I am looking at upgrading from HKS 272 cams to HKS 280 cams. I have a few questions.

1. Is this upgrade any good?
2. What is the maximum I can rev to on stock valvetrain?
3. Is there a clearance issue with these cams?
4. On a stock turbo car with stock block and head would the 280 make any more than the 272 cams?
5. Will I lose any power down low?
6. Can these be tuned with stock MAF and self flash? I also have an ECU+ which should be able to tune these also.

Any other input would be great!

 

these sound like newbie questions. I think you already know the answer to most of these.

1. Upgrade is good depending on what you are trying to setup the car for
2. Some have revved past 8k consistantly and are reporting no problems. With the stock turbo, there's no point in revving that high though.
3. No.
4. Yes
5. Most likely if you dont change your timing
6. Yes

Personally, I'd recommend doing a 280i and keep the 272e for now. Its a good compromise between good top end and low-midrange. Especially w/ a stock turbo

 

As I think I know the answer I never like to assume this because it never hurts to ask questions sometimes.

I have down enough searching and felt like making my own thread.

 

Its not worth the money or hassle to upgrade from HKS 272s to 280s. I bought 280s and then sold them after realizing it was just going to be a big waste of time.

 

btw, what are you setting the car up for?

 

I am setting up the car to drag and autox, although it is my DD so I need to make sure I can still park the car, idle, etc.

 

I don't know whether or not the 280's are advisable for auto-x, but at any rate, and to make them idle 1/2 way decent and get good turbo spoolup, you'll need adjustable cam gears.

 

I got Vishnu gears and I am considering +2/0 for the timing.

 

Yeah, I use Vishnu gears with my 280i/272e, HKS cams, on a 10.5 TiAl turbo. I did the +2/0 setting originally and it definitely helps spoolup and midrange torque. But, you gotta like choppy idles.

Then I retarded to +1/-1, which is still great spoolup and torque, but has a wee bit improved idle compared to +2/0. Currently, I am running 0/-2, but will soon go back to the +1/-1 which is my overall favorite.

The only problem with the advanced cam settings, aside from the choppy idle and the trade-off in topend, is that it tends to induce detonation upon throttle tip in the low to middle rev range.

 

sparky- what are you using to tune your car with & what injectors are you running?

TIA

 

I am running a non-SMART XEDE with an off the shelf 2003-2004 v.390 map. My friend, JRSimon, tweaked the XEDE timing table just a bit by removing 0.2* of ignition timing above 4000 R.P.M. This I run on stock injectors and a NISSEI FM, BRE8's at 0.024", ported TiAl 10.5, 280/272's(0/-2), on the absolute worst sump pump 89 octane available in the 3rd world.

With this tune, we have been able to run between 21- 24# of boost w/o any trace of knock at 3000 ft. elevation in warm ambient temps(87*F.). I am currently running it at 21# w/ zero knock. The -0.2* of ignition retard did the trick as it got rid of a persistent knock event at 4000-4500 RPM.

The problem with the advanced cam timing settings is that you have to be real careful about ignition timing because these settings tend to increase the dynamic compression of your engine. My Dumbo guess is that there is a greater tendency toward preignition with advanced cam settings.

 

you dont need cam gears to get 280 cams to idle or spool up. Misinformation abound. My idle is set at 1k and its a little lumpy but i dont mind just kinda a pain to drive at low speeds and in parking lots.

 

With your cams set at 0/0 they will sure idle smoother than the +2/0, which give a p*ss poor idle. The advantage of the +2/0 is not the idle characteristics, but the improved spoolup and greater midrange torque than the straight up or the retarded settings too.

With +2/0 settings my 280/272's spooled the TME to 21# by 3200 RPM. You can't do that with your 280's set straight up(I think).

Edit: I'd better clamber down into the bunker.

 

Please explain the low speed a bit more...

 

longer duration cams dont like low rpm's you loose some driveability at 1-2k rpms. I would stick with hks 272's unless you like a bigger hit up top as with my setup.