99 Evo.. More compression or big bore?
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6th Gear
Joined: Dec 2015
Posts: 12
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From: Millington, IL
99 Evo.. More compression or big bore?
Hey guys I have a 99 softail and looking for some more power. It's got s&s carb, s&s cams( not sure on the size) and some supporting stuff. It made about 88 hp on the dyno. Would like to keep up with some of my buddies with twin cams but don't really have the spare money to do a big bore for $1000. Haven't had any luck finding used set ups and I could up the compression to 10.5-11.0 for roughly $200. What's everyone's thoughts?
Elite HDF Member
Joined: Oct 2005
Posts: 3,872
Likes: 83
From: Canton, Michigan
To get the most out of a bump in compression, you most likely will need to swap out the cam. Find out what you have in it, that will help.
IMHO, 9.5-1 is a decent compression ratio for the EVO. If you're making 88 hp on the dyno already, that's pretty darn good for a basically stock 80 cubes. You might be able to push it up to 90-95 with the compression increase and some head work, but there are a ton of variables.
If you're reaching for 100+ hp, the solution is more cubic inches. Save your money and look into stroking it out to 89". Then if that's not enough you're next move is adding jugs and going to 96".
Just my 2 cents....
IMHO, 9.5-1 is a decent compression ratio for the EVO. If you're making 88 hp on the dyno already, that's pretty darn good for a basically stock 80 cubes. You might be able to push it up to 90-95 with the compression increase and some head work, but there are a ton of variables.
If you're reaching for 100+ hp, the solution is more cubic inches. Save your money and look into stroking it out to 89". Then if that's not enough you're next move is adding jugs and going to 96".
Just my 2 cents....
Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
Been there, done that (compression , bigger bore, different heads).
IMHO - not really worth it. Just tune the stock really well: cam (you got it), jet kit (you already got an S&S - good enough by itself), well, maybe a set of pistons to boost the compression to 9.5. Make sure your ignition timing is good - do the static timing with whatever module got the LED.
Old timers (the ones I REALLY believe) say: stroking - bad!
88 on a dyno? Just don't touch it man!
It will pay off in the future with reliability, flawlessness, coolness (literally). Much better than TC's
IMHO - not really worth it. Just tune the stock really well: cam (you got it), jet kit (you already got an S&S - good enough by itself), well, maybe a set of pistons to boost the compression to 9.5. Make sure your ignition timing is good - do the static timing with whatever module got the LED.
Old timers (the ones I REALLY believe) say: stroking - bad!
88 on a dyno? Just don't touch it man!
It will pay off in the future with reliability, flawlessness, coolness (literally). Much better than TC's
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,104
Likes: 7,632
From: Poolville
No matter which way you go it's gonna cost. If you can do a big bore for $1k then do it. But your gonna have to do already an 89"er. To just simply increase the comp is not the answer. All cams have a specific comp range not to mention the proper head work. Your not gonna do that for under $1k to achieve even 95/95.
Have you thought of a gear ratio change. It does make a difference and cost a hell off a lot less....
Have you thought of a gear ratio change. It does make a difference and cost a hell off a lot less....
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
There ain't no way he got those numbers without a compression bump.
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Hey guys I have a 99 softail and looking for some more power. It's got s&s carb, s&s cams( not sure on the size) and some supporting stuff. It made about 88 hp on the dyno. Would like to keep up with some of my buddies with twin cams but don't really have the spare money to do a big bore for $1000. Haven't had any luck finding used set ups and I could up the compression to 10.5-11.0 for roughly $200. What's everyone's thoughts?
Someone has already done a lot to your motor for you to see 88 hp.
You're not gonna see a lot more out of that motor without stroking it.
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Seasoned HDF Member
Joined: Nov 2010
Posts: 17,548
Likes: 7,181
From: Oxford, Nc
Currently putting out 88HP? Running Weisco 10:1 pistons, EX 3030 cam, S&S carb with a Thunderjet AND flowed heads I put out just under 80 HP ('98 Dyna, no longer mine.) 88 HP would take a hotter set up than mine - maybe an 89" stroker kit? (There's not enough meat to do a big bore on an EVO (IMO.)
So I'm afraid that I've got to suggest that the 88 HP is an inaccurate number (trying to be polite here.)
So I'm afraid that I've got to suggest that the 88 HP is an inaccurate number (trying to be polite here.)
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Seasoned HDF Member
Joined: Mar 2010
Posts: 21,104
Likes: 7,632
From: Poolville
Without a doubt it was. Not sure if the newbie really knows what he has and whats in it......Not knocking you man.... Just saying....