Badass Thread . It would be sweet if there was more on lobe separation angles and cam center lines as a reference with factory gears for people who don't know how.

 

I need some help choosing between the Jun 272 and Kelford 272. Kelfords have more lift but less duration. Jun 272s have more duration but slightly less lift. I'm running a stock 4g63 with internal wastegated TD06SL2, TOMEI expreme elbow, downpipe and header, fujitsibu catback all 3", hard-piping with stock intercooler and 70mm Throttle body. Im aiming to get a wider torque curve that keeps torque till 8000rpm (numbers dont really matter to me as long as the torque is reliable), mainly for track use while being daily driveable. And do I need to change the valve springs and retainers. This is for an Evo V.

 

Higher lift means more torque everywhere.

Higher duration favours higher rpm and moves peak torque to higher rpm. That also hurts lower rpm torque.

I would go kelfords anyway.

 

As the poster above me mentioned, more duration equals more power in the upper rpms.. it will stretch your powerband out further.

With that being said though, I'm running kelford low lift 272's, on a 2.4 which doesn't like to rev.. and after setting it up to taper boost up as it revs out, my HP peaks at about 8k. If it was a 2.0, it would peak probably 8500+ Without tapering the boost up, it would be a good 500 or more rpms lower, still not bad for a 2.4.

Point being, a good set of 272's like the kelfords will stretch your powerband up pretty high with a decent sized turbo especially on a 2.0

Other things to consider.. what kind of valve train setup do you have, and are you running SD or a MAF. You can run a big set of cams on SD and have it be streetable, and if your springs can support them.. it will ensure you have the top end you are looking for. If you are on a MAF, and don't have the valvetrain to support 8000+, and don't want to give up low end power, don't overdue it.

 

Thanks guys, so Kelfords are better because I get torque everywhere while still getting enough torque low down and upto 8000rpm. As insurance you'd advice me to get the valve springs and retainers anyways, right?

 

I will be converting to SD. I was inclining towards using stock valvetrain while keeping under 8000rpm, but definitely going SD. Valve train upgrade is something Im beginning to consider as necessary. Thanks again.

 

My limiter is set at 8100. I shift at 8k.. power peaks there, but pulls flat above that from what I can see...so I would rev further... but all I have other than the cams, is MAP upgraded springs. The rest is stock, so between that and mine being a short rod 2.4 I keep it limited there.

 

What about GSC R2s?

 

Just measured a pair of used GSC S2 cams with dial indicator. No visible wear, good condition.
The real fugures are as follows:
Both cams are 226 degrees duration @ 1mm lift instead of advertized 230.
Maximum lift of intake cam is 11.5 mm instead of advertized 11.2 mm.
Maximum lift of exhaust cam is 11.3 mm instead of advertized 11 mm.
The shapes of lobs are not symmetrical.
Exhaust Valve closes 118 degrees after maximum lift ( Center line) instead of advertized 115.
Exhaust Valve opens 108 degrees to the maximum lift (Center line) instead of advertized 115.
Intake Valve closes 106.75 degrees after maximum lift ( Center line) instead of advertized 115.
Intake Valve opens 119.25 degrees to the maximum lift ( Center line) instead of advertized 115.

Valves opening and closing timing is not working if the cams center lines are lined up as per GSC recomendtions ( 107/113) due to the shorter actual duration at 1mm lift and not symmetrical shapes of lobs.
Conclusion: the optimal position for these cams can be found on the dyno only...

 

some more on gsc cams. basically the same results like we got. http://www.dsmtuners.com/threads/deg...estion.396120/

 

This makes me want to replace my old school HKS 272s!

 

Those really are good cams.

I swapped a set of those in, made quite a bit more power.. made a best of 510whp... then I swapped in a set of Kelford 272's and springs, and didn't make much more power at the same boost (e85.. pump the diff might be a bit more). Don't get me wrong, I'm happy with the Kelfords... but those HKS cams really do work well, even though they are "old technology" and "dated" and not very aggressive etc.

I will mention I did run those HKS cams at -3.5 deg both intake and exhaust. Because I have a 2.4 and at that time I had stock gears. This actually made them have a pretty good top end. From the research I did, the best setting for high end HP was -4 intake and -1 exhaust. I put adjustable gears on with the Kelfords so I never got to test that. I'm running the Kelfords at about -1 i/e .. maybe -1.5deg. Possible I could see even more top end gain from retarding them further, but I didn't see any research like I did for the HKS that showed any gains running a lot of retard. Could play around with it too, but the car pulls past 8k, and I don't want to rev this short rod any higher anyway.

 

Just bought a set of GSC R2 to go in my 2.4 LR that we are building currently. Here is the included cam card. We will most likely degree these in and will report our findings when we get there.

 

Any information on the works cams specifically evo ix 274?

 

are there any pair of cams that would have a direct replacement with the stock ones ? What would my options be ? The dealer is charging 422 each one