GTB (1997) & V3 sti cams.......are they the same?

[wildturkey]

building up a block......have some GTB heads with factory cams. Have heard V3 cams are more agressive. Are V3 cams considered an upgrade over factory (97) GTB cams? any advice

[Guest boostin]

Yup, V3 & 4 cams are the most aggressive factory cams.

[ReubenH]

There's actually a debate over this, weather they are the same or different. Some have measured and concluded they are the same, some say the GTB ones are different. I've even heard things like "the GTB ones are better for the higher revs", cause of the TT's making power later in the rev range, but you can NEVER truly believe what you hear on the internets! (<-- that's the disclaimer btw)

I find it hard to believe they would be the same, i just don't know which are better in that case.

I could probably safely say.... it's NOT worth the trouble! EJ20R's are damn nice engines in the first place.

[BC5RA]

As far as i know V3 STI cams feature higher RPM, and the V4 STI cams fill out the midrange.

[Guest]

I have seen good results from both v3 and v4 sti cams with different setups well out weighing the difference in the cams. I wouldn't bother changing gtb cams out for v3 sti cams, would be i'll spent money.

[smokn4]

 boostin said:

Yup, V3 & 4 cams are the most aggressive factory cams.

is it just the v3/4 sti cams that are more agressive on these versions or both the wrx and sti

[Guest]

Has anyone had good results with gtb heads and cams ?

[Koom]

 Qwerty said:

Has anyone had good results with gtb heads and cams ?

Mine was making about 195kw atw (15psi) with GTB heads and cams. Will see soon how much further I can push them with the big turbo now strapped on.

Planning on putting some V3 STI RA heads on eventually (with some real race cams tho )

Back when I first built my engine, my flatmate had a near identical setup but with V3 STI heads/cams and the differences in dyno plots was pretty much due to the turbo's as he had a VF23 (or 24?) and I had a TD05. We were within 5kw of each other on the same dyno a few days apart.

[Optical]

i talked to someone yesterday who had actually measured them...

gtb shares the exhaust cam with v3 sti. gtb intake cam has the same duration but slightly less lift.

v4sti cam has the same duration as a v3, but marginally more lift.

so v4 sti > v3 sti > gtb

v5+ cams got a bit soft in comparison, but the port shape is better

[Guest]

hmmm must be true then !

go the v4

[BC5RA]

I also spoke to someone who did some basic measurements before sending a bunch off for profiling.

V4 STI 9.1mm lift vs GTB 8.6mm lift

Optical; seems we are referring to the same person (just popped over to the other site)

[ReubenH]

I was informed the other day that BG5B GTB cams = V3 STi cams, and BG5C = V4 STi. I did some sleuthing on the part numbers

Numbers are for the Right head, intake then exhaust. then Left head, intake then exhaust

V3 STi

13031 13032AA240 1996/0401 - 1997/0731 EJ20K

13034 13035AA240 1996/0401 - 1997/0731 EJ20K

13037 13038AA240 1996/0401 - 1997/0731 EJ20K

13052 13053AA240 1996/0401 - 1997/0731 EJ20K

BG5B GTB

13031 13032AA240 1995/1201 - 1997/0731 EJ20R

13034 13035AA240 1995/1201 - 1997/0731 EJ20R

13037 13038AA240 1995/1201 - 1997/0731 EJ20R

13052 13053AA240 1995/1201 - 1997/0731 EJ20R

V4 STI

??

??

??

??

BG5C GTB

13031 13032AA390 1997/0601 - 1998/1130 EJ20R

13034 13035AA390 1997/0601 - 1998/1130 EJ20R

13037 13038AA390 1997/0601 - 1998/1130 EJ20R

13052 13053AA390 1997/0601 - 1998/1130 EJ20R

Numbers matched up... sorta. You can see there that the 96-97 sti has the same cams as the 95-97 GTB (BG5B). But i can't find the V4 STi cams. It just gives me the V3 part numbers...

Make of this what you will gentlemen. Would be nice to have some of the parts guy's chime in...

[Guest]

 ReubenH said:

Make of this what you will gentlemen. Would be nice to have some of the parts guy's chime in...

K!

From a parts point of view, this is for replacement parts. Keep in mind back in the mid 90's WRX STi's were still hand assembled, so you can't rule out that the original parts weren't modified by Subaru Technica International when they were assembled in the plant at Ota-Gunma.

[Guest]

set of STi V4 heads (complete) sold On TM for $300 couple of days ago

http://www.trademe.co.nz/Browse/Listing.aspx?id=241589766

[Guest]

V3/4 Heads are the same if you look at them with your eye balls but there is variation and its in the cam lobes not realy noticeable

valve lift and duration is where it is

Got v4 head and cam and seen plenty of v3's but got plans for it

got cam part numbers some where for Dtype STi, R/RA-STi Dtype STi, R/RA-STiR/RA-STi Etype 22b STi Btype STi Ctype STi, RA-SCTi F, Gtype STi,

what the hell was the Question?

[readosnr]

ok to get this completely accurate lets look at this as 4 engine types

EJ20R GTB Manual engine (206kw engine)

the BG5-B engine was different to the BG5-C engine (both were the same as their BD5 sedan counterparts)

EJ20K STI

Ver 3 STi engine was different to Ver 4 STi engine

CAMSHAFTS (not including wrx, wrxra, ej20h twin turbo auto or manual)

V3 EJ20k and BG5-B EJ20R were the same

V4 EJ20k and BG5-C EJ20R were the same

Cyl Heads

Ver 3 and ver 4 had the same bare heads (same as wrx, wrx ra, 22b & auto models of same year)

EJ20R heads were the same between the BG5-B and BG5-C