Jump to content
SAU Community

Recommended Posts

I have retarded the timing on my RB20 by exhaust cam by 4deg running 19psi with a slide hiflow and have noticed the difference right away.

Firstly the A/F ratio went from a flat 12:1 to a bell curve starting at 12:1 at 3400 and leaning out to 12.6:1 at 5000 and then settling back down to 12:1 at 7000. I used a tech edge with data logging to measure this.

I have reset the base timing to 15deg as it actually dropped 3 deg after retarding the cam timing.

The car is now coming on boost slightly quicker and hits full bost around 200-400 rpm quicker depending on the gear and the midrange FEELS more responsive. peak power feels the same but it gets there quicker so the whole package feels faster.

I added fuel to compensate and bring the AFR's back to a safer level and keep it to 12:1 as close as possible.

I have not touched the timing map as there is no detection of knock. I use a modified condenser microphone connected to a laptop recording in real time and can be referenced to the rpm scale of datascan.

so all in all looks like quite a decent gain. seat of the pants tells me there is no more power just power earlier in the rev range and let's face it all RB20's need earlier power delivery.

without tune yes there was more response but it was leaning out. so i have already added fuel and there is more response but no more peak power.

I am only speculating as i have not had it on a dyno. but it comes on boost faster yes :no:

there would still be gains to be had even form a stock turbo. the amount of overlap Nissan designed was a compromise between response and power and emissions. with the amount of overlap they run stock you get a longer cleaner burn but less power.

so you may gain some midrange power with a stock turbo but there would be cheaper ways of getting the same performance increase from a relatively standard car.

You can buy one of the arospeed cam gears for $70 but a mechanic would charge you $200 to install it and you will need to pay for atleast an hour of dyno time to get a confirmed result. so it would end up costing you almost $400.

For that amount you could buy and install

front+dump pipe, FMIC, SAFC or a boost controller. all of these will give you good gains. the cam gear is really something you would do after the more common mods.

very worth while if you have already done the basics.

After going for a nice long drive lastnight i can say boost comes on just that bit earlier and makes a big difference in how the car behaves.

sweeeeet.

getting my aerospeed exhaust cam gear installed, exhaust manifold studs replaced, gaskets replaced, and dyno tune with the FPR, Z32 afm, SITC, SAFCii and the Slide highflow. Got the fuel pump, the intake and exhaust is full sorted. Should be good ! :D

under $700 too

is it worthwhile adding adj camgears to an engine with stock turbo (to tweak power delivery rather than for outright power gains)?

or should you only consider this if you've upgraded your turbo too?

In previous threads some people have had no gains by retarding the ex cam on a fairly stock motor. The problem with a stock turbo is the small turbine wheel, which causes backpressure. This back pressure causes the spent gases to re-enter the combustion chamber if over lap is too great.

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

    • I have had the r3c in for years now, maybe close to 7 years and it has never missed a beat, anyone can drive it. Super easy to drive around town, the hotter it gets does get a little hard but it holds the power easy as 
    • Shit thing to find eh? I guess the big issue is that whatever "fix" you do now, it might slow the rust down but won't fix it. I just wanted to add that in no way is fixing sheet metal in 3 dimensions the place to start with welding....that is a pro only job because its too hard to work out where things should be, let alone doing a clean enough job that it can look OK and still be strong too.  I needed to get a new rear quarter panel on the GTR and it took a pro weeks to get the old one off cleanly, new one on in the right place and looking somewhat like it should have with most of the previous connecting panels in place. Gluing a couple of bits of metal together with a welder in the garage is doable, but that is totally different to doing panel  replacement
    • This seems to be a very popular swap since all the turbo skyline prices went through the roof! I'll let someone more familiar chime in, but I understand that yes you probably want to swap the loom in to swap out the auto TCM stuff. You should not assume everything just plugs in either, you need to check at least the ECU wiring diagram for any differences at the plug at the left headlight and probably the ones near the ECU that join the dash loom too  
    • hows it fellas, my first post here which seems crazy cos half the forums i read are like the same age as me haha. to make a long story short ive got an r34 sedan (rb25de neo auto) which im swapping to a s0/s1? rb25det, r33 big box and nismo gt pro lsd. i have the motor and gearbox all bolted up outside the car, old motor and trans out. i bought the motor with stock ecu and loom, do i switch over to that? or will it be easier to get a r34 manual ecu and keep the loom if thats even possible.  also engine mounts look different, anything else thats different or incompatible? cheers, hope this all makes sense Paddy
    • att.4QNbuJlz_gNZPFBGFqeEvxSUHXkGt7z40V59MrtXTPg.mp4    
×
×
  • Create New...