Cam choice?? Decisions, Decisions

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Carbonfibre said:
hobot said:
Carbonfiber is just testing me and that's what I'm all about on my special Peel. Any weakness in her handling or my understanding could well be the end of us.
If you are new to Commandos, there have been a number of people that tried to detune a Combat by putting in standard cam. This raised dynamic CR to point detonation became a limiting factor. Yet with 2S cam detonation was much less if any issue on same octane. You will just have to take my word for it or study up your self why a cam that has both valves open very much at same time needs higher CR ratio to function as power adder, or even idle.

Any one with creek water handy or windshield washer fluid can have 116 octane about anywhere they go. Jim's pistons are 10:5 but Peel will only have 7.5 on start up and slow idle d/t too over lapped a cam for road use : )

Review DynoDaves cam graphs, many are just slight modification off the 2S cam. Increasing engine displacement tends to tame a hot cam made for a smaller engine. Smaller ports tend to tame down a more radical cam. Combined effect would be it comes on cam sooner and behave nicer down low.
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Any idea why exactly a longer duration cam needs higher compression pistons to work properly? I get the impression that this would be useful info for most of those interested in this thread.
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well we past 116 and you are still a negative jack ass will you EVER GET THE HINT you must have a mental issue with hobot. if you don't like his post's JUST LEAVE i am sure you WONT BE MISSED HERE!!!!
 
Relax on Carbonfiber, he pokes me too but as I said its part of my Peel hobby to deal with the smirking. Besides it gives me a reason to double check stuff- just in case he's right : ( If he half way stays rational, then me too not put him down on his reasonable conclusions w/o direct experience of Peel's expressiveness.

One not correct thing is the data I fed the calculator to spit out 11.83 static CR
and the 7.8 effective ratio is a bit higher than other calculators figured. Will try again but not sure if calculator stuck on 96 cid engine as smallest to input.


Any idea why exactly a longer duratipistons to work properly? I get the impression that this would be useful info for most of those interested in this thread.
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Reasonable as can be here.
Basically, short duration cam closes valve early to trap a lot of pressure when rpm slow enough there is not much ram velocity inertia to keep flow going if valve still open while piston rising. Long duration cam lets rising piston push charge back out the carb or into open exhaust valve, until rpm, piston speed rises enough a ram charge effect occurs to 'over charge' jug.

Here's hot rod site article on this and summary paragraph and how it applies to Peel's deal.
http://www.chevyhiperformance.com/techa ... index.html
it appears that building a performance street engine that combines a decent-duration camshaft with enough static compression ratio to create 175 to 190 psi, will reward you with a very snappy engine that is not only responsive and fun to drive, but makes decent power as well. For example, you can run 11:1 compression on pump gas if you use a long-duration cam with a late-closing intake to bleed off some of that low-speed cylinder pressure. This is the main reason why camshaft companies recommend higher static compression ratios with longer-duration camshafts. This is an attempt to improve power at low and midrange engine speeds by making up for the late-closing intake valve with more static compression.
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