High compression?
#1
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?
#2
#3
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; 10-29-2008 at 03:33 PM.
#4
#5
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.
#6
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.
#7
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#8
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.
#9
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
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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.