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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Tuning intake and exhaust /cgi-bin/YaBB.pl?num=1242574807 Message started by diamond jim on 05/17/09 at 08:40:07 |
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Title: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 08:40:07 I've been researching more on intake tuning and exhaust tuning. I found these formulas for exhaust tuning: For diameter: d^2=SxRPMxD^2 /108,000 d is pipe diamater S is the stroke D is the piston diamater ^2 means squared For length: L=TxV/ N L is pipe legnth T is camshaft timing in crankshaft degrees V is speed of wave in exhaust pipe(1,700) N is RPM desired (500 RPM below peak) Are any of you familiar with these formulas? I'm trying to improve my knowledge of pulse wave tuning and how it can shift the powerband up and down. |
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Title: Re: Tuning intake and exhaust Post by PTRider on 05/17/09 at 08:53:34 Which rpm peak do you wish to tune for? 6500 engine red line? 5400 rpm power peak? 3400 rpm torque peak? (My guess would be for the power peak.) Your local library might be able to get you a copy of Scientific Design of Exhaust and Intake Systems, Third Edition, Phillip Smith and John Morrison, Bentley Publishers, ISBN-13:978-0-8376-0309-4. Ask the library for an inter-library loan to borrow the book from another library. Or, buy it for $30. Or PM me and I'll lend you my copy. http://www.bentleypublishers.com/automotive-engineering/Scientific-Design-Exhaust-and-Intake-Systems.html By the way, Smith and Morrison say that optimizing the intake is about half as effective as optimizing the exhaust. |
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Title: Re: Tuning intake and exhaust Post by verslagen1 on 05/17/09 at 09:34:30 So running a few numbers... d=rpm x .000469009259 inches 1.41 @ 3k 1.88 @ 4k 2.35 @ 5k 2.81 @ 6k The ID of the pipe is some where around 1.75 So we are tuned for peak torque. |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 09:43:16 I'll look at the college library. Here's a great read: http://bmwmotorcycletech.info/InExTuning.htm Also, my M50 pipes have the same ID as the LS650. It is known for it's torque as well. I cut one of my M50 stock pipes and use the header for quick bolt on testing when working on the S40. It's about 24" long but for basic stuff (see if the engine still starts and runs kinda stuff) it beats installing the entire S40 exhaust as mine is now a full one piece setup. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 10:08:42 63706766797472707B24150 wrote:
why do i end up with a 1.75-1.8 inch pipe as the id for 6500? 3.76x6500x14.376/108000= 3.2 which is the square of a number between 1.75 and 1.8.... where did i mess up? i come up with 1.75-1.8 inch pipe @ 63.5 inches for the optimum 6500 rpm pipe.... |
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Title: Re: Tuning intake and exhaust Post by verslagen1 on 05/17/09 at 10:16:05 oops I forgot to take the square root. :-[ d^.5=rpm x .000469009259 inches 1.19 @ 3k 1.37 @ 4k 1.53 @ 5k 1.68 @ 6k 1.75 @ 6500 So we are tuned for peak HP |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 10:21:07 Regarding the intake, there are inevitably trade-offs for the sake of noise, harness, vibration, ease of maintenance and more often packaging. While the engineers worked to optimize the package as much as possible, there are some areas of improvement present. The six inches in front of the carb, IMO, is one of the biggest areas for improvement and the biggest bang for the buck. It, too, is effected by pressure pulses like the exhaust just in reverse. Getting both sides to match across the broadest rpm range is my goal. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 10:27:23 52415657484543414A15240 wrote:
ahh, much more similarity now...lol i got 1.2@152 inch length for 3k, 1.55@84.6 for 5k, and 1.75@63.5 for 6500.... what's the overall length of your longshot system, Jim? |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 10:29:37 want to see some rediculous numbers? input metric figures with the inch formula... rofl, i got a 9 inch pipe id for 6500 rpm using metric... kinda was a clue that i made an error....rofl |
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Title: Re: Tuning intake and exhaust Post by verslagen1 on 05/17/09 at 11:13:38 d'jims longshot is much easier to figure out than the stock can due to the infernal baffeling. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 11:21:43 2B382F2E313C3A38336C5D0 wrote:
yeah, the roundabout path to the atmosphere once the gas leaves the headpipe is quite the mystery.... im guesstimating the headpipe at roughly 30" length.... think im close? |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 18:02:48 212D3E3F242D20207D7F4C0 wrote:
ahh, much more similarity now...lol i got 1.2@152 inch length for 3k, 1.55@84.6 for 5k, and 1.75@63.5 for 6500.... what's the overall length of your longshot system, Jim?[/quote] It's 62" long. Pipe diameter is 1.75". |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 18:24:29 575A525E5C5D57595A5E330 wrote:
ahh, much more similarity now...lol i got 1.2@152 inch length for 3k, 1.55@84.6 for 5k, and 1.75@63.5 for 6500.... what's the overall length of your longshot system, Jim?[/quote] It's 62" long. Pipe diameter is 1.75". [/quote] ok, so you're redline tuned... ill bet one of those dr650 9.5:1 pistons and Lancer's second grind bumpstick would add quite the afterburner to your ride.... but id really love to see what just tuning your spark would do.... the factory curve has got to be way conservative.... |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 18:34:52 I think it's about 9" longer than the stock can. Is the stock muffler ID 1.75"? Seems like it's 1.5". What rpm is the stock exhaust tuned to? Also, with the lower compression of these engines isn't the spark already advanced a little as compared to a higher compression engine? If it could be advanced, would the line between power gains and increased heat be narrower on this engine than others? I'm familiar with advancing the spark on older engines with some compression loss to maintain but not advancing solely for performance gains. I must rely on y'alls expertise in that regard. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 18:50:53 323F373B3938323C3F3B560 wrote:
higher compression can take more advance, usually, assuming a suitable fuel.... heat is controlled by jetting it rich enough it runs cool, that's what the plug exam tells you... you wouldnt be able to advance it as much as watercooled lung of the same size, but ill bet you could massage a few more ponies just by tweaking the curve... of course, the first step would be to put a CDI unit in it... the stock box isnt CDI, i thought it was, it makes the most sense, but it isnt... check the wiring diagrams... the coil is hooked to the 12v system... cant do that with a CDI, it can only be hooked to the box, or you get a high voltage spike frying all the diodes in the bike... so the iggy on this beasty is closer to a ford TFI (like a late 80s mustang)... unfortunately, adjustable CDI boxes cost a grand, or so.... though ill bet one could find a reasonable CDI spark intensifier used at a swapmeet... you'd still have the stock curve, but a way hotter spark... your perceived results from the kamikaze are actually more impressive with the pipe math... your power should be way low in the bottom end, and it isnt.... |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 18:57:30 the headpipe is 1 1/2 if it's really double tubed... so Lancer has posted, and as ive never seen him run for office, i have no reason to doubt him... so the pipe is probably dimensioned for the HP peak in the literature, around 5000 to 5500... as Verslagen pointed out, the zig-zag flow of the gas in the muff makes an "overall length" measurement kind of hard without dissection... the varying diameters on the interior of the muff will have an effect too.... |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 19:12:12 Yep, it is actually 1.5". For my exhaust, the first half (header) is 1.5" and the second half (pipe) is 1.75". So for formulas would it be reasonable to split the difference and use 1.625"? There will be a pressure drop when the exhaust passes from header to pipe but how significant do you think the 0.25" increase is? I also need to correct info I posted somewhere about my quick test pipe from my M50 (800cc v-twin). It is 1" ID. I mentioned somewhere that it was 1.5" ID. http://i255.photobucket.com/albums/hh128/russ_diamond_jim/S4022076.jpg |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 19:19:55 so, basically, all we've learned here confirms the assertion that this motor is but 1/8 of a 320 cubic inch v8... the pipe sizes jibe with what they hang as smallblock exhausts.... so, better inhaling, better exhaling, the next stop logically is spark... it's the only performance mod left that doesnt open the motor... then you can do a max stock baseline to compare internal mods too.... after that comes the real gains, but the real expense too... |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 19:27:16 What is the opening point of the exhaust valves BBDC with the stock cam? |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 19:32:53 6F626A6664656F6162660B0 wrote:
it's a 224 degree at .050 lobe... so figure 20-ish, no more than 25 BBC, just as a guesstimate... the dr650 manual shows the cam profile, but not the savage...lol |
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Title: Re: Tuning intake and exhaust Post by verslagen1 on 05/17/09 at 19:44:32 6B666E6260616B6566620F0 wrote:
Cremonestly putting on engineers hat... Minors rule ;D Measure each section for length and diameter. Calculate each section as if it stood alone. Then calculate the percentage of each duct to the total length. Multiply each section by it's percentage and sum together. Taking off hat and tossing over shoulder, it's the weekend, don't want that on fer very long. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 19:45:38 525F575B5958525C5F5B360 wrote:
ok, just reread that post... id calc the speed for the 1.625 pipe, and run all further calcs with all 3, and you'd get the answer by which most emulates your real world results... |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/17/09 at 19:48:39 2A392E2F303D3B39326D5C0 wrote:
Cremonestly putting on engineers hat... Minors rule ;D Measure each section for length and diameter. Calculate each section as if it stood alone. Then calculate the percentage of each duct to the total length. Multiply each section by it's percentage and sum together. Taking off hat and tossing over shoulder, it's the weekend, don't want that on fer very long.[/quote] you am de man, sir!! thanks for the tip, Verslagen |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/17/09 at 22:01:31 So, running the diameter numbers, the stock header is tuned for max torque around 4250 rpms (using 3750 which is 500 below peak rpm). For length at peak at 4250 rpms I get 101.54". 1700/3750 x 224 (degrees) = 101.54 This is about double the length of the stock exhaust which is approx 51". 101.54/2 = 50.7" So is the stock exhaust tuned for exactly half pressure waves at 4250 rpm? Or is my math all hosed up? If it's true, then extending or shortening the exhaust by 1" increments moves the peak up or down by about 62.5 rpm with each 1" change. And my 9" longer than stock exhaust has moved the peak up about 562.5 rpm, or just under 5000 rpm, compared to stock. Then there's the transition from 1.5" to 1.75" pipe. On V8 motor headers, a reduction in pipe diameter of 1/8" will move the torque peak down about 650-800 rpms and the converse is true if pipe diameter is increased every 1/8" the peak torque is raised about 650-800 rpms. How much would the peak of our singles move with each 1/8" change in diameter? |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/18/09 at 00:29:34 716275746B6660626936070 wrote:
close to a match, id say.... |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/18/09 at 06:34:51 Listed specs show stock as: HP: 30.00 @ 5400 RPM Torque: 33.6 ft.lbs @ 3400 RPM Compression: 8.5:1 Bore x stroke: 94.0 x 94.0 mm (3.7 x 3.7 inches) What is the diameter of the internal pipe of the stock muffler and the overall length of the stock exhaust? I sold my stock muffler a while back. |
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Title: Re: Tuning intake and exhaust Post by Duane on 05/18/09 at 08:42:35 After all this info, mabye I'll ride my stock muffler till it falls off or rusts out. ;D |
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Title: Re: Tuning intake and exhaust Post by bill67 on 05/18/09 at 08:46:54 Stock s40 comes with a tuned intake and exhaust,Suzuki does as good as the other motorcycle companies in doing that. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/18/09 at 08:59:34 2A272F2321202A2427234E0 wrote:
id of the muff and length of stock exhaust are problematic measurements... as resident mad scientist Verslagen pointed out, the path the exhaust follows through the muff is far from a straightline, and 1 would have to calculate free volumes to get effective "pipe ids" for the various legs of its trip through..... i think one would have to section a complete muff lengthwise with say a bandsaw, and bust out the dividers... id suspect one would find an initial "expansion chamber", and a few choke points followed by smaller expansion chambers.... muffs are at odds with max performance... the ideal pipe is sized to retain as much energy in the exhaust stream as possible, while the muff absorbs that energy to slow the gases exit, and decrease the pressure diff at the muff outlet... the evidence of the energy absorbtion is the bluing that inevitably shows on the muff inlet... |
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Title: Re: Tuning intake and exhaust Post by verslagen1 on 05/18/09 at 09:11:38 the Hartman muf mod is worth a read. So D'Jim, when you going to the Dyno? |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/18/09 at 09:30:56 616A6F6F3534030 wrote:
but the manufacturers have to meet all kinds of criteria that force them to compromise on the "tuning" of the intake and outlet planes... the object of this exercise isnt to say "wow, what crap suzi markets", it's more to find a combo that maximizes available power, and gives good ridability... one could max out redline power easily(just use a 63 inch long open 1 3/4 inch pipe, a velocity stack, and a 91 dr650 cam, and then jet accordingly), but the ridability would be terrible...it would give a very narrow powerband, and only be suitable for high rev use... that would cut service life down drastically...it would be just as easy to tune it to run in any narrow band, the real challenge is to wring as much usable power as possible across the rev range.... |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/18/09 at 10:11:06 2F3C2B2A35383E3C3768590 wrote:
Here in a few minutes. Actually I'm running by the shop there to see if he's got a 55 polit with no bleed holes or something similar. He's the guy that used to be a big time biker I mentioned about several weeks ago that was in his car and got ran over buy a city garbage truck maybe 10 years ago. Yep, ca-ching $$$. So he used the money to build a bike shop and he specializes in performance tuning. Of course he does 90% harleys. Money is super tight right now seeing as I am unexpectedly on a 1/5th schedule this summer. The summer schedule is 10 weeks. That means I work one day per week. The time off of is nice but the hit in the pocketbook is a killer. If he's not too outrageous $$$ on his dyno runs, I'll see if I can come up with the $$$ without the wife getting ill. The guy I met on the VTX, the one that forgot his kickstand was done and couldn't figure out why his bike wouldn't start- he's a local cop and he's the one who told me about the shop. He said they get calls alot for that road cause bikers get work done and when they leave the shop, well, they want to see what they got for all that money they spent. I'll see what the guy charges. Funny, I was just riding and experimenting with the pipe butterfly. When I close it the bike feels more like stock. When I open it up it's a different story at pretty much across the rpm band. When I come up to Deals Gap I'll let you guys ride it and see for yourselves. Ditto on what Marshall replied above. I'm having a total blast experimenting and discovering what this bike can do. It's like a puzzle. The rewards are there. You just got to fit the pieces together right. I'm a mighty happy camper right now. Suzuki did a very good job on this bike. But I dig the heck out of talking about the meat and gravy of the performance of this bike and the fabbing, building and testing that goes with discovering it. |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/18/09 at 10:54:50 might want to check some 2 stroke exhaust theory too, Jim... i have a feeling that much of modern muffler sizing is related to expansion chamber sizing... proper dimensioning would simulate a longer pipe of the proper cross sectional area, as well as reducing the pressure differential at the outlet(while maintaining the rarification on the trailing edge of the pressure wave), thus reducing noise in a less performance depleting manner.... yep, these beasties are almost ideal test-beds.... |
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Title: Re: Tuning intake and exhaust Post by verslagen1 on 05/18/09 at 11:28:27 If the guy is doing that for the harley's, he might be interested in your mod's so he do the same for them. Kinda win-win situation, you do some experimentin' and he sells it to who ever. |
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Title: Re: Tuning intake and exhaust Post by LANCER on 05/18/09 at 13:59:05 5E4D5A5B44494F4D4619280 wrote:
If he has been doing performance stuff for years then he has probably been down that road a number of times already. Keep in mind that the Savage is pretty much the same as one cyl on a HD, thats why so many like the HD mufflers...they work for us. But it never hurts to talk to the guy since sharing info is how stuff gets better. By the way, if anyone wants to get into some real practical stuff on header & exhaust design then go to www.headersbyed.com, he has been making systems and parts for pro racers and retail since the early 60's...the dude know's his stuff. He use to have his data sheets on his old website but they are building a new one and I have not seen them yet on the new site version. He sells a really nice info and parts package that has tons of tech info in it and is well worth the $$ if you are into learning all you can on exhaust system design. |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/18/09 at 14:27:03 I'll look for Ed's stuff. The shop is called Rod's Performance Shop. He siad he'd dyno and do the gas analyzer to let me know if I need to do some more jetting work for $55. Him and his old mechanic, who when I walked in was pulling a drill with one of the longest drill bits I've ever seen, out of the back of a muffler on harley that raised on one of their three lifts, seem to develop a quick fondness of the little thumper. "I haven't seen a single cylinder bike in year", the old guy said. Rod liked the combo bar end turns/mirrors and the exhaust butterfly mod. It was pretty cool. At first I thought I sensed the 'ol 'it ain't a harley' vibe but that impression turned out to be wrong. However, of a little concern, was that I brought in the stock pilot jet to show him to see if he had a #55 with no bleed holes. Although he had 3 huge tackle boxes worth of jets, he couldn't find nor recalled ever having any that looked like the stock pilot jet. He had a yamaha V-star 1100 carb there all gutted out. Jets are different on it too. Also, no main jets in the style we need. I'll be in Huntsville the rest of this week. Mom is having knee surgery tomorrow so I'll be staying with her. Next week I'll see if I can do it. |
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Title: Re: Tuning intake and exhaust Post by LANCER on 05/18/09 at 19:18:34 Sounds like you may be able to develope a good relationship with the guys. Independent shops usually have better attitudes toward out of the ordinary bikes. There is a small independent shop close by me, a one horse shop all the way, the owner is John and he is a good guy. He specializes in older HD's but will take in an model HD...does not work on foriegn stuff directly but will crank up the dyno when I need to. |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/18/09 at 19:49:39 That sure sounds a lot like what I'm seeing here. I found his website. It looks fairly new. http://www.rodsperformance.com/ I did a quick search and found in a forum where a guy rode 4 hours just to get a tune at Rod's. Check out this link- go down to the last 3 posts of the thread. http://www.v-twinforum.com/forums/twin-cam-engine-mods/141225-103-blueprint-results.html Some other post. http://www.cvoharley.com/smf/index.php?topic=36485.0 |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/19/09 at 13:31:34 Marshall, your 1/8 of a V8 logic works great using the Mustang's 4.6 liter V8 although the displacement is a little smaller. Mustang GT 35 cubic inch/ 575 cc single cylinder 90.2 mm bore/ 90.0 mm stroke 300 hp total/ 37.5 hp per cylinder 320 ft lb total / 40 ft lb per cylinder Suzuki LS650 40 cubic inch/ 650 cc single cylinder 94.0 mm bore/ 94.0 mm stroke 30 hp/ 33 ft lb I'm thinking the LS650 can be tuned to similar numbers of a single cylinder on the Mustang engine (37.5 hp/ 40 ft lb) via intake tuning, properly jetting the stock carb and tuning the exhaust. Then you'd likely hit a ceiling that would require more aggressive mods including performance cam and carb for any additional gains. Anyone got any dyno run info on a LS650 with Lancer's perf cam and carb? Unless I'm reading this chart below totally wrong, this shows that Jason's '96 LS650 with simple carb rejetting and a supertrapp registered an additional 4.25hp, or about a 15% difference. That's like an additional 45hp for a stock '09 Mustang GT. Not bad IMO. It also smoothed out the power curve as well. Imagine what this setup + improvements to the intake would show. http://www.thumperpage.com/articles/pix/bef_aft.jpg |
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Title: Re: Tuning intake and exhaust Post by marshall13 on 05/19/09 at 21:36:05 well, good and bad news for you... the bad is, you cant match the torque figure without a higher CR, or running fuel and a CDI... the torque, being determined by averaging the cylinder pressure through the power stroke, multiplying that by the area of the piston crown, then multiplying by the stroke... as you're looking for a 20% increase, it aint happening just by increasing packing efficiency... the good news? the HP figure is very doable, im willing to bet your ride peaks at about 40... ;) |
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Title: Re: Tuning intake and exhaust Post by diamond jim on 05/20/09 at 13:47:08 I understood about half of what you just wrote! Gives me more to research and learn. But there is definitely a noticeable power gain. Don't know if it's quite up to 40hp yet. Possibly with the dyno & exhaust analyzer I'll be able to get the carb spot on and approach that number. Here's where my thinking is right now. 1. Put the pod filter and sporty muff on last fall and followed general carb tuning guidelines. It felt like there was a little loss in low end torque. mid range improved. (evidence suggests I lost intake runner length with no airbox) 2. I put the new pipe on. The pipe made a little more power in the low to mid range during normal riding. The power band did seem a little broader. Seemed more sound improvement. (we know now that the pipe moved the peak torque up) 3. I replaced with pod filter with the first Kamikaze intake. That was my first "WOW!" moment. 4. Refined and added turbulator to the Kamikaze intake. Here's what I'm thinking. The pipe shifted the torque higher in the band. The intake, with what appears to be the proper intake length for my pipe, combined with turbulence reduction/improved velocity especially at lower rpms, not only restored torque to the low and mid range but enhanced it. The result, I believe, is a much flatter torque curve than stock with some power gains across the range. The intake and exhaust compliment each other IMO. Are they perfectly matched? No. But I'd love to tweak them to work even closer together in the 2K-6K rpm range. Currently my carb setup is: #55 pilot with bleed holes, IMS out 1 turn, #155 main, 2 #4 washers. I'll do the dyno eval soon. The variables that I can easily mod for improved tuning are pipe length, pilot jet, washers and main jet. I'll see what they recommend after eval and post. |
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