got a b18c motor too high on compression done everything i can plugs,higher ocatane, dyno tuned, etc...now im planning to change to a thicker gasket. was wondering if i swap my head(stock GSR milled i think) to maybe a ITR or b16 will that afftec the compression??

 

yes... it will lower the CR alot...

 

will a STOCK ITR vs. a STOCK GSR give me a lower C/R?
thanks

 

yes

 

what do you have done and what are you tuning it with.. unless you are running some crazy **** you should be able to tune out the detonation

 

my curent c/r is 12.9:1 for some reason my motor pings @4k+ rpm. my buddy has a very similar setup but his is fine. i have used colder plugs and took it for a dyno tune. my tuner even said this is weird. he removed so much timing its close to nothing. and added a load of fuel. any suggestions will help!!
thanks~

 

im just curious... whats your setup???

 

Nearly 13:1 compression? What octane fuel are you using?

 

yeah, what's your setup? static compression is not nearly as important as dynamic, and how it is achieved. the shape or the piston domes and that of the combustion chamber play a big part, as do the cam profiles, manifolding, and tuning.

ahh- found it:

> >b18c1
> >polished crank
> >CTR over size
> >over size bored
> >honed
> >clean
> >dected
> >JDM rods
> >ITR valuetrain set
> >dected the head
> >Dc 4-1 header
> >ALL new gaskets -pvc-O rings-all new tunning parts.
> >oil pump- water pump
and running on p28 hondata s200.

bigger cams with more overlap/duration will bleed off compression. JDM DC 4-1 is decent (the larger collector helps), but you might want to ensure that at the flange it is slightly larger than the exhaust ports, to help prevent reversion, which can cause knock. on intake side (which intake mani do you have?), make it so that the intake charge doesn't have to climb a step into the combustion chamber where the runners meet the ports on the head. also, if you're using the Skunk2 intake manifold, the TB-to-runner (especially #4) transition can use a lot of smoothing, so that the air doesn't have to make such an abrupt turn around such sharp corners- i.e. grind the **** out of it; enlarge the hole into the plenum at the tb interface, as well as that from the plenum into the runner. make sure that not only do you have enough fuel, but that your injectors aren't too taxed, and that your fuel pump is sufficient. smooth the domes of your pistons and combustion chambers, so there are no sharp edges. be sure that your water and oil temps and pressures are good. using the b16 head casting will lower compression, but might not work to eliminate pinging, since the quality of the combustion with the flat b18c quench pads might be better. ideally, you want as much biasing of the intake charge to the exhaust side as possible to help ignition/combustion, and the least amount of surface area in the combustion chamber necessary for quality flow and burn. i'd swap the pistons for pr3 or ITR slugs and keep the gsr head, but most will likely say otherwise, and say to use a thicker headgasket. (ask omniman. he made more power with smaller domes, but the same compression (decking/milling).)


Modified by slofu at 11:18 PM 8/19/2003

 

hey slofu thanks for the reply...how much do pr3 pistons go for??
how much c/r do you think i can lower (rough estimate) if i use a thicker head gasket and a b16 head ?
im kinda short on funds
thanks

 

did you sand down yr piston tops.. to remove all the sharp edges??

 

yup did all that

 

what injectors u running?? if stock that might be the problem.. Try upgrading to RC 310. on my b20, it had RC 310.. and detonated slightly.. but only when i put a lot of load on it.. ex 5th gear going 40mph and going up a hill. On those kind of things, i would have to downshift to put less load on my engine..

 

you can prolly get pistons on ebay for close to the cost of a quality headgasket. if you use your rings in the same cyls/positions, you can possibly safely re-use them on the new pistons, and not need a hone.

 

i have over sized CTR pistons right now, what would a good swap be in my situation?

 

i'd say get the same sized USDM ITR (P73-A0) pistons; depending on how much the head and deck were shaved, you'll still be >11:1. (i used the C-Speed Racing Compression Calculator, with the deck-height for the b16a, since no stock b18 block i've measured had .030" piston-to-deck height, and yours is decked anyway.)

if you want more compression later, another possible aid to raise it while reducing the chance of detonation is to use flat-faced valves; they reduce the combustion chamber surface area, and don't allow for as much 'pocketing' for air to separate from the gasoline to make it harder to burn when the pistons compress the intake charge. they provide better quench/'squish' for a more complete burn, and better efficiency.

all of the recent negative press on Supertech/Rev/Endyn/Skunk2 valves might deter many, though i just sent ***** at Supertech my older, unused Supertech (flat-faced) valves for new, improved models with harder tips. he was very friendly and accomodating; recommended. also, be sure that if you use these with titanium retainers, your keepers are the newer black nitride-coated stockers (if you're using stock keepers).

for more valvetrain upgrades later, get Rocket's ef-1 valvesprings and titanium retainers, and cams with roughly the same profiles as Jun 3's. as long as you have the proper manifolding and have it tuned with Hondata, you can make good, reliable power with this setup.