After the release of the new HKS 280 cams I decided I would try them out on our shop Evo here. Well to my suprise after hearing all the praise from them they came up short.
The car tested has the following mods: --------------------------------------------------------------------------------

Mods: AEM EMS (TopSpeed Tuned), 720cc injectors, HKS RS suction, HKS 264(prior to the 280's)intake and exhaust cams, 3" turbo back exhaust, ARC fmic, arp headstuds, ATS triple carbon clutch, HKS DLI , (shell 93 pump gas)

Run#12 is with the HKS 280's (pump gas)
Run#18 is with the HKS 264's (pump gas)

As you can see from the graph the car made almost the exact same power only with a slower spool. One thing I did notice is that with the 280 cams installed the is I had a really hard time keeping the boost higher than 20psi at redline, which was not a problem with the 264's. I would not recommend these on stock turbo I feel that they are way over kill, and the 264's or 272's do a whole lot better on the stock turbo. The HKS 280's may work better with a ported exhaust manifold and 10.5 exhaust housing to keep boost up at topend where it was falling off but that is only a guess. I would expect the 280's to be a killar big turbo cam, and plan on keeping them in the car when the larger turbo gets installed.

 

still good number nonetheless

 

Just posted the RACE GAS numbers I got with the 280's in the car.

https://www.evolutionm.net/forums/sh...d.php?t=124576

 

Thats funny, Buschur got really good hp increase with the 280's

 

Buschur did state having problems in keeping boost above 20 psi but its true. unless you dont have a bigger turbo 280's are over kill i would just stay with the 272's they are good with stock and upgraded turbos thats just m opinion great job guys thanks i needed that graph =)

 

I seriously love the unbiased testing you're doing.

Can you say "overlap"? I'm guessing the increased overlap is what is killing spool and the ability to keep the boost up. The intake charge is basically flowing right through the intake valves and right out the exhaust valves. I'm not sure I'd use these for a big turbo unless I was looking for an economical drop in installation that doesn't require new springs and retainers that a higher lift cam such as Revolver cams or Piper cams do. The increased overlap is going to hurt spool for a big turbo. Perhaps some cam gears could dial things back in to shape.

My feeling is that HKS brought these to the market to cater to the "if it's bigger it must be better" crowd of bolt on enthusiasts. At least that's my bench racer take on them...

 

Dang those are some nice numbers

 

unless I read the graphs wrong .. the 280's spooled and peaked about 200rpms earlier than the 264 cams .. HKS don't design things to 'cater' to certain groups .. ever asked why HKS is sticking to their 10 year old cam design versus the newer higher lift cams ??

 

No, it is the opposite the 264s spools earlier.

 

Run #12 is 264 = black / grey line = slower spool

Run #18 is 280 = blue /red line = faster spool

 

Maybe you are right, I will try to repost the graph with different colors so it will be easier to read.

 

Interesting that 280's made more torque...i would expect the 264's to blow away 280's in torque and the 280's to make more power than the 264s

 

Yeah, because if they went with a higher lift design their users would be forced to upgrade springs & retainers. This would push the total cost and hassle of the cam upgrade out of the reach of most bolt-on users.

Everything I've read about cams for turbo engines says that excessive overlap is bad. I'm not sure how these 280s can increase duration without increasing overlap and killing turbo spool. Based on the testing I've seen so far on these cams they do seem to impact the spool.

 

cool !!
I won't be surprised too if the 280's spool faster than 264

 

Thanks for the comparo