High compression?
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
High compression?
Anyone out there running 10.5:1 compression in your baggers and if so what cams do you have? I'm thinking of raising the compression in my bike, but don't want to go with a long-duration cam and lose the low-end throttle response. Thinking of keeping the S&S 510G cams, which look pretty similar to the SE 211 cams. Anyone have these SE 211's? Any starting problems?
Outstanding HDF Member
Joined: Aug 2008
Posts: 2,090
Likes: 7
Dont, dont, dont, dont. Oh, and by the way,......DONT try to run 10.5 compression. Take it from someone that has been there and done that. You can make almost as much HP and TQ at 9.5 to one and run any gas you want. If you have not already, take a look at the Andrews TW54.
Tourer
Joined: Aug 2007
Posts: 250
Likes: 0
From: Jackson, MI
Just another opinion.... IF your motor is set up correctly for it, 10.5 comp isn't bad at all with 91octane!!! BUT your motor has to be set up correctly- cams, squish, etc all play a role. This is what I have learned recently while looking into a build for my Road Glide this winter. Check out HQ, their kits all utilize 10- 10.5 to 1 compression for baggers.
From what I have gathered, while you may be able to make almost as much peak torque, that extra compression brings the torque on earlier down low and flattens out your overall torque curve. Flat torque curves make ya fast and the bike fun!
Jason
From what I have gathered, while you may be able to make almost as much peak torque, that extra compression brings the torque on earlier down low and flattens out your overall torque curve. Flat torque curves make ya fast and the bike fun!
Jason
Last edited by speedglide; Oct 29, 2008 at 03:33 PM.
Thread Starter
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
OK, so I now have two polar opposite responses. The one in favor seems to echo what I've been thinking about the + side. What is your expericnce, just-to-annoy-you? Why so strongly advising against?? What was your setup when you ran 10.5:1 and what happened to it?
Intermediate
Joined: Oct 2008
Posts: 35
Likes: 23
From: Georgetown, TX
I am running 10.5:1 and have 100 ft#s from 1800 to 3200 rpm and pk hp of 93.4 on a 96" 2007 Roadglide with stock pistons. I have Woods TW-7 cams, Screamin' Eagle MCR Heads, ThunderMax Autotuner, V&H ProPipe, and am using a .030 Cometic gasket. Yes boys and girls, that equals 10.5:1 Compression.
I do need to take the time am get it on a dyno to tweak the timing, but It runs just fine with 10,000 miles on it.
Compression releases are a must if you are running anything like 10.5, and I like the Manual Compression Release SE heads just fine.
I do need to take the time am get it on a dyno to tweak the timing, but It runs just fine with 10,000 miles on it.
Compression releases are a must if you are running anything like 10.5, and I like the Manual Compression Release SE heads just fine.
Thread Starter
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
Lots of torque at low rpm! That's what I'm after! Do you have the spec sheet on those cams, and can you send them to me or post them here? Trying to figure out what cam gives enough overlap to keep cylinder pressure low enough to start, but still small enough to keep the power down low. I'd really like to keep the cams I have but suspect they might not be well suited to high compression.
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Road Captain
Joined: May 2006
Posts: 720
Likes: 2
From: Kansas
Northeast;
I had S&S 510's, and had a hard time with pinging even at 9.5:1, it was not too bad until the heat of summer, then I had to de-tune it so much to keep from pinging, adding fuel and retarding timing, that a stock bike could out run me....
like mentioned earlier, heads, cam, compression, squish, and ignition timing are all factors when putting a top end together...
I've learned alot since then and I am done with science projects, trying to mix & match parts that I think should work together, I will be buying a complete engineered kit (jugs, pistons, heads, cams, ignition, etc.) from a reputable builder that has all that stuff figured out already... more $ up front, but cheaper in the long run than throwing different parts at it all the time trying to get it to run like I want it to. I plan to spend around 3k and get a very good running motor, around or over 100/100, that will last a good many miles.
maybe with the correct squish the 510 would work good at 10:1 or more (shrug)
good luck,
K.
I had S&S 510's, and had a hard time with pinging even at 9.5:1, it was not too bad until the heat of summer, then I had to de-tune it so much to keep from pinging, adding fuel and retarding timing, that a stock bike could out run me....
like mentioned earlier, heads, cam, compression, squish, and ignition timing are all factors when putting a top end together...
I've learned alot since then and I am done with science projects, trying to mix & match parts that I think should work together, I will be buying a complete engineered kit (jugs, pistons, heads, cams, ignition, etc.) from a reputable builder that has all that stuff figured out already... more $ up front, but cheaper in the long run than throwing different parts at it all the time trying to get it to run like I want it to. I plan to spend around 3k and get a very good running motor, around or over 100/100, that will last a good many miles.
maybe with the correct squish the 510 would work good at 10:1 or more (shrug)
good luck,
K.
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Intermediate
Joined: Oct 2008
Posts: 35
Likes: 23
From: Georgetown, TX
Lots of torque at low rpm! That's what I'm after! Do you have the spec sheet on those cams, and can you send them to me or post them here? Trying to figure out what cam gives enough overlap to keep cylinder pressure low enough to start, but still small enough to keep the power down low. I'd really like to keep the cams I have but suspect they might not be well suited to high compression.
TW-7H
20/40
42/18
42/18
240
240
240
.575
.575
.575
.194
.176
.176
HI-LIFT
New for 2006 2007 Bolt-In Super High Torque for SE Performance Heads
Bobby Woods is a great guy and very helpful. He knows his stuff.