 10:48 PM
I demoed a 72" IS4500 ferris with the 35hp briggs big block on 26 acres of high school property. It used about 2 gallons per hour. By comparison, my 72" Sabre tooth with the 31hp diesel burns just under 1 gallon per hour on the same property. Power seemed about equal.

tacoma200
09-13-2006, 10:51 PM
2 gph! Wow, thats alot of fuel.

qualitylawnmanagement
09-13-2006, 11:28 PM
I have an 28hp EFI Kohler on my new mower and it is one sweet engine and plan to buy another one in the spring. Has enough power to get the job done. As any mower no matter what horse power rating you still have to go slow threw tall grass. Just because you spent the money for the big block doesn't mean you will be able to go full speed threw tall grass.

tacoma200
09-13-2006, 11:51 PM
I have an 28hp EFI Kohler on my new mower and it is one sweet engine and plan to buy another one in the spring. Has enough power to get the job done. As any mower no matter what horse power rating you still have to go slow threw tall grass. Just because you spent the money for the big block doesn't mean you will be able to go full speed threw tall grass.
Your probably right. I'm like Tim on "Home Improvement", always wanting a bigger better tool for the job.

green acres lawns
09-14-2006, 12:19 AM
I have an 28hp EFI Kohler on my new mower and it is one sweet engine and plan to buy another one in the spring. Has enough power to get the job done. As any mower no matter what horse power rating you still have to go slow threw tall grass. Just because you spent the money for the big block doesn't mean you will be able to go full speed threw tall grass.
Thats true, but it has to be a lot wetter and thicker before the diesels and big blocks have to go to work.

dvmcmrhp52
09-14-2006, 12:37 AM
Dave I swear to ya my 35 Briggs full throttle sounds like my friend's 182 Cessna on takeoff...no lie :laugh:

I believe it rod, and sometimes if you're not careful that 35 briggs can take ya airborne just like that Cessna......:waving:

Tharrell
09-14-2006, 08:54 AM
That 35hp, is it a daihatsu? I may have mis spoke in an earlier thread about a Bunton 33 with a 72" deck. It was watercooled and YES, it did sound smooth like an airplane, particularly when the blades were engaged.

dvmcmrhp52
09-14-2006, 01:21 PM
I have a 35 hp Briggs & Scrapiron on my Ferris 4000...it just loves fuel I can tell ya.





Hey Rod,
On a more serious note, how's the vibration from the 35?
I sometimes wonder over a long period how the frames and such will hold up with the increase in vibration. The Lazer XS has a heavier frame, but without a real shock absorbing mounting system how long do you figure the frames will take the abuse?

rodfather
09-14-2006, 01:34 PM
Hey Rod,
On a more serious note, how's the vibration from the 35?
I sometimes wonder over a long period how the frames and such will hold up with the increase in vibration. The Lazer XS has a heavier frame, but without a real shock absorbing mounting system how long do you figure the frames will take the abuse?

I just recently Dave had to replace the front A-frames/forks whatever on both sides at 800 hours. One broke in kind of a freak way when I was using it. I welded it back up in my shop so we could finish the day and then said screw it, I'm replacing both if I can. They were substandard IMO being tubular with the metal not very thick at all and the welds not all that great either. The ones on there now are square and much thicker metal.

Shocks seen to be fine, vibration in the seat with the blades engaged at max rpm not noticeable. Like I previously mentioned, you HAVE to wear ear protection when operating it. First day I had it I didn't have any earr plugs and I had a screaming headache after 10 minutes of use (thank God it was close to Miller Time).

Rear side A-frame let go on one of our 3000's early this year. It was still under warranty so no biggie.

dvmcmrhp52
09-14-2006, 02:26 PM
Thanks Rod, I tend to think we'll see more of this sort of thing with the increases in horsepower and larger wheel motors and pumps for speed.
Time will tell........So far the XS is holding up but I'll be checking it thoroughly come season end.

tcls83
09-14-2006, 04:02 PM
Well, think of it in this way if it makes any sense.

Newer Corvettes are known to get 25-30+ MPG (driven normally) with their V8s. It's mainly because the engine is under little strain since the car is so lightweight, and requires very little effort when driven at "civilian" speeds. I wonder what the fuel mileage would be if you put the Cavalier's 4 cylinder engine into the Corvette. I would imagine that the 4 cyl. engine would be under more strain, leading to more fuel usage, even if you have 4 cylinders less than the V8.

Now to compare that with mowers, I think the "big blocks" would be under less strain compared to the smaller mower engines because they are torquier, and the strain on mower engines is mostly constant, since you are using it to cut grass 99% of the time. So the when the engine is under less strain when it is running during using what the machine was intended to do, I'm thinking you would get better fuel economy. Now if you left both (big and small block) mowers parked running at full throttle for an hour, obviously the small block would use less fuel, but I'm thinking it wouldn't when both machines are cutting grass for an hour.

What do you think?

REALSLOW
09-14-2006, 07:08 PM
Well, think of it in this way if it makes any sense.

Newer Corvettes are known to get 25-30+ MPG (driven normally) with their V8s. It's mainly because the engine is under little strain since the car is so lightweight, and requires very little effort when driven at "civilian" speeds. I wonder what the fuel mileage would be if you put the Cavalier's 4 cylinder engine into the Corvette. I would imagine that the 4 cyl. engine would be under more strain, leading to more fuel usage, even if you have 4 cylinders less than the V8.

Now to compare that with mowers, I think the "big blocks" would be under less strain compared to the smaller mower engines because they are torquier, and the strain on mower engines is mostly constant, since you are using it to cut grass 99% of the time. So the when the engine is under less strain when it is running during using what the machine was intended to do, I'm thinking you would get better fuel economy. Now if you left both (big and small block) mowers parked running at full throttle for an hour, obviously the small block would use less fuel, but I'm thinking it wouldn't when both machines are cutting grass for an hour.

What do you think? If you are mowing real thick grass then the mileage of a Big block may be better than a strained smaller engine. Also all that power allows you to run at a lower RPM usually which will give better mileage. Just look at a Diesel low RPM = Good gas mileage. I want a 72 Hustler because I love the chasses and do not want anything else but cannot get a motor that can keep up with the chasses in a Hustler , IT IS REALLY PISSING ME OFF!.

TLS
09-14-2006, 07:38 PM
If you are mowing real thick grass then the mileage of a Big block may be better than a strained smaller engine. Also all that power allows you to run at a lower RPM usually which will give better mileage. Just look at a Diesel low RPM = Good gas mileage. I want a 72 Hustler because I love the chasses and do not want anything else but cannot get a motor that can keep up with the chasses in a Hustler , IT IS REALLY PISSING ME OFF!.

I hear ya on wanting more power in the SuperZ's.

Their chassis is one of the best I've ever seen. Very well laid out, and strong.

Wedge a vertical shaft 35hp Vanguard Big Block in there, and I'd be a happy camper!

mowtech
09-14-2006, 11:05 PM
If you are mowing real thick grass then the mileage of a Big block may be better than a strained smaller engine. Also all that power allows you to run at a lower RPM usually which will give better mileage. Just look at a Diesel low RPM = Good gas mileage. I want a 72 Hustler because I love the chasses and do not want anything else but cannot get a motor that can keep up with the chasses in a Hustler , IT IS REALLY PISSING ME OFF!.

Nope, not true. A gasoline engine is most efficient at wide open throttle. When the throttle is not open all the way you incur throttling losses--that is it takes more energy for the piston to pull the air/gas mixture through the carburetor. The most efficient use of an engine is to have it matched to the load.

Oldtimer
09-15-2006, 08:39 AM
The Big Block is really making a good name for itself. All big block engines are manufactured by DBS, a Briggs & Stratton Commercial Power joint venture with Daihatsu, a member of the Toyota Group. The engine is a bit thirsty but that is the price we pay for higher horse power from a gasoline engine.

Very few diesel powered mowers are used enough to justify the difference in price. A few thousands dollars extra to get a diesel will require a lot of hours to make up for the additional cost of gasoline.

Oldtimer

luckylawnboy
09-18-2006, 04:52 PM
I read today Kawasaki is releasing a FC 1000V wich is a 999cc motor making it the largest displacment air cooled twin out there sounds great!!. I kove my Briggs. No oil consumption, and great on fuel, I like to look at it like acres per gallon. 72" cut 12 mph @31hp vs 60" cut 10mph 25 hp.... if one mower can cut 8 acres per hour compared to 5 acres per hour,,,if your cutting a 25 acre field 3.1 hours at 2gph wich is high IMO is 6 gal, vs 5 hrs at 1.5gph is7.5 gal. plus the extra labor to cut on the slower unit. I just did the numbers in my head for a comparision these are not accutate just guesses.

luckylawnboy
09-18-2006, 04:57 PM
I also saw Snapper is releasing a 3500 Pro series mower. 32hp briggs 26" tires bigger pumps and wheel motors, 73" cut 57.5 wide rear track looks like an impressive machine. I have been searching for more info.. I also scheduled for a demo.. Can't wait