Camshaft Choice - Sacrifice and Driveability

[Allan74]

I am just getting ready to order my CAMs finally and need a little help.

Anyways, I am having a difficult time choosing, as I don't have the experience with this motor. I don't wanna go too small, but I still want some driveability as STREET CAR is concern#1.

Plug'N Play CAMs are NOT an option (type A, B, C etc.) as I want atleast 9.5+ Lift.

Option#1:
Matched Int/Ex @ 264/10.5 ...or... 264/10.0 ...or... 272/10.5

Option#2:
UNmatched Int/Ex @ 272/10.5 Int + 272/10.0 Ex ...or... 264/10.0 Int + 262/9.7 Ex.

Ideally, I would like to run 272/10.8 Int + 264/10.5 Ex .....but Greddy doesn't offer those sizes, unless I run a 280/10.8 Int + 272/10.5 Ex which is TOO MUCH I think for a 'street car'.

Greddy Cam Choices:
http://www.greddy.com/products/display/?Category=engine&SubCategory=40

Ideas ? upside ? Downside ? Pros ? Cons ? Help ?

Am I approaching this all wrong ? trying to go with a bigger Int CAM and slightly smaller Ex cam just to help IDLE a bit and the worry of Reversion (like the OEM cams try to accomplish with their stagger) ? Should I be looking the OTHER direction ? (smaller Int, bigger Ex ?).......or just keep them matched for simplicity ?

I should also add, the Head will be completely built (Springs, Retainers, Guides......maybe+1 valves, maybe not) and ported.

Thanks,
Allan

[Allan74]

Here are choices I have come up with from Greddy's ProCam List......

----------------------------------------------
#1 - 264/9.7 Intake Cam + 264/9.7 Exhaust Cam (simple, matched)

#2 - 272/9.7 Intake Cam + 272/9.7 Exhaust Cam (simple, matched)

#3 - 272/9.7 Intake Cam + 264/9.7 Exhaust Cam (simple, shorter Ex Dur)

#4 - 272/10.5 Intake Cam + 272/10.5 Exhaust Cam (matched, but maybe too BIG ?)

#5 - 280/10.8 Intake Cam + 272/10.5 Exhaust Cam (un-streetable ?)
----------------------------------------------

The #3 option seems to be the front runner for me, in terms of what's available and overall street car application.

Thoughts ?

[sidewayz32]

Well for me I would look at my driving habits,streetable is a matter of opinion.
So do you find that you tend to follow the speed limits a lot and not get the revs up? then I would go with the smaller cam. Do you see where im going with this? personaly I drive like a mad man everywhere except side street's,school/park zones etc... So the choice is clear for me BIG lol also im in love with the sound of an rb with huge lift and duration

[mcfly]

I remember someone talking about how terrible greddy cams are behind the numbers.

I will try and find the thread it had decent facts

But go big lift no matter what. since most come with big duration as well you may as well go both and rev to 9.

[Allan74]

Mcfly, do you think #5 in my list is a little TOO MUCH for my application ? or just stick with #3 and call it a day ?

[mcfly]

it was apexi cams that were the ones to stay away from.

#5 would be awesome so long as you can deal with an 1100 idle or so.
you wont loose any driveability or low end. mid range and top will benefit a lot.

[XXXsebXXX]

it was apexi cams that were the ones to stay away from.

#5 would be awesome so long as you can deal with an 1100 idle or so.
you wont loose any driveability or low end. mid range and top will benefit a lot.

I have Mines 260 cams and I run a 1100idle so...RB engine dislike to be treat under 2000rpm. From my point of view I think that if you want a great streetable car you wouldn't put twin or triple plate clutch or big single, its like everything: you get used to!

good luck Allan

[Allan74]

From my point of view I think that if you want a great streetable car you wouldn't put twin or triple plate clutch or big single, its like everything: you get used to!
You are totally right !.......lol

I guess it's just idling in traffic that scares me, or the thought of 3-foot'd driving at the lights, trying to keep the car idling/stoped etc at the same time.

[XXXsebXXX]

I have a good friend running HKS (unknown duration/lift) camshafts with a T04Z turbo setup and the tune was done with 1800 idle, he reports no problem with the driveability.

[sidewayz32]

that is a really high idle,could you not add a vac booster to help idle,stalling out while stopping?

[mcfly]

there is no reason the idle has to be at 1800, you can tune out big cams with nearly every standalone on the market now.

We are not dealing with hks 312's or anything.

[Skym]

Cams are good if done right (match configuration) and car is quick.

From what I have noticed, more cam duration or playing with adjustable camgears (adjust overlap between intake, exhaust cams) upsets the idle. Most ECU's should make engine run smooth at idle with higher duration cams than stock. But blip the throttle and that soon changes.

More duration = less bottomend hp but gains at mid to peak hp. Also more aggressive cams shove the peak torque, peak hp (powerband) up the revrange.

Cams are worked out to match port size, valve size, intake, exhaust manifolds, turbo size, etc. It's not as easy as saying that cam will do, as it needs to be worked out.

There are programs floating around that you input the engine info into and they help to work out the correct setup before buying any parts.

For example on Kelford cam website (software) -

http://www.kelford.co.nz/computer-software/

If you don't have access to that program, fill out this form on Kelford cam website and ask for their recommendation (custom made cam) -

https://www.capella.co.nz/sites/kelford.co.nz/design-shop/

Their cams provide good hp gains over other cams at lower boost levels. But evens out when you run higher boost levels.

Look at the links I posted on GTRC for EVO cams to see what I mean -

http://forums.gtrcanada.com/showthread.php?t=47644&highlight=cams

Most buy turbo's, cams, exhaust manifolds, etc from the same manufacturer, like HKS, Apexi, Greedy, etc, as they have worked this out for the customer.

Sometimes you can substitute the turbo, manifold parts from manufacturers mentioned in paragraph above for custom made parts, which might be cheaper.

[Allan74]

Well, I am desperate now......

There doesn't seem to be stock on anything in the US - everything is special order from Japan at this point.

I need BIG (well Med) CAMS.......
The rest of my valvetrain will be here any day and I wanna get my head into the shop.

[mcfly]

As we just discussed, you grow another inch of manhood with 270x10.

How can you say no now?
Plus i think everyone wants this idle.

http://gtrvision.com/play.php?vid=151

[Allan74]

How about this:

Greddy Pro Cams - Matched 110deg.Int/114deg.Ex Both 9.7mm/272 Duration @ 32mm bs. Anything larger is 31mm.

The easy way ? no crazy shimming etc.

[mcfly]

yeah shimming would be "decent"

either way they make shims in sizes that would work well with 31mm bc anyways.

[christ.deyoung]

What turbo are you going to run with these cams/how much power?

[Allan74]

What turbo are you going to run with these cams/how much power?
Small Turbos to begin with. Nismo RS-580's.
I wanna try a 'Mines-type' setup with small turbines and big cams for response, but the possibilities will be endless as I am building the shit out of my motor with basically the strength of the 05U block/crankshaft as the upper limit for the future.

[rb-racer]

where are you finding the nismo rs580 turbos?

[Allan74]

where are you finding the nismo rs580 turbos?

I own them already.

[christ.deyoung]

What did you end up going with for cams? I'm in the market for some 272ish 10.Xmm cams and I haven't decided on what to get...They'll probably be seeing Manley or Supertech springs and retainers some new guides, and seals for 8500 rpm service (not the cams, lol). Do most cams need different lifters to make for a smaller bc, or can you just use thick shims?

[GTR--J]

Interesting dyno comparison with a Supra on different cam profiles.

Hks 264/264, 272/264 And 272/272 Testing by SP ENGINEERING!!!! - Supraforums.com

[Allan74]

What did you end up going with for cams? I'm in the market for some 272ish 10.Xmm cams and I haven't decided on what to get...They'll probably be seeing Manley or Supertech springs and retainers some new guides, and seals for 8500 rpm service (not the cams, lol). Do most cams need different lifters to make for a smaller bc, or can you just use thick shims?

I ended up going with Tomei 270/10.25mm on both Int & Ex .... and (as recommended) Tomei oversized Lifters. I also picked up Tomei Cam Cap Studs to help ensure that I can stick with my game plan and continue building everything for 9,500 RPM.

As far as the rest of my valvetrain goes, I went with a complete Manley setup for Springs/Ti Retainers/Locks that are good for big lift and big RPM obviously. I also purchased Manley Pro Flo Extreme-Duty Stainless Steel oversized +1mm Valves, for both Int & Ex. I did end up using Supertech Magnesium Bronze guides, as Manley doesn't make them...for RB26/SR20 anyways.

I still have to pickup a set of heavy duty HKS Valve Seals, as most OEM's won't seal over 8,500+ RPM and I have Yonaka's which are basically OEM if I am not mistaken.

I am also going to measure the valve seats and try to pickup some Tungsten ($10/each)replacements, as I refuse to pay $700 USD for Tomei Beryllium-copper ('berry rings') valve seats and they are not the best for heavy Stainless valves anyways. Since I am using Stainless Valves, my choices are pretty open, as Stainless conducts heat very well and can be used with a larger number of different 'harder alloys' or 'tool-steel' materials for seats.

For smaller base circle cams, I am sure you can get away with just shimming, but I decided to stick with the 'recommendations' from the manufacturer, since I wanted to KNOW that I would be good for high RPM and big power without worrying about anything.

I really spared no expense on the cylinder head so far (and am still considering purchasing a brand new cylinder head to use), I just hope I can find someone who I am comfortable with (along with the shortblock) to do the port/polish work and machining/assembly. For me, that's my greatest fear - spending a shit load of cash, then having it wasted on a shit build/work by someone.

[Kras]

ah man your car is going to be insane when finished

[Allan74]

when ......finished
That's the 'key' word unfortunately.......LOL

The road ahead is long....and no 'light at the end of the tunnel' in site.

I can't see my car even close to finished before next summer (2011).....and even that's a BIG maybe.

[mcfly]

Welcome to the big build dream. No car for years on end.

Endyn does valve seats.

[Allan74]

Welcome to the big build dream. No car for years on end.
No shit....


Endyn does valve seats.
I will check and see what they use/offer.

[mcfly]

Interesting dyno comparison with a Supra on different cam profiles.

Hks 264/264, 272/264 And 272/272 Testing by SP ENGINEERING!!!! - Supraforums.com (http://www.supraforums.com/forum/showthread.php?t=404377)

this pretty much confirms what I told Allan and what I live by, go big or go home. Unfortunately Allan chickened out a little bit :p

With this test there was one unaccounted variable. The 272 was a 9.3mm lift where as the 264 was a 9.0mm.

Then there is the rb26, we are so much luckier then the 2jz guys as we have super heads in regards to available lift.

[mitch32]

I really wanted the big lift cams but chickened out cause of driviablility and didn't want to buy the extra buckets. I went with baby poncams-b and uprated springs, and decided to do some extensive porting via a well known head builder (cost alot more then those buckets would of with a simple port match to boot). Just reading this thread makes me regret going small lift (that signal gtr sounds too good)!

Rb26 have really nice heads, we got unlucky with oiling issues, but unlike supra's our heads are simply amazing (or thats atleast what I tell myself when I go to sleep!)

[Gaelen]

I've driven cars with 280/11.8mm cams in them. It's not at all unstreetable, if you know how to drive and it's tuned its totally possible.

Pick the cams you want and just drive the damn car already! :D

[Allan74]

this pretty much confirms what I told Allan and what I live by, go big or go home. Unfortunately Allan chickened out a little bit :p

I'll admit, I did chicken out a bit......lol

I think for me though and the fact that I will always run low-mount twins, the 270/10.25 are going to work out quite well, as my powerband is not going to be up high enough to take advantage of larger camshafts and they may have proven themselves to be working against me in the end.

[christ.deyoung]

So would 270 and 10.8 be too aggressive or produce minimal benefits for a pump gas, <600whp GT4088 with an 8500-9000 rpm limiter?

[Allan74]

So would 270 and 10.8 be too aggressive or produce minimal benefits for a pump gas, <600whp GT4088 with an 8500-9000 rpm limiter?

Well, I guess if I was going big single, I would have probably gone with that Camshaft as well......but that's about as much as I can comment.

[mcfly]

So would 270 and 10.8 be too aggressive or produce minimal benefits for a pump gas, <600whp GT4088 with an 8500-9000 rpm limiter?

I say go for them, you wont be disappointed.

Allan, I forgive you. I was trying to precariously live through you since my car will be years to come.

[Allan74]

Allan, I forgive you. I was trying to precariously live through you since my car will be years to come.
LOL....I have a feeling mine wont be as far ahead of yours as you might think, at the end of the day. Like I said, I am being realistic and shooting for 2011.