High Compression

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Aug 8, 2012 | 11:51 AM

LowriderHarold

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Road Captain

Joined: Aug 2012

Posts: 625

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From: New Albany, Ms.

High Compression

Good day, gent's. I'll try to keep this short. Bought a stock 80ci , 1996 Lowrider, couple yrs. back, low miles. Back in the spring, put S&S lifters,S&S Quickie pushrods, Andrews EV13 cam, Dyna ignition, Vance & Hines Longshot's. Already had a S&S Super"E" installed. Took it to my tuner, & we dialed it in , 71.30 hp/ 81.92 tq. Pulls real strong, what I want with 2 up riding. Problem is, my oversight, base gaskets, underneath jug's, will have to be replaced this winter. So since , I'm gonna have the head's & jug's off, I wan't to get the most power out of the engine, & keep reliability. Been looking real hard at a place called Head Quarters, that sells a service, of head work, cam, pistons, etc. been reading a lot of posts on this forum, about them, & believe thier kits will do what they say. My only concern is, & question, the pistons, that they use are 10.5:1. Anyone here , running this high a compression, on a stock stroke & bore Evo, & if you are, what kind of problems, if any are you having. I live in the deep South, real hot in the summer, & have had problems , with high comp car engines , back in the day, Thanks for any info.
Haroldinfo will be aaaaaaappreciated1E0.to 10.5:1 using domed pistons
5:1o 10.5:1 using domed pistoto 10.5:1 using domed pistons
ns

Aug 8, 2012 | 04:35 PM

grbrown

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Joined: Jun 2007

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From: Bedford UK

Hi Harold and welcome to HDF from the UK. There are a few sponsors of HDF who are engine specialists and can answer your question, even offer their services to improve your engine.

To partly answer you, many years ago the thinking of the day was to stroke an Evo to improve performance, but the knowledge of head porting and improved cam design available today means it is no longer necessary to increase capacity to get big improvements in performance.

Aug 8, 2012 | 07:45 PM

brainless fxst

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Joined: Jul 2012

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From: upstate ny

That can is not big enough for that compression

Aug 8, 2012 | 09:55 PM

badcooky

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Joined: Jan 2012

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From: Location location.

I run 10.5 or 10.2 to 1, can't remember which,it shouldn't get too hot unless it's lean or has too much ignition.
Mine runs very well.

Aug 9, 2012 | 05:38 AM

Tom84FXST

Seasoned HDF Member

Joined: Nov 2009

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From: Farmington ,MS

Quote:

Originally Posted by LowriderHarold

I wan't to get the most power out of the engine, & keep reliability.

Everything is a compromise. I am quite sure their set-up will make better numbers on a dyno, but sometimes that does not translate into more fun riding. To run that much compression, you will have to run a cam with longer duration...which will move your power higher up the RPM band...which may not be what you want for 2 up riding. Compression that high will also make your motor VERY finicky when it comes to fuel...detonation will be a problem when you get a tank of "bad gas". For a motor that you plan to use mainly for 2 up riding, increasing the displacement for HP is a better plan than increasing compression IMO.

Aug 12, 2012 | 07:37 PM

Mike T

Outstanding HDF Member

Joined: Aug 2010

Posts: 3,486

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From: Union,Ms

I have 10:1 Wiesco pistons in my bike. I have no bad issues and you'll have to find a cam that works well with it. 92 octane gas is a must to prevent detonation. It really woke my Evo up.

Aug 12, 2012 | 07:45 PM