Smartest way to raise compression ratio? - VTXOA
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post #1 of 52 (permalink) Old 05-09-2017, 01:47 AM Thread Starter
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Smartest way to raise compression ratio?

This bike could be producing over 120hp if the ratio was at 10.5/1 why is it at 9/1 and how can we fix that without hurting the internals or using blowers
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post #2 of 52 (permalink) Old 05-09-2017, 09:18 AM
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Why? Because Honda wanted a reliable engine and for it to run on the lowest octane available.

How? Pistons, but you will have to find someone to make them for you because most of those aftermarket parts have stopped being made since the bike is 10 years out of production.

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post #3 of 52 (permalink) Old 05-09-2017, 09:37 AM
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contact Wiseco.. they custom make pistons.

a few here have installed higher compression pistons... NO WHERE near that amount of increase...
higher compression will also require 93 octane fuel.. what about higher lift camshafts..

Like Mr. Spike said. out of production for 10 plus years.

to me your numbers do not seem possible.. the 1800 does not do 120hp.



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post #4 of 52 (permalink) Old 05-09-2017, 09:46 AM
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Quote:
Originally Posted by chuck_VTX F View Post
contact Wiseco.. they custom make pistons.

a few here have installed higher compression pistons... NO WHERE near that amount of increase...
higher compression will also require 93 octane fuel.. what about higher lift camshafts..

Like Mr. Spike said. out of production for 10 plus years.

to me your numbers do not seem possible.. the 1800 does not do 120hp.
I think 120HP may be in the cards, but you will need compression plus you'll need to get the engine to breathe. You are talking about head work and time on the flow bench. This gets down to a good valve grind with multiple facets to increase flow. Then maybe while normally aspirated. It really is far easier and way cheaper to just add a nitrous system.
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post #5 of 52 (permalink) Old 05-09-2017, 09:51 AM
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Or the supercharger as seen in another thread
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post #6 of 52 (permalink) Old 05-09-2017, 09:56 AM
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Or the supercharger as seen in another thread
Of course, you gotta love a blower!!! That makes for some serious head turning everywhere you go.


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post #7 of 52 (permalink) Old 05-09-2017, 10:58 AM
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I'd just go ahead an spring for the Ducati Diavel and have those numbers plus some to spare..
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post #8 of 52 (permalink) Old 05-09-2017, 12:22 PM
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Quote:
Originally Posted by Harkon View Post
I think 120HP may be in the cards, but you will need compression plus you'll need to get the engine to breathe. You are talking about head work and time on the flow bench. This gets down to a good valve grind with multiple facets to increase flow. Then maybe while normally aspirated. It really is far easier and way cheaper to just add a nitrous system.
I know it can be done.. not CHEAP.. or easy.

over sized valves, 5 angle valve job.. ported and polished intakes.. . chrome moly studding.
high end carburetors.

cheaper to get a used pro-stock V-Rod. and put street tires on it.



2005 VTX1800 "F" type II, Silver Tribal, 73,000 Miles, Purchased Feb, 2005.
MTC clutch & springs.. K&N Air Filter. Garmin 2597 GPS.
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post #9 of 52 (permalink) Old 05-09-2017, 12:40 PM
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Originally Posted by chuck_VTX F View Post
I know it can be done.. not CHEAP.. or easy.

over sized valves, 5 angle valve job.. ported and polished intakes.. . chrome moly studding.
high end carburetors.

cheaper to get a used pro-stock V-Rod. and put street tires on it.
Way true brother. Actually for 120HP I don't think you'll even need to go pro-stock. I'll bet a good stage 3 build will get you there and then some. I know some have dynoed their 103 Dynas with a 107 kit at over 120HP. Minimal head work, but big cams and pistons, proper 2:1 exhaust. Not bad for an air cooled pushrod engine. Big $$$$ though. I'd bet pro-stock be bigger $$$$.

I like Spike's idea about the blower. Maybe not the biggest bang for your buck, but certainly the one with the most sex appeal AND still way cheaper than tearing things apart.


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post #10 of 52 (permalink) Old 05-09-2017, 01:00 PM
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Kent Stotz got 250+ with a turbo pushing 25psi
http://www.stotzracing.com/news111304.htm

I was lucky enough to see Kent's garage and that Turbo VTX. Plus a lot of Honda R&D parts like chain drive trans for his drag VTX. Very nice guy and pushed the VTX to the limit

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