how much more power will the honda .25 over sized pistons make over standard size pistons?

 

come on anyone??

 

itll give you a little more HP

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bolivianstrtwpn &raquo;</TD></TR><TR><TD CLASS="quote">itll give you a little more HP </TD></TR></TABLE>
lil as in how much 1 or 2 or 5-10
i'm just wondering around how much it will increase
is it really worth the money to bore the block

 

The over-sized factory pistons aren't intended to increase power, they're designed for use when material must be removed from the cylinder walls. You'll see an extremely negligible increase in power, and it would definitely not be worth the money to have them installed as a power-adder.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 &raquo;</TD></TR><TR><TD CLASS="quote">
lil as in how much 1 or 2 or 5-10
i'm just wondering around how much it will increase
is it really worth the money to bore the block</TD></TR></TABLE>

i dont know about the increase in HP but they will be a good part to add to your set-up...your cams will like the higher CR if you get the .25 OS CTR pistons

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by James. &raquo;</TD></TR><TR><TD CLASS="quote">i dont know about the increase in HP but they will be a good part to add to your set-up...your cams will like the higher CR if you get the .25 OS CTR pistons</TD></TR></TABLE>

CTR's are a completely different story. His original post implies that they will be the original pistons in a .25 over size. In that case, the CR would actually be very slightly lower than stock.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">

CTR's are a completely different story. His original post implies that they will be the original pistons in a .25 over size. In that case, the CR would actually be very slightly lower than stock.</TD></TR></TABLE>

ohh mybad on me...but anyways i dont think its worth it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">

CTR's are a completely different story. His original post implies that they will be the original pistons in a .25 over size. In that case, the CR would actually be very slightly lower than stock.</TD></TR></TABLE>

How would they be lower? If he put stock O/S pistons in he would actually gain about 10cc's and .05 compression points.

 

OS pistons will increase your compression ratio, however, it's an insignificant amount.

It'll add .25 whp....lol.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr Milano &raquo;</TD></TR><TR><TD CLASS="quote">How would they be lower? If he put stock O/S pistons in he would actually gain about 10cc's and .05 compression points.</TD></TR></TABLE>

You're right, with the actual figures varying depending on what engine we're talking about. I did the calculation incorrectly.

 

every little part counts. If you're buying new pistons why not?
Don't buy them as a power added though (it might add like 1 hp)

 

not worth the money save up and bore out to 85mm

 

If your going to rebuild the motor, it is a must to bore it out the block and go with oversized pistons. (some argue that it depends on mileage) I would opt for either JDM ITRs or CTRs oversized to gain some more compression. Reason for boring it out is that the cylinder walls are not straight after a motor has alot of mileage. You want to have the cylinder walls straight again to match the new pistons you are putting in. Its worth the extra money in my opinion and you will get a better ring seal. Sleeving the block is an extra 800$ plus the cost of rods and forged pistons. Good Luck!

 

That's what honing the block is for.

 

Stock displacement - 1765.8cc
.25 over " " " - 1771.25cc
Displacement gained - 5.45cc

Power won't be noticable at all.

 

i have a related quick question why is .25 over 81.25 and .20 over 81.5 ? am i missing somthing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by igotyofire &raquo;</TD></TR><TR><TD CLASS="quote">i have a related quick question why is .25 over 81.25 and .20 over 81.5 ? am i missing somthing?</TD></TR></TABLE> because "20" over you are referring to is INCHES.
0.50mm is 0.0196850 inches.... which is commonly referred to as "20 over"