Camshafts
Camshafts
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** I want to start by saying I am not super knowledgeable about building heads nor all the small details. I have just compiled my research and used math/logic. **
Honestly camshafts are one of the least important things in a basic RB20 build. Stock camshafts and valvetrain can hold 400 hp and 7500 no problem. If you are looking to refresh your valve train, go for higher rpm or are looking to squeeze out every bit of power, then upgrade cams. The factory cams are more than enough for a basic street car.
Increasing the lift of the cam will increase the distance the valve opens while increasing the duration will increase the time the valve is open. Both will result in more flow through the engine. There are a million arguments of people on the internet of which one is more desirable, but in an RB20 there are limitations. Any camshaft with a lift greater than 9.3mm will need some machined clearance on a stock head. This adds cost and complexity to the build. Aftermarket cams also require the use of upgraded valve springs and depending on RPM goals a solid lifter conversion is a good idea.
What about the duration? The general rule of thumb is that the longer the duration the further the power is shifted up the RPM range. Having very large cams will result in less mid-low range power and more top end. Great for a drag car, but less desirable for driving around town. Assess the goals for your car and pick a set up that best suits your engine. You can see a back to back cam dyno graph below testing 2 different durations.
I cant mention cams without talking about cam gears. Again these are not a must have for a basic RB20 build. They can be used to move the power band around a little, but for the money you are better off buying other upgrades. By advancing the timing a few degrees you can spool up a turbo faster or by retarding the timing you can squeeze out a bit of peak power. A good tune is needed to see these changes and it is not advised to touch the timing without the guidance from a good tuner. I want to also note that I would only ever put on cam gears that have a "5 bolt" design. Some early cam gears only have 3 bolts you loosen to adjust them and there have been many cases of them coming loose and ruining engines.
Cam Recomendations
Cam Recomendations
**Valve springs and a tune are a necessity when upgrading cams to extract out more power.**
Basic Build:
Stock cams are more than adequate for 350-400 hp builds. I would personally upgrade valve springs for a little more RPM and run it at 8000+ RPM.
Street Car:
If you must upgrade, the Tomei Poncams or the Kelford 262/262 with valve springs are what I would go for. These cams keep the car streetable and dont compromise on low end drivability.
Track Car:
Tomei Procams or a high lift Kelford makes for a cool idle and a peaky power band. Sustained high RPM will actually make these cams useful. Just know the car will not be very fun at low rpm, espically if paired with a big turbo that comes on later in the power band. You will also need to fully upgrade the rest of the valve train and convert to solid lifters.
Cam Options
Cam Options
These are readily available options for RB20 engines. More head part numbers can be found on the Part Numbers page.
Camshafts (Intake/Exhaust):
Note: Any cam with a 9.3mm lift or higher will need upgraded valve springs. Any cam with a 9.3mm lift or higher will need clearance with the head. Some cams require solid lifter conversion.
RB20DET Redtop Cams - 248/240 - 7.8mm/7.8mm
RB20DET Silver Top Cams - 240/240 - 7.8mm/7.8mm
RB20DE Silver Top Cams - 232/240 - 7.3mm/7.8mm
262/262 - 9.3mm/9.3mm - PN: HL182-A
272/272 - 9.35mm/9.35mm - PN: HL182-B
280/280 - 9.35mm/9.35mm - PN: HL182-C
272-264/264 - 10mm/10mm - PN: H182-SC
278-272/278 - 10mm/10mm - PN: H182-SD
Poncam Lash Pair- 258/258 - 8.5mm/8.5mm - PN: TA301B-NS07A
Intake - PN: TA301D-NS07A
Exhasut - PN: TA301F-NS06A
Procam Solid Pair - 272/272 - 10.25mm/10.25mm - PN: TA301A-NS07A
Intake - PN: TA301C-NS07A
Exhaust - PN: TA301E-NS06A
Note: Will need solid lifters, shims and springs for Procam Solid.
Poncam Lash Pair - 256/256 - 8.5mm/8.5mm - PN: 143019
Procam Lash (OEM)
256/256 - 8.5mm/8.5mm - PN: 1411256085 / 1412256085 (same as pon)
260/260 - 8.8mm/8.8mm - PN: 1411260088 / 1412260088
270/270 - 8.8mm/8.8mm - PN: 1411270088 / 1412270088
Procam Solid Lifter
260/260 - 9.25mm/9.25mm - PN: 1417260092 / 1418260092
260/260 - 10.25mm/10.25mm - PN: 1417260102 / 1418260102
270/270 - 9.25mm/9.25mm - PN: 1417270092 / 1418270092
270/270 - 10.25mm/10.25mm - PN: 1417270102 / 1418270102
Note: Will need solid lifters, shims and springs for Procam Solid.
Jun Machine Shop
256/256 - 8.5mm/8.5mm - PN: 1004M-N074 / 1004M-N174
256/256 - 9.3mm/9.3mm - PN: 1004M-N075 / 1004M-N175
264/264 - 9.3mm/9.3mm - PN: 1004M-N076 / 1004M-N176
272/272 - 9.3mm/9.3mm - PN: 1004M-N077 / 1004M-N177
Cam Dyno Graphs
Cam Dyno Graphs
Kelford 262 Cams vs Kelford 280 Cams
Kelford 262 Cams vs Kelford 280 Cams
RB20DET
Credit to: Brandon Bull
Unknown Engine Mods
Turbo: PTE 6266
"The back to back tested was carried out on my built rb20 with a auto trans, red line is 262 duration cam and pink line is the 280 duration cam, you can see the trade off in the lower rpm and higher rpm between the both, I personally think the 280’s were better on my set up it revs 9000rpm being street/darg set up it can breath more freely in the higher rpms where rb20’s like to be, same boost levels and ramp rate on the dyno and timing full back to back, hopefully this helps you with your cam choices of duration with your rb20 builds"
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