Rule of thumb: A good flowing head with a relatively small cam will make good power. A poorly flowing head with a large cam will be a dog.

In short, cams cannot 'make up' for a poorly flowing head. The head is the ultimate limiting factor. Choosing a cam set is like choosing an injector size - decide (realistically) what you need and don't get larger than you need.

 

You will definetly see a huge difference. I have polariods of the pockets when they were stock compared to the ported pockets. HUGE Difference. Also the stock valve seat is way low in the pocket so to be able to bring that up with a 3 angle or 5 angle will help with flow also. The Intake ports on the Head i found to be actually pretty good. The exhaust ports on the head are about the worst i have seen. There is major porting that can be done on the exhaust ports almost a good 1/4 inch all the way around jsut to match the exhaust gasket.

By freeing up flow in the head you are able to run higher lift cams or duration and see more gains then you would with a non ported head. Of course i havent been able to verify this but from the machine shop that did my pocket port said they seen another mitsu head with similar design pick up 40whp just off the pocket porting. I took it with a grain of salt but we will find out soon how things go.

Ted B:
Ya i will get you those Tomei numbers soon as i get home but from what i remember i think it was 218 at 1mm but i will verify that once i get home like i said.

I have a scanner at work but its not in color so that wont help any otherwise i would scan in the polaroids of the stock pockets compared to the ported pockets to show you guys the difference. I do have pictures of the full engine build but that really have nothing to do with the topic.

The 1mm over valves really are not necessary you wont see much of a difference as far as size and really i just wasted money getting the 1mm over the drop ins but i got a good deal on them so why not. Its the Sodium Nitrate that really makes them stand out. They are able to withstand heat better from the coating on them and the stems are nicely shaved to help with flow that is the main area you will see a advantage.

Chris
Chris

 

No doubt that head porting is one of the oldest tricks to getting more power. However, what has to be done here is to determine what is the expected flow potential from the head, and this is done through actual flow numbers and a bit of mathematics. If the head easily flows well enough at our expected flow rates such that it isn't an issue for a motor that is limited by the stock turbo, then it probably isn't worth the effort and expense for these applications. After all, if one can reach the theoretical power limits of the stock turbo with the head as-is, then I'm not certain what left there is to be gained from spending the money to port the head.

However, when we begin talking of big turbos and very high power numbers, the port flow ability becomes increasingly important.

 

If one wants to install a set of cams and forget about it, the 264s are a solid choice. The 272s appear to give a bit more tuning potential with supporting mods (including gears). There are back-to-back dyno tests that have been posted that illustrate the differences between the 264, 272, and a combo (one of each). The differences between them are not very large, and I'd make a decision based upon what you see as a realistic endpoint for modding the car. There are 264 equipped cars running 11sec E.T.s, so that should put things into perspective.

 

Agreed!

Chris

 

the most helpful thread ever!

 

so with me being on more of a drag race type setup. With the right supporting mods like cam gears tuned correctly, full exhaust, I have an intake and ic pipeing, probably gonna do the 10.5 hotside for now, and eventually a turbo upgrade, would I be able to squeeze out a few tenths more with 272's over the 264's or would the gains be less noticeable. thanks agian.

-Chad-

 

The differences I've seen in the comparisons did not appear to be worth a few tenths.

You may find this page helpful, and the trends are more or less what you should expect:

http://www.automotosports.com/cam_test.asp

 

So , by that info 264/272 would be a better , if not "best" combo for stock heads ?
BTW ---- very good info here .

 

I disagree.. If you look again the 264/264 seems better all around. The 264/272 gained only 1 HP and .1 TQ, but the spool up was slower.

That page is one of the reasons I picked my set up. I stared at the page for quite some time before I even called Al. IMO though, both would be a great choice. And from that page the 272/272 really doesn't gain much over the 264/264 (look at the dyno comparing them) but the spool up slower and the idle and low end torque are worse. 272/272 would probably be better if you're going bigger turbo.

Just my thoughts.

 

I see some people voted for the works cams. How are they. I was kinda of eyeing them but they seem a liitle high in price compared to the HKS.
For those of you have them what kind of gains have you seen?
Do you have dyno sheets?

 

For this, the 272in, 264ex is for you. I personally have the 272 straight & the car is well tuned & runs like a beast up top(power hits hard from 4000rpm and up) but if i were to do it again the only other combo i would go with is the 272in/264ex as it hits from 2000rpm and up from what i am hearing(& breaks tires 1st, 2nd & 3rd) which would be ideal from road racing/auto X.

 

If your talking about the AMS "cam test page" thats on a 1g head so it might not be the same for evo heads ? But still some good info...

 

True, and that's why the numbers should be taken lightly. The trends however should be the same.

Also, I should add that these charts reflect the cams installed straight up only. The longer duration cams offer more tuning flexibility (with cam gears), and obviously, various timing settings are not tested here. Therefore, what you are seeing, especially with the longer duration cams, is not necessarily reflective of their absolute potential.

What it does prove however is that bigger is definitely not always better when it comes to cams, injectors, certain exhaust components, etc.

 

Honestly i still would have to say with the options posted above that you are looking at the best would be whatever will meet your needs. So you are going to drag race you say. So you want lots of top end since every time you shift you will be in the upper RPMS anyway which is where the 272/272 comes in. Now if you plan on doing some AutoX then you would want some low to mid end power which is where the 264/264 combo would be beneficial.

Like my new found friend Ted B mentioned you can always get the 272/272 and adjust the cam gears for whatever you plan on doing that day and if you are willing to do that then the 272/272 combo might be best for you. Im not a real big fan of mixing the 264/272 combo's but that is just me. The only cam company that is currently doing that is Revolver and there is not a huge jump in duration with there cams like you would see if you were to go with the 264/272 combo.

I dont know if you guys have seen this but AMS did a cam test along time ago on a 94 Eagle Talon which of course has the 4G63 in it just a different varient of it. There results were as follows

Stock Mitsubishi Camshafts:

Peak HP: 309.5

Peak TRQ: 295.3

Spool up on street: quick, full boost by 3.2K RPM in 3rd gear with good power when off boost and as it's coming onto boost.



Web Cams - Street Grind:

Peak HP: 314.3

Peak TRQ: 295.3

Spool up on street: slower than stock, full boost by 3.4K RPM in 3rd gear with less power off boost than stock cams.



Crower - Stage 3 Grind

Peak HP: 322.6

Peak TRQ: 314.0

Spool up on street: much slower than stock (the worst of all the cams) with full boost hitting by 3.6-3.7K RPM and a definite loss in power off boost compared to stock cams.



Jun Stage 3 Grind

Peak HP: 323.7

Peak TRQ: 323.2

Spool up on street: Car was not driven on the street.



HKS 264 Intake 264 Exhaust

Peak HP: 323.1

Peak TRQ: 333.0

Spool up on street: As good as stock (3.2K RPM), with off boost power the same if not better than stock.



HKS 264 Intake 272 Exhaust

Peak HP: 324.2

Peak TRQ: 333.1

Spool up on street: Slightly slower than stock (3.3K RPM in 3rd gear) and a very slight loss in power in off boost conditions.



HKS 272 Intake 272 Exhaust

Peak HP: 325.2

Peak TRQ: 323.4

Spool up on street: Slower than stock, full boost by 3.4K RPM in 3rd gear with a slight loss in power in off boost conditions.

As you can see the 264/272 combo made the most torque by like .1 ft lbs but made 1whp less then the 272/272 combo. Of course you also see the 10ft lbs of torque that the 272/272 combo lost over the 264/272 combo. All these were done with the cam gears set at 0/0 so if you were change them you could gain some of that torque back. Personally i still think that there are better options out there then the HKS cams but hey i think i have said enough about that. Hope this helps some.

Chris