Jump to content
SAU Community

Recommended Posts

  • Replies 82
  • Created
  • Last Reply

Top Posters In This Topic

So if the Stock GTR cams work in the RB20 could you use aftermarkets? Like HKS Step 1's? HKS web page with cam specs translated into egrish

R32,33 IN 264 degrees 8.7 110 degrees

EX 272 degrees 8.7 113 degrees

Rb20 IN 264 degrees 9.0 110 degrees

EX 264 degrees 9.0 115 degrees :)

So if the Stock GTR cams work in the RB20 could you use aftermarkets? Like HKS Step 1's? HKS web page with cam specs translated into egrish  

R32,33 IN 264 degrees  8.7  110 degrees  

           EX 272 degrees  8.7  113 degrees  

Rb20 IN 264 degrees  9.0  110 degrees    

        EX 264 degrees  9.0  115 degrees  ;)

i don't see why you couldn't? i think cams are generally for 'rb' engines so as to work in either rb20/25/26

just be wary that after a certain amount of lift, the rb20 head needs to be modified i think to accomodate the installation. can someone clarify this further?

The GTR cams are a mild upgrade that don't cost too much. Good bang for your buck. :cheers:

When you get into aftermarket cams the costs are substantially higher. Not just for cams themsleves, but valve springs, convert solid to hydraulic followers, machine head for lobe clearance etc. Suddenly it is not such good value as for the same money you can buy more effective upgrades.

Plus an RB20 is 2 litres and the larger cams you put in the more rev happy you needo be

The workshop where my car is claims the RB26 cams in Rb20 have been tried, and the result is ordinary... ie you lose power down low, and any top end increase seen with these cams isnt worth the trade off...not the expected result from a mild lift and duration increase. Also sighted concern over a solid lifter cam being used with hydraulic lifters.

So since they have my car, and they are advising against leaving the cams in, well im going to get them to take them out...for no other reason then if my engine dies after the tune, then i hadnt gone against their advice and they can be held more accountable.

Out of interest does anyone know if cams for sold lifter engines have a more aggressive cam lobe, whereby accelerating the valves open / closed any quicker then used for hydraulics...still having the same duration and total lift, but different gradient to fully open?

The workshop where my car is claims the RB26 cams in Rb20 have been tried, and the result is ordinary... ie you lose power down low, and any top end increase seen with these cams isnt worth the trade off...not the expected result from a mild lift and duration increase

Can anyone verify that coz if i do the GTR cams I don't want to lose anymore down low power/torque :wassup:

Also sighted concern over a solid lifter cam being used with hydraulic lifters.

Good point,can that be promblematic later down the track?

The GTR cams are a mild upgrade that don't cost too much.  Good bang for your buck.  :cheers:  

When you get into aftermarket cams the costs are substantially higher.  Not just for cams themsleves, but valve springs, convert solid to hydraulic followers, machine head for lobe clearance etc.  Suddenly it is not such good value as for the same money you can buy more effective upgrades.

Plus an RB20 is 2 litres and the larger cams you put in the more rev happy you needo be

Well in my case I'm in the USA. Finding stock GTR cams is like looking for a Unicorn. If I do find them there won't be a big diffrence in price vs Aftermarkets :mad:. I have some stuff already just looking down the road.Pics of the stuff I have so far for the RB20 I'm not too worried about the lost of low end power, just a trade off you have to live with for topend.

BlueRB240 ... is that plenum for an RB20, looks neat!

Joel...are these figures right? The RB20 has 240deg - 7.8mm lift on both intake & exhaust , whilst the RB26 has 240deg - 8.5mm lift intake & 236deg - 8.2mm lift exhaust...is that right.

So yeh, the lift is really all thats really different between my R32 RB20DET cams and R33 GTR V-Spec cams. And even if the ramp rate was different, one would assume (i do a lot of that) that it becomes an issue as revs increase, not at idle or low revs (????)

Im over it now, ive only driven the car about 6 weeks this year, and it has cost me too much money (not alot compared to what most spend, but more then i lile spending)...just want to enjoy it again like i use to when it had the std turbo/injectors/ecu etc etc

Yer thats right, well according to tomei.

http://www.tomei-p.co.jp/_2003web-catalogu...haft-specs.html

Whats considered the Vspec N1? (as per the above link) ???

Maybe the higher ramp rate is causing problem with air velocity due to the RB20's slower piston speed?!?!? Theories.. :cheers:

What causes NA cars with big cams to have poor vacuum at idle...too much lift? Could it be a vacuum thing at idle...i dont know?

Camshaft overlap - when the duration is large and/or the centerlines are too close together.

Yer it is overlap.. Maybe the lack of piston speed in the RB20 (shorter stroke) isn't enough to create a decent air velocity hence fuel atomisation goes up the crap?!?!

Might start looking around to how ramp rate affects short stroke motors.

So any thoughts how these would work:

Tomei 256° / 8.50 inlet (PONCAM)

Tomei 260° / 8.50 exhaust (PONCAM)

on an RB20DET with a 420hp turbo...too big on the exhaust side, should i stick with 256 on inlet/exhaust.

Essentially if im not going to run GTR cams, i still want something to help beef up the mid-top end

as i own a R31 Rb20det ... cam duration being IN : 248deg and EX :240deg .. with 7.8mmlift

upgrading to the gtr IN : 240deg and EX : 236deg the 8.5mm lift .. will i actually gain anymore .. and is it possible to tune them with adjustable timing gears pacifically for more torque rather than top end power..

Well done to Waz on the successful setup ..sounds very promising for the other rb20 owners thats for sure

well when i had the GTR cams in (apart from not holding idle) when i drove the car it was super laggy down low, and didnt come on very hard at high rpm... which is what R31 power is describing. there were no other issues with my engine as when i re-fitted the std cams the car was back to perfect running order

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

    • So, I started this repair and got as far as "fixing" the holes with some fibreglass. God all those years working on boats came back quickly. I decided I'd reach out to some rust guys just to see what they would say about it. I came across a guy about 40 mins away and went to see him. He said the windscreen needs to come out, that there might be some more bits around the windscreen and he'd quote them at the time. But his quote was $300 to remove and replace windscreen and $3k for the damage he can see. He said he could respray the roof for $1200 and the bonnet for another $800 (somebody has previously rattle canned it, its horrendous). This is $5300 + any small additional bits. It's a lot, I get that and the name of one of my fave youtube channels 'Not Economically Viable' comes to mind.  I'm not being financially rational, but I've taken him up on the quote. He's opening a new shop in November with more room, so we're waiting for that. I'll leave the currently missing headliner out until then. I'm looking forward to it being fixed and having the paint looking nice again (lots of clear coat issues on the roof too). / flame suit on.
    • Oh and some up-and-comings; New rear drivers wheel bearing. I'll do that this weekend while the diff is out. The car is already up and the d/c axles and missing exhaust will help with space. This is the last bearing for me to do and I've been dragging my feet on it. I also have some new EBC blue stuff pads for the car and some new brake fluid. I haven't ever flushed the fluid in this car and looking forward to it. I have 600 degree fluid to put in. Not exactly "race fluid" but better than the typical stuff I have been using.
    • A proper clutch/plate type mechanical diff with quite a lot of pre-load and high locking % is better for drifting. Much more consistent in its behaviour. A helical can be annoyingly vague and inconsistent in how it responds under the sorts of abuse found in drifting.
    • Some updates here. I pulled the entire interior out, minus some trim to respray the seats with Colourlock dye. It turned out really nice though I accidentally let the dog in the car after and she scratched up the front seat.  This is what it looked like before, the colour was just washing out everywhere but thankfully the leather was in good nic. Then after the respray   And after the bloody dog jumped in The headliner is out waiting to be retrimmed, but it will stay out now until Nov - see why below. I replaced the stereo/headunit with a period-styled Android headunit. I have no after pics, but I'll get some. This is because of the missing pixels. I tried to fix this twice with replacement ribbon cables but couldn't. Also the bluetooth interface I'd bought for this was crap. Then there's the rusty roof. Pics and info in this other thread. I have decided to get this repaired professionally, but I'll update that thread. This is why the headliner will stay out for now. I'll be getting the roof and bonnet resprayed at the same time the rust is fixed. I also had an interesting issue with my drivers door lock.  For a small period I was having issues getting any 12v power to the car - I mean *any*. It would have no dash lights, nothing. It happened while I was at the shops and I couldn't get in the car. So, we had 2 problems. The most pressing here is that I was locked out. I have only a single physical key hole on the car, the drivers door and no amount of turning would unlock the car. Surely it doesn't need power for this? The second issue is why am I losing all power periodically, The battery isn't dead, its almost like the battery isn't even there. Two issues that were surprisingly easy to fix. You fellow BMW over-engineering lovers will appreciate this. The lock in the door has 5 states; mechanical lock, electric lock, neutral, electric unlock, mechanical unlock achieved at -90 degrees, -45 degrees, 0 degrees, 45 degrees and 90 degrees. Although, the unlock is towards the front of the car, so opposite for LHD countries. Sticking the key in and turning 45 left or right is what is used 99% of the time. It activates the central locking etc. 90 degrees is for dead battery access and, obvs, only un/locks the one door. But because the mechanical lock is never used and is 27 years old, it seizes up. I was totally unable to turn the key far enough to get to the mechanical unlock (At the time of locking myself out, I didn't even know this was a thing). I eventually did it with some vicegrips and teflon spray.  I made a quick vid for other E39 peeps.   The battery issue is totally new to me also - It wasn't making sufficient contact between the post and the terminal. The terminal was bolted on tight, but the car wouldn't have power. After checking the battery with my multimeter I accidentally contacted the terminal and the battery post and the car got power. The battery was only a few years old and in good condition. I cleaned the post and the terminal with a wire brush, bolted it back on tight and never had the issue again. I'm still surprised that despite having solid contact it didn't work. Also, the car was getting Warragamba sized pools of water in the back when it rained. My initial concern was another rust problem. But when I went out on Weds while it was raining and while I had no headliner in I could see a steady stream of water coming through the roof mounted aerial. As this aerial is for the (now removed) car phone I pulled it out and whacked a blanking grommet in the hole. It seems fine now. I'm thinking I might get the hole permanently filled when the rust is fixed. Moving forward and things in progress; The tailgate needs some attention. I have taken all the trim off to clean it all and address some small rust spots. I have partially done all of this but I'll finish it up hopefully this weekend. As all the trim are now entirely devoid of trim clips I have bought a heap of strong velcro and I'm hoping it does a good enough job as any of this trim in good condition is super expensive and usually in Europe as we dont have many of the wagons here. Suspension and brakes!!! This is exciting. In the front; New control arms New sway bar links New lower Eibach springs (the only modification I'm planning on this car) M Sport shocks (these came with the car and will replace the longer shocks in the car) New top mounts Used 540i calipers (stock brakes suck!) New 540i disks and pads (22x296 mm for 528 and 30x334 mm for 540i) New front wheel bearings (thank all that is holy for bolt on bearings!) Annnnd in the back; New control arms New sway bar links Adjustable air suspension arms (fool the car into what the current height is so the self levelling suspension can match the new front ride height) New ball joints I'll also be doing a brake fluid flush while I'm in there. I'm planning on switching the car over to the 16's that came with it so I can clean up and respray the M Sport 17's. They've lost a lot of colour over the years and have some gutter rash. None of this will start until the E90 is back.
    • You mean you will regret it for drifting duties? I don't quite follow.
×
×
  • Create New...