Upping Compression Ratio

[ElectrO]

I was curious, Owning a F22 (European) The compression is a low 8.8:1 and If i changed the pistons and such to get the compression well into the 10:1 - 11:1 would I run into trouble, like too much heat?
Also what sort of benefits would one gain from improving the compression that much?

If anyone can shed some light on this for me, I would appreciate it

Thank You

[h22sparkle]

not really in my eyes if its properly tuned. But you have to be on top of your tuning game with enough fuel a couple of boltons and shit. With more compression come more power I believe the theory is the more compression is more power but detonation is no joke.

[gloryaccordy]

Upping the compression will make some power, but not a super significant amount. If you go from 8.8 all the way to 11, you'll prob. get at most maybe 15 more hp. The engine dynamic will be changed though so it would probably be best to get an AFC, as the ECU probably won't be able to account for the changes fully. If anything it will retard you to death.

*EDIT*- Are you making 160+HP at the wheels? Are you SOHC or DOHC? VTEC or non-VTEC That's pretty impressive if it's at the wheels! I can't imagine what you might have did though if you haven't touched your head.

[Fearit22]

I'm pretty sure you would get more than 15 hp from that kind of increase. In his sig it says bhp... body horsepower = crank horsepower.

[xScott]

If you relly want to feel the effects of a higher compression ratio, you need to build up the head too. Port and polish the head and intake manifold, port match the intake manifold to the head, bore out the throttle body, put in new springs,retainers, and valves, new/regrind the camshaft. Its kinda one of thoes things where you might as well rebuild the whole motor to relly see some gains.

[91AccordSE]

I always thought bhp was Brake Horsepower, as in at the wheels ( or whats measure at chassis dyno places). I dunno. Someone wanna clear this up?

[MRX]

i was under the impression bhp meant "base horsepower" as in stock flywheel hp. Its a general rule of thumb that for like every point of compression u go up its 3%-5% hp increase so doing the math in my head the amount that upping 2.2 points would yeild would be like 7 hp - 11 hp. Other aspects of ur engine will also effect the output tho like whether or not u use a thick head gasket or a thin one to add a bit more compression. If u do in fact raise the comp. ratio remember to use the highest octane u can, change ur radiator fluid for cooling, and get some good dyno tuning done cause ur high priced pistons will be better used as kitchen utensils if not taken care of. Horsepower costs both money and time.

[Andrew]

BHP Stands for Brake Horsepower. It is an indication of power at the flywheel. It's still used in the UK as a common figure, however, it fell out of use in the U.S.A. during the 1970's.

Before the Society of Automotive Engineers (SAE) intervened automakers were commonly known to strip engines of their essentials when measuring BHP, artificially inflating sale-car power figures. The SAE reccomended hp SAE as a power measurement standard which required the engine to be mounted in the vehicle and operated the same as sale models and it has been the common denominator since.

Electro - are you using a manufacturer rating in your sig? If not, who in the heck went to the trouble of measuring your power at the crank?

[HondaFan81]

Originally posted by cb7deathride
If you relly want to feel the effects of a higher compression ratio, you need to build up the head too. Port and polish the head and intake manifold, port match the intake manifold to the head, bore out the throttle body, put in new springs,retainers, and valves, new/regrind the camshaft. Its kinda one of thoes things where you might as well rebuild the whole motor to relly see some gains.

i've heard this somewhere before..... hahaha gea

[HondaFan81]

we have a winner....what does he win?

Originally posted by Andrew
BHP Stands for Brake Horsepower. It is an indication of power at the flywheel. It's still used in the UK as a common figure, however, it fell out of use in the U.S.A. during the 1970's.

Before the Society of Automotive Engineers (SAE) intervened automakers were commonly known to strip engines of their essentials when measuring BHP, artificially inflating sale-car power figures. The SAE reccomended hp SAE as a power measurement standard which required the engine to be mounted in the vehicle and operated the same as sale models and it has been the common denominator since.

Electro - are you using a manufacturer rating in your sig? If not, who in the heck went to the trouble of measuring your power at the crank?

[HondaFan81]

aight, some useful info...

I'm increasin my compression ratio from 8.8 to 11:1 and I've been talkin to many people and the increase itself persay will not give me that much power, but in combination with my regrind camshaft, upgraded valvetrain, P&P intake manifold & cyl head....it's all gravy baby and I/H/E.

Increasin compression, yea heat will increase but if you go with colder spark plugs (1-2 steps...prolly goin with 2 NGK BKR7E) and a lil MSD 6A-L, NGK, MSD or Magnecor wires action isn't gonna hurt, but insure nice powerful spark with a blaster coil.

I have a new radiator in it already, goin with new timing belt & water pump, gonna check out my 110K oil pump or buy new stock. My block will be cleaned out when I get it bored over 0.020" so coolant ports & oil passageways will be mint. My fuel pump & injectors will upgraded to provide additional coolin factor

I'm not worried bout overheatin

[91AccordSE]

Back to that whole BHP thing..I think...

Lookin around online, I found a site, that does say that BHP is/can be measured at the flywheel, thereby giving you the horsepower at the flywheel. However, if I (and this site) am not incorrect, then BHP can aslo be measured on a chassis dynomometer (power delivered to the wheels). So I think, that earlier definition given, was only 50% correct. Not trying to steal his thunder or anything, just tryin to get that facts out.

This Sound correct?

Heres the site..

[MRX]

Aluminum radiator might help to keep the engine a bit cooler also...i think thats what i tried to post b4

[gloryaccordy]

Re: Back to that whole BHP thing..I think...

Originally posted by 91AccordSE
Lookin around online, I found a site, that does say that BHP is/can be measured at the flywheel, thereby giving you the horsepower at the flywheel. However, if I (and this site) am not incorrect, then BHP can aslo be measured on a chassis dynomometer (power delivered to the wheels). So I think, that earlier definition given, was only 50% correct. Not trying to steal his thunder or anything, just tryin to get that facts out.

This Sound correct?

Heres the site..

I just want to know more about the motor itself, and how the measurement was made, as there's about a 30HP difference between crank and wheel HP for ~160hp at either end. If he's making 190 crank HP I'd like to know the secret engine he has.

[91AccordSE]

Earlier, in that post about "BHP" and such...it says BHP is still used in the UK as a standard measurement. ElectrO did say that he has the Euro Spec motor. SO im thinkin that the horsepower that he has displayed there, is at the crank, with just the motor, the bare necesssities. Maybe im wrong. Electro, you there?