Interested in using a dyno & a friend is interested in purchasing one..... we've started some researsh & jus wanted to know which do most people prefer & which one does AMA use. Factory or Dynojet..... I'm trying to find out if their is a way to compensate for ram air when dynoing.....!!!!!
http://www.factorypro.com/dyno/dyn_ec9a.html from what i can gather, a current dyno is a lot more accurate than a drum dyno, but the downside is they cost more... so i guess it all boils down to what you're willing to spend.... looks as though a current dyno will run you from 15 to 20 grand.... I'm wondering how much of that you could recoop just by mounting it on a trailer and taking it to the WERA and CCS rounds????
A leafblower also uses the airflow through it to cool itself, i.e. it's heating the intake airstream. That means your intake air temps will be different than ambient, making it difficult to record where you're at. Yes, it's probably a small effect, but flowbenches use these same corrections so it's not something that can totally be ignored.
I use dynamometers everyday where I work (www.automotivetestinglabs.com) for emissions and performance testing both. Inertia dynos are cheap, eddy current dynos are better for steady state tuning, but the best is an AC electric dyno. A cheap inertia brake can be had for under $10K...our emissions grade AC dyno was over $250K. If I were you and you're just getting your feet wet...get an inertia dyno and you'll learn the basics and go from there. The most common faux paus that I see people make is not keeping the test conditions the same. Make sure all your dyno pulls are at roughly the same ambient conditions(temp and humidity). Also...don't try to make any comparisons if your oil and coolant temperatures are all over the place from run to run. Trying to simulate ram air effects...good luck. The best way is with a speed modulated fan in front of the bike. The one at my work maxs out at 50 mph...if you wanna go any higher than that and you'll have more $$ in your fan than the dyno. Lastly...remember the dyno is just another tool for tuning...the most important tool you have is your brain. Have at it...you'll enjoy!!!!
Re: Re: Know anything about DYNO's??? Ceasar Gonzalas dragged one around for a year or two back in the 90's. I'm not sure how much he recouped.
Other thoughts.... I have am also of the understanding that an eddy current dyno is better for tuning injected bikes. The drum on an eddy current type creates a load on the engine which more accurately simulates real world conditions, allowing you to more accurately tume the EFI based on throttle postition, etc. Whereas the drum on an inertia dyno doesn't load the engine with anything more than it's own weight (1600 lbs, I believe?) and when tuning an injected bike on an inertia dyno you could end up with a very rich condition if you just tune by hp #'s. Some of the EFI bikes (Suzuki does, not sure about others) have a "feature" that if the bike is accelerating too quickly, the system automatically leans the mixture. On an inertia dyno, the drum is able to accelerate quick enough to cause this to happen. Then you adjust the EFI for big Hp, and when you back it off the dyno, you actually end up rich, and down on Hp. The current dyno keeps that "feature" from activating because of the loading on the engine, there by causing theoretically, more accurate EFI tuning. Just what I've been told though...... If anyone else can elaborate on this, please do. I might have gotten my conditions backwards.
check into the superflow it is a little bit more money but well worth the extra dough. It even has a dynojet correction factor!
dynos..been using them for 4 years straigt w/ turbo'd fuel injected F2's, F3's, Turtle. kick ass! dynos RULE. you have to spend time setting them up though. what was said before that eddy current dynos are better than inertials is true. we have an eddy current dyno here at tech controlled and recoded w/ a very simple but precise controller. you set rpm and it reads power and torque, and it has a competer output for data logging. that is THE KEY to tuning, esp running a normally stock f3 w/ a turbo and electromotive TECII fuel injection and ignition. the best ignition system on the market. the TEC III is even better, using a HC16 instead of a cruddy old $10 HC11 for the processer. ours was an engine dyno, but either way, they both work the same. just don't lose the 10% ish power through the chain and rear wheel bearings and tire deflection and whatnot. also, someone else hit the nail on the head. conditions being constant, or having the formulas for correctly correcting your hp and torque curves. you need to ALWAYS write down your temperature, barametric pressure, and if you want to be anal like i was, get a wet bulb anamometer, and swing it around w/ a towel on it, and the temp drop will tell you the humidity, or sometihng like that. it's the smallest correction factor involved, but it does make a difference if you're shooting to be 1/2 hp below the limit for FUSA, or anything. one night (ok, i think we finished around 4am or so, but you know the drill... class all day, eat, work on car in machine shop building new intake manifold or fixing turbo oiling problems caused by that damned 20mm restrictor (a BIG pain in the butt till we built our own 3 stage dry sump system... something that erion racing told me that "we could NEVER do that, only the huge factory teams w/ the million dollar budgets and 10s or 100's of people working full time could do that." that's funny, we build a new one each year, and it's worked flawlessly since 1999! so much for their advice...) anyways, back to the point...we had a pretty good power curve and were tweaking TOG (time on for one gamma), IOT, and the ignition curve, as well as the accel and decel enrichments, and the other correction factors like coolant temp, MAT, etc, and we had gotten 93hp out of her, and about 50 ft-lbs of torque, curve looked like aiyr's rock. this was like tuesday night. wednesday we burn another 10 gallons of gas at least and tweak some more for hours. we're looking at each other dumbfounded, "why the hell are we getting 5 hp less with the same program, yet we've tweaked it even more????" thought about some more. an hour later, i was like..."wait, these are uncorrected numbers and the temp in here is like 10 degrees hotter. DUH!! once we corrected both sets of numbers w/ the barmetric pressure (vs 1atm, 760mm Hg, etc) and temp (27 C, or 300Kelvin), our wednesday's results had a couple more foot pounds of torque and more power throughout by 1 or 2 hp. moral of the story...take your environment into account! also, as far as accel and decel enrichments go, you can get qualitative numbers on an eddy current dyno, but not quantitative, because they aren't designed to be accurate under varying speeds. you can still, however, load the engine, run #1 w/ enrichment #1 and time how long it takes to go from 2000 rpm to 15k, then fatten it a bit or lean it out, and retime it. that'll work. if you want any help, give me a call. i need a machine shop for myself! i'll be out of here for 2 wks starting august 10th, back in DC finishing my ducati and riding the hell out of it as well as putting my trailer totalled zx7 back together w/ another roller that didn't do cartwheels down 66 last summer. good luck. hope the shop is doing well. how's mouse trap doing...??? ha ha ha. not to well, i've seen and heard. oh well, not enough honesty or business sense, but if mouse would keep to his plan, he COULD build his own wheels/exhausts/etc on some CNC's, and eventually build his own bike. i might build a streetfighter 900rr turbo, maybe build my own trellis frame, so long as i can get accesss to a TIG, or get my MIG to work well enough and get some good chro moly or 1020 steel (don't ruin heat treatment w/ mild steel after welding, and don't have to put frame in your mom's kiln to re heat treat it when it's done....wait a second... that's what i'll do! boo yaaaaah. it's not just a pottery studio...it's a motorcycle/pottery studio! shit, they get up to 1200 degrees, that's plenty! let me know how your search is going, etc. later, Turbo Dave
Re: Re: Re: Know anything about DYNO's??? A friend and I beat 'em up to get 2 bikes run for $20. The year was '97 Mark.
