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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Camshaft /cgi-bin/YaBB.pl?num=1538169488 Message started by hotrod on 09/28/18 at 14:18:07 |
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Title: Camshaft Post by hotrod on 09/28/18 at 14:18:07 Any updates from members using the DR-650 cam ? |
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Title: Re: Camshaft Post by Drifter.. on 09/29/18 at 11:37:10 Or dyno charts for Savage cams or reviews from people who have changed cams? I understand the DR cam as ground from the factory is not a good match for the savage, but the 90-95 cam can be used as a blank welded and reground by Webcam or through Lancer. |
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Title: Re: Camshaft Post by Dave on 09/29/18 at 17:16:03 5F69727D6F7E6935351B0 wrote:
DragBikeMike is trying to prove that theory wrong: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1525327311 |
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Title: Re: Camshaft Post by Drifter.. on 09/30/18 at 10:46:51 Thanks for the link Dave! Interesting read did DBM or anyone else do a dyno run? |
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Title: Re: Camshaft Post by Dave on 09/30/18 at 13:27:03 182E353A28392E72725C0 wrote:
I think so....you need to go back 10 or so pages to find it. Look for the things that DragBikeMike posted. |
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Title: Re: Camshaft Post by batman on 09/30/18 at 14:32:18 DBM did do a dino ,the result was 33.5 max hp out of the DR cam with an otherwise stock engine. This rings true as the largest increase in hp comes from increased displacement and/ or compression ratio , a cam is like icing on the cake ,it will maximize the increase of a piston change but doesn't create much hp used alone .(2.5 hp in DBM's case) |
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Title: Re: Camshaft Post by Fast 650 on 09/30/18 at 23:18:33 You have to keep in mind that his engine was still running the factory exhaust pipe too. It needs a bigger pipe even with a stock engine, so it wasn't going to gain much with the cam swap and the stock pipe. |
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Title: Re: Camshaft Post by batman on 10/01/18 at 12:06:26 Fast 650 , I don't think a larger exhaust pipe would have helped. Does a 2"pipe make more hp than a 1.5 "pipe ? no it doesn't ! it is more important to keep velocity(flow) up in the exhaust pipe , it is after all being pushed out by the pressure of the expanded gases and the piston rising . DBM 's use of the DR cam may have increased the compression slightly, but not enough to require a larger pipe and one might have actually reduced Hp gains. |
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Title: Re: Camshaft Post by verslagen1 on 10/01/18 at 13:16:52 Yes I don't believe a larger header would've made a difference. But a muff with less back pressure than stock? Sure. |
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Title: Re: Camshaft Post by DragBikeMike on 10/01/18 at 14:05:14 See my post titled "Stage I Dyno Results". I did the post on 6/21/18 (I think). With some simple mods and the DR cam, horsepower increased 11.3% (30.1 to 33.5) and torque increased 20.6% (31.8 to 38.4). The power band was expanded significantly. It ran quite a bit better, and the investment was minimal. I'm a bit uncomfortable with the absence of the oiling holes in the lobes. I think I have about 800 miles on it now and will be opening it up to adjust valves and visually inspect the cam lobes. I'll let you know what I find. Opinion: Its an inexpensive part the yields a nice little kick. It really compliments a less restrictive intake and exhaust. It has some overlap and TDC lift so you get a little exhaust action helping to pull in the incoming charge. Now it has a sweet spot right at freeway speed (about 60 mph over here). So far, no complaints. Works good. We'll see how the inspection goes. |
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Title: Re: Camshaft Post by DragBikeMike on 10/01/18 at 14:16:35 Regarding the pipe: Since I did that dyno pull I installed a Mac header with a section of flexible exhaust pipe inserted to reduce the ID from 1.79" to 1.5" (as I recall). It feels really good and I've had to increase jet sizes dramatically. It's still seat-o-da-pants so don't know for sure if the pipe made more power or not, but like I said if feels and sounds good, and it's likin all the additional fuel (usually a good sign). I personally don't think a 1.25" header pipe is a good fit for a 40 CUI engine (unless maybe it's installed on a piece of farm equipment). Just about any tech article you pick up suggests a header around 1.5" to 1.63" for that displacement. The 1.5" seems to be working good so far. |
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Title: Re: Camshaft Post by batman on 10/01/18 at 22:11:14 I don't think our header pipe is a 1.25" . I believe it's 1.3".(15.5% larger than a 1.25) |
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Title: Re: Camshaft Post by Fast 650 on 10/02/18 at 08:34:20 >Does a 2"pipe make more hp than a 1.5 "pipe ? no it doesn't ! it is more important to keep velocity(flow) up in the exhaust pipe , Okay, let's take a look at that. Industry accepted figures are 280 to 300 fps at the rpm you are making peak power.Speeds above that start creating restriction due to friction. With the stock bore, 1.3" ID gives 291fps at 3500 rpm At 6500 rpm the velocity is over 540 fps. In what universe would that not be restrictive? 1.5" is 300 fps at 4800 rpm 1.625" is 293 fps at 5500 rpm 1.75" is 294 fps at 6400 rpm With the stock bore, either the 1.5" or 1.625" ID would be a good choice. With the 97mm bore, 1.625" would be the minimum size and 1.75" would be the maximum that you would want. |
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Title: Re: Camshaft Post by DragBikeMike on 10/02/18 at 10:43:00 My bad on the 1.25" ID. I got sloppy there. The stock header is actually 1.27" ID (measured at both ends with a snap gage and micrometer). The port is 1.30" ID. How did you get 15.5% larger Batz? I calculate the cross section of a 1.25" diameter to be 1.23 square inches, and the cross section of a 1.30" diameter to be 1.33 square inches. That works out to the 1.30" diameter being 108% I know its a mute point since the actual header pipe is really 1.27", but I want to make sure I understand your approach and how you got the 15.5% value. Hey Fast 650, at what RPM do you get 300 fps on a 1.27" ID? With my current setup, I'm running in the area of about 4200 to 4500 when I blast the freeway. Maybe that's why I'm likin the 1.5". |
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Title: Re: Camshaft Post by Fast 650 on 10/02/18 at 11:07:30 With 1.27", 3400 is 297 fps. Look at your dyno graph again and you will see why you are liking the 1.5" pipe at that rpm range. 4500 rpm is about 282 fps. You are getting into the good part of the power curve at about that speed and that is where the pipe is starting to accent that. You are still running the factory muffler so that limits your pipe length. With the DR cam, about 37" length would tune the pipe to better match the cam if you can squeeze that in with your muffler. |
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Title: Re: Camshaft Post by DragBikeMike on 10/04/18 at 12:57:14 I did the inspection of the cam. I logged about 750 miles since the last inspection. Valve clearance was OK all around. Exhaust valves were at .006" (I readjusted to .004") and intakes were .004" (I left as-is). Visual inspection of cam lobes through the intake valve cover showed no signs of pitting or spalling, 360 degrees around the lobes. You need a small flexible light to do the inspection. Its humbug but still doable. So far so good. It didn't blow up yet, even without the oil holes. |
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Title: Re: Camshaft Post by Drifter.. on 10/05/18 at 19:24:31 So it sounds like the oil holes are not that important on a DR cam.....? Probably worth doing on a cam not already installed for added insurance and peace of mind! What oil are you using? |
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Title: Re: Camshaft Post by DragBikeMike on 10/06/18 at 06:52:49 I’m traveling right now so I can’t go down to the garage and double check, but as I recall I filled it up with Mobile 1 synthetic, 20W-50, air cooled V-Twin. I know that’s controversial but, hey, I’m a quirky sort. |
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Title: Re: Camshaft Post by hotrod on 10/06/18 at 10:10:40 Looks like I'll try the DR cam. It's been years since I've installed one . I remember using a math formula to find the Cam Lobe Center. This number would change, and alter the powerband, if you moved the cam in the modified sprocket. Some cams list a cam lobe center .Some performed better outside of that spec. Does the DR list a lobe center number, and is that number the one we should be reaching for ? |
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Title: Re: Camshaft Post by DragBikeMike on 10/07/18 at 10:10:29 No lobe center setup on this one. Just line up a mark on the end of the cam with the horizontal surface on the head when crank timing mark is at TDC. I’d send a pic but I don’t have access to my laptop right now. The all inclusive Clymer manual gives some details. Most important detail is to apply the sealant for the head cover sparingly (very, very sparingly). |
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Title: Re: Camshaft Post by hotrod on 10/07/18 at 15:38:32 Thanks DBM |
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