Pros/Cons of more compression, also pushrod length question......
Pros/Cons of more compression, also pushrod length question...... Ok, heads have to come off anyways, and I am going to add the TR 230/224 cam, my question is this: I don't have the money to port the heads right now, but am leaning toward getting them milled to increase my compression. First of all, how much do I have them milled to obtain 11.0 to 1? (Stock is 10.1 to 1, correct?) Secondly, will my pushrods become shorter in the same amount of milling? I.E. I have the heads milled .050, the pushrods need to be .050 shorter? Thirdly (is that a word?) How much will this jump in compression help me? 5 rwhp? 10 rwhp? 15 rwhp? Also, what are the pros/cons of more compression? Thanks, Shawn
<small>[ August 25, 2002, 05:16 PM: Message edited by: SPANKY LS1 ]</small>
<small>[ August 25, 2002, 05:16 PM: Message edited by: SPANKY LS1 ]</small>
Re: Pros/Cons of more compression, also pushrod length question...... Ask Roy I think it worked out great for him he milled off .050.
You will need shorter pushrods if the base circle of the new cam is near stock.
You will need shorter pushrods if the base circle of the new cam is near stock.
Re: Pros/Cons of more compression, also pushrod length question...... Thats where I got my inspiration. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> How much will .050 raise compression?
Re: Pros/Cons of more compression, also pushrod length question...... Spanky,
You'd have to mill the heads about .035 to make a 7cc drop in combustion chamber volume. This would give you 11.06:1 with true flattop pistons, stock head gaskets and cubic inches.
You would probably need to go with a slightly shorter pushrod as well but it would be best to check geometry once the heads are bolted on to get the exact length necessary.
Ususally each single point increase in compression (in the range of 9:1 to 12:1) would be worth about a 3-4% increase in power.
One bonus of the increase in compression is the taming affect it has on large camshafts. i. e. you can run a more rambunctious cam with higher compression.
Hope this helps...
Shane
<small>[ August 25, 2002, 05:49 PM: Message edited by: XtraCajunSS ]</small>
You'd have to mill the heads about .035 to make a 7cc drop in combustion chamber volume. This would give you 11.06:1 with true flattop pistons, stock head gaskets and cubic inches.
You would probably need to go with a slightly shorter pushrod as well but it would be best to check geometry once the heads are bolted on to get the exact length necessary.
Ususally each single point increase in compression (in the range of 9:1 to 12:1) would be worth about a 3-4% increase in power.
One bonus of the increase in compression is the taming affect it has on large camshafts. i. e. you can run a more rambunctious cam with higher compression.
Hope this helps...
Shane
<small>[ August 25, 2002, 05:49 PM: Message edited by: XtraCajunSS ]</small>
Staging Lane
Joined: Nov 2001
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From: Sydney, Australia
Re: Pros/Cons of more compression, also pushrod length question...... Added compression can be a good thing and give you a smidgin more power but your car will always be sensitive to small changes in fuel quality and thus more prone to detonation.
If you want more power, go safe and just up the 'cubes'. Leave the 'huge' compression ratios to motors that live on avgas or big octane race fuels.
If you want more power, go safe and just up the 'cubes'. Leave the 'huge' compression ratios to motors that live on avgas or big octane race fuels.
