eg6hatch

I was wondering if any one can answer this question, i have a b18c gsr, i am putting itr cams in it, and i have the head off, i just bought ctr valve spring and retainers, my question is, i can see that half of the gsr valve springs already are dual valve springs, is there any point to put the ctr valve springs in, and if there is, how much will it help me on rpm limits, and valve floating. Thanks alot.

TallAssFilipino

The B18C SiR-G engine? Anyway, do you know if that already comes stock with the dual valve springs?

ej0513

i believe that GSR intake springs are equivilant to ITR/CTR exhaust. so you really only need the intake springs and retainers and you can just switch the GSR intakes to the exhaust side.

eg6hatch

Yeah, i knew one of the sides had dual, jsut not for sure, and i didnt know if the ctr's were as strong, so if it were you, and you had the head off, would you do anything to the vlave springs or not, if i dont need to , it will save some time.

eg6hatch

Also with the ctr's what would i be able to rev to(obviously with the appropriate ecu program)

New Image

As far as the rpm's that the <FONT COLOR="red">Type-R</FONT> valve springs can handle i don't know. i wouldn't go past 8,400 rpm. i do know that the GS-R's dual intake valve springs are stiffer than the <FONT COLOR="red">Type-R's</FONT> only because the <FONT COLOR="red">Type-R</FONT> valves are lighter.<FONT COLOR="blue"> (So is there any point in putting in the CTR dual intake valve springs?...well, not unless you are replacing the valves in my opinion) </FONT> Using the <FONT COLOR="red">Type-R</FONT> valves may be something to consider though. They are the same diameter as the GS-R valves only they are lighter and have improved contour for better flow.

You should install the <FONT COLOR="red">Type-R</FONT> intake valve springs on the exhaust side of the head because the GS-R only has dual springs on the intake valve. (The dual exhaust valve springs are important to help handle the increased velocity that the much higher lift <FONT COLOR="red">Type-R</FONT> exhaust cam has on the valvetrain...1.1mm more lift than GS-R). The GS-R dual intake valve springs can be used with the <FONT COLOR="red">Type-R</FONT> cams because of their stiffness which i already touched on.

Expect a gain of 8-9 top end hp- more when timing is optimized. Just using the <FONT COLOR="red">Type-R</FONT> intake camshaft alone (cost saving measure cause you can avoid buying exhaust valve springs) has been proven to gain 6-7hp.

Cam Specs: (USDM) (duration and overlap in degrees)
GS-R: intake cam- 230 duration, 10.7mm lift
exhaust cam- 227 duration, 9.4mm lift
17 overlap<FONT COLOR="red">
Type-R</FONT>: intake cam- 240 duration, 11.5 lift
exhaust cam-235 duration, 10.5mm lift
25 overlap





Modified by 94JDMEG at 1:53 AM 10/9/2004

AsianMullet

good info to know....i have my old stock valve springs all thrown in a box at home. how did you identify the difference in the intake and exhaust springs anyways? i should've separated them more neatly.

eg6hatch

Yeah i know, i bought these ctr's and the dude jsut put them in a box two, but i do wish he would of marked them, how do you tell intake and exhaust?