rb26 cams in rb20 with standard ECU works!

[WazR32GTSt]

Who doubted Sydneykid? you should be ashaimed of yourselves...

we had this thread:

http://www.skylinesaustralia.com/forums/sh...ead.php?t=43571

then this thread:

http://www.skylinesaustralia.com/forums/sh...ead.php?t=38857

.........now its my thread!

RB26 CAMS IN AN RB20 WITH STANDARD ECU WORKS!!!

bought my R33 GTR Vspec cams off GT51R (you may have seen him from the cover of HPI a few issues ago). took them to the mechanic and he said it wouldn't be an issue with fitting.

everyone kept trying 'at home' and saying its not working it must be the ECU but with no proof that the ECU was playing up. In most cases they changed more than one thing so its hard to point the finger when this happens.

so yesterday they begun the process of removing my old cams and then eventually in went the rb26 cams. My mechanic mesured them side-by-side before they went in and said the duration was about the same with only about half a millimetre increase in lift. sounds just like what it should be. at this point he said it won't idle very lumpy at all from what he has seen in the past and there should be no issues with stalling or anything.

i went there after uni today, worried that i'm going to get there to hear 'sorry mate it won't idle' and i would have to double to labour cost to get them removed but i was greeted with 'nah simple cam change, mate' and it idled great the first time! only $250 for the cams and $250 for the labour!

now the seat-of-the-pants-o-metre result?

not as great as documented on the forums, but good top-end power and better torque all over. BUT note my lack of modifications:

- FMIC

- 3" front/dump

- high flow panel filter

- cold air feed

Note: stock ECU

the turbo spools up much faster but i can feel the restrictive exhaust after it starts making boost like its struggelling to let the gasses out

i think that with more mods then i would have gotten the 15rwkw increase skdneykid talked about but i would hypothesise that its more about 5rwkw all through the rev range that i got.

so there we have it - being a qualified scientist its in my nature to not believe someone else unless it either makes absolute sense or ive tried it myself.

next on my agenda is 3" cat/cat-back and re-tune ECU to optimise the setup i have. maybe even an rb25 turbo if the hip-pocket ain't too depleted

its cam time, rb20 owners!

[Cubes]

So no adj. cam gears then..

Sounds interesting all the others had bad idle problems and you didn't.

[Roy]

Cool, on paper there is no reason why such a small cam upgrade on a relatively std AFM car should cause dramas.... when you have an ECU with bigger injectors and crazy rich Jap ecu, a faulty AFM which intermittently cuts out , then you ask a car with an already marginal ECU to run the car now with new cams.... well if you read the above posts you will know my problem. Nothing a Q45 AFM and Power Fc wont be kicking in the ass.

Shame you only have SOPS figures, but to me they are good enough, if you can feel it then its all good

[bbenny]

well done, im really pissed mine didnt work!

i dont understand why, but my car wouldnt accept them, when i changed back to standard cams there were none of the problems i had before with idling!

congrats! might have to try it again sometime in the future.

[Sydneykid]

Well done WazR32GTSt, I was starting to doubt myself :confused:

No I wasn't, I knew if I could get it to work anyone could. :thankyou:

[WazR32GTSt]

Well done WazR32GTSt, I was starting to doubt myself  :confused:  

No I wasn't, I knew if I could get it to work anyone could. :thankyou:

all hail king Skdneykid !

i'm just glad i din't try it myself as although i can hold a spanner well, at the end of the day i don't have the required tools to do it the way i would like

plus, really i don't have the required knowledge to know what bolts need to be tightened certain amounts and what bolts to leave blah blah ...

haven't really given the car a good go yet as it was raining on the way home and i was just talking it a bit easy. will be going on the VIC cruise (Mt Dandenong) tomorrow so can give it a bit then to see exactly how much the engine characteristics have been altered

[Cubes]

Take note of fuel consumption also.

[jnr32r]

Spewin Ben!!? LOL sorry man i feel ur pain.

Wont be trying mine for another 3 weeks or so, ill keep you posted.

WazR32GTSt, hows the idling and the sound? Did you get your std cams back?

i guess what im trying to get at is, are you sure they were changed....?

[Roy]

Spewin Ben!!? LOL sorry man i feel ur pain.  

Wont be trying mine for another 3 weeks or so, ill keep you posted.

WazR32GTSt, hows the idling and the sound? Did you get your std cams back?  

i guess what im trying to get at is, are you sure they were changed....?

So you think the seat of the pants difference could be the fact that driving home his wallet was a bit lighter

[mabru]

I have to point out that there is a slight difference between the R33 Vspec exhaust cam and the R32 GTR exhaust cam, the lobe center angle on the R33 is 120 degrees (same as the RB20det) and the R32 is 125 degrees. I'm not saying that's why they worked so easily but it would help explain the near-stock idle qualities.

-Matt

[bean_8044]

Im just wondering if anyone has thought about the type of cams that they are getting. I have R32 GTR cams and R33 GTR Vspec cams and the lobes are different on the Vspec exhaust

[jnr32r]

LOL @Roy...

Hold on but BBenny's cams are from a 33 Vspec too !?!?!

[Sydneykid]

Hi guys, next weekend I will be trying a pair of R34 GTR cams in an RB20, well if Mick (ex SubZero) ever sends me the R34GTR top end we will. Interesting to see how they go.

[DoughBoy]

Hey, if the lobe centers are ground differently on RB20 vs RB26 cams then the ignition timing is definately going to be out by a fair amount when the cams are installed "straight up", although most of you guys doing this conversion are retarding the exhaust as well.. Hrm going by Tomei's site lists both the RB20 at 120, the RB26 at 125, now add on the 4 deg retard most of you guys are throwing in and the timing is out by 9 degrees?

[Sydneykid]

Hey, if the lobe centers are ground differently on RB20 vs RB26 cams then the ignition timing is definately going to be out by a fair amount when the cams are installed "straight up", although most of you guys doing this conversion are retarding the exhaust as well.. Hrm going by Tomei's site lists both the RB20 at 120, the RB26 at 125, now add on the 4 deg retard most of you guys are throwing in and the timing is out by 9 degrees?

Not for me. :angel: After the new cams go in, I set the CAS position using a timing light. If I then retard the exhaust camshaft, I reset the CAS so the ignition timing is where it was when I tuned it last time. You generally have to play with the static timing a little anyway to achieve the best average power.

But you're right, anyone who does it by lining up their marks on the CAS body will have a problem.

[Roy]

But you're right, anyone who does it by lining up their marks on the CAS body will have a problem.

I dont need a timing light, ive god a good eye for these things, and my car and me, we have an understanding... :Oops: I fiddle it stops running, car gets towed

[Sydneykid]

Don't feel privileged, it happens to all of us you know. :uh-huh:

[bbenny]

while on this topic of timing i find now that i have installed the adj cam gears, my car loves to have some highly advanced timing like 30deg adv! is that strange? i moved it back to 25 but it feels like a slug compared to 30, however the engine note is a little smoother....

the adj pulleys are 2deg advanced on inlet and 3deg retard on exhaust.

[WazR32GTSt]

jnr32n - idiling has no issues at all. sound is much nicer under throttle but much the same at idle (ie not really lumpy). my standard cams were DEFINATELY changed as my mechanic is a family friend and also i have my std cams back.

Well if there were going to be any problems they would have surfaced at the cruise on Saturday through Mt Dandenong. The install is fine and everything is going well.

some things to note after further driving:

- fuel consumption has not been logged yet as i havent given it enough time of normal driving

- top end is much improved over stock i think ive picked up a fir bit of power there

- bottom end much the same (although my std exhaust is hurting my result) although throttle response seems to be better

can't wait for a 3" cat-back to be added to really make use of the higher lift cams

you are all talking about 'retarding the cam' etc. and about having trouble with the timing. my question is: if i check my timing with a timing light will it not be reading correct?

[bbenny]

timing light should be correct regardless as you are retarding the camshaft only, ignition timing should read whatever you set it at.