Uprated Cams

Cliff · Post by **Cliff** » Thu Oct 13, 2005 11:54 am

Can anyone educate me on what the advantage would be of uprated cams?

Any help would be much appreciated.

Cheers

Cliff

PaulWarner · Post by **PaulWarner** » Thu Oct 13, 2005 12:15 pm

With adjustable cams you can change the timing to get more power, though this usually occurs higher up the rev range, great on race cars where you are constantly on the power but can make a street car less friendly to trundle round town.

Depends how aggressive you want to change th timing and what you want to use your car for?

iainh99 · Post by **iainh99** » Thu Oct 13, 2005 12:18 pm

Hi Cliff

The basic advantage of putting upgraded cam on your car is:

Increases valve open time - which in turn increase the amount of air and fuel going into the cylinder, and therefore gives you more of a bang.... so more power.

the disadvantage is that depending on how wild the cams are, the idle can be affected.

(turbo)
256 - Almost like standard
264 - Fast Road
272 - Competion

IH

cantfindausername · Post by **cantfindausername** » Thu Oct 13, 2005 12:29 pm

There is also valve lift that you'll need to consider.

However, I've not to date seen any duration information on the main stream cams (HKS etc) that is taken from 0.05" lift, which is the duration that actually matters.
If you're putting in uprated cams its worth getting adjustable cam gears so they can be tweaked and tuned accordingly.

iainh99 · Post by **iainh99** » Thu Oct 13, 2005 12:47 pm

Does anyone know if the cams be changed, without disturbing the head?

I think they can but I'm not sure.

Cliff · Post by **Cliff** » Thu Oct 13, 2005 12:48 pm

Great, cheers for the info guys..

MR2Mania · Post by **MR2Mania** » Thu Oct 13, 2005 12:51 pm

cantfindausername wrote:There is also valve lift that you'll need to consider.

Exactly! And the 3SGTE responds well to extra lift, which is why the Piper profiles are so good. It also means that you can run less duration to get the same airflow, which less duration means less lumpy engine.

Cliff · Post by **Cliff** » Thu Oct 13, 2005 12:55 pm

Thanks for the input Dino.

cantfindausername · Post by **cantfindausername** » Thu Oct 13, 2005 12:55 pm

What is the MAX lift anyone has ever produced on one of these heads?

I dont want to start another head work topic before too many people chime in, I'd just like figures that have been tried out.

Cliff · Post by **Cliff** » Thu Oct 13, 2005 12:58 pm

Thread Hijacker..

Only kidding..

MR2Mania · Post by **MR2Mania** » Thu Oct 13, 2005 1:07 pm

cantfindausername wrote:What is the MAX lift anyone has ever produced on one of these heads?

Well, the Rev1/2 head has a physical limitation as to how much lift it can run, hence why the largest Piper profile for this head is a 264 with 10.2mm. In contrast, the HKS cams for the early engine go as high a the 272 profiles, but max lift is 9.2mm.

I'm not quite sure how much peak lift the Rev3+ head can handle ultimately, though.

V8Killer · Post by **V8Killer** » Thu Oct 13, 2005 2:46 pm

The lift on my head is around 11mm on the intake side and around 10.8mm on the exhaust side.

BTW...am using piper cams too

cantfindausername · Post by **cantfindausername** » Thu Oct 13, 2005 3:14 pm

Where does the physical restriction come from? Would it come into contact with the cam cover? too big for the lifters?

Also what size are the standard lifters on these? Anyone?

MR2Mania · Post by **MR2Mania** » Thu Oct 13, 2005 3:22 pm

cantfindausername wrote:Where does the physical restriction come from? Would it come into contact with the cam cover? too big for the lifters?

There are 2 restrictions:
1) The lobes get close to the head casting in certain places. It might be possible to improve this with some grinding, but not sure how much by.
2) The shim-over-bucket config will tend to spit shims out after a certain ramp rate, which obviously gets steeper as you use more and more lift. You can overcome this by converting to shimless or shim-under-bucket (as on the Rev3).

Also what size are the standard lifters on these? Anyone?

Are you asking what standard max lift is, or what the size of the buckets are? Stock lift is 8.2mm on both sides for the Rev1/2, and 8.7mm on the Rev3 inlet.

cantfindausername · Post by **cantfindausername** » Thu Oct 13, 2005 3:28 pm

So it is mainly the fact they're shim over bucket lifters.

I'm going either Rev3 or Mk3 so thats ok for me

I need to find out if there is an "effective cam follower surface of 31mm."

Is this industry jargon for something?

MR2Mania · Post by **MR2Mania** » Thu Oct 13, 2005 3:32 pm

cantfindausername wrote:So it is mainly the fact they're shim over bucket lifters.

No, it's not the main problem, as it can be totally eliminated, whereas the other problem will still have some kind of physical limit. This kinda thing's been done in the states, though, so worth seeing how much lift they've managed to afford themselves.

cantfindausername wrote:I'm going either Rev3 or Mk3 so thats ok for me

It's a good idea, especially if you plan to rev high.

cantfindausername wrote:
I need to find out if there is an "effective cam follower surface of 31mm."

Is this industry jargon for something?

Who's asking for it? I'm assuming that they're implying the cam lobes are 31mm in width or lower??

cantfindausername · Post by **cantfindausername** » Thu Oct 13, 2005 3:35 pm

I'll find out what they mean exactely. Just wondered if it was a common question.

I'll hop over to the states and see what they have lifted to too

Cheers
Ant

cantfindausername · Post by **cantfindausername** » Thu Oct 13, 2005 4:58 pm

Just found a good bit of info on cam specs....

Stock 2nd gen motor: (intake and exhaust)

Advertised duration 236 degrees

Duration @ 0.010" lift: 260.0 degrees
Duration @ 0.020" lift: 211.0 degrees
Duration @ 0.050" lift: 160.5 degrees

Max Lift: 8.52mm (0.335")

Stock 3rd gen motor INTAKE:

Advertised duration 240 degrees

4 degrees more duration, .5mm more lift than the 2nd gen

Stock 3rd gen motor EXHAUST:

Advertised duration 236 degrees

Duration @ 0.010" lift: 260.0 degrees
Duration @ 0.020" lift: 211.0 degrees
Duration @ 0.050" lift: 160.5 degrees

Max Lift: 8.52mm (0.335")

HKS 256 cams:

Duration @ 1mm lift: 216 degrees

Max lift: 9.0

HKS 264 cams:

Duration @ 1mm lift: 224 degrees

Max lift: 9.2mm

The HKS 2nd gen "low lift" 264 cams use a lobe centerline of 110deg ATDC intake, and 103 deg BTDC exhaust.

HKS 272 cams:

Duration @ 1mm lift: 232 degrees

Max lift: 9.4mm

The HKS 2nd gen "low lift" 272 cams use a lobe centerline of 110deg ATDC intake, and 108 deg BTDC exhaust.

HKS "high lift" 256 cams:

Duration @ 1mm lift: 216 degrees

Max lift: 9.5mm intake, 9.2mm exhaust

HKS "high lift" 264 cams:

Duration @ 1mm lift: 224 degrees

Max lift: 10.0mm intake, 9.7mm exhaust

HKS "high lift" 272 cams:

Duration @ 1mm lift: 232 degrees

Max lift: 10.4mm intake, 10.2mm exhaust

The HKS 3rd gen 272 "high lift" cams use a lobe centerline of 111deg ATDC intake, and 116 deg BTDC exhaust.

TODA cams:

NOTE: These are advertised duration only, usually assumed to be 0.020" or .5mm.

Duration Max Lift(mm)
256_____8.5
256_____9.0
264_____8.5
264_____9.0
264_____10.3
272_____8.5
272_____9.0
272_____10.3
280_____10.3
288_____8.5
288_____9.0
288_____10.0
288_____10.5
304_____8.5
304_____9.0
304_____10.5
310_____10.5
320_____10.8

JUN cams:

Part # 1004M-T001 (intake) 1004M-T101 (exhaust):
256° duration 9.0mm lift

Part # 1004M-T002 (intake) 1004M-T102 (exhaust):
264° duration 9.0mm lift

Part # 1004M-T003 (intake) 1004M-T103 (exhaust):
272° duration 9.3mm lift

www.imoc.co.uk

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