OK, I recently had my car custom tuned by Shiv at the Dyno4mance dynoday. I wasn't too terribly impressed with the numbers my car put up. It wasn't anything to do with the tuning (the car runs great) but, more my setup. I've got some exhaust issues that are causing some back pressure high up in the RPM range. So, the numbers didn't really bother me and I'm addressing that issue.

My situation is this: I have comp 272's in my car. Shiv said he never tuned them before and recommended their usual -2/-2 timing for them. I never played with cam timing figuring Shiv would optimize that to suit his tuning on the dyno but, it never happened. Vishnu recommended running the HKS's at -2/-2 and that is what I have the Comps set at. However looking at the cam specs from they are fairly different in Lobe centers and LSA. I'm wondering what settings would be closest to the recommended settings? I'm sure I'm just going to end up playing with a bunch of different settings anyway and I know every car is a little different but, I just want some added input.

Comp Cams 272+
Advertised Duration - 256 deg Int / 257 deg Exh @.004
Effective Duration - ___ deg @ 1mm Int / ___ deg @1mm Exh
Lift - 10.8mm Int / 10.2mm Exh
Lobe Centerlines - 104 deg Int / 112 deg Exh
LSA - 108 deg
Valve timing @.050 INT. 2 BTD 28 ABD; EXH 35 BBD 5- ATD
Upgraded valve springs recommended

HKS 272
Advertised Duration - 272 deg
Effective Duration - 214 deg @ 1mm
Lift - 10.8mm Int / 10.2mm Exh
Lobe Centerlines - 110 deg Int / 110 deg Exh
LSA - 110 deg
Stock valve springs OK

Thanks for any help.

 

Well, I'm glad to see that apparently everyone knows about as much as I do on this.

I'm going to try advancing the intake cam to 0 and see how that works first. If my logic is correct that should put the LSA about the same as the HKS and should not be a problem.

 

Hello my friend, I am lost on this, otherwise I would have said something. My HKS 272's were set at -2/-2, my HKS 280's were set at -2/-1 (or the other way around), now they are at 0/0. I would just sell the car, and get a Schwinn!! The Pixie wheel, and the streamers would make you look COOL!! Put a Front-mount flower basket up there, and the chicks will dig you!!!

Wish I could help you out more!

 

He speaks the truth. Just remember to tuck your pants leg in your sock to prevents accidental transfer of chain lubricants to you Carpi's.


LOL

I don't know. I don't know anyone running those cams.

 

 

Kyle-

After a custom tune at a certain setting, it can be a little risky to change your cam timing. The tune was optimized for the setting you have, and moving the gears will throw it off a bit.

Some cars are just stronger than others. Mine for example, has always been 10-15whp weaker than other Evos with the same mods. If it feels nice, I'd suggest you just leave it. -2/-2 is a good general setting.

 

Seth,

I spoke to Shiv and he said a couple of degrees either way is fine. I'm not looking to make any crazy changes.

I think it is not going to make much of a difference anyway. I just advanced the intake to 0 and couldn't tell a difference other than the idle getting choppy and a slight loss in vacuum.

I'm going to try -2/-4. Either way I'm pretty sure I'll end up back at -2/-2 until I can build my test pipe, LICP and, get back on a dyno to verify safety and results. Right now I'm just tinkering for fun.

 

Schwinn my a*s. Do you realize it's 90 degrees with like a 1000% humidity here?Are you trying to kill me? I'd do better with one of those personal submarine things.

If anything I'll get a Vespa and put a puppy in the basket up front. Then I'll have all the honies. B*thces can't resist a puppy and guy wearing a helmet that makes him look like he's retarded.

 

gotta try that!

 

 

Like you haven't already.

Good one. You almost had me.

Just make sure it is one of those bass boat color all sparkly helmets with a big bubble shield.

 

I tried -2/-4 it seems to be a little stronger up top then it was and seems to build a little more boost. I logged a couple of highway on ramp charges with my scan tool and don't see any appreciable differences in a/f and no timing being pulled or anything like that so I'm going to roll with this for now.

 

I was thinking of getting the Competition Cams 272's and E-Mailed them a while back. They recommend that the cams be installed straight up for the best performance. I still believe that you may be able to fine tune the cams with the cam gears, but I would do it on a Dyno so you could see if there are any gains.

 

That's not right.

The Comp Cams 272s are set at 104/112. To get to 110/110, you would need to retard the intake cam 3 degrees and retard the exhaust cam 1 degree. You'll lose a slight bit of spool and pick up a few hp up top.

 

Thanks TedB. I was thinking that when I bought them Comp said they were designed to be at 0 that's why I advanced the intake to that but, it would idle very rough and didn't feel right. I'm not entirely sure that 110/110 is really where they want to be anyway. I was just curious how far off the "standard" they were.

Right now the -2/-4 feels pretty good but, not enough of a difference to say it's better or worse than -2/-2 for sure. I'm not going to mess with anymore until I get some dyno time.