So i have a stock B18B1 and i'm already bored with it but in the future i plan on building an all-motor b-series (although a k-series setup would be cheaper and more powerful in the long run i will never make enough power in this vehicle to find useful since it it a front-wheel drive layout) so i plan on using a 2000 USDM B18C1 block and 2000 JDM B18C5 head with P73-00(JDM B18C5) pistons and B18B1 rods and crank with a 2-layer headgasket. I was using C-speedracing.com's compression calculator and it calculated a 11.7:1 compression ratio. I was also reading on team-integra.net and found this "So you can make more power by improving burn efficiency via increasing the static CR up to a point. For street engines, the maximum static CR on pump gas is around 12.5:1 CR if you know how to tune. If you do not, the maximum is around 11.5:1 CR. For a race engine, the point at which cranking pressure causes negative work or parasitic friction and affects power output is around 14:1 CR. Alcohol-fueled race engines can afford to run 15-17:1 CR, since the alcohol cools the chamber and lowers both the cylinder temperature and detonation risk. Methanol race engines run much richer air-fuel ratios (around 5-6:1) than gasoline engines, as well." that being said i would believe the static compression ratio i want to run is safe and reliable as long as i treat it well as far as fluids and don't run it hard all the time and break it in correctly. Can i run 93 pump gas on this setup with a proper tune since the compression ratio is lower than 12.5:1 or do i need another type of fuel additive? Any input will be appreciated and rep will be given.

 

You will be good at 11.7:1 with a good tune. That is a very good streetable compression ratio.

 

Would you change anything about the setup so far KJ?

 

why a one layer head gasket? reliability would be a concern with that.

 

Higher compression but you are right it does sacrifice reliability. Come to think of it an aftermarket 2-layer headgasket from either Spoon Sports or Mugen would benefit more as far as reliability.

 

The 0.2 points of compression is not worth the sacrifice of a 3 layer mls gasket. I would use b16a pistons instead of type R's. By my own compression calcs done by pen and paper the b16a pistons give about 11.5:1 compression and they fit ls rods with no machining necessary. With itr pistons the rods need to be milled on the small end or the pistons need to be fly cut.

 

So you would use an OEM 3-layer headgasket? Do the B16B pictons fit on Ls rods also? Wouldn't they render a stronger, more reliable motor?

 

he did a 3 layer on my motor and the car made great power then on its smaller build. still have a 3 layer setep oem. the car hauls ass! think they would "dont quote me" but they would give you too high of a comp ratio to be totally streetable. no you would have to de-tune to run pump gas and escape detonation.

did a search and it looks like the ctr pistons would fit on ls rods but only the b18a rods. the b18b rods is not a direct fit. also it is recomended to shave the piston and not the rod to make them fit together.

 

listen to kj. dont run b16b pistons. i really wouldnt run anything over 11.5:1 in fl due to the summers heat. it can be a neussance for normal driving with big compression. 3 layer gaskets are great. b16 pistons (either jdm or us) are perfect for ls rods.

 

having gone 12.5:1 on a street motor, I can say my new max comp ratio for 93 octane is 11.8:1 - at least at this elevation and with our summer weather. You just don't have the wiggle room you need for tuning.

Also, as I believe that there is only one reason raising compression to any significant degree should be done, and that is to support more aggressive cams.

My point is, come at it from the other direction. Big cams make power but bleed off compression, so what do you need to maximize power? Answer is more compression. Just raising compression for the sake of compression never made much sense to me. It's part of a strategy to support other elements of the build, imo.

I would decide on cams and then match compression to fit them.