what cams to get????

so i have searched really didnt find what i am looking for

i have 272 cams from a local cam grinding shop want new cams but dont know what to get

i was looking at these cams

click

i do have a 2.3 stoker bottom end wit a 35r set up i have the fuel system and all supporting mobs

but i think that the cams i got from the shop arent that great

 

It really depends on your setup. Power levels you want to achieve, turbo selection, etc.

You really can never go wrong with a good set of 272's (FP, COMP, HKS) especially in a 2.3. Unless your running some big huffer flowing alot of air, for a street car 272's would most likely be your best bet, also factoring in that you cant rev that high, the one thing to take full advantage of bigger cams like 280s or 288's.

If youre unsure about your cams, get a set of comp 101200's or HKS 272's and im certain youd be satisfied.

 

well im gonna be taking it to 8 grand will the hks 272 go that far??? i tried looking it up but couldnt find
anything

 

[prove_it]

With a 35r pushing past 8 grand, I would maybe give Kelford a call and ask about their 280 cams. You'll be moving a bunch of air with that turbo on a 2.3 stroker, especially past 8k rpms.

On our 76mil 2.3L Evo when we switched from HKS 272's to the Kelford 282's we picked up about 50whp after 7600.

Also you didn't mention if your daily driving this, or what you need for low end and mid range.
You can always swap out valves for some higher flowing valves and run the 272's if you want to maintain a more streetable car while still achieving a good head flow rate.

 

yeah i street drive it about twice aweek

i have 1mm o/s intake valves wit a port and polish

im trying to make it a track car but have it street legal and make as much power and torque as possible

 

Yeah get yourself a good set of 280's then, preferably Kelfords like mentioned above.

 

[atc250r]

I had 280's in my car with a similar set up but a 2.0L and I ended up taking them out. They did make the car pull like an animal from 4000 or 4500 up to the 8500 rev limit (not so good for a stock rodded short block) but they also killed my off boost torque. The mountain I go over to work everyday I used to be able to climb in 4th gear at about 50mph and accelerate at will, after putting the 280's in if I hit the bottom of it at 50mph I'd end up starting to lose speed and downshift to 3rd. If I wanted to pull in in 4th I'd have to hit it at 60mph but it was a 40mph zone and the cops would wait for people to "attack" the hill. I ended up going back to a 264/272 combo, the dyno tests that were published showed little difference HP wise between that and 272/272 set up. If you want to play on the street I'd probably go with the 272's although you have a 2.3L so that should soften the 280's up some. Didn't FP make cams specifically for stroker motors?

John

 

The +1mm vlaves are gonna kill any off boost power anyways, so might as well make use of them when on power and rock 280's, ya know?

 

how does the 1 +values kill off boost? i was told it helped the flow of the head am i wrong on this?

would stock stainless steal values be better for my set up? if i were to go eirther way wit the cam (280s or 272s)

 

[toybreaker]

Quote:

The +1mm vlaves are gonna kill any off boost power anyways, so might as well make use of them when on power and rock 280's, ya know?



That might be true on many engines, but these 1st gen 4g63's are a bit of a unique case. The heads on these cars have simply huge ports as delivered, and the only place they really need any love for optimal performance is in the valve bowls. (The ports are so large, in fact, that many people looking for drivability/modest power levels and higher efficiency are moving towards the 2g/later small port heads.)

When I was still in the machine shop a few years ago, I played with throating the valve seat, matching the valve bowls, and blending the transition. I found significantly better drivability (off boost) from this mod, even on my modest set-ups.

The gains from having less random turbulence, and a more even cone more than make up for any teeny loss of velocity.

This is because the machine work (from mitsubishi) leaves a lot to be desired in the transition between the valve seat and the bowl.

The bowl is *generally* larger than the seat. Add in core shift, and all bets are off as to the actual match of the seat to the bowl. (I have yet to see one that was matched well enough for me to run out of the box.)

With a large bowl/small seat, and a bit of core shift, you end up with a situation where a "ledge" is formed in the airflow path.

The effects of that mismatch are a turbulent, non linear flow right in the area you want everything to be orderly. Getting the airflow distributed as evenly around the valve as possible is by far the most efficient technique for getting air into and out of the chamber with minimal pumping losses. It also aids in cylinder to cylinder distribution. This brings the weakest cylinder much closer to the others, and allows you to get a more predictable tune that's closer to optimal with less chance of the lean hole getting pissed and showing it's displeasure with knock. (remember, that fancy a/f gauge is reading an average of all four cylinders a/f ratio. You can and often do have one hole weaker than the rest, and if you're ballparking the a/f and then tuning to knock, well, you just gave up a buncha power/efficiency tuning to the weakest cylinder)

This cylinder to cylinder disparity is especially true on the intake side, and is really noticeable in the lower airlow numbers. Optimising distribution results in a much more responsive motor when you're operating in the lower airflow region, because you can dial in more aggressive timing without the weakest cylinder knocking.


In addition, for higher output set-ups, it has been my experience that going to 1mm oversize valves, opening the seat up to the bowl diameter and blending the transition makes a significantly larger difference than just a 1mm change in diameter would suggest on paper. Reducing the turbulence/restriction at the valve seat/bowl area will result in higher airflow at the same (or lower) boost levels, and that really pays off accross the entire dynamic range of the engine.

/ubbthreads/images/graemlins/cliffs.gif The devil is in the details on these motors, and a noticeable increase in performance can be obtained with a little work in the valve bowls.

While it's true that just chucking in 1mm oversize valves will not give much benefit...because the seat/bowl mismatch has not been addressed... 1mm larger valves, combined with an optimal seat/bowl transition is one of the easist paths to good power combined with excellent efficiency.

Combine that with a well matched cam set and an efficient turbo, and you're good to go.



Now, back to the original subject, cams. /ubbthreads/images/graemlins/smile.gif

 

im aware. i did some extenstive testing on a flowbench with a 1g head and the biggest gains were in the bowls removing those huge casting lips before the seat, its amazing how bad the castings really are on some 6 bolt heads. Ive always stayed away from big valves though since the one time i used them in a 7 bolt head on a 6 bolt block, even with the port work and a good 5 angle vj it was a noticable loss down low.

i was referring to the turbulence caused by the valve head being so close to the walls of the combustion chamber. But i guess in all reality, the shear tq increase factor of the 2.3 would make up for any other loss whether it be from big valves or big cams anyways.

But judging with his mods and what not, i would lean towards the 280's allowing him to get the most effeciency out of his setup. And even so, most times any loss of low end power could me bade up for with come cam timing adjustments. Theres ways around it all, just depends on what way you take.

 

[toybreaker]

Quote:
im aware. i did some extenstive testing on a flowbench with a 1g head and the biggest gains were in the bowls removing those huge casting lips before the seat. Ive always stayed away from big valves though since the one time i used them in a 7 bolt head on a 6 bolt block, even with the port work and a good 5 angle vj it was a noticable loss down low.



That's a completely different ballgame.

The small port 2g heads won't like a change at the valve unless the rest of the area, and the port runners are reworked to take advantage of it.

Biasing the airflow away from the chamber walls (tipping the cone) is black magic, and I've only seen a couple of people that could do this well. (myself, not included /ubbthreads/images/graemlins/blush.gif )

Chris Beran (BOOSTIN HARD) has got this mod down to an artform.

Anyway, this thread is about cams, and I'm out of my depth once we go past a 272 cam set from a reputable manufacturer.

About all I can add to that discussion is that I have learned the hard way that not many regrinds measure out to their cam card... /ubbthreads/images/graemlins/banghead.gif

Just getting a set of cams from a reputable manufacturer with the the same "advertised" lift/duration as the mystery cams has picked up substantial power on more than one occasion. /ubbthreads/images/graemlins/wink.gif

 

I agree. i had a set of the DKS 272 regrinds, and even after HOURS of dyno time and adjusting the cam timing it never really impressed me. Idled like sh*t and didnt make as much power as i had expected. I swapped them out for some HKS 272's and with the gears zeroed out it made 16whp more than the best results i got from the "regrinds".

From now on ill just stick to what i know will work instead of taking a chance on some mystery regrinds as you would say.

But to the OP, i dont think you will go wrong either way, by picking up soem HKS, kelford or comp 101200's (272's), but i also dont think youd go wrong picking up a set of 280's from either of the same manufacturers. If money grew on trees a viable option would buy some 272s and 280s and see what you benefit either way, but thats usually not the case.

 

i got a money tree out back but it took me a while to grow lol

but how street able are the 280 cams? cause i take it im gonna have to up my idle to 1000 rpms to run them right?

 

ehh it depends. Kelford and HKS are pretty mild at idle. Youll have to turn it up a bit, but its not gonna be lumping at 1500 or anything.

PS can i borrow a branch or two from that tree? LOL

 

ok that doesnt sound too bad


thanks for all your guys help

ill dig up one of the trees for ya

 

[atc250r]

My BC 280's were OK at idle, it was a lumpy idle but it sounds bad ass and I never had problems with my power brakes. They had their own issues elsewhere though, as I mentioned in my previous post.

 

[Garage_Defeat]

I vote for FP4r Cams. Upgraded to these from my trusty HKS 272 cams.

-Dan

 

[iceman69510]

I heard 264s kill your idle, but only in PA.

 

^^^ ah...ah..ahhhhh.