Need Some Advice Rb26, Pfc, Cam Gears, Cams?

[depalma-bcnr33]

to all my fellow rb's,

need some help...

i recently had my 33gtr dynoed at protek in preston and made 185kw atw with all stock except exhaust and intake.

sooo, i got a bit used to the power and spontaneously bought a PFC and cam gears, im also looking at some 260 9.15 poncams but not sure just yet.

after lots of reading and searching on the forums i still cant find the exact answer im looking for...

1. what kw should i be able to milk to the wheels with the PFC and cam gears???

2. what kw should i be able to milk to the wheels with the PFC and Cam gears and cams, and what will that cost me roughly if i do it properly (i.e valve springs etc)???

keep in mind the car is my daily driver so want to keep a safer tune...

thanks will apreciate any feedback/adviceeeeeeeeeeeeeeeeeee

also, anyone recomend a good tuner in melbourne???

Edited January 18, 2008 by depalma-bcnr33

[eddieeeee-ro]

my mate has the same mods on his 33 gtr, running 1 bar on the stock turbos 260kw atw.

[TommO]

2. what kw should i be able to milk to the wheels with the PFC and Cam gears and cams, and what will that cost me roughly if i do it properly (i.e valve springs etc)???

You won't need valve springs etc for 260/260 9.15mm lift Poncams. You might need to replace a few shims but it depends how lucky you get. Shims are $20-$30 each. Max you'd have to replace is 24, most get away without having to replace any. Mine get fitted next week, I'm hoping I don't have to replace many... I was quoted $350 for install of cams, and then $500 for dialing in cam gears + tuning.

Are you running stock turbos? I'd consider upgrading them to GT-SS's or something. Once you start pushing the stockers, you can easily get yourself into trouble if one blows up.

Hard to tell you a power figure anyway, however there's no doubt it'd be much more than you have now

Regarding a tuner, I've heard nothing but BRILLIANT things about Race Pace... I don't think that's they're full name, I'm sure someone will point you in the right direction.

You might want to replace the stock fuel pump as well.

Edited January 17, 2008 by TommO

[depalma-bcnr33]

thanks.. yeah ive heard a couple of whispers about race pace as well but cant find them on the net :S, yeah still on stock turbos so ill tune it to 13psi.

fuel pump is a good idea, totally forgot about it from what i know maxes out at about 240awkw??

anyone else recommend a tuner (experiences) or know where racepace is? or any advice im all up for it.

[djr81]

thanks.. yeah ive heard a couple of whispers about race pace as well but cant find them on the net :S, yeah still on stock turbos so ill tune it to 13psi.

fuel pump is a good idea, totally forgot about it from what i know maxes out at about 240awkw??

anyone else recommend a tuner (experiences) or know where racepace is? or any advice im all up for it.

It is uncommon for people to change their cam shafts before their turbo chargers - simply because you wont get a gain for your money. Use the stock cams & adjust them using the gears you have bought. Only after you have changed the injectors/fuel pump/air flow meters/turbos/boost control plus a bunch of other bits should you need to look at cams. That point is a way past the 400rwhp mark.

As for power outputs on stock turbos with the PFC & gears you should be in the low to mid 300rwhp mark. Don't push the ceramic turbos too hard - no more than 14lb anyway.

Edited January 18, 2008 by djr81

[rev210]

It is uncommon for people to change their cam shafts before their turbo chargers - simply because you wont get a gain for your money. Use the stock cams & adjust them using the gears you have bought. Only after you have changed the injectors/fuel pump/air flow meters/turbos/boost control plus a bunch of other bits should you need to look at cams. That point is a way past the 400rwhp mark.

As for power outputs on stock turbos with the PFC & gears you should be in the low to mid 300rwhp mark. Don't push the ceramic turbos too hard - no more than 14lb anyway.

As someone who has done the poncam tomei cams on stock turbo's I would say otherwise for gains not being good for the money. They are excellent gains actually. Driving the car with stock turbos and upgraded cams over standard is a fantastic experience.

You are going to see the same substancial increase in the power curve shape along with the benifits of lower rpm/boost less aggressive tuning on fuel/timing and lower temps to make the same peak power all good things for standard motors and turbos.

I'm going to do it again in the not too distant future with this bunky gtr I have.

Later on when you upgrade the turbos they are still in there to be used.

Edited January 18, 2008 by rev210

[TommO]

Yeah, I've always been told cams + cam gears, even on stock turbos, end up with great gains.

[RPMGTR]

It is uncommon for people to change their cam shafts before their turbo chargers - simply because you wont get a gain for your money. Use the stock cams & adjust them using the gears you have bought. Only after you have changed the injectors/fuel pump/air flow meters/turbos/boost control plus a bunch of other bits should you need to look at cams. That point is a way past the 400rwhp mark.

As for power outputs on stock turbos with the PFC & gears you should be in the low to mid 300rwhp mark. Don't push the ceramic turbos too hard - no more than 14lb anyway.

Very good advice.....No need to look at a cam catalogue until you are well past 400rwkw...

We rarely put cams in RB26's anymore and are making more/better power than ever!!

[rev210]

Very good advice.....No need to look at a cam catalogue until you are well past 400rwkw...

We rarely put cams in RB26's anymore and are making more/better power than ever!!

Seems to be contrary to bulk of actual experience with GTR owners globally and manufacturers claims.

I'm interested in why you think it is all the same

[acsplit]

Seems to be contrary to bulk of actual experience with GTR owners globally and manufacturers claims.

I'm interested in why you think it is all the same

Lets just say first hand experience counts for more than manafacturer claims and kidz on teh internetz!

[monga]

stock turbo's will limit you to under 300-350hp, upgrade them then get the power fc then cams,

expect 400hp then or more

[depalma-bcnr33]

thanks for the feedback, most of the advice seems to be contrary to one another. i dont think i will be upgrading the turbos to anything massive (i.e past 290 awkw) because a forged rebuild isnt really feasible in the near future because im still at uni (peasant wages). i was thinking maybe some steel wheel 34's or maybe n1's at most to save the life in the motor.

cams was an idea i had so that i could get the same power with less boost, and seeing that i was doing pfc and cam gears thought i might as well chuck it in. its a tuff decision and in response to RPMGTR i dont think my car will ever see 400awkw lol... im more after the high 200's with great response and not so much boost, 1 bar absolute tops.

all feedback appreciated guys, anymore personal experiences and findings would be great, ive got the cash just deciding.

anyone recomend more tuners? anyone ROUGHLY estimate a price for the install of cams, or the other option n1's?

[rev210]

Lets just say first hand experience counts for more than manafacturer claims and kidz on teh internetz!

I hear what you are saying. Doesn't really answer the question. I have had 'first hand' experience of exactly the opposite, as have plenty of others on this forum and abroad who don't fit the 'kidz on the internetz' category. They seem to validate manufacturers claims. And why wouldn't they, the theory supports the 'real experience' and manufacturers claims (based on real test engines) also. There was a bloke on these forums a while back who worked for one of the manufacturers (tighe?) and had access to a cam design program that gives pretty good info on what changes to cam design will have on a given motor. I cammed up the exhaust side of an Rb25 with pretty much exactly the gains he suggested set at the timing he mentioned.

Lets hear some actual reasons in design why this might work.

[rev210]

stock turbo's will limit you to under 300-350hp, upgrade them then get the power fc then cams,

expect 400hp then or more

Thats nice if all you are after is peak power. A correctly cammed motor has an earlier and fatter power band. The average power is much higher and therefore the car significantly faster in every regard.

[djr81]

The problem with all this is people are not addressing the ancilliaries that the motor will require to reach the kinds of power levels they claim. There are three things needed to be focussed on:

1: The limits of the stock Air Flow Meters.

2: The limits of the stock fuel system.

3: The limits of the stock pistons.

Now from my experience and from comparing my Poncam RB26 with others of the same level of mods minus the cams - yes the Poncams will allow you more airflow at higher rpms. But this is at 400+rwhp. Much below this figure & certainly anything below 4500rpm you will be worse off.

The second item needing addressing is the cost. Simply put, whilst cam shafts are relatively cheap to purchase installing them properly with shim adjustment and then cam gear adjustment on the dyno is an expensive exercise. Given that a pair of new turbos runs to approx $2500 for Garrett goodness I would question the logic of running stock turbos near the edge of their reliability envelope - stock cams or not. Remember it is not boost that kills the turbos it is shaft speed - the more rwhp you make the more shaft speed you have. Whilst this will be a little less with larger cams you still run the risk of destroying a turbo which in turn may well wreck your motor.

Now don't get me wrong I like the nature of the RB with the 260 poncams installed. They will make power to 8000rpm & beyond with them. But unless your engine is strong enough & its ancilliaries large & reliable enough to allow it to run this kind of rpm/hp you are largely wasting your money. Other, more beneficial things need to be done first.

[rev210]

The problem with all this is people are not addressing the ancilliaries that the motor will require to reach the kinds of power levels they claim. There are three things needed to be focussed on:

1: The limits of the stock Air Flow Meters.

2: The limits of the stock fuel system.

3: The limits of the stock pistons.

Now from my experience and from comparing my Poncam RB26 with others of the same level of mods minus the cams - yes the Poncams will allow you more airflow at higher rpms. But this is at 400+rwhp. Much below this figure & certainly anything below 4500rpm you will be worse off.

The second item needing addressing is the cost. Simply put, whilst cam shafts are relatively cheap to purchase installing them properly with shim adjustment and then cam gear adjustment on the dyno is an expensive exercise. Given that a pair of new turbos runs to approx $2500 for Garrett goodness I would question the logic of running stock turbos near the edge of their reliability envelope - stock cams or not. Remember it is not boost that kills the turbos it is shaft speed - the more rwhp you make the more shaft speed you have. Whilst this will be a little less with larger cams you still run the risk of destroying a turbo which in turn may well wreck your motor.

Now don't get me wrong I like the nature of the RB with the 260 poncams installed. They will make power to 8000rpm & beyond with them. But unless your engine is strong enough & its ancilliaries large & reliable enough to allow it to run this kind of rpm/hp you are largely wasting your money. Other, more beneficial things need to be done first.

Hi djr81,

I certainly can't agree more with your comments about focusing on engine and ancillaries abillity to match a desired power level, it's good advice for any new or future GTR owner.

And you draw good attention to the fact that 'bolt in cams' aren't always a simple drop in and go. People should budget for more than just some cams.

But, I think from the outset people often miss the potential and real benifits of installing the right cams by assuming they ought to be tuned in such a way as to attain more outright top end power.

Setting up cams, for many seems to be focused exlusively on bigger power numbers on thier local dyno.But, what if you looked at the best gains selected cams have always offered in the abillity to give you greater tuning control over the shape of your power band ,'boost on'.

I installed cams (260s) on my old Aussie R32 GTR as both a performance mod and a way to increase the motors longevity.

As you mentioned, I looked at the limits of stock - Pistons / fuel system/airflow meters/ old motor etc..as having a horsepower limit. The old Rb26 also would ideally like to live life at lower rpm with less heat as well.

Along with a few other things I looked at the option of cams to help me acheive more within those limits and succeeded.

With a set of tomei cams in on stock turbos I could do things like;

* bring the boost in 500rpm or so sooner.

* have more power everywhere once boost was on (the fun part of the rpm range)

* make the same 'limited' maximum power level as stock cams, to ensure airflow meters/fuel pump/pistons etc are within a safe margin.

Importantly I made this peak power figure with;

* less rpm

* less timing

* a richer AFR (under boost/load)

* less boost (meaning happier turbos)

* lower intake temp (lower boost)

I had no orginal plan to upgrade the turbos, only did that after one died of old age. My main reasons were ;

* to make the car perform better under boost (the fun part of the rpm range)

* to increase reliabillity of the motors more sensitive areas by decreasing its efforts in the airflow/pumping air dept. when getting it's neck wrung.

A set of 260's may not be the best cam combo to get the most out of the stockers but, I do know they work much better than stock cams, making more power once positive boost is reached.I know This by virtue of spending quite a few hours on both cams (tomei & stock) altering cam timing tune on exactly the same motor, setup and basic conditions. My regret is I should have taken a bunch of printed graphs home to post up. Will next time, promise

I just think it's important to avoid focused talk about 400rwhp or any other number as a single number, determining when cams should or should not be bought.

[djr81]

Well this is the best I can do. It compares 4 RB26's in varying states of tune - the lowest with stock turbos/stock cams on 13# as a base line. From there up all of them had Garrett GT28-60 707160-5 turbos. The lowest output was on stock cams (With a gentle tune & low boost), the next (mine) on 260 Poncams 15# boost & a gentle tune, the last a harder tune (about 20# I think) & 260 Poncams.

Now, whilst one of the graphs is not in shootout mode (making absolute comparisons difficult) you can see that the stock camshaft Rb brains the aftermarket items at anything much below 5000rpm. The stock cams tend to run out of steam at about 6500rpm, however.

So I would make the generalisation that the Poncams move the torque curve up the rpm range by about 1000rpm.

Now this comes with a bunch of caveats, not the least of which is that I didn't spend any time looking for power below 4000rpm. Also the cams on my car are not phased properly (lack of time at the time - they are 0 degrees). I would think I could pick up some more low end with different phasing. Lastly my motor is on stock internals so it has been wound down to 435rwhp to give the poor thing half a chance.

As far as your list of outcomes from the cam/tune they are exactly objectives I had in mind when I bought the cams for my car, ie to get the hp I was chasing in the rpm range with the least amount of stress on the motor possible.

dyno_comparo.PDF

[Beer Baron]

it's pretty simple., for stock turbos and street use cams are a waste of time. you will get very good gains from tuning the stock cams with adjustable cam gears.

rev201, I hear what you are saying mate, but I reckon you could have got most of those gains with just some cam gears and tuning. very curious to see any before and after graphs though if you have them?

[Swiper the Fox]

it's pretty simple., for stock turbos and street use cams are a waste of time. you will get very good gains from tuning the stock cams with adjustable cam gears.

rev201, I hear what you are saying mate, but I reckon you could have got most of those gains with just some cam gears and tuning. very curious to see any before and after graphs though if you have them?

Right again BB...your good.

yes proven that the cam gears and a good tune will do more on stock cams with stock turbo's than cam upgrade will.

i tuned a stocker and set the cam gears up on a car and made 287KW at an SAU dyno day (i think this is still a record)

but....if you have the cash the cam upgrade will produce another small gain.

[rev210]

it's pretty simple., for stock turbos and street use cams are a waste of time. you will get very good gains from tuning the stock cams with adjustable cam gears.

rev201, I hear what you are saying mate, but I reckon you could have got most of those gains with just some cam gears and tuning. very curious to see any before and after graphs though if you have them?

Hi Beer Baron,

I can only find 1 of the series of dynos I did for the cams on the stock turbos, an early one unfortunately and not the most impressive, at least not to dyno queen obsessed people

I ended up lopping the peak around 300rwhp on purpose but I was making it in the end around 5,000rpm from memory at basically 10/11psi on the later tune before one of the rickety old turbos let go.

As you can see, I was making full boost and 160rwhp at 3,000rpm on a 'nanna' tune. 10psi stock turbos with the cams.

It pulled like a freight train by comparision to the stock cams, which at 3,000rpm had a joyous 40-50 or so rwhp less on the same motor. making that attessa work plenty early.

The bummer is I should have collected more of the tuning graphs for prosperity, as a comparison on the same car/motor/time is really the only way to go ideally.

djr81,

if we compare what mine has 'down low' just from this graph you can see tomei cams absolutely hand standard ones thier ass not the other way around.

actually in terms of lag/power at 3,000rpm it lays the smack down on a stock turbo R33 gtst rb25, in fact a little more than a RB30DET with rb25 turbo. oooh thats gotta hurt!

I'm investigating going down the same path again and I have absolute confidence of the outcome on stock turbos, as unremarkable as they are.

Edited January 21, 2008 by rev210