these are the parts that i have so far-
B20B Bottom End
Ported B16A Head
Toda Valve springs
Toda Spec-C cams
Redline Motorsport Developments Cam Gears
ARP Head Stud Kit
Eagle H-Beam Conrods
Skunk2 IM

the motor was making 168hp at the wheels running toda a's. and ran a 12.6 in a stripped out, old civic. the tuner is guessing around 180hp with the spec c's, i'm hoping it'll stick my integra in the 13's (not forgetting that dyno readouts here are quite different to the states due to the different dyno types). it was basically putting out about 40-50hp more than a stock type-r- in the old trim.

what else should i be looking for while the motor is apart? i've had a few people suggest that i should get myself a set of forged pistons... worthwhile? they add quite a bit to the cost. presently the motor has a 10.2:1 cr. does it really need to be much higher?
I've still got a fornight or so to decide upon pistons...

 

Im not sure of the exact specs of Toda Spec C's. But I am pretty sure I know for a fact that they need more compression then that to take full advantage of them. You may be overcamming your motor if your compression is that low.

Bump up your compression

 

You really need to re-evaluate the plans for your motor...you kinda have it all wrong. Patdemps is correct, you are "overcamming your motor." The overlap on the TODA C is over 50 ABDC (above bottom dead center). This will make your dynamic compression ratio go down because the intake valve will still be partially open as your piston is on its compression stroke. You wont get much power from the cams this way. You are better off using a skunk2 stage 1 cam with 10.2 compression. Also, the TODA C and other high lift/duration cams do not make max power until over 8000RPM. You are using a B20, which has an 89mm stroke. This crankshaft is not really suited for high revving, and even when it is balanced and reinforced its not a good idea. You can always de-stroke the B20B/Z with the B18C crankshaft. You lose a little displacement but its worth it to safely revv to 9500 to get max power out of an aggressive camshaft.

 

the stock bottom end is good for around 9000rpm (provided you can find a block with straight bores- apparently alot of the b20 blocks have problems with inconsistant bores), i know two guys that have been running stock b20 blocks up to that rpm and have so far clocked up 80k km between them. no cracked sleeves.

not to offend because i do appreciate your point of view- but have you actually seen graphs supporting the 'overcamming' theory?
i ask because i've heard many people mention this on the forums, but never seen any tests to confirm it.
my tuner reffered me to some testing he did on a dc2r race car with a stock bottom end with the 11:1 cr or whatever it is, running toda a's, toda b's and toda c's. in a nutshell, a's and b's had identical low end power after tuning with b's having better mid and top range, the c's were tuned to produce more power throughout the entire rev range.

when mine is built and tuned we'll know for sure since i already have the 168hp figure from the same bottom end and head, with toda a spec cams being the only difference.

either way, thanks for the input

 

1. You said you're gonna have 10.2:1 compression, right? With that compression you will still make good top end power, don't get me wrong. However, your low end and mid range will suffer. Search for a link to a dynamic compression ratio calculator and you will see how low your dynamic compression will be with the overlap on Toda C's. The DC2 with 11.1:1 still has mid range power because 11.1:1 is a nice C/R for 91 octane gas and aggressive cams. 10.2=/=11.1

2. Yes. The B20 block/crank is good to 9000 RPM but IMO you need more revvs than that to make use of TODA C's. I've seen dyno plots from cars with JUN III's, which have less lift/duration than TODA C's and they make max power somewhere over 9300 RPM. Your setup seems like it needs TODA B's or Skunk2 stage 2's, and if you want to use the TODA C's, you need at least 11.0+ C/R.

 

a sacrifice in low-mid range is, imo, acceptable as that would probably be made up for by the extra 200cc-odd capacity. on top of that, the power band is as much a product of tuning as the parts, with correctly dialed in cam gears, and correctly tuned hondata, i'm sure i will make good power with the setup.

anyway, as i said earlier, i will have plenty of opportunity to compare a's and c's after the motor is completed and tuned. at the end of the day, if i'm not pleased with the result, i can always swap to stage 1's, 2's, b's or similar.