Just had Cam Gear fitted, Results

[Bass Junky]

Hey Ppls.

Well I just had my HKS Cam gear installed at a very reputable workshop and had it dynoed both before and after.

I decided to get dynos before and after so everyone could see exact results for your information (bloody cost me heaps too!!!)

We found virtually zero difference between standard or HKS, and have dyno results to prove it.

The car was left strapped to the rollers whilst the install took place to ensure that the results were controlled properly (moving the car on the rollers can effect results).

The techician is extremly experianced with these engines so he's not a hack.

I haven't been on a long fang to gauge full 'seat of the pants' results, but the dyno says no change.

They told me that with programmable engine management I would see more results, as I could then adjust the timing as nessecary.

Anyway, I will post up dyno charts this aftenoon to show you all.

Also, I had a run done with and without my exhaust silencer (which I will also post up) and the results are remarkable. HUGE drop in power through the whole rev range, as well as big boost drop up top.

Anyway, stay posted for pictures.

BASS OUT

[Jay95R33]

Wow...

But I suppose the gains come from running more timing.

What was the adj cam gear set at? 3 or 4 degree retard ??

J

[Bass Junky]

It was at 4 degrees, ans the base timing adjusted to suit also.

[Warpspeed]

Do you know what the actual exhaust valve opening and closing points were before, and after the four degree change ?

[Bass Junky]

The car was run on the dyno, then fitted with the cam and retarded the timing 4 degrees, and then run again.

I don't know what the actual opening and closing point were before.

Maybe the Neo6 does not get the same results as the other RB25 DETs???

[Jimbo2000]

wowx2

never seen no improvement from cam gear change

power FC time mate

[Guest Robo's]

Well i know the R34 does have a different cam profile to the R33. I dont know whether this is the cause though. Still i would suspect a small gain.

[JimX]

wowx2

never seen no improvement from cam gear change

power FC time mate

Well you can add me to your list then At least for now, it may change in the future after I tune my PowerFC.

I put in my gear and set it to 4 degrees, and the car ran noticably worse. It lost all its top end and maxed out the injectors a lot earlier. Now it could have just been that it lost its top end because the injectors were maxed out. But because the AFM wasn't maxed out, I'm thinking that it was just upsetting the timing too much.

I also tried 3 degrees with similar results, but it wasn't as bad as 4 degrees. So I put it back to 0 and that's where it is now and running pretty good.

When I get my PowerFC tuned (along with injectors and AFM upgrade) I'll get them to play around with the gear setting. If they find it works best on 0 degrees, out it goes and back goes the factory gear.

[predator]

You're running no form of aftermarket management?

Isn't the idea of a camgear to run more agressive cam angle? if the stock ECU is just adjusting its own timings anyhow (which i believe it largely does this off the A/F mixtures it "sees").. that would be expected wouldn't it?

[Steve]

Did you reset the base timing between runs? it is pretty importand, as without doing this, there will be very little results.

If you think about it, 4 degrees is a fair bit, and if it isnt doing something major, perhaps its not being set up properly.

I had a 'reputable' tuner try and dial in my exh cam, but didnt go near a timing light, just used the first (pre dial in) timing mark - and surprise, the results were almost non existant.

[Warpspeed]

If you have absolutely no idea where each cam is with respect to the crank, how do you know moving it a bit in one direction is ALWAYS going to give a certain result.

It seems to me, you need to know where you are, and where you should be, and shift it by as much as you need to get there.

[Bass Junky]

The installer was the gentleman who used to set up the Gibson Motorsport Skylines which many times won the Touring car races and Bathurst, so I figure he knwos what he's doing. He's also busy setting up Targa cars.

The position of the cam in respect to the crank isn't really relevant as the cam gear lines up with four bolts for clamping and one dowel hole for positioning, so it can only go on one way and in one position. Twisting the outside pulley section in relation to the inside boss is what adjusts the timing either in advance or retard.

BASS OUT

[Warpspeed]

You say that the cam with respect to the crank is not relevant ?

Well then what is the point of retarding it then ?

Of course it is relevant. The whole purpose of the cam is to open and close the valves at the right times. There are a whole lot of things that can shift the cam timing, especially stretch in the timing belt.

[Jay95R33]

The only thing that I can think of is that the different cam profile on the NEO engine negates the use of a adj cam gear to adjust the cam timing....

Although it's strange that it didn't have SOME sort of effect, either gained or lost power..

I'm still running the stock ECU on mine (series 1) and you can actually see the slight buldge in power where (I presume) the cam gear comes to effect...

J

[Bass Junky]

Warpspeed: I'll rephrase myself.

You know where the cam is in relation to the crank as the standard pulley is already in the zero degree position. The adjustable cam gear simply replaces that pulley identically when the setting it as zero. When you adjust the centre of the gear, you either advance or retard the timing of the cam.

[Bass Junky]

Oh, yes the base timing was also reset.

[51jay]

Well I got a VERY noticeble increase in low and midrange torque. Mine was retarded 4 degrees. These days if i'm just staying with traffic flow it never comes out of 4th til i get below about 1200 revs....though it doesn't pull well untill it's back up to 1800

[whatsisname]

I've gone through the exhaust cam gear process twice now, old engine & new one. Both times we've found 4' retard has made ~10rwkw gain & NO loss anywhere in the rev range. We have also played around with the stock VCT inlet gear (can be adjusted from factory) but haven't found too much extra.

[Bass Junky]

whatsisname:

Are you able to install an Adjustable Cam Gear on the inlet side as well, without completely removing the factory VCT gear?

As in, will I still have the VCT with the Adjustable Cam gear??

The reason I ask, is because if I can install both, then I can have light weight gears on both to reduce rotational mass and maybe advanve the inlet a little.

BASS OUT

[whatsisname]

Hmmm...... not sure if you could do an aftermarket/VCT combo mate? I don't see why you couldn't make the VCT assy bolt onto a HKS/OS Giken/Grex etc... cam gear.

As I mentioned above, the stock VCT inlet gear can be adjusted anyway. For a very minor reduction in rotational mass it's hardly worth the changing to an aftermarket gear, unless you wanted both the gears to look sexy.