| Hadrian |
Posted
Wednesday, Feb 7th 8:41am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 2
Australia, Melbourne
E21 323i |
What do people think about this camshaft for an M20? Max lift 0.288" and 296 deg duration.
I know a camshaft with high duration such as 296 degrees would cause a loss in low-end torque/power BUT the car will be running on tripple 40 carburettors, is it true that with ITBs a higher duration camshaft can be used with less/no adverse efffects? (such as poor driveability at low RPM). And is the case the same with a multiple carburettor setup?
Any help/opinions will be appreciated  |
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| imaradiostar |
Posted
Wednesday, Feb 7th 8:58am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1005
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i |
Carbs should go well with that cam. To make it worthwhile you should have a corresponding increase in compression ratio (11:1ish?) and a bottom end and cylinder head that are built to take the higher revs the engine will be likely to see.
Do you have a spec for the lift at the valve?
jamie |
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| Hadrian |
Posted
Wednesday, Feb 7th 10:22am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 3
Australia, Melbourne
E21 323i |
| imaradiostar wrote: | Carbs should go well with that cam. To make it worthwhile you should have a corresponding increase in compression ratio (11:1ish?) and a bottom end and cylinder head that are built to take the higher revs the engine will be likely to see.
Do you have a spec for the lift at the valve?
jamie |
Probably don't really wanna rev more than the stock limit untill I have a fresh motor (current one is at ~360,000kms)
I don't know anything about cam profiles but isn't it 0.288" ? Or is that something else?
Thanks,
Hadrian |
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| Marquis_Rex |
Posted
Wednesday, Feb 7th 2:41pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 516
UK
BMW 323i 2.7-as featured in Total BMW Nov 2002,Porsche 911/993TT |
| Hadrian wrote: | | imaradiostar wrote: | Carbs should go well with that cam. To make it worthwhile you should have a corresponding increase in compression ratio (11:1ish?) and a bottom end and cylinder head that are built to take the higher revs the engine will be likely to see.
Do you have a spec for the lift at the valve?
jamie |
Probably don't really wanna rev more than the stock limit untill I have a fresh motor (current one is at ~360,000kms)
I don't know anything about cam profiles but isn't it 0.288" ? Or is that something else?
Thanks,
Hadrian |
I thought you guys were Metric down under?
Anyway, the 0.288" lift is 7.3mm cam lift which assuming an M20 average rocker arm ratio of 1.55 gives a peak valve lift of about 11.4mm. the duration is long, but just how peaky the cam is depends on the actual valve event timing.
The ITBs will give the engine good tolerance to more overlap. Just bear in mind that this cam will bias everything to above 5000 rpm. Make sure that that is what you want! |
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| Hadrian |
Posted
Wednesday, Feb 7th 11:34pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 4
Australia, Melbourne
E21 323i |
Yeah we are metric, I think the camshaft was made in America though.
5000 is a little too high I think.
Thanks all |
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