Adj. Camgears and Low/Mid Power Improvements

[Cubes]

I am going to fit a set of Adj. Cam gears as soon as i do my next mod ... Turbo..

What I wanted to know is if any one had set the cam gears up to try and gain some down low/mid range power.

Top end power will be up around 200rwkw if not over with the new turbo as i figure if i loose say 15rwkw to gain a good chunk in the mid even possibly bringing the turbo on a little sooner it would be excellent for the street and really nice to drive.

I do remember reading back on SDU when i first bought my r32 a bloke with a R33 GTR set up a set of adj. cam gears to offset the turbo lag, he claimed that it actually brought the new turbo's on earlier..

Any one fiddled??

[BOOSTMEISTER]

I have HKS gears on my car and they are dialed in as best as we could do. with the vg30 turbo we got noticeable gains in the bottom and top end but not much in the middle....it takes a while on the dyno to get them right but its a fairly easy task. One tip the settings for a GTR are totally different for the RB20. I would give you the specs but I am not sure how much the turbo affect it.

[ricknismo]

is it something like 4 degrees retard on exhaust side and 2 advance on inlet?

[Sydneykid]

Copied from post earlier today...........

by changing the overlap/separation on the inlet and exhaust camshafts you can most definitely improve the responsiveness of the engine.

However it is a lot easier to set them up for maximum horsepower, we simply run the car up on the dyno and determine where in the RPM band it currently makes its max horsepower. We then work through the combinations of advance on the inlet and retard on the exhaust until we achieve the highest reading at the predetermined rpm. We may move up a down a little in the rpm range just to make sure the adjustments have not altered the maximum power rpm point. Generally speaking there will be little if any adjustments required in the fuel and ignition maps. This process normally nets a 10 to 15 bhp increase at that rpm, but sometimes we loose as much as 10 bhp in the lower rpm positions.

Setting the cam timing up for best responsiveness is a lot more difficult as you are tuning through a range of rpm not just a single point. The way we do it is to tune as above but at the maximum torque rpm. Depending on the boots rise, we are aiming to increase the torque for at least 1,000 to 1,500 rpm around that point. We find that in order to get a good increase we need to change the ignition and fuel maps. Typically we will get a 20 bhp increase at that rpm, but loose up to 10 bhp at the maximum horsepower rpm.

Once we finish on the dyno, a road (better is track) test to confirm we have achieved not only a torque increase but a response increase as well. Our experience has been that if we have to make large changes in the ignition and fuel maps we will get a big improvement in response. Conversely if we only make very tiny adjustments, the response improvement is not as great.

Hope that helps.

[ricknismo]

I know fine tuning is required but I was after general terms until I can get it to a dyno (which probably wouldn't be soon). I've heard pretty much the exact same setting from a million people on the exhaust side but no comment on the inlet side.

[adam 32]

joel i just posted something about this 2-3hrs ago and got 2 pages of responses. check it out

[Sydneykid]

Hi joel, try 2 degrees advanced on the inlet and 4 degrees retarded on the exhaust.

[Cubes]

wow... this is an old thread..

Thanx Sydneykid.. What turbo did you end up deciding on for your sons R32? VG30 or RB25?? I wasn't happy with the loss of response with the vg30 terd

[Sydneykid]

Hi Joel, thought that might be the case, it's been our experience that the VG30's are now too old and out of date technology. We are going to use an RB25DET turbo hi flowed by our usual supplier (GCG) on jnr's car. But the car has changed, it's a 180 SX with the SR20 in 'er. Should be good.

[Cubes]

ahh.. Nice.. Those GCG Turbo's definately are the way to go.

I've heard a lot of good reports about them.

I remember you first got me thinking about them.

So why the180sx? The SR20 a little bit better for a street application? More torque?

[yogi000]

I know this is an old old old thread, but i'm trying to find alittle something out,

When adjusting cam gears is this correct ?

1. Advancing the cam = rotate clockwise

2 . Retard the cam = rotate counter clockwise

is this correct or have i got it all wrong?

Also on the JUN cam sprockets, is each increment 1 degree or 2 degrees??

Cheers!

[Skylineusa]

I found some good rules for setting up a cam;

Advancing the cam gear opens a valve earlier, and closes it sooner... retarding the cam gear, opens the valve later, and closes it later... since all you've done is moved a fixed event.

Advancing Intake and Exhaust : This will provide the car with more bottom end power, and will decrease top end. Advancing both cam gears will move overlap earlier.

Retarding Intake and Exhaust : This will increase the cars top end, but will decrease low end. Retarding both cam gears will move the overlap later and but will not change the amount of overlap.

Advance Exhaust Only : This will help the cars top end, and it reduces overlap.

Retard Exhaust only : This will help the cars mid range power, very useful for cars with big turbos / big cams. By increasing overlap, It decreases lag significantly. Doing this will bring the boost on all at once.

Advance Intake only : This will increase overlap and helps the cars bottom end and mid range power. This mod will bring the turbo on all at once.

The lift has a dramatic effect on low R.P.M. performance, but has a lesser effect at higher R.P.M.s.

Duration has the opposite effect of lift. The longer the duration, the more the R.P.M. horsepower will be boosted, but it is at the expense of lower R.P.M. horsepower.

As we all know, it's a bunch of trade offs. What one tuner might think is a good trade off, another will think its a bad trade off. That is when the debates will start.

[Skylineusa]

Here are the stock cam specs from an R33 GTR, the R32 should be very similar.

Intake: 240 duration @ 8.58mm lift.

Exhaust: 236 duration @ 8.28mm lift

I cannot find anything on the timing events, if any of you have them post them up.

__________________

[Sydneykid]

I know this is an old old old thread, but i'm trying to find alittle something out,  

When adjusting cam gears is this correct ?

1. Advancing the cam = rotate clockwise

2 . Retard the cam = rotate counter clockwise

is this correct or have i got it all wrong?

Also on the JUN cam sprockets, is each increment 1 degree or 2 degrees??

Cheers!

The engine turns clockwise, so if you turn the CAMS clockwise you are retarding.

Each tooth on the pulley is 15 crankshaft degrees, count the marks for one tooth.

Hope that helps

[aridyne]

Is there any major differences between the JUN/HKS/APEXI/TOMEI/GREEDY Cam Gears?

Price obviously, but they all do the same job right?

I just know if any are better then others for certain reasons or is it all just branding that has the price differences.

[benm]

Some people on the forums say that the HKS teeth wear out quicker. To be honest 80% of the 'big powered' Skylines i've personally looked under the bonnet of over the past month have been using HKS so it must be the minority that have warn teeth, im personally using a HKS.

The diff in price is about $30 between the cheapest and the most expensive.

Edit: Oh and heres a dyno graph of my before/after... it's ~$200 well spent.

[yogi000]

Thanks Sydneykid for that, will try the setting you mentioned above and see how my seat o meter responds

[aridyne]

Some people on the forums say that the HKS teeth wear out quicker. To be honest 80% of the 'big powered' Skylines i've personally looked under the bonnet of over the past month have been using HKS so it must be the minority that have warn teeth, im personally using a HKS.

The diff in price is about $30 between the cheapest and the most expensive.

Yeah I have heard the same thing about the HKS, I was thinking either Apexi or Tomei as they are both just a repituble as HKS. Tomei from my understanding don't use Aluminium but rather Duralium which is an alloy of it but well better quality and I think for $200 bucks ea, they are worth the buy?

[BoostdR]

The engine turns clockwise, so if you turn the CAMS clockwise you are retarding.

Each tooth on the pulley is 15 crankshaft degrees, count the marks for one tooth.

Hope that helps

i think he meant to say :

The engine turns clockwise, so if you turn the CAMS COUNTER clockwise(inside of adj cam gear)u are retarding.

Each tooth on the pulley is 15 crankshaft degrees(7.5 degrees cam) each cam mark = 2 degrees at the crank.. So when we say 4 degrees retard the exhaust cam it's actually 2 marks on the camshaft pulley. Beware of some chinese markings as the Advance and Retard are labled backwards. Check them against a photo of a HKS pulley.

Edited October 21, 2009 by BoostdR

[TriniGT]

I think that was five years ago, check the post date .