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View Full Version : Are High Compression pistons worth it?


harrytuckerr
13-01-2013, 05:09 PM
I am about to get my head fully upgraded in my DC2 with new cams, valve springs, retainers etc, and I was wondering would it be worth me getting the bottom done too with new bearings, high compression pistons, rods etc. Would I see much power benefit for the price I would be paying for doing it?
DreadAngel
13-01-2013, 05:39 PM
What spec cams? Cause that along with what engine and compression will let us very roughly guesstimate what it could produce...
stndrd
13-01-2013, 05:48 PM
It all depends on what you want from the car. The higher the compression ratio, the larger the camshaft profile you need to run to utilise the compression, which in turn makes the car less and less daily drivable.

Yes it is possible to get a good set up happening with a nice 11-11.5:1 static compression, but much higher and it will become a weekend only or track only engine
harrytuckerr
13-01-2013, 05:52 PM
thanks for the response guys. I'm putting in Skunk2 tuner series stage 3 cams. I was looking at around 11.5 comp ratio pistons. how would this be?
harrytuckerr
13-01-2013, 05:54 PM
http://www.ebay.com.au/itm/CP-Forged-Pistons-Eagle-Rods-Type-R-B18C5-11-5-1-81-5mm-/290580367331?pt=Motors_Car_Truck_Parts_Accessories&hash=item43a7f087e3&_uhb=1#ht_5149wt_1037

Looking at these pistons and rods to be exact
lil_foy
13-01-2013, 06:14 PM
They pistons will yeild almost 12:1 compression with a b18c2 head.
harrytuckerr
13-01-2013, 06:40 PM
They pistons will yeild almost 12:1 compression with a b18c2 head.

Why's that?
lil_foy
13-01-2013, 06:44 PM
Why's that?

B16/b18C Type-R heads have a larger combustion chamber then the b18c2 heads, because of this you will have approximately 0.2:1 more compression. Speak to your engine builder and tuner before you go ordering any parts imo.
kraiye
13-01-2013, 08:54 PM
as above, speak to your builder/tuner before purchasing. but with those cams... definitely go high comp pistons!
i have pro1's in my b16a with b16b ctr pistons and its a screamer :)
a little frustrating if you get stuck in traffic a lot though
harrytuckerr
13-01-2013, 09:09 PM
B16/b18C Type-R heads have a larger combustion chamber then the b18c2 heads, because of this you will have approximately 0.2:1 more compression. Speak to your engine builder and tuner before you go ordering any parts imo.


thanks heaps, I'll give my builder a ring tomorrow.
harrytuckerr
13-01-2013, 09:10 PM
as above, speak to your builder/tuner before purchasing. but with those cams... definitely go high comp pistons!
i have pro1's in my b16a with b16b ctr pistons and its a screamer :)
a little frustrating if you get stuck in traffic a lot though

will do! so did the pistons make a big difference? have any ball park figures in gains?
kraiye
13-01-2013, 09:26 PM
sorry I don't have any figures before the build to compare. final figure was 125kw atw and there's not much to it under 5000rpm. I've recently be re-reading info about cams etc and everything i've found so far says that to get the most out of big cams, go for higher comp pistons.
lil_foy
13-01-2013, 09:58 PM
thanks heaps, I'll give my builder a ring tomorrow.

No worries, just remember the difference in the heads and you'll for the most part be consistant with ordering. If you're looking to order parts look at Real Street Performance, I just ordered all my internals and they were by far the cheapest option out there. Goodluck! keep us posted with what you decide