Civic EG

ok so i trying to figure something out. i read online that the itr, ctr, and b16a share the same heads and that they are stamped pr3 can anyone confirm this. i know the difference from the itr, ctr from the b16a is a hand port job from honda.

now the other problem is trying to figure out the combustion chamber ratio on all 3 motors. if they all have the same cylinderhead then why is it that the ctr has a lower compression then the itr.

for an example
ctr pistons in a b16a will yeild 11.1 ish. but ctr piston in a b16b has a 10.8
it should be the same if i put ctr pistons in my b16a if they got the same heads also usdm itr pistons in a b16a will yeild 10.4 ish but they got a lower dome then the p30 b16a pistons.

the usdm b16a pr3 has a compression of 10.2
jdm b16a p30 has 10.4
usdm itr p73-a0 has 10.6
jdm itr p73-00 has 11.1
ctr pct has 10.8

usdm 99-00 or jdm 88-91 b16a piston
jdm b16a piston
usdm itr piston
jdm itr piston
ctr piston

yes, they all have the same head. each one has a completely different piston though. the reason the ctr doest share the same cr as a b16a is because it has the taller deck hieght of the itr/gsr block. for the compression ratio for each piston in a different motor you need to take into account the compression hieght of the piston. which is where the piston pin is on the piston. each one is different. the head alone doesnt define the cr in a motor. you have to factor in the bore, rod length, compression hieght and hg thickness along with the cc of the piston and head.

ctr pistons in a b16a equals a 11.9:1 not 11.1:1

ctr in a itr equals 12.73:1

wow ok that would explain alot.
so would it be worth putting ctr pistons in a b16a dd motor

blk92hb wrote:wow ok that would explain alot.
so would it be worth putting ctr pistons in a b16a dd motor

also wondering this.. i have them in my b16a2 i just bought and im wondering if its reliable,,

blk92hb wrote:wow ok that would explain alot.
so would it be worth putting ctr pistons in a b16a dd motor

You will have to get Retuned with a Very good tune, and run 92-93 Octane. Running at the Comp on a Hot Day with out a good tune or a "Base Map" can ruin your engine.

With gas prices in the US expcted to reach over $4.00 a Gallon by Summer for 87 Octane, I would say not. Not for a Daily Driver anyways. If it was a Track car then it wouldn't be a bad idea. I Personally wouldn't do it for a Daily Driver.

chrono404 wrote:

blk92hb wrote:wow ok that would explain alot.
so would it be worth putting ctr pistons in a b16a dd motor

You will have to get Retuned with a Very good tune, and run 92-93 Octane. Running at the Comp on a Hot Day with out a good tune or a "Base Map" can ruin your engine.

With gas prices in the US expcted to reach over $4.00 a Gallon by Summer for 87 Octane, I would say not. Not for a Daily Driver anyways. If it was a Track car then it wouldn't be a bad idea. I Personally wouldn't do it for a Daily Driver.

What sort of tune would we be looking at.

Evobeast wrote:

chrono404 wrote:

blk92hb wrote:wow ok that would explain alot.
so would it be worth putting ctr pistons in a b16a dd motor

You will have to get Retuned with a Very good tune, and run 92-93 Octane. Running at the Comp on a Hot Day with out a good tune or a "Base Map" can ruin your engine.

With gas prices in the US expcted to reach over $4.00 a Gallon by Summer for 87 Octane, I would say not. Not for a Daily Driver anyways. If it was a Track car then it wouldn't be a bad idea. I Personally wouldn't do it for a Daily Driver.

What sort of tune would we be looking at.

Take your car to a Reputable Tuning shop Locally. You will want them to Dyno Tune your car for you. It wont be cheap for a good tuner, However it will be much cheaper then having to rebuild your engine.

I would never recommend anyone to run on a StreetTune. Its doable however wont be near as good or more important reliable as a Dyno Tune. Dont Trust anyone who can Chip your ecu with out doing an actual tune. Also never buy a Chip off ebay.

What sort of tune would we be looking at.[/quote]

Take your car to a Reputable Tuning shop Locally. You will want them to Dyno Tune your car for you. It wont be cheap for a good tuner, However it will be much cheaper then having to rebuild your engine.

I would never recommend anyone to run on a StreetTune. Its doable however wont be near as good or more important reliable as a Dyno Tune. Dont Trust anyone who can Chip your ecu with out doing an actual tune. Also never buy a Chip off ebay.[/quote]


i just purchased my car for winter (so i don't have to drive my jdm evo). here in Canada it get pretty damn cold, and they use tons of salt.

anyways, i was told that the ecu was "chipped". motor is a B16a2 with the ctr pistons. what should i run for an ecu? or will a dyno tuner write me a new chip?

ok thanks chrono