rb26 cams into rb25

[rb25]

its been discussed before, so lets try to clear it up. can rb26 cams work in an rb25? what would need to be done?

i think they would, it is just a matter of using the rb26 cam gears, solid lifters and disabling the vvt solenoid. would using gt-r cams help make significantly more power down low because you've eliminating the vvt (and the design of the gt-r cams themselves obviously)? would this setup also work with a powerfc and give a better tune without the vvt?

how would you set the cam gears. retard 4 on ex. and adv. 2 on in? also, if using solid lifters does this allow a higher redline, say 7500 - 8000rpm. alot more oil may also be held in the head using solid lifters i am told aswell, is this true?

what do you guys think?

-rb25

[Sydneykid]

its been discussed before, so lets try to clear it up.  

1. can rb26 cams work in an rb25?

2. what would need to be done?

3. is just a matter of using the rb26 cam gears

4. solid lifters

5. disabling the vvt solenoid

6. would using gt-r cams help make significantly more power down low because you've eliminating the vvt (and the design of the gt-r cams themselves obviously)

7. would this setup also work with a powerfc

8. give a better tune without the vvt?

9. how would you set the cam gears. retard 4 on ex. and adv. 2 on in?

10. also, if using solid lifters does this allow a higher redline, say 7500 - 8000rpm.

11. alot more oil may also be held in the head using solid lifters i am told aswell, is this true?

what do you guys think?

-rb25

Suggestions follow...

1. yes

2. remove rb25 cams, put in rb26 cams

3. yes on the inlet, RB25 pulley is OK on the exhaust

4. not necessary

5. yes

6. no, less power down low, that's what VVT is for (plus emmisions of course)

7. yes

8. no

9. that's a good place to start

10. not really, it may allow the engine to stay at higher rpm longer. But the other parts of the engine may suffer as a result.

11. no

Hope that helps

[MJ]

So to do this all you need are the rb26 cams and rb26 intake cam gear (i got a hks ex gear)?

Is it a worthwhile upgrade? and what kind of power can be expected from doing this?

[Sydneykid]

So to do this all you need are the rb26 cams and rb26 intake cam gear (i got a hks ex gear)?

Is it a worthwhile upgrade? and what kind of power can be expected from doing this?

Depends on what else you have done, how good the tuner is and what sort of condition your engine is in. Never actually stuck a set of GTR cams in an RB25DET, but going on the RB20DET improvement from the same upgrade, I would reckon on 20 to 25 rwkw if all the above is good.

[MJ]

Thanks for your reply SK. I have been doing some searching and i havent been able to find anyone that has done this on a rb25 before.....

If a set of GTR cams can be had for $250-$300 and ill be generous and say $400-$500 for a install and tune why havent more people done it if theres a 20-25kw increase to be had? It seems like a good kw to $$ upgrade to me.

id be interested to hear anyones results

Cheers

Matt

[nv033]

will the rb25 cam gear fit onto the rb26 exhaust camshaft?

i actually had the rb26 camshaft in the inlet by mistake with rb25 cam gear....is this why it wouldnt idle? or is it because the vvt was still hooked up? what are the duration and lift differences between the two? cheers!

[Jimbo2000]

Thanks for your reply SK. I have been doing some searching and i havent been able to find anyone that has done this on a rb25 before.....

If a set of GTR cams can be had for $250-$300 and ill be generous and say $400-$500 for a install and tune why havent more people done it if theres a 20-25kw increase to be had? It seems like a good kw to $$ upgrade to me.

id be interested to hear anyones results

Cheers

Matt

[Jimbo2000]

bunyip

[Sciby]

Call me weird, but if someone was willing to find a cheap set of rb26 cams and cam gear, i'd risk it.

Oh, and a good tuner.

[GTRgeoff]

Got a set almost in my hot little hands and a good tuner. Keep you posted.

[Sciby]

Should be interesting... good gains for rb20... and now maybe for RB25's... it'll be hard to get a set of GTR cams.

[MJ]

Thanks for the reply fellas, this is the next mod i am considering. I like the idea of it just for the sound the car will make and also beable to use a clear cam cover, and of course some more power

[R33vit]

I'v been thinking about this for sometime now. I'm keen to see where this goes, I'd even be willing to try it if I could get a hold of some cams

[Jimbo2000]

this is an definate idea for me too in the next few weeks, lets just see if my engine stays in one piece after the track on monday

[nv033]

I'v been thinking about this for sometime now. I'm keen to see where this goes, I'd even be willing to try it if I could get a hold of some cams

ill try and arrange something old man :headspin: :headspin: in and out in a day??

[rb25]

damn, i thought i was going to be the first one to try it on these forums

-rb25

[GTRgeoff]

Sydneykid, just reviving this, why did you recommend the RB26 Inlet gear?

[rb25]

another question that comes to mind is about the gt-r cam lobe ramp-up, is it sharper than the gts-t hydraulic cam (its a higher lift so it has to be sharper somewhat)? would the sharper and higher lift flog out the hydraulic lifters?

ive decided to give this mod a miss and just get some tomei's cams that'll just drop in no ginning around.

-rb25

[N I B]

We are doing this conversion but modifying the inlet cam to run the VVT. May be crap but costing nothing to find out so will let you know.

This is on GTSt VSPECs GTS that has 450rwhp on the Stock cams so should be an interesting test.

[GTRgeoff]

Steve, without the cams and gears in front of me I'm puzzled. Does the GTR inlet cam have a different attachment for the gear?

RB25, the cam theory will be pretty mush the same for any high lift cam. Greater acceleration of the valves and springs, and I believe the Tomei's are higher lift and similar duration to the GTR cams, so will be more aggressive with the lifters. SK has been pretty detailed in the RB26 into RB20 thread if you take a look.