I'm currently in the process of acquiring parts for a new build. This car is NOT going to be a daily driver, and is NOT going to see a lot of driving time- it's simply going to be a toy for me to have for nice days.

My plan:

B18C5 bottom end
- 84mm
- 95mm eagle stroker crank
- LS eagle rods
- not sure what pistons yet. 9:1 probably

B16A2 Head
- Skunk2 pro series springs/retainers
- Skunk2 forged valves (std comp)
- P+P (unknown specs as of yet)

My question is, how do I effectively manage compression ratio with the addition of the longer stroke/different from OEM head? I'm unsure of the height difference (if any) by using a B16A head on the C5 block. I also have to take into consideration the 95mm crank of course.

Hopefully someone has a similar setup and can help out.

Thanks!

 

the b16a head is the same pr3 casting as the type r head that comes on b18c5...for a daily go with a 89mm crank from an ls its way stronger than the crappy eagle cranks...theres a few around here that have broken..i have yet to see an oem crank break...go 10:1 compression to help build boost faster....even the fastest outlaw guys running 8s are using oem b18b cranks....and the 95mm crank will limit the rpm u are going to be able to spin...and if u have ever driven a turbo honda you will know they love to go to 9k ...and more

 

agree on 10:1 plus for compression. not sure why so many people on this forum are stuck wanting 8:5-1 and 9:1?

one of the ongoing projects at english racing is even 11:1 and running 9s

http://englishracing.net/media/rides...d-96144-fp3065

 

If its a pump gas car only it sbetter to run lower compression for higher HP numbers but if its not a strickly pump gas car then higher compression is fine, just be sure to have a good set of slugs that can handle turbo and higher compression, i've whitnessed first hand an 11 ish compression weiso come apart with boost

 

totally

i was just wondering why high hp was needed on the street. you could run less boost on a 11:1 engine on the street and have a snappy little car, then on 110 octane or even e85 use more pressure when racing

 

Agreed, I dont know why so many peopel want HUGE pump gas numbers. Honestly im at 400whp and its really about all thats useable on the street even with boost by gear, if i turn the boost up and higher and try to tune it just blows the tires off so it is what it is lol

 

The reason most weekend drivers build 9.5 or 9.0 compression motors instead of 10 or 11 is that compression is permanent. You can't change it with a dial on a boost controller.

You can change boost to fit the octane, conditions, or scenario you see fit.

Also, higher compression motors with big boost, like those 9 second cars some people mentioned, will probably have a much shorter bearing life. A car running 9.0 or 9.5 compression on up to 20 to 25psi of boost can see "infinite" or mileage in excess of 100k on a bearing set/build. A track car running 11:1 compression and solid boost will probably need rebuild every 25k miles or so.

 

Very good useful information, I learned something new here today.