Upping compression?
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2nd Gear
Joined: Sep 2014
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From: Oklahoma
Upping compression?
Hello all, new to the hd forums although I've learned quite a bit already I had some questions regarding compression on my 13 dyna fld. Just recently put in a set of S&s 583 easy starts and a powervision tuner but the bike acts like a turd. I have tried like 4 different tunes and she just needs more. My question is there any way to jack compression up to 10.5:1 with a bolt on kit? I don't want to do any machining on it. Before can swap I was hitting around 37-40 mpg and now I'm lucky to get 26. It ran good when we were up north but really lacked on the power side, and we came home to oklahoma with the 103 degree weather and she falls even harder. Not to mention the ping I get down here that I wasn't getting up there. Thanks in advance and I hope to hear all insight, constructive or not all is appreciated.
HDF Community Team
Joined: Jun 2006
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From: san antonio
As Kirby has pointed out, you don't need more compression. However, you do need a dyno tune. Stop messing around with maps; never will be right. Get the bike on a dyno and in the hands of a competent tuner.
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2nd Gear
Joined: Sep 2014
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From: Oklahoma
So let me ask a couple more questions. What is stock compression? I thought it was around 9.0:1 and the reason I went with the powervision was the autotune kit for it with the wide band o2s. It was supposed to be plug and play and just run the autotune after each mod? And I was eyeballing the 113" kit from revolution. Any thoughts on it? And if 9.8:1 is ideal for the 583 easy starts what is best way to get compression there from stock? Will I need to mill the heads? Or just put a different set of pistons or? Thanks again!
HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
So let me ask a couple more questions. What is stock compression? I thought it was around 9.0:1 and the reason I went with the powervision was the autotune kit for it with the wide band o2s. It was supposed to be plug and play and just run the autotune after each mod? And I was eyeballing the 113" kit from revolution. Any thoughts on it? And if 9.8:1 is ideal for the 583 easy starts what is best way to get compression there from stock? Will I need to mill the heads? Or just put a different set of pistons or? Thanks again!
I have no opinion on the 113" Revolution kit but do know that case boring is required which means pulling the lower unit for the machine work. Going that far, I would be going for 117" with some 4.125" cylinders.
I am not a tuner and can't speak to the Power Vision auto tune feature but I believe there is plenty of power available with your current configuration but you need to get the bike on a dyno and in the hands of a competent tuner; auto tune will never get it right. With the corrected CR and CCP being a bit on the high side, you need a dyno tune to eliminate the ping. As you went north and moved higher above sea level, CCP dropped which would account for the lack of detonation at higher altitudes.
I would suggest some decent head work to beef up your current configuration; keep your 583 cams and have heads worked around those cams, perhaps an exhaust change (don't know what you are running) and a professional dyno tune. Then evaluate how the bike performs before deciding to go bigger. JMHO.
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2nd Gear
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From: Oklahoma
Thanks again for the insight all. And djl it has the bassani road rage 2-1 already and stage two harley breather. I want to put a better breather and that on as well. According to revolution their 113" kit requires no machine work. I figured I would go ahead and spring for it when money permits. Regaurdless eventually I want to shoot for the 115 horse and around 120-130 torque in the end. Went with the cams to get some low grunt while I work on the rest of goodies for a build. I figure I may need a different set of cams to achieve my goal but thought these would tide me over till I could research and get all my ducks in a row. But so far other than a little grunt it looks like a different set of cams will be in order.
Last edited by Gerain15; Sep 5, 2014 at 01:37 PM.
Road Warrior
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From: Oakdale Ca.
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2nd Gear
Joined: Sep 2014
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From: Oklahoma
I figured the 583 would be biggest lift bolt in and the guy on ebay said they would be more in my riding style than the tw56 cam I was eyeballing. I wish I would have done a bit more research and talked around more though.
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Road Captain
Joined: May 2014
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From: San Diego
Per S&S, the 583 is 10:1 and below compression ratio cam. Its probably in your tune. I have a base PV tune from Dynojet that I got for a S&S 97 Big bore, 583 cams, Bassani RR 2into1, and FM stage 1 AC. Runs fine to me but will need to fine tune it.
HDF Community Team
Joined: Jun 2006
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From: san antonio
Thanks again for the insight all. And djl it has the bassani road rage 2-1 already and stage two harley breather. I want to put a better breather and that on as well. According to revolution their 113" kit requires no machine work. I figured I would go ahead and spring for it when money permits. Regaurdless eventually I want to shoot for the 115 horse and around 120-130 torque in the end. Went with the cams to get some low grunt while I work on the rest of goodies for a build. I figure I may need a different set of cams to achieve my goal but thought these would tide me over till I could research and get all my ducks in a row. But so far other than a little grunt it looks like a different set of cams will be in order.
120TQ from a 107" build is doable; my all bore 107" carbed '02 FLHT makes that number and if it was an EFI bike, I would expect a bit more. You have a decent exhaust system but it will take just the right cams and exhaust combination and a spot on tune to see 115HP/120TQ. TQ is doable but the HP might not hit the target.
You have a good foundation to start from. Headwork and more cam, like the TMan 662-2 or a comparable grind should get you real close to you numbers without breaking the bank. You will have no trouble selling the 583 cams; a very nice set.