wondering how much power is gained from raising compression ratios?

for example, if i were to put b16 pistons in my b18b and do nothing else, what sort of gains could i expect to see?

 

Look at the RSX vs the RSX-S. The type-s makes 40 more hp, but the same amount of Tq. The difference in compression is 9.8:1 compared to 11:1. Yes the head is completely different too, but a lot of the gains can be attributed to the C/R too.

You will need some tuning, but you will notice a difference.

-PHiZ

(i'd save the money spent at the machine shop on going turbo though ;p )

 

yeah i probably wont actually do it, i was just curious.... cuz there is a lotta hype to having a higher c/r

 

The increase in compression just makes the whole package work better, but by itself is not a mod that will make a whole lot of difference. It is the one mod that doesn't have a trade off (aside from requiring better fuel) and will give you more power throughout the whole RPM range. When you go with more radical cams, its a good idea to raise compression @ the same time to gain back some of the bottom end that you lost, and to make even more top end.

 

Compression is not overrated, in fact it is somewhat underrated in the Honda crowd.

Example:
JDM B16A, 160hp, 111lb-ft, 10.2:1 compression
USDM B17A1, 160hp, 117lb-ft, 9.7:1 compression
USDM B18C1, 170hp, 121lb-ft, 10.1:1 compression

Think about it. The displacement of the B17A1 is between the B16A and B18C, however it makes the same horsepower as the B16A. Why? the compression is lower. That is one of the two downfalls of the B17A, and had it had 10.1:1 pistons, it would have had an easy 5hp more.

 

aright, you spend the money to put half a point more compression in a B17, and you'll be just that much cooler. "can you hear that half a point more compression? it really made the car sooo much faster." Just put a bigger fart can on it, it'll at least sound faster.

I'm saying for a street car...intake, egg sauce, header...don't even bother, it doesn't even matter. If your building a race gas autox or drag car and your changing to big cams, even bigger ports, huge headers, & an enormous coffee can out back, then you definitely should bump compression.

 

You have no grasp of the concept at hand. If he bumped the compression up to about 11.5:1, he would have more usable power through the entire rev range with no problems, and this can be done cheaply with used stock pistons and new rings.

 

yeah i have a set of b16 pistons, just sittin in a box....

i also have a b18c5 bottom with b16a1 head just sittin on a pallot, waitin for a tranny/clutch/flywheel and ecu (or a buyer )

soooo what im wondering is if maybe somebody bought my engine-on-a-pallot, if it would be worth my while to use the cash and get some crower cams and new valve train and put in the b16 pistons or if it is more work than it is worth and maybe i should just take the proceeds from the sale, save a few extra bucks up, and buy a b18c1 complete swap.

lets keep in mind that im not looking to run 12's or really even 13's.... but 14's would be nice. and no, turbo is not an option, my car has 217k on it and i dont think it would hold up for long with any amt. of boost.

 

now we're talkin. but you wanna put cams and pistons on a 217k bottom end? you prolly should rebuild the whole assembly. swapping in a c5 would prolly be your best move though with the oil squirters in the bottom end. then save up and put the cams in that thing.

 

you gotta think about this man....

if i have the bottom end apart, putting different pistons/new rings isnt gonna make it a 217k bottom end... the new rings will restore a lot of the life in the engine. sure most of the components will have 217k but compression lost due to old rings will be restored. also, being apart the engine will probably get new parts like head gasket, timing belt, water pump, the usual stuff.... i am by no means considering taking it apart, puttin in new pistons, and leavin the old shat in there.

also the c5 swap isnt really an option for a long time cuz its gonna be a while before i have the cash to get a tranny/clutch/flywheel and ecu....

the reason i pointed out the fact that i have 217k is because i wanted to state that im not going turbo, that would require a rebuild plus the cost of the turbo, i might as well finish my c5 swap....