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Author Message   Aaron Posted on Tuesday, August 06, 2002 - 10:41 am:        Saro, it's mostly an assumption from looking at failures. I've seen, for example, a sprocket shaft spun in the flywheel, with less torque than we're generating. That's really my biggest worry, how much torque the whole flywheel assembly can take. I'm not so worried about the rpm or the forces generated from that. I also saw someone break a pinion shaft last year in a 100" Sportster, the same pinion shaft that's in my bike. I still don't fully understand that failure, seems like that's not the stressed side. I don't know how much torque he was making, but he was just running on gasoline, normally aspirated. I'm making substantially more I'm sure. Power is just a matter of selecting nitrous jets. The hard part is making it live long enough.   Vr1203 Posted on Tuesday, August 06, 2002 - 10:56 am:        Peter, I thought you'd never ask! We moved things around and came up with more than the Aerocharger people claim on their website.103hp. I was kind of disappointed. But its a opportunity to seek better components.And so the name of the game is REBUILD.And I ask the membership; 1.what are the best pieces to use in the engine? 2.I,m going leave the turbo setup under the bike 3.I would like more boost, and have it adjustable as in ,external wastgate. 4.I would like to see high rpm 5.looking for big numbers, 150hp+   Peter Posted on Tuesday, August 06, 2002 - 12:47 pm:        Jim, What heads/work, compression, cams, pistons etc are you running now? I was hoping to get 120+ out of mine, but I've got nothing to base that on except their website and the thoughts of one of the people there. PPiA   Blake Posted on Tuesday, August 06, 2002 - 01:12 pm:        Yeah, the article about addign raw NO2 to an injected bike's intake made it clear that the NO2 level was moderate, from a 10 to 20% increase in HP output. Here's another idea.... rig a/the O2 sensor to kill the ignition if the engine goes too lean in nitrous mode. Seems like that would be an easy thing to do. A voltage operated switch that only comes online when the boost button is depressed? Or rig it to a warning light if killing the engine is too problematic.   Redstripe Posted on Tuesday, August 06, 2002 - 05:34 pm:        Aaron, Wouldn't the issue of the sprocket shaft have more to do with the amount of HP and the RPM involved in that? Perhaps it's wise to make sure they hadn't boosted up the rev-limiter, as more RPM makes more centrifugal force to make the shaft spin in the flywheel? J.   Aaron Posted on Tuesday, August 06, 2002 - 06:08 pm:        Jilles, torque is the twisting force being applied to that shaft, and it's on center with the flywheels so centrifugal force isn't stressing it. There are parts that are being stressed by the rpm, like the rods and crankpin, but they concern me less. I'm mostly worried about putting 170+ft/lbs of torque through that sprocket shaft.   Blake Posted on Tuesday, August 06, 2002 - 08:26 pm:        Aaron, what is the shaft diameter? Most failures I've seen of reciprocating parts are fatigue induced. You did REAL good by going for the cryo treatment. You might ask if the other 100 incher's shaft was similarly treated. If it was, a defect was likely involved. Are you sure the flywheels aren't transmitting lateral loads into the shaft?   Aaron Posted on Tuesday, August 06, 2002 - 11:55 pm:        Of course the flywheels transfer laterl loads into the shaft, that's gotta be how he broke the pinion side. But the sprocket side failure I witnessed was a twist thing. The diameters are the same as the ones in your bike! High quality pieces of course. I saw a marked reduction in failure rates when I started having my race cars axles and gearbox parts cryo'ed. So I'm hopeful. Still concerned, though.   Vr1203 Posted on Wednesday, August 07, 2002 - 01:44 am:        Aaron,How long will the cryo' last?.... I could do the intake and use it as a intercooler!   Blake Posted on Wednesday, August 07, 2002 - 02:53 am:        Right, the torsional load by itself would not be so likely to cause a fatigue failure, but with the addition of the cyclic lateral/bending loads you then have a means to instigate and propagate a crack until it is severe/large enough and the shaft fails catastrophically in torsion with the telltale 45o twisted cleavage failure section. The primary chain subjects the sprocket shaft to quite a bit of cyclic bending too.   Aaron Posted on Wednesday, August 07, 2002 - 08:31 am:        Thanks for those reassuring words! You suppose removing the rotor increases that cyclic bending any? Vr, the cryo should be a permanent change, I believe.   Jeffb Posted on Wednesday, August 07, 2002 - 12:37 pm:        Aaron, I just thought I would throw in that the 100" engine you saw break last year wasn't exactly the same set up you are running, although the area that broke is identical to your pinion shaft. Another thing to consider is that the bike that engine was in set a record in M-PF at 180 mph. I don't know the exact HP Brian had there, but I do know that is fast for a open sportster on fuel. Jeffb   Aaron Posted on Wednesday, August 07, 2002 - 12:58 pm:        Jeff: it's DAMN fast for an unfaired 100" bike on gasoline, it was very impressive! I didn't really look at the bike good or talk with him much because we were so consumed with Dale's bike. But believe me, I took notice of the speed. He had to have a ton of power to go that fast with no fairing. And, although he ran it in a fuel class, he told us he was running it on gasoline. Intriguing comment that there were differences ... obviously things like heads and cyls and cams are going to be different, but your statement implies something may have been different that could've contributed to the failure. Different bore & stroke? Not a 4x4? I don't expect you to spill the beans. Thanks for the comment, though. I'm sure you can see why failures like that worry me, though. Clearly we're out there on the edge with these power & torque levels. Oh well, can't accomplish anything unless we try. BTW, my bike is carrying some S&S decals this year ... there's been some favors done that *really* helped us out.   Jeffb Posted on Wednesday, August 07, 2002 - 01:48 pm:        Aaron, I don't even know the bore and stroke of his engine. (Probably because he knows I would spill the beans) But I know it wasn't a 4x4. The shaft he used was the press in pro stock shaft (pg. 11-33 of your S&S catalog) These shafts have been taking 250+ HP for 7 seconds at a time with no failures. I guess the salt is a different test bed. Gald to hear that S&S will be on board this year. I don't have much pull around here, but if you need anything let me know. Jeffb   Pammy Posted on Wednesday, August 07, 2002 - 02:56 pm:        Jeffb, you can tell James Semonelli that he needs to bring that girls bike that he rides out to the salt. I dare him...   Jeffb Posted on Wednesday, August 07, 2002 - 03:25 pm:        I will be sure to tell him those exact words when he gets back from Sturgis. Do they have girl's bike classes out there? JB   Blake Posted on Wednesday, August 07, 2002 - 04:10 pm:        Cheers to S&S then. Hmmm, well, if the rotor were acting in some capacity as a harmonic balancer... it might help, then again it might hurt too. Without doing a formal analysis there's no way for me to know. Sorry. Didn't mean to give you bad dreams. With the cryo, I'm sure you'll be fine though. Heheh, I think VR was making a funny, aluding to cryo treatment lasting long enough to intercool his turbo.   Blake Posted on Wednesday, August 07, 2002 - 05:53 pm:        Give me the diameter and material and I can at least figure the yield strength in terms of combined torque and bending. Seeing the surprisingly large numbers that I expect will result might make you feel better. I don't have a service manual, always use the PDF version and since my HDD crash, I haven't reloaded it. You on the other hand you probably know the diameter off the top of your head. Oh heck, I'll just give you the basic formulas... Torsional shear stress (t)... t = TD/2J where T is the torque in IN-LBs (IN-LB=FT-LB*12), D is the diameter in inches and J is the polar moment of inertia in IN4, which for a solid round section... J = pD4/32 Combining and simplifying you get... t = TD/(2pD4/32) = T/(2pD3/16) Use the above to calculate actual torsional shear stress. If, knowing the ultimate shear strength (Fsu)of the shaft's material, and you simply want to solve for the required minimum diameter to carry torque (T), the above equation reduces to... D=[(16T)/(pFsu)]1/3 If I recall correctly, you mentioned that your crankshaft was forged from 4130 low ally steel. That material depending on heat treat, has a typical shear strength in round numbers ranging from 80 ksi to 150 ksi. Take away 10% for the high temperature environment and apply a reasonable factor of safety (150%) and you end up with an allowable shear stress from between 50 and 90 ksi. The next problem is to figue out what the peak torque on the shaft is... I have no idea. Well maybe a wild arse guess is in order... Try 1,000 psi times the bore area times 1/4th the stroke = ~12,000 IN-LB = 1,000 FT-LB. Sounds about right for an RMS (continuous) output of over 190 FT-LB (166 FT-LB + 15% = 190 FT-LB) for two such cylinders (95FT-LB RMS each). Now we need to factor in the shear and bending loads imparted by the sprocket/chain... Peak chain tension depends on peak shaft torque and sprocket pitch radius. I dunno the sprocket pitch radius. I'll work it in greek then. oops, gotta go play some raquetball. Will finish this later... Here are torque only results to wet your appetite... Fsu (PSI) T (FT-LB) T (IN-LB) D (IN) 50,000 1,000 12,000 1.0692 50,000 1,100 13,200 1.1037 50,000 1,200 14,400 1.1362 60,000 1,000 12,000 1.0062 60,000 1,100 13,200 1.0386 60,000 1,200 14,400 1.0692 80,000 1,000 12,000 0.9142 80,000 1,100 13,200 0.9437 80,000 1,200 14,400 0.9714 90,000 1,000 12,000 0.8790 90,000 1,100 13,200 0.9073 90,000 1,200 14,400 0.9340 We'll need to use a stress interaction formula to calculate the real required diameter based on the chain tension and the distance from sprocket centerline and bearing centerline. You get those rough measurements (within hundredths is fine) and I'll work this out just for fun. I AM sick.   Aaron Posted on Wednesday, August 07, 2002 - 05:59 pm:        "I AM sick." I'll go along with that! Sorry to disappoint you, but I don't know the diameter of either shaft off the top of my head. The left side there's no real reason to measure, you push a pair of tapered bearings on there with a spacer in between them to set the end play. The pinion side, yeah, you measure it as well as the roller diameter for the little caged needle bearing and the i.d. of the race in the case, and there are like 4 or 5 different bearings you can buy to get the fit right, and we did all that, but I don't remember the numbers off the top of my head.   Pammy Posted on Wednesday, August 07, 2002 - 10:19 pm:        Jeffb, He usually calls from wherever he is...He tries to disguise his voice so I "won't be mean" to him....Ha! I think he can race with the dwarf on the barstool.....   Dawg Posted on Wednesday, August 07, 2002 - 11:53 pm:        Does anyone have any experience with any of the Nallin products on an X-1? I was thinking of having them do some head work for me but I dont know how the fuel injection will handle the compression increases I have a power commander but still no way to play with timing. Everyone tells me to get rid of the injection but I want to keep it and make it run into the high 10's, just dont want to eat a bunch of motors trying.   Blake Posted on Thursday, August 08, 2002 - 04:15 am:        Dawg, Call Nallin Racing, talk to Brian. He may have something that will interest you.   Rempss Posted on Thursday, August 08, 2002 - 09:46 am:        Dawg, I have the 1250 Kit and Stage 2 headwork from Nallin. Brian is the best guy to talk to directly, he will take the time to go over what you are looking for and make educated recommedations based on that information. Blake, "He may have something that will interest you." Are you implying he has come up with something new for the DDFI system? Perhaps timing, I don't want to call him if nothing "new" is available. Jeff   Blake Posted on Thursday, August 08, 2002 - 04:37 pm:        Didn't mean to imply Nallin Racing has anything new wrt DDFI, but they can help Dawg with the Nallinizing of his X1. It is definitely doable.   Rattler Posted on Friday, August 09, 2002 - 09:45 am:        Aaron, I'm thinking Brian Perkin's Sportster was a S&S Stroker kit of some sort for 100". That would be in line with what S&S usually does...they love the Strokers fer sure. Anyway, I remember his speed times too as impressive, but thats about it. Dale A.   Jeffb Posted on Friday, August 09, 2002 - 10:55 am:        Rattler, Like I said before, I don't know the combination of Brian's 100" but the bore was larger than 4". It wasn't a stroker or any kit S&S has ever even thought of selling. S&S also didn't have anything to do with what Brian did last fall. He designed the engine on his own and paid for everything out of his own pocket. That is what is impressive to me. Jeffb   Vr1203 Posted on Friday, August 16, 2002 - 02:14 am:        Peter and Roc, How can I get more boost out of my Aerocharger? Is there different exhaust side housings?Are all the Aerochargers suppied to the bike market the same size? A smaller exhaust housing should give more boost, right? Blake you have a great sense of humor   Peter Posted on Friday, August 16, 2002 - 02:51 am:        Jim, How many pounds of boost do you have now? Do you have an adjustable waste gate on it? PPiA   Roc Posted on Friday, August 16, 2002 - 11:17 am:        VR1203 - I bought mine used and it will put out 15 pounds, according to the boost guage. These units don't use a waste gate, right? They rely on a variable pitch of the impeller blades. This makes me think that the change is to be made to the vaccum opperated control unit, adjusted to supply more pitch. You may have to call them.   Skulley Posted on Wednesday, September 04, 2002 - 04:52 am:        Can I run a Nallin big bore kit with stock heads and cams? Have race ECM, header, pipe, and force intake.