Ever heard of windage issues in TC engine?
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Ever heard of windage issues in TC engine?
I touched on this in a previous post. I had my 95" dyno'd at Sturgis this year. It has 10.3:1 pistons, S&S super stock heads, 570G cams and Super E carb. Dyno'd at 72hp and 95ft#, but only on the best run. Most runs were more like 62hp. Dr.Dyno believed it to be a windage issue. He said the a/f ratio remained constant, pointing away from carb. Due to the inconsistencies in runs, he would not try to adjust timing and advance curves. He kept going back to a "non destructive oiling issue such as crank windage or a driveline drag". I rode 1000 miles to get it there, I never felt anything that felt like drag in the drivetrain. He ran about 15 runs, most in the 60hp range, then it jumped to 72. Still low in my opinion considering the mods. Any ideas? The top end only had 2000 miles on it when dyno'd, it seems to have loosened up a bit since then. I haven't been back to the dyno yet. Now I have about 5500 on the top end.
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RE: Ever heard of windage issues in TC engine?
Where you come into "windage issues" is with cam duration, how long are vales held open. Since I don't know the exact mods done to your engine, I am going to be general. Overlap, how long the intake and exhaust valves are open at the same time. Then throw in head flow and pipes. if your heads don't move exhaust gases out to the pipes and the pipes don't move air you get spent exhaust trapped in the combustion chamber. Normally a good indicator or air retained is indicated by increased misting into the air cleaner.
without good heads and exhaust you put too much back pressure in the cylinder, and with the valve overlap, it'll blow exhaust back out the intake when the intake valve opens, since the intake and exhaust valve are both open at the same time, for a short period. the idea is for the suction of the exiting exhaust to get the intake cycle started a bit early, in effect " cheating" to get better performance. with too much backpressure, the extra pressure will puch the intake charge back up the intake manifold, spraying gas on you.
without good heads and exhaust you put too much back pressure in the cylinder, and with the valve overlap, it'll blow exhaust back out the intake when the intake valve opens, since the intake and exhaust valve are both open at the same time, for a short period. the idea is for the suction of the exiting exhaust to get the intake cycle started a bit early, in effect " cheating" to get better performance. with too much backpressure, the extra pressure will puch the intake charge back up the intake manifold, spraying gas on you.
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RE: Ever heard of windage issues in TC engine?
With what you have in your build,I doubt you have stock exhaust or at least mufflers.Since you have S&S heads,try calling them with your issues.That CO.has done their homework and cant beat the package setups they sell.That dyno guy offer any advice?Or did he just take your $$$.Mixing performance parts doesnt always work.I agree you should be making beteer #s.
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RE: Ever heard of windage issues in TC engine?
Of course the dyno guy was quick to take my $$$, this was at sturgis after all. He only offered the opinion that it was windage or a driveline drag. He said I would need to study the oiling system to see if anything could be done. Translation, pay me and good luck!!
I think I need to find a knowledgable tuner in my area. I am no vet at motorcycle building, but I am a 15yr. auto mechanic. These motors are not rocket science. Where the art comes in is squeezing every pony out and I will be the first to admit I am lacking experience in that department. I'm confident the hardware is all in order, it's just a matter of dialing in the timing and carb. And, pittguy, I am running V&H long shots. My next move is a 2 into 1 pipe, then find a good dyno man.
I think I need to find a knowledgable tuner in my area. I am no vet at motorcycle building, but I am a 15yr. auto mechanic. These motors are not rocket science. Where the art comes in is squeezing every pony out and I will be the first to admit I am lacking experience in that department. I'm confident the hardware is all in order, it's just a matter of dialing in the timing and carb. And, pittguy, I am running V&H long shots. My next move is a 2 into 1 pipe, then find a good dyno man.
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RE: Ever heard of windage issues in TC engine?
Your #s are off more than windage would probably cause.I tend to believe the tuner just wanted your $ and was in a hurry for the next guys.Dyno #s arent set in stone,two different tuners on the same dyno can come up different readouts.Just strapping the bike down can play w/readouts.Alot of these guys are snakeoil salesmen spending the summer jumping from meet to meet.Get a good local tuner-ask around-and have him set your bike up.
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RE: Ever heard of windage issues in TC engine?
its called "SUMPING"...you cut or nicked or didnt change the three o-rings on the oil pump and are filling the crankcase with oil...that oil is draggin on the crank and killing your power
it aint got a damn thing to do with cams or the s&s package...your combo should easily make over 100/100 all day, any day...pull your cam chest apart and for 5 bucks replace those o-rings...lube em good with assembly lube ... to center the pump, install the 4 pump bolts only finger tight...install the cam plate bolts and torque them...pull the plug wires and fuse to the injectors...have a buddy spin the motor as you tighten the 4 pump bolts...walla, big power....oh and dont forget to pull the bottom crankcase drain plug and get the oil out...betcha got a quart or better
it aint got a damn thing to do with cams or the s&s package...your combo should easily make over 100/100 all day, any day...pull your cam chest apart and for 5 bucks replace those o-rings...lube em good with assembly lube ... to center the pump, install the 4 pump bolts only finger tight...install the cam plate bolts and torque them...pull the plug wires and fuse to the injectors...have a buddy spin the motor as you tighten the 4 pump bolts...walla, big power....oh and dont forget to pull the bottom crankcase drain plug and get the oil out...betcha got a quart or better
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RE: Ever heard of windage issues in TC engine?
THink I have to agree with Bryan on this one....
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RE: Ever heard of windage issues in TC engine?
Before you pull anything apart (because I doubt this motor is sumped as the #'s are too high for a sumper) remove the allen plug on the bottom of the engine case. If more than 12-14 oz oil comes out you're sumped. The very last 2 pages of the service manual engine section give the torque for the plug. If you don't have one, I'll look it up. Also, the only o-ring that contributes to crankcase sumping is the one that goes on the end of the oil pump snoou where it goes into the crankcase.
I would do this because you would be nuts to teardown a motor when you have this tell tale test to do.
Personally, I think it's the pipes and jetting/timing. I would run a Crane HI4 ignition, and then get it dialed in. Are you running baffles?
I would do this because you would be nuts to teardown a motor when you have this tell tale test to do.
Personally, I think it's the pipes and jetting/timing. I would run a Crane HI4 ignition, and then get it dialed in. Are you running baffles?
