cam advice for 88 to 95 big bore
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Cruiser
Joined: Jul 2008
Posts: 117
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From: Uk and French Pyrenees
cam advice for 88 to 95 big bore
Hi All.
I've been riding my 2000 Road King with S and S Barrels, Andrews 37G cam with S and S gears and the SE Ignition kit. Its carbed with a 42 Mekuni. I'm loving it for touring and its sure quick from 3000 up and cruises no problem at 95 +. Puts out a 100hp on the dyno but...Thing is that its edgy at low RPM. I am looking for a way to re claim some of the low end torque without compromising the great pull in mid range...Any advice.Willing to compromise some high rev power for grunt...
I have the current set up on a delkron cam plate and am thinking about building a second plate with different cam set up that I can swap out when not touring.Its expensive tho!!! So anyone got some hot tips for getting what I am looking for ( cam change? Port the heads? Bigger Manifold? Change the ignition...Not sure which way to go. Thanks all.
I've been riding my 2000 Road King with S and S Barrels, Andrews 37G cam with S and S gears and the SE Ignition kit. Its carbed with a 42 Mekuni. I'm loving it for touring and its sure quick from 3000 up and cruises no problem at 95 +. Puts out a 100hp on the dyno but...Thing is that its edgy at low RPM. I am looking for a way to re claim some of the low end torque without compromising the great pull in mid range...Any advice.Willing to compromise some high rev power for grunt...
I have the current set up on a delkron cam plate and am thinking about building a second plate with different cam set up that I can swap out when not touring.Its expensive tho!!! So anyone got some hot tips for getting what I am looking for ( cam change? Port the heads? Bigger Manifold? Change the ignition...Not sure which way to go. Thanks all.
Last edited by burgs; Jul 13, 2010 at 10:49 AM.
HDF Community Team
Joined: Jun 2006
Posts: 12,773
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From: san antonio
Are you sure about your static CR? Your chamber volume would have to be near 82cc which means that you would have had to have some head work done and running a .030" head gasket. If you haven't had headwork done or running a thinner head gasekt or running a domed piston, you static compression is not likley to be 9.5. Being absolutely sure of your static CR with the current setup is necessary to respond to your question.
The 37G intake closes at 38*, most other cams that will be recommended will have earlier intake close events which will bring down your corrected compression. To move the TQ curve to the left, you will need higher corrected compression. You could do that by advancing the 37G by 4* and still keep cranking compression below 190psi. Very similar in profile to the SE204 which, IMHO, is a very underrated cam. The lobe separation of the SE204 of 96/112 will produce more low end than the 37G with a lobe separation of 100/106.
Sounds like you have a good running build and I would be reluctant to make any major changes, you know, "if it ain't broke.......". FWIW, and that's not much, it won't cost much to try running the 37G advanced 4* and see if that does the trick.
First things first, you really need to know your true static compression before moving forward. If static CR is not 9.5, some head work and decking may be the solution.
Another and perhaps better solution is to change primary gearing to 24/37; you will be amazed and the low end.
The 37G intake closes at 38*, most other cams that will be recommended will have earlier intake close events which will bring down your corrected compression. To move the TQ curve to the left, you will need higher corrected compression. You could do that by advancing the 37G by 4* and still keep cranking compression below 190psi. Very similar in profile to the SE204 which, IMHO, is a very underrated cam. The lobe separation of the SE204 of 96/112 will produce more low end than the 37G with a lobe separation of 100/106.
Sounds like you have a good running build and I would be reluctant to make any major changes, you know, "if it ain't broke.......". FWIW, and that's not much, it won't cost much to try running the 37G advanced 4* and see if that does the trick.
First things first, you really need to know your true static compression before moving forward. If static CR is not 9.5, some head work and decking may be the solution.
Another and perhaps better solution is to change primary gearing to 24/37; you will be amazed and the low end.
Last edited by djl; Jul 13, 2010 at 12:26 PM.
Thread Starter
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Cruiser
Joined: Jul 2008
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From: Uk and French Pyrenees
Thanks guys for the feedback. I've got the compression ratio for my set up ( S&S Big bore with stock heads...) Its 9.7:1. Not particularly high. As I said I wanted a set up with good mid range pick up for touring and a reasonable top end. I got that but after two ears, and with only about 1/3 of my miles done touring, I'm just trying to make the lower end a little easier...Thanks for the tips.
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Road Captain
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What pipe are you running with that set up? I have a similar set up on my Dyna and haven't noticed any real losses low down. I've got a V&H 2-1 Pro-pipe which gives good manners through the rev range. If you have drag pipes or true duals you may well be damaging your low rev performance.
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Thanks guys for the feedback. I've got the compression ratio for my set up ( S&S Big bore with stock heads...) Its 9.7:1. Not particularly high. As I said I wanted a set up with good mid range pick up for touring and a reasonable top end. I got that but after two ears, and with only about 1/3 of my miles done touring, I'm just trying to make the lower end a little easier...Thanks for the tips.
Scott
HDF Community Team
Joined: Jun 2006
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From: san antonio
Thanks guys for the feedback. I've got the compression ratio for my set up ( S&S Big bore with stock heads...) Its 9.7:1. Not particularly high. As I said I wanted a set up with good mid range pick up for touring and a reasonable top end. I got that but after two ears, and with only about 1/3 of my miles done touring, I'm just trying to make the lower end a little easier...Thanks for the tips.
Like Scott suggested, if you are sure about the compression, the 26 closes at 35*, three degrees earlier than the 37 which would move the torque to the left but give up some on top; there is always a trade off.