Alright so I'm beginning to look at cams for my Evo IX and I have settled on buying a set of Juns, that part is certain. But my question is which cam would be better for my car/desires.

Mods:
- Stock 2.0L
- Stock turbo now, possible upgraded stock frame in future, 400whp MAX
- Exhaust/Intake/DP/255/Injectors/3 port/etc

What I want from the cams is extremely little to no increase (or even a reduction) in boost threshold, and essentially equal or better transient response/time-to-torque as stock cams along with power gains of course. I know the Mivec allows you to run a large cam and loose very little boost threshold (verified by dyno graphs and everyone here) but not many people talk about transient response- and it is to my understanding that a large set of cams will tend to dull this. I know the 272s should pick up more top end than the 264s, but if this comes with at significant cost to transient response I would rather accept the assumed more moderate horsepower gains of the 264s.

Does anyone have any input? Can the Mivec be used to pull good transient response out of some big 272s? Other thoughts? Let me know! Remember - my goals are not big power numbers on the dyno, but rather driving feel and a broad powerband.

 

I had the JUN 272's in my car with an old FP Green, and made over 400 hp on 93 oct. 380 hp on a low reading Mustang dyno. Transient was good, definitely a lot of fun, but you'll be hard pressed to do better than stock cams in that regard although a good MIVEC map goes a long way. I have the cams still if you are looking for some used ones.

 

Yeah I'm not sure how greedy I'm being with what I want from a set of cams - I know there are tradeoffs everywhere. I'm hoping though someone can chime in with some 264 experience or even better a relative comparison of the 264s vs 272s. Because if there's going to be a significant difference in boost recovery between the two I'll probably stick with the 264s.

 

Anyone have more insight??

 

get some 272's and call it a day. your butt dyno will not notice a difference in the boost and recovery. i would go the 272's.

 

I went with HKS 264's personally for the reasons your contemplating ; my car is setup for autocross, so transient response is extremely important. The 272's are not necessary if you really only want 400hp. Most people just follow the mold, and buy the 272's because they don't understand everything involved, and it's easy for any shop to just throw those in to hit a target HP number.

 

or... ask your tuner. that's what i did.

 

If I were to do it all over from the beginning....I would keep OEM cams with OEM turbo.

 

I had the same dilemma a few months back, my plan is to maximize power gains on a stock engine & turbo (non-mivec) & I'd hate to lose any transit response. After a bit of research about cams, I chose the GSC S1s, at 268 degrees is a kind of compromise between 264 & 272.

 

So far, in your experience, how do the GSC S1's compare to the stock cams as far as turbo spool-up and transient response are concerned(seat of the pants)?

 

This guy made 400 whp on stock cams.
https://www.evolutionm.net/forums/evo-dyno-tuning-results/693187-evo-9-se-stock-turbo-stock-cams-93oct.html

 

I think it has been pretty well documented on this forum that if you have a MIVEC motor, you will not loose any boost threshold with something equivalent to a GSC S2 or so or smaller. Transient response, however, is different and isn't shown on the dyno so a lot fewer people have concrete info.

Also, duration listed by manufacturers doesn't exactly tell you how aggressive a cam is. For example the Jun 264 have a relatively high effective duration and can therefore be considered "more aggressive" than an HKS 272, among other cams.

I was really hoping to magically find someone who has experience with Jun 264s or 272s and compare them with the stock cams, and to see if they change the characteristic of the car in off/on throttle situations. Idk if that person exists though lol