B18C + B16a Pistons

[egb18c]

ok,lemme start by saying that m gonna overhaul my car.because the piston ring kong edy.

so ive done some google here n there,found that B18C + B16a Pistons will produce much higher compression ratio.
11.6:1 i guess.

ok,now this is the problem,the compression ratio is too high.How to make it less compress?
can i just fit in thicker head gasket?like 0.5/0.45 mm?(is it correct?)
this will produce around 11.1:1

will this work?bcos my budget is really low.n changing the pistons is all i can do right now.

btw,its b18c GSR.

 

[shiroitenshi]

Err how does B16A equate higher comp? You sure you don't mean B16B pistons?

Compression ratio can be changed by

a) thicker gasket (dual layer) b) deeper valve pockets. c) for dynamic CR, retarding intake cam (clearance must be checked)

One more thing though.. depending on your head used.. your CR will vary, so check.

 

[J101]

b16a pistons inside b18c should be better than CTRs...use back the original head gasket.

 

[shiroitenshi]

b16a pistons inside b18c should be better than CTRs...use back the original head gasket.

really, I thought the B16B pistons have higher dome volume?

 

[udengfahlawi]

if comparing the two, B16B piston in B18C block will give higher CR than B16A piston in B18C....if i not mistaken the B16B in B18C will gives about 12.0:1....i think J101 is referring to B16B in B16B block i.e. standard CTR, which CR about 11.4:1.....

 

[I3en_I3en]

Honda, Acura Tech Website, tutorials, tuning and HOW-TO's. Drag racing, street racing, road racing - C-speedracing.com

 

[J101]

better in the sense of safer. lower than CTRs. :)

really, I thought the B16B pistons have higher dome volume?

 

[egb18c]

heik.
if i put b16b in b18c GSR ya,it should make bout 11.9/12.0 CR,so it will b knocking n so on.
so why should i put expensive piston while i can put cheaper piston in my engine ryte.this is because all i want is about 11.1/11.0 CR.just like the ITR.more than that i afraid the engine will b knocking.
am i right here?

btw,how bout the clearance?the piston will not touch the head?

n how bout the thickness of the head gasket to achieve CR of 11.1?

 

[shiroitenshi]

heik.
if i put b16b in b18c GSR ya,it should make bout 11.9/12.0 CR,so it will b knocking n so on.
so why should i put expensive piston while i can put cheaper piston in my engine ryte.this is because all i want is about 11.1/11.0 CR.just like the ITR.more than that i afraid the engine will b knocking.
am i right here?

btw,how bout the clearance?the piston will not touch the head?

n how bout the thickness of the head gasket to achieve CR of 11.1?

piston touching the head, that one dependent on wrist pin location, if it's the valves, you can mill the valve reliefs. miling the valve reliefs also decrease compression.

I'm wondering if you are using B18C GSR head, or the normal B16A head.

How are you measuring compression? with a burette or ?

 

[J101]

- the main reason why u spend more on pistons due to the fact u wanna last longer and able to withstand the heat abuse.

- if you want to get a ITR setup, get ITR pistons then. but to get an ITR performance, there are more things involve. i suggest you get a ITR longblock package with the ECU.

- knocking or not knocking will be based on your tuning and the choice of your mapping style to suit the weather condition in malaysia besides thinking of hardware.

so why should i put expensive piston while i can put cheaper piston in my engine ryte.this is because all i want is about 11.1/11.0 CR.just like the ITR.more than that i afraid the engine will b knocking.
am i right here?

 

[egb18c]

piston touching the head, that one dependent on wrist pin location, if it's the valves, you can mill the valve reliefs. miling the valve reliefs also decrease compression.

I'm wondering if you are using B18C GSR head, or the normal B16A head.

How are you measuring compression? with a burette or ?

owh.I'm using B18C GSR with stock head. the reason why i want to put b16a pistons bcause i have to overhaul my engine.

i calculate the CR by using
Honda, Acura Tech Website, tutorials, tuning and HOW-TO's. Drag racing, street racing, road racing - C-speedracing.com

but it doesnt says that whether the piston will touch the head or not.

 

[egb18c]

- the main reason why u spend more on pistons due to the fact u wanna last longer and able to withstand the heat abuse.

- if you want to get a ITR setup, get ITR pistons then. but to get an ITR performance, there are more things involve. i suggest you get a ITR longblock package with the ECU.

- knocking or not knocking will be based on your tuning and the choice of your mapping style to suit the weather condition in malaysia besides thinking of hardware.

but my budget is really tight.thats why i only cheap parts to make this mod.

ok,lemme say that my budget is around RM1-1.5k including the overhaul job.
so what can i do more besides installing the pistons?

 

[shiroitenshi]

owh.I'm using B18C GSR with stock head. the reason why i want to put b16a pistons bcause i have to overhaul my engine.

i calculate the CR by using
Honda, Acura Tech Website, tutorials, tuning and HOW-TO's. Drag racing, street racing, road racing - C-speedracing.com

but it doesnt says that whether the piston will touch the head or not.

If using GSR head, the comp will be different, because the combustion chamber volume compared to a B16A head is different.

whether or not the piston touch, you can observe by measuring the height of the piston from the wristpin. (if you have both, just put them both side by side, then put the wrist pin (no need to press them in, just put so that the pistons are level side by side. you can see which one is higher, and may hit the head or not.)

 

[J101]

the pistons and the overhaul..i dont think theres anything much else since the budget is tight.

but my budget is really tight.thats why i only cheap parts to make this mod.

ok,lemme say that my budget is around RM1-1.5k including the overhaul job.
so what can i do more besides installing the pistons?

 

[egb18c]

If using GSR head, the comp will be different, because the combustion chamber volume compared to a B16A head is different.

whether or not the piston touch, you can observe by measuring the height of the piston from the wristpin. (if you have both, just put them both side by side, then put the wrist pin (no need to press them in, just put so that the pistons are level side by side. you can see which one is higher, and may hit the head or not.)

ahha,yupe gsr combustion chamber is smaller than b16a's,dats why the compression ratio is high when put b16a piston in b18c gsr.

bout the piston touch or not the head,i think i'm gonna leave it to the mechanic.i hope they know what are they r doing.

so the b16a piston in b18c gsr seems ok la?jes need opinions.bcos i dont wnat to waste my money that i have(really small wallet)hehe.

 

[egb18c]

the pistons and the overhaul..i dont think theres anything much else since the budget is tight.

owh a friend of mine suggested adjustable cam and adjustable fuel regulator.
price at rm200-300.
which is better?worth a buy?
or wut i need is to buy that VAFC?

 

[J101]

since its a long block from the gsr, the b16a p30 pistons will still be high compression. ITR ones should be safer and better than stock gsr as an upgrade.

u can do the math here using stock OEM 3 piece gasket
Honda, Acura Tech Website, tutorials, tuning and HOW-TO's. Drag racing, street racing, road racing - C-speedracing.com

if u have extra, after running in, get it run on the dyno and see if you need
any fuelling assistance like FPR, piggyback, fuel pump and etc.

 

[shiroitenshi]

For me, dyno not so important for initial base tune. since the stroke doesn't change, the ignition tune isn't that important, because the piston speed is not different that that of the stock engine.

What you might want to do is run it a little rich for safety, either by bumping up fuel via FPR or VAFC.

The adjustable cam gears you can play with to shift the peak torque of the cams. standard B16A cams has a peak of 3K or so for low, 6-7K for high.

Playing with cams timing you can shift that peak torque to 4K, and 7.5-8K. obviously doing this will kill a bit of your low end power.

FPR is really a shortcut way to increase fuelling all over the map, while VAFC allows for specific areas of fuel tune by playing with the RPM points and getting the AFR curve as smooth as possible.

However, with the GSR head, there is that issue about secondary runners. So far, I haven't seen a very powerful GSR setup, and I believe the problem lies with the secondary runners. Hondata has the option to tune this, but heh.. I don't have a GSR engine.

 

[evoX2]

for gsr intake manifold, my mech just removed a hose/cable, the butterfly valve is always open.

 

[DCSone]

ExoX2,

how about ur fuel consumption? mine full tank can go up to 350km onli. ori GS-R engine without butterfly valve same as yours...

egB18c,
same like ur situation now, want to overhaul da engine because the compression is not balance suspect 1-2 of the piston ring got problem.
my planning is to get B16A head + ITR piston.