ok i heard i will lose compression by puting the type r head on to the gsr block im guessing thats becouse of the pistons so the question is should i mill the head to get the better compression or should i get the type r pistons,,,,,if i need to mil it how much should i take off and if i get the pistons which should i get ctr or itr and would i run in to any problems with a tune on s200 or s300.... type r head has jun valveterrain with stock type r cams and gears aem fuel rail and reg with a jg manifold and a 65 mm throttle body with prelude injectors.... my block is stock

 

the reason that the compression will be lower than with a gsr head is because of the combustion chamber volume 42.7 of the gsr head vs. 41.6 on b16 and ITR heads, not the pistons - how could the pistons be the reason that changing heads would net a lower compression when they have not been changed or modified?

 

ok so how do i get the compression back up to were it should be when i swap the head on to the block sry new to the whole head swaping i was taking a guess at the pistons....i know pistons would up the compression and milling the head would to but how do i increase the volume.... wut do u mean but by chamber volume ....

 

Stock compression on a USDM B18C1 is 10:1

B18C1 with ITR head compression is 9.8:1

B18C1 with ITR head and 2 layer head gasket instead of OEM 3 layer is 10:1

If you want more compression than 10:1 find different pistons B16 or ITR will give more.

I have some ITR pistons laying around f/s

Answer your question?

 

Yeah the ITR and CTR pistons will raise your compression, but the CTR will increase ur compression more than the ITR... if you're just wanting the compression same as stock, you should just get the headgasket Scotty Doesnt Know was talking bout.. if you put either of the 2 pistons sets in it will raise your compression to over 11.1:1 I think the CTR's will make it almost 12.1:1 if not a little more..

 

that answers my question ,,,,wut will i be looking at 1/4 mile wise with nitto 450s just a guess will having that head make a noticable diference over the stock gsr?

 

wut do u want for the pistons and wher u located

 

we cant tell your 1/4 times every CAR is different

 

yeah thats wut i though just figured id ask... r itr pistons 81mm bore or r they 81.5...and would ctr pistions be ok to run in this set up with out checking for clearance

 

With a 3 layer gasket GSR block with ITR head and USDM ITR pistons will be 10.6:1

JDM ITR and B16 pistons would be around 11.2:1

 

why are you even switching the head? If it is because it has the parts the you have listed, just use them on your stock head - they will all work with the exception of the intake manifold which you could sell and get one for a gsr head. What will this car/motor be used for - this will help us help you with your parts selection?

 

i guess i could just build the type r casting. but the reason i wanted to just swap the head is becouse i cant have this car down for more then a weekend cuz im in the military so yeah..... y wont the manifold swap to the gsr head....when the stock type r intake manifold with swap over.....car and motor will be used for daily driving

 

The ITR and CTR pistons are 81mm bore, unless you get them bigger.. the manifold won't fit on a GSR because the water port is different.. a stock type r manifold's flange is the same as a B16 manifold.. the type r head is a b16 head that is hand ported and has the bigger cams, springs, etc..

 

GSR pistons are 81mm bore also. The difference in displacement is from the crank not the piston bore so all those different pistons are interchangeable.

The ITR intake manifold will not fit the GSR head

If I were you I would use the ITR head over the GSR it is superior imo. Slightly better flow, better valve train.

Just take one layer out of the gasket if running stock pistons. I PMed you a good compression calculator to play around with to figure out what you want.

 

Just to give you a visual the combustion chamber on the gsr hear is square so thats why the volume is higher as opposed to the stock type r the combustion chamber is rounded and for an example I would use jdm ctr pistons 81mm stock borewith that type r head. that will give you a better than stock combination. A stock 00 type-r motor in a eg with a 2.1 60 foot ran a 13.8 in my hatch car with driver weighed about 2300. Like you were told before evryone is diffrent. I had 5 lug suspension with no traction bar also and my motor was extremly healthy. With a good 60 foot it could have been a 13.6 13.5.

 

all the b series motors have the same bore unless its a b20. SO use some ITR pistons or just do like somone already said and take a layer off the HG to get the CR back to normal.

 

if we are just trying to get the compression higher, I would go with B16A pistons as the compression will be slightly higher than with ITR pistons and would be a decent compliment to a mildly built head provided that the air is coming in and exiting adequately.

 

ya I agree. ANd you can get nippon CTR pistons on ebay pretty cheap. Its like $165 for a set i think.