Archive through July 10, 2013

[dfrisk]

NIC - SON had a buddy with a BBF 460 displacing 598 CID, 104 MM inlet turbo... pro-built motor... could make 2000-2100 HP if you turned the boost up a little, even 2200-2300 HP if you dared.... It had head studs too. BIG head studs.... six per cylinder... Ford Motorsport made a kit for them. It was in a GEN I Lightning p/u. I rode in it for a bit the morning of the LAST Formula 1 race at Indy. Standing start, matted the gas pedal, shift light came on almost instantly @ 7800 RPM... shifted to second, shift light came on again 2-3 seconds later... 104 MPH.

The owner took it to IRP drag strip, even with an NHRA approved 10-pt cage, racing seats & 5-pt harnesses, Tech team said, "Don't bring IT back here again!" after his first run. It would break traction mid-quarter mile # 140 MPH with 31-12.50 slicks.

His turbo'd small block 357 Windsor was almost as fast and a lot more "tunable".... Also had head studs! Ohhh and the SBF Lightning was the tow vehicle for his BBF truck. Imagine towing with a 10-second F150.

I don't know why a K321 out of a 147 CC had nine head studs, but mine did... and still does. I doubt I'd have put studs in it, if it had bolts in it when I got it, but I sure wasn't going to replace studs with bolts since I already had the studs. No problems with the studs, head gasket, or head in 175 hours of running. I doubt I put 1400 hrs on this engine like I did with my old K241, I suspect I'll put 500-600 hrs on it, then pull it apart, replace the rod bearing insert, rings, clean-up the valves,ports etc. and put it back together.

 

[nbextermueller]

Got a pleasant phone call today. Lucas Oil is stepping up their support for our club. A "championship package" to be given out at every event, Plus the usual season ending stock pile!

They want more presence at each event! Can do! Cause if you've read any of my posts on here, you know I use it in all my stuff I can because it flat out works!

 

[jcleer]

Ok guys have a question for ya,,,,On my dads 782 puller. It has a 25hp v twin engine when we bought it, it had a really screwy exhaust. We have since put a non equal length 2 x 1.250 into 3.00 stack. It helped but I was wondering about doing 2 separate stacks 1" thru the flange then 1.250" thru the 90* up then 1.50" to 8"-12" above the hood. Of coarse these would be equal length too. My thinking is all the Harley V twin big performance pipes are this way not 2 into 1. Granted a kohler 25hp is not a Harley but similar.

 

[dfrisk]

JOE - Sounds like you're trying to come up with a tuned length header system on the 25 HP V-twin engine in the 782. A WHOLE lot of science is involved in coming up with a properly designed tuned system. Lot of measurements needed to even get started, plus we need to know operating RPM ranges, peak HP RPM, Peak torue RPM, etc. etc.

Then comes the fun part, trying to create an exh system that fits without getting in the way of the engine and tractor.

Couple general rules I've gathered from studying engine tuning for 45 yrs. Two-into-one exh. systems improve torque, mostly at low & mid-range RPM, and really don't hurt torque at higher RPM that much. Longer tube headers/exhausts help improve low & mid-range torque. Larger diameter tubing slows velocity of the exh gas flow which kills torque. Short "Zoomie" headers are mostly for high RPM use, longer headers are for slower engine speeds.

You do a search on motorcycle exh design and there should be days of interesting reading on-line. Years ago a feature editor by the name of Gordon Jennings wrote a lengthy series of articles for Cycle Magazine about all manner of engine related topics. Even after 45 years, the information is still timely. He wrote a book, "The Two-Stroke Tuners Handbook" which was facinating... unfortunately not pertinent to your 4-stroke 25 HP V-twin. And I'm not aware of a 4-stroke equivalent to Gordon's book. But I think you're on the right path. Study what people are doing with Harley's, and other V-twin bike engines.

 

[nbextermueller]

John, I agree with Dennis on your approach. The current design with a 3" exit is waaayyyy over kill. 3" is over kill on most V8 dual exhaust.

Sounds like your new plan is much more in line. You could look into making a tuned exhaust, but my education has shown that "close to tuned" is not much better than "not tuned". And by "tuned" I mean taking into account exhaust gas expansion, sound frequency, scavenging, temp loss.... It's getting in to NASCAR/indycar/F1 territory.

I personally shoot for about what your doing with a properly designed crossover for proper scavenging to keep velocity up. Ideally, using a your exhaust port including valve and exhaust pipe show flow around 80% or better of the CFM of the intake with valve. Of course the requires a flow bench.

But I like your plan. Our club doesn't allow anything over 16hp. But we have alot of twins. In fact my brother and dad both pull with 16hp flat/opposed twins only. They make great torque. Seems to me the V motors like alot of RPM.

If I was to build a V twin, I'd be focused on high load, load rpm torque in cam and exhaust design, even if it sacrificed a few hundred RPM down the track.

 

[jcleer]

Ok sorry guys for not giving enough info..We are limited at 5000 rpm max, 26" pro tires, 1000 # light class, 1100# heavy class.

 

[jcleer]

Here are our class rules for this class.
STOCK APPEARING TWIN
46 Cubic Inch and under
Class 1: 1000 pounds
Class 2: 1100 pounds
5000 rpm max
26x12x12 pro tire
13" hitch height
Alum. wheels Ok
+6" wheelbase
Factory Frame
Stock Crank
46 cu In
Any piston, camshaft, valve
OEM intake
Downdraft Carb
1"venturi
No 2 Barrels
Tractor rear end
stock cast head
shields
fenders
steel flywheel
electric fuel pump
governor
kill switch
wheelie bars

 

[nbextermueller]

Looks like that class is all porting the head, cam, and compression. Alcohol or E85 for sure.

How exactly do they set a 5000rpm limit AND require a governor? What governor is going to allow that RPM?

And I thought my club had sparse rules. There is ALOT of playing room in there. Any rules on ignition? There is alot to be gained with proper timing curves. And you do need a curve unless you never drop below 4500 during a run (meaning you end the run spinning the tires.)

I have a few tricks up my sleeve that I won't mention publicly that address timing. It a spot in tuning that is over looked by most people not running NQS.

Nearly every tractor in my club has stock points or ignition on engines they have spent $1,000s on. That $300+ piston and race gas doesn't do jack without proper timing, especially if your going to spin it past 3600rpm.

But I just own the club... I'm not allowed to help the guys. I'm supposed to be neutral. And I swear I am. And yell at my people who aren't.

 

[jcleer]

I forgot to mention No alcohol of either kind is allowed at our club . As far as I know it is the stock governor with a stop screw. They are set at wide open throttle no load. Not sure if thats a good thing, but we are all tech'd at that so I guess its fair. I will post a pic tomorrow of governor so you all can see it. As for the ignition...rule states any. Here is a link to the club if you want to check it out. http://www.groundpounderspulling.net

 

[nbextermueller]

Seems, pretty straight forward. I'd still be running E85. It is a "pump" gasoline. You need about 30% bigger jets to do it though.

There are a lot of 82 series tractors in your club!

 

[jcleer]

Yeas there are alot of 82 series there. Some of them have older wide frames but have put the CC sheet metal on. Here are the pics not that great, camera phone.

Spring in foreground is from governor arm to thrttle.

Cable on top is choke, there is one under it that comes from the pedal then to arm that has governor spring, then to the sqiwlgly arm that goes to the carb.

Ditch Digger, tractor was already named when we got it but it fits since dad is a heavy equipment operator (semi retired)
Yeah as for the fuel there is a specific gravity that it has to pass. Some run VP gas or Turbo blue. We run Cam2.

 

[nbextermueller]

Interesting to see the CCC Cyclops fenders on there. 82 series never cam with those. I wonder if its an 82 with newer fenders or a cyclops with older front clip...

Otherwise pretty awesome.

 

[jcleer]

Its a 82 series. I ran the vin. It was 4 months from the end of the run IIRC.
She still just baffles me though, We cannot get the nose to raise. It always spins out. We did put an overdrive set of gears in that helped get us farther down the track but still wont come up. All the weight added goes on the rear too nothing up front.

 

[nbextermueller]

Well, you've got a lot of weight out front already with that 25hp engine in there.

So obviously you have a traction problem. Is the hitch as close as you can get it to the rear end housing? And your using the full 13" allowable height? If yes and yes, then I would say despite having pro tires, you need to try different tires. What tires are you running? Are the chevrons more than 1/2" deep? Is the rear differential welded solid?

How about pictures of these items?

 

[jcleer]

The hitch is pretty close to the rear end, My be get it a 1/2" closer. As for the 13" that was just changed for our class at the end of last year, so I cant answer that one. Hopefully that is what we need we were at 12". Tires are 1/2 deep yes. As for welding the rear end none of the twin guys here have theirs welded and highly recommended not to. Not sure why. Just going by what they said (and yes I trust them). We have never had a one wheel spinout either but it could happen I suppose.

 

[nbextermueller]

That extra 1" or more will make a big difference. As for welding up the rear. I would make the assumption that they don't recommend it cause then you'll likely tear out the pinion or break the carrier with a modded 25hp.

Personally, it's worth the risk. I don't want any possibility of a slip. We regularly put 35-40hp @ 5500 rpm to the ground with our flat twins. And yes, we've popped a few rear ends. But that's what parts are for. Championships cost $$. Even in this silly redneck sport.

Edit: regarding the tip not to weld up...I'm not doubting the trustworthiness and friendships you have in your club. Similar to our club, I'm sure they are all very nice families. But I've never met a competitor that would give out enough advice to beat him. So remember to think out side the box and use their advice as "suggestions" not "answers" until the suggestions they provide result in you beating them. Guys are always more than willing to give out advice until you regularly beat them. Then they come calling you...

It is such a fun sport. Your first pull is the same weekend as mine. Good luck man! And watch those rear tire pressures. The holes you leave in the dirt tell you a lot about your traction situation.

 

[jcleer]

Thanks for input Nic. And good luck to you too.
Here are pics of my sons after I just painted it. He picked the color!

I know its green, but it's 2010 Camaro synergy green!!!! Pictures don't due the color justice.

 

[nbextermueller]

Looking good. Weird to see pulling tractors with turfs... Not a common thing around here.

 

[jcleer]

Our lesser hp classes have 23" tire rule. 9 outo 10 times cut turfs will outpull bars cut or uncut!!

 

[nbextermueller]

Hey Joe, how'd your first pull go? Any improvement with any of your pullers?

Our first pull was rained out. Track was just too wet to save. Bummer too, the weather was awesome!