compression ratio?

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Jan 28, 2006 | 01:45 PM

mojo workin

Thread Starter

Cruiser

Joined: Jan 2006

Posts: 223

Likes: 0

From: Wisconsin

compression ratio?

I'm a novice and need your opinion on compression ratio. I have a down payment on, and will be buying my good neighbor's 05 FLHT. He works at the CVO department in Milwaukee. Before he put any miles on it, he went through the motor. In Wisconsin, we have 93 octane. He said when traveling, I could run into much less octane. He told me to run it for awhile this summer and see how it goes. If I decide to go back to th 9.1 pistons it wouldn't be a problem. He would change them back at no cost. He had mentioned it's currently set up around 108 HP when dynoed and going back to 9.1 would probably drop it down to around 100 HP. My quesion is, would I feel that much drop in HP? Is it better to sacrifice the HP so not to mess with octane booster or have performance problems?

Current Set-up:
16326-02 - HTCC pistons 10.5-1
22439-00A - HTCC ported heads
16549-99 - 1550 cylinders
25155-00 - 257 cams
29635-99 - intake manifold
27934-99 - 44mm CV carberator
29440-04 - air cleaner
31794-04 - ignition module
31932-99A - plug wires
31553-99 - coil
80400-01 - SE Exhaust (2 into 1)
65115-98B - SE Exhaust (Kirkers)

Jan 28, 2006 | 02:45 PM

CHEYENNE

Road Warrior

Joined: Aug 2005

Posts: 1,545

Likes: 5

From: NEW LENOX, IL

RE: compression ratio?

If you know for a fact you can find 93 octane anywhere you ride then I would leave, but with that being said if you plan any rides across state lines I highly doubt you will always find 93. I would drop it down so that I can be able to ride across the states and not have to worry about any problems with the performance of your bike from not having the right octane running.

Jan 28, 2006 | 07:38 PM

scttgr8

Road Master

Joined: Jan 2006

Posts: 1,219

Likes: 2

From: Indianapolis

RE: compression ratio?

92 octane is easily available in indiana. 93 at some places

Jan 29, 2006 | 11:04 PM

OG_electra_glide

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Joined: Jan 2006

Posts: 373

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From:

RE: compression ratio?

why don't you ask your good neighbor? Seems to me he'd be a good source of advice for this question.

Jan 29, 2006 | 11:38 PM

Pauljr

Cruiser

Joined: Jan 2006

Posts: 233

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From:

RE: compression ratio?

I run almost the same set up. I ride 20 to25 thousand a year and only rarely run into a problem. But I was thinking I might carry a couple of octane booster pacs to use in a pinch. I did put reg 87 in once and my bike pinged its head off. never doing that again. Man your going to have a hoot with all that power. I think its worth looking for premium fuel. ENJOY !!

Jan 29, 2006 | 11:40 PM

juscoop

Tourer

Joined: Dec 2005

Posts: 314

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From: Corpus Christi,TX

RE: compression ratio?

Buy some of the octane boost capsules and keep some extras in the bike

Jan 30, 2006 | 01:16 AM

jeepster09

Grand HDF Member

Joined: Feb 2005

Posts: 4,307

Likes: 9,428

From: Twin Cities Minnesota

RE: compression ratio?

Have any of you actually had any luck with octane booster? I haven't. Most gas stations in my area of Minnesota only have 91 octane. Unless you are looking to race regularly drop the compression down, or look at different cams to use with your combination. Make it a real world bike that you can just ride and have fun with with out the worry of burning a piston.[sm=happy046.gif]
My bike runs any premium crap I can get with out pinging and still makes good power.