Jump to content
SAU Community

Recommended Posts

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!

:cheers::(:):rant::D

  • Replies 82
  • Created
  • Last Reply

Top Posters In This Topic

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

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.

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

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....?

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 :)

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

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?

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. :D

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

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

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 :D

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.

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?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Lucky man, who owns it in the family? Any pics? 
    • The engine stuff is Greg Autism to the Max. I contacted Tony Mamo previously from AFR who went off to make his own company to further refine AFR heads. He is a wizard in US LS world. Pretty much the best person on earth who will sell you things he's done weird wizard magic to. The cam spec is not too different. I have a 232/234 .600/603 lift, 114LSA cam currently. The new one is 227/233 .638 .634. The 1.8 ratio roller rockers will effectively push this cam into the ~.670 range. These also get Mamo'ified to be drilled out and tapped to use a 10mm bolt over an 8mm for better stability. This is what lead to the cam being specced. The plan is to run it to 6800. (6600 currently). The Johnson lifters are to maintain proper lift at heavy use which is something the LS7's supposedly fail at and lose a bit of pressure, robbing you of lift at higher RPM. Hollow stem valves for better, well everything, Valve train control. I dunno. Hollow is better. The valves are also not on a standard valve angle. Compression ratio is going from 10.6 to 11.3. The cam is smaller, but also not really... The cam was specced when I generated a chart where I counted the frames of a lap video I had and noted how much of the time in % I spent at what RPM while on track at Sandown. The current cam/heads are a bit mismatched, the standard LS1 heads are the restriction to power, which is why everyone CNC's them to get a pretty solid improvement. Most of the difference between LS1->LS2->LS3 is really just better stock heads. The current cam is falling over about 600rpm earlier than it 'should' given the rest of my current setup. CNC'ing heads closes the gap with regards to heads. Aftermarket heads eliminate the gap and go further. The MMS heads go even further than that, and the heads I have in the box could quite easily be bolted to a 7.0 427ci or 454 and not be any restriction at all. Tony Mamo previously worked with AFR, designed new heads from scratch then eventually founded his own business. There he takes the AFR items and performs further wizardry, CNC'ing them and then manually porting the result. He also ports the FAST102 composite manifold: Before and after There's also an improved racing crank scraper and windage tray. Helps to keep oil in the pan. Supposedly gains 2% power. Tony also ports Melling oil pumps, so you get more oil pressure down low at idle, and the same as what you want up top thanks to a suitable relief spring. There's also the timing chain kit with a Torrington bearing to make sure the cam doesn't have any thrust. Yes I'll post a before and after when it all eventually goes together. It'll probably make 2kw more than a setup that would be $15,000 cheaper :p
    • Because the cars wheels are on blocks, you slide under the car.   Pretty much all the bolts you touched should have been put in, but not fully torque up.   Back them off a turn or two, and then tighten them up from under the car with the wheels sitting on the blocks holding car up in the air.
    • Yes. Imagine you have the car on the ground, and you mine away all the ground under and around it, except for the area directly under each individual wheel. That's exactly how it'd look, except the ground will be what ever you make the bit under each wheel from
    • Yes, if you set the "height" right so that it's basically where it would be when sitting on the wheel. It's actually exactly how I tighten bolts that need to be done that way. However....urethane bushes do NOT need to be done that way. The bush slides on both the inner and outer. It's only rubber bushes that are bonded to the outer that need to be clamped to the crush tube in the "home" position. And my car is so full of sphericals now that I have very few that I need to do properly and I sometimes forget and have to go back and fix it afterwards!
×
×
  • Create New...