I posted this over on DSMTuners as well but I am not getting any real answers so I figured I would re-post here to see if anyone can give me some real answers. I know that I have a eagle but the motor is the same and the cam results should be as well.

I am looking into getting cams and I want to go with a 272 264 set up. I see some varying information about how to do it though. What is the difference between going with the 272 on the intake vs having it on the exhaust. Which one will give better spool which will give better bottom or top end? I have looked around for conversations on this and for some reason every one gets side traced and never results in any real solid information being brought to light. I am not looking to discuss whats better ex straight 272's just doing S1's etc. I am just looking for solid what happens when type of information. If some one can give dynos that would be great but even just some personal experience would be appreciated.

 

Is this on a DSM or an Evo?

HKS 272s are rather small by todays standards and normally if anything get installed 272/272. Running a 264 intake cam you will notice almost no lope but very little gains (throughout the entire powerband) around 15-20whp in my experience. No loss in spool and in my testing a little better power AFTER peak power, less fall off if that makes sense.

Running a smaller cam on the exhaust doesnt seem to work well as the balance between intake flow vs exhaust can cause backpressure issues in the turbine housing faster. If you let more in you have to let more out.

I could sim the combo but I will have to see if I have the 264 lobecenter info.

Aaron

 

I run the 264/272 HKS combo in my car. According to VD, I gained absolutely ZERO peak horsepower. What I did gain was spool and midrange, almost 30 wtq and 30 whp. And exactly as Aaron mentioned, the power drop off was less dramatic.

 

This is on a DSM. I think that is the first real info that I have gotten so far. so what your saying is doinga the 272 as the exhaust cam offers a similar change to doing the 264 cams but with a longer power range giving a fatter curve to it. Now Delta Cams says they only recommend doing the 272 as the intake cam for some reason. any one know why this is?

 

If I had to guess, its because they are not "only" in the mitsubishi business. 272 cams where HUGE back in the day. They were hard to idle and control and apparently made BIG power. But, in this day and age, they are relatively small and a stock ECU can control even bigger cams.

 

DSMs are slightly different animals compared to the Evo at least when it comes to idle. We did a back to back on a car on Tuners though going from this combo to S2s on a 3065. I would have to look at the thread but remember small cams on DSMs lead to knock more readily for a given boost level. I would run 272/272s in a DSM...and do. The Little Auto runs those and a 2.3 coupled with the FP turbos for the times it runs.

 

let me rephrase that, they only recommend that when doing this combo the larger be on the exhaust, from what I can guess they would want the turbo to provide the exhaust resistance I just dont know what that provides you with. They have no opposition to the use of larger cams they simply state that putting the 272 on the exhaust side is better when doing a combo set up

 

Its all about centerlines.

If the spread works better and is wider with the 272 (should be by reason) on the exhaust and it has more lift on the exhaust (it would compared to a 264) that is why they are recommending it that way.

I ran a stock IX MIVEC intake cam before there were any options with an HKS280 exh and picked up 400rpm of good power out the top I hadnt had before. Ran a 11.54 that way on a car with just 3" TBE, LICP, HKS 280 exh, and an old school Green when my car was a 6 speed (had to rev the crap out of 4th).

 

my kingdom for an HKS 280* exhaust cam

I happen to have the backwards 272* intake and 264* exhaust cam setup for my Evo3 with a 2.3 with Evo X twin scroll with 20g compressor side. I hope it does not kill my power band.

I may just end up getting the FP2 exhaust cam as just the HKS exhaust cam is almost $100 away from a set of S2's.

 

why did you go with the 272 on the intake, do you know what the difference is between that and having it on the exhaust?

 

Id love to replace a hks 272 exh to my hks 280. Thoughts on that stagger.

 

I bought them off another Evo3 owner locally, his car came with them from japan and he thought they were both 272's.

The only thing all my internet searching has found is that it was hot **** when HKS were the "only" people who made cams for the DSM's and cam gears were not plentiful and it was an "easy" way to apparently take out some overlap.

I under stand duration is how long the valve is open and lift is how far the valve is opened but as far as the effect a shorter duration exhaust cam will have vs a longer duration one is lost to me when both are used with the same duration intake cam

 

The basics of what happens is that a larger cam like the 272 has a better volumetric efficiency at higher RPM's where as a lower duration like a 264 has a better volumetric efficiency at lower RPM's that's why the more radical the cam the higher you have to rev the engine to produce power. Now running a combo of 2 different duration should effect the VE by allowing either more air in or more air out.

What I am trying to figure out is what cam will have what effect. I would assume that one would cause better low end power and one better high end, as well as having the turbo spool a bit faster I just don't know which one does what, but that answer doesn't seem very easy to come by.

 

i ran 272's on my dsm and she ran like a beast, just putting in my opinion if that helps (not tryna b a d*ck)