| Cams - Click HERE for Original Thread |
| boostedwrx |
So im going to be ordering some cams when I get back from work in a couple of weeks and so far im looking at 272's and 280's
so my question is how much of a difference power wise am I looking at?
and how much worse can the idle get from 272 to 280? |
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| bowtie |
pardon my ignorance, but is a "272" or "280" some specific type of cam? Or is that just the duration of the cam you're looking at buying?
ps what car, what's your engine build, what's the rest of the cams specs? :S |
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| RADRIDE |
Those sound like HKS cam specs. It all depends what kind of mods/turbo you are running. Too many variables. You haven't given us enough info.
R.K. |
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| boostedwrx |
Bowtie, those are the cam durations
and to Rad, the motor is a 8.5:1 CR 2.3L Sleeved EJ205 Subaru running a rotated GT3076R Turbo with all supporting fuel/oil mods.
the cams also arent hks the 272's are Jun and the 280's are brian crower |
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| RADRIDE |
In my personal opinion the 272's would be perfect. To run a 280 you would need a higher rpm and more power to fully utilize that setup. Again just my opinion.
R.K. |
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| dc2696 |
| Fuck duration whats the lift? |
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| boostedwrx |
Thanks Rad
I kind of thought the 280's were to big but it never hurt to ask anyone |
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| boostedwrx |
quote:
Originally posted by dc2696
Fuck duration whats the lift?
Lift in mm for 272 is 10.16
Lift in mm for 280 is 10.80 |
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| bowtie |
Yeah to be honest I dont know jack about 4 cylinder OHC setups. :/ maybe if it was a v8 OHV ... =/ so if my comments are wrong, someone please tell me.
i dunno if it was a v8 i'd suggest no more than 280 degrees duration...any more than that is a fairly radical grind. but I guess it depends on what you want, low speed power or high speed effeciency. Is it an automatic or manual transmission? and what's it idling at? a crutch to fix up some low speed power loss on automatics is to put in a high rpm stall converter...but i'm assuming its a manual.
If peak horsepower is your goal then get something with a long overlap and long duration...but you'll get a bad idle, low manifold vaccumn at idle, worse fuel economy. If you get a cam with less overlap (ie a larger lobe center angle) then you'll have a cam better for street conditions.
Neither of those cams appear to have that super high lifts.
I dunno, but I'd say check your valvetrain and consider how much life you want it to have. I don't know how valvetrains in OHC 4 cylinders are compared to OHVs, but consider the strength of your valvetrain, higher lifts increase wear on the valvetrain and youmight need stiffer springs in your heads. ask whowever manufactures the cam what their recommendations for valvetrain upgrades are (if required) and what the expected life of the cam and valvetrain life is. I dunno if this is required for your heads, i'm not familiar with that particular engine.
also if youre using a long duration cam and a laggy or long spooling turbo then having a long-duration large-overlap cam will really make it worse |
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| boostedwrx |
Thanks bowtie
I think I will end up with the 272's
The car is a manual and I will be doing the valves/springs/and retainers as well
thank god Jun makes a full kit for all of this :D |
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| bowtie |
| if you can, install bronze valve guides (if your car doesn't already have it) when you do your top end stuff...theyll probably help to increase your valveguide life |
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| tokes |
Go 280's without a doubt. Everyone rants and raves about small cams being the best for response and mid range power. But have you ever heard of the Mine's R34 GTR? Touted for having amazing response and fantastic mid range power. Cams are over 290 degrees of duration and 11.5mm of lift.
Go 280's. You might lose 200 RPM's of spool up, but the mid range and top end power after the turbo is cooking will be worth it, especially with a GT3076R. That extra lift really helps too. |
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| bowtie |
| 280 isn't really too too aggressive. I'd say go 280 as well. Find out how big your lobe center angle is though. |
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| boostedwrx |
| keep in mind I also want this car to be streetable too |
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| tokes |
The difference in idle between 272's and 280's is going to be essentially nonexistant.
To me, having 10-15 more WHP in the mid range when you want to give it a little poke to pass someone or merge or whatever is better than having 5 more WHP from idle untill your turbo spools. |
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| boostedwrx |
quote:
Originally posted by tokes
The difference in idle between 272's and 280's is going to be essentially nonexistant.
To me, having 10-15 more WHP in the mid range when you want to give it a little poke to pass someone or merge or whatever is better than having 5 more WHP from idle untill your turbo spools.
Good Call...
so far im leaning towards the 280's then |
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| dc2696 |
Whats the stock lift? I know on my engine (8.5mm stock lift) my bosses have to be cut/clearenced to run anything over 9.53mm(weaksauce). Also your idle will prolly be the gay, I couldn't care less about how my car idles but my car is alittle more themed to track than street and doesnt daily driven.
The 280''s sound good, 10mm's is decent lift too I go with them. |
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| boostedwrx |
quote:
Originally posted by dc2696
Whats the stock lift? I know on my engine (8.5mm stock lift) my bosses have to be cut/clearenced to run anything over 9.53mm(weaksauce). Also your idle will prolly be the gay, I couldn't care less about how my car idles but my car is alittle more themed to track than street and doesnt daily driven.
The 280''s sound good, 10mm's is decent lift too I go with them.
Stock lift is 9.27/9.17...they should clear...if not I will get them to clear :D |
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