i dont know everything and dont claim to, but i'm building a $6000.00 plus stroker motor to go in my bronco, all the work will be done my self with exception of the machine work, its gona push 500HP, will run on pump gas with no additives, and will be TURN KEY fuel injected daily driven transportation. You know, I'd hate to think I dont know what im doing, any body wana help? now i'm CONFRUSED! DW

 

Don't get me wrong DW, I'm with you 100%.

 

why do you people dwell on things that are totaly irelevant to street motors? If took any two identical vehicles only differens was one of them had the motor bored 0.030 over you could not drive them each 5mls down the road and back and tell me which one was which if your life denpended on it. all the man wanted to know was how much power difference boring the motor would, you couldn't tell the difference unless you had both motors on a dyno and both under controlled idencticle conditions, So why even bring it up? it rediculous? you people are worse than kids on a play ground you argue over things that are totaly irrelevant. DW

 

And there you have it. If you bored a motor over .030 it wouldn't be enough that you could tell a difference.

 

So who's arguing? I'm not. We're both right- he won't notice any more power from just an increase of .030" in bore size. I just said he'd gain a little compression. Then somebody jumped on me and said I was wrong when simple math and common knowledge says otherwise. All I did was clarify. I ain't gonna lose any sleep over it.

 

You won't "gain" enough compression to blow out a candle in monsoon. Its not worth even thinking about.

 

1pump is correct, it will raise compression:

For the subject engine: 302 (3.00" stroke, 60cc chambers with 5cc valve reliefs in pistons, .047" gasket thickness [Fel-Pro #1011-2])

Standard 4.0002" bore: C.R.=9.2725
Overbore, 4.0300": C.R.=9.3807
Overbore, 4.0600": C.R.=9.4893

These numbers are not from an internet plug-and-chug calculator, they were done on my TI-89, and are correct to 10 decimal places.

I don't know how much compression it takes to blow out a candle in a monsoon, but at least now you have some numbers to discuss, instead of DW talking about how everyone is being rediculous because they disagree with him.

On most engines with V.E. ~ 85-90%, 1 point of compression is worth between 30-40 HP. Given the test subjects above, this means an additional 4-5 HP for a .030" overbore, or 8-9 HP for a .060" overbore. I realize that .060" is too much for street, but at least I'm throwing out tangible numbers that I calculated myself for you to at least see the numerical trend. 4-5 HP is within the error tolerance specs of most Dynomometers, so you probably would never know the difference. It will also not likely be the determining factor between running 87 or having to buy premium, but all little things add up.

 

i do belive i said about the same thing on power gains earlier in the post, my the whole [point is, is the question at hand was answered right off the, so exactly what the relevance of this whole conversation? its pointless knull and void information for the average joe, especialy when dealing with street engines. ????? why even bring it up? DW