Does anyone know or done this before?, im trying to lower the comp. on my motor with a b16 head but the manifold on my jrsc is for the gsr, can i drill holes to line up to the b16 head?, my setup is a high comp.(11:4) gsr motor jrsc'd on 5psi, motor made 235hp but im gonna change the sk2 pro1 cams for itr/gsr combo as well as increase boost to 10psi and maybe a diffrent header. any help is appreciated.

 

i would try it with the pro1 cams on 10psi first befor switching them ,

and also if the b16 b18a/b heads are the same stud pattering then u can do it just look for the thread that shows the guy puttin the gsr intake mani on a ls , buy the gasket first line up the holes then drill out the ones that dont line up and make sure it isnt interfering with anything major on jrsc

 

The intake ports will be off. The GSR ports are higher in the casting than the B16/ITR.

 

There is a few other ways to drop the c/r .5 to 1.0 if u want to take the time to do it.

 

the only way i know is either swap out the head and or swap the flat valves to oem or change pistons to lower the comp.
So no ne has ever done this? the ports do look a little of when i compare a b16 gasket to my spare oem gsr i.m but it looks like i have enough room on the jackson manifold to drill the correct holes but will the ports be extreamly off or could i have it slightly ported to line up??

the only other thing i noticed was the coolant passage is higher on the gsr manifold id have to drill out another hole and fit a fitting for the hose and plug the origanal passage seams like alot of work or no?

 

bump

 

U can also take a little off of your combustion chambers on the head. Remove any sharp edges and polish it slightly, that can get you down .75 c/r.

 

there was a guy in the all motor forum that put a stock gsr intake mani on a ls head and netted some good gains try to find that guy or thread where he did it and it should give u a pretty good run down on what u have to do .. and if u want to lower comp one easy way would be a thicker head gasket .. not the best way to do it it but its always efective

another way to drop the compresion is if u have adjustable cam gears u can set it so they bleed off a lil bit of compresion

 

Thanks, anyone else??

 

leave the compression where is at run a colder plug

 

With the extra overlap, you'll be getting more intake air pushed into the exhaust, which reduces the overall air in the cylinder (some people call it dynamic compression) - and thus lowers the knock threshold a tad. Speaking of which, the quench pads on the gsr head increases the knock threshold over the B16, so the reduced compression may be a wash. A 0.5 point reduction is barely enough to make a difference. I'll just assume you have an LHT-intercooled JRSC for 10psi, since 10psi on a stock JRSC will not give pretty IAT's.

Call Cometic and see about a thick HG, they do tons of them for other cars. Otherwise pull your pistons, mill the dome down, and enjoy your lowered compression. If you do it right, you do not need to replace any bearings or rings.

 

Thanks, Yes im aware that the sk2 pro1 cams are keeping the dynamic compression down, the cams are acually helping but also killing power,
comp. is at 11:4, head has high comp. valves also, if i use a b16 head it should be around 10:8 that should be safe to run 9-10psi, i dont have a lht yet soon though lol. im running the ngk plugs from moss motors, i'll look into a thick gasket but im not sure if there made for b series motors. im assuming i might as well ditch the sk2 cams if i ever swap a b16 head but maybe ill keep em then retune after to compare it to the itr/gsr cam combo i will go with.

 

There has to be someone thats done this.

 

bump

 

bump for help

 

why not just get a b16 jrsc intake ??

 

You can run a cometic 2mm head gasket and it will lower your compression to 10.5 and you can boost to 10 easy.You will just have to readjust the timing belt because it will get alot tighter with the thicker head gasket bro.Good luck.

 

Im kinda stuck i have no idea what bore my block is lol its a gasr block with usdm itr pistons well i know i ordered a oem gasket kit when i assembled my motor so im thinking its still 81.mm so i guess i need the cometic 81.mm bore, 2mm head gasket, so if my current comp. is 11.4 with this cometic gasket it will come down to 10.5?? how did you figure that?

 

Most Honda OEM headgaskets are .5mm overbore from the factory to allow 1 headgasket (only 1 part number) to cover all Honda overbore pistons (.25mm over and .5mm over)

 

Thanks jaker!!, has anyone heard anything negative about the cometic head gaskets? a friend of mine says he knew someone who got one on his turb setup and it kept leaking although thats just one story, im thinking it would be the easiest way lower my compression although not sure how much it will lower it, comp. is at 11:4..

 

ttt