Fluidplay

Unrelated to the OP, but good information on the subject of cams...

Jon Milledge Engineering

CAMSHAFTS

High Performance & Racing Cams for:
Porsche 944T, 944, 911, 944S, 944S2, 968, 968T
These camshafts are specifically developed by us and are not just someone else's regrind. All camshafts feature the latest technology ground on computer generated profiles.
944/928 2v Camshafts

Series II computer generated profiles, designed, developed and tested in 1997-2008. All 944 camshafts are ground on new German semi-finished billets. All profiles are proprietary and unavailable from any other source. Dyno tested at our $100,000 dynamometer facility. All 944 2V cast billet Cams - $800. 944 2V cams ground onto customers core. 944 4v cams ground on customer core, $960 plus welding if required.

Normally Aspirated
IS4-14 944 2V Regrind on customer core. Power band as stock. Idle as stock. .474 cam lift intake and exhaust. Uses stock valve springs for drop in installation. 8-10 bhp improvement.

S3-14 944 2V Best power band 3600-6500 rpm. 900 rpm idle. .474 cam lift intake and exhaust. Stock base circles. Can use stock valve springs or prefer 944 Turbo valve springs for best results. 12-18 bhp over stock camshaft with stock exhaust. Needs stock fuel system pressure with Motronic at click 1. Tested against all comparable competitors camshafts and proven better.

277-14 944 2V Best power band 4000-6600 rpm. 900 rpm
idle. .474 cam lift (In & Ex) with stock base circles for drop in
performance. Uses stock or 944 Turbo valve springs for best results. Motronic chip must have rev limit raised for best results. 14-20 bhp over stock camshaft with non-stock
exhaust. Needs stock (37 psi.) fuel system pressure with
Motronic at click 1. Tested against all competitors camshafts and proven better. None were comparable.

CS-14 944 2V Best power band 4200-6800 rpm. 1000 rpm
idle. Off idle lope. .474 cam lift (In & Ex) with stock base
circles for drop in performance. Uses stock or 944 Turbo
valve springs for best results. Motronic chip must have rev
limit raised for best results. 18-26 bhp over stock camshaft
with race exhaust. Needs custom Motronic chip or
aftermarket engine management. No equivalent competitors
cam. Used where lift is restricted to stock but racing cam is
allowed.

8SR-14 944 2V Best power band 4000-6900 rpm. 1000
rpm idle. .502 cam lift (In & Ex) with near stock base circles.
Uses 944 Turbo or race valve springs (recommended) for
best results. Motronic chip must have rev limit raised for best results. 28+ bhp over stock camshaft with race exhaust.
Needs custom Motronic chip or aftermarket engine
management. No equivalent competitors cam. Used where
lift is un-restricted but racing cam is allowed.

B13-10, B13-14 for 944 2V race Best power band 4400-
7200 rpm. 1100 rpm idle. Off idle lope. .539 cam lift (In &
Ex). Modified hydraulic lifters required. Race valve spring &
retainer package required. Motronic will not work. Bhp
available depends upon tune of engine. No equivalent
competitors cam. Used where lift is un-restricted but racing
cam is allowed. B13-10 has better midrange power, B13-14
has better top end power.

Race Solid Lifter 304M2/280M-10 for 944 2V Best power
band 5000-8200 rpm. 1300 rpm idle. Off idle lope. .595 cam lift In, .510 Ex. Race solid lifter, valve spring & retainer
package required. Motronic will not work. After market
engine management only. Bhp available depends upon tune
of engine. No equivalent competitors cam. Used where lift is
un-restricted but racing cam is allowed. Best results with
unrestricted intake, fully ported cylinder head with larger
valves, racing header, high compression, dry sump oil
system.

N7/N9 4V Near stock, S, S2, 968 cores .437 lift IN, .385 lift
EX Stock lifters OK, Stock valve springs.

N11/N9 4V More intake lift and duration than N7/N9. S, S2,
968 cores. Recommend S valve springs. Peak power near
7000 rpm. Turbocharged
277/XS-14 944 2V Best power band 3600-6500 rpm. 900
rpm idle. .474 cam lift IN & .434 EX with stock base circles
for drop in performance. Uses 944 Turbo valve springs. 15-
22bhp over stock camshaft with improved exhaust. Needs
stock (37 psi.) fuel system pressure with Motronic at click 1.
Tested against all comparable competitors camshafts and
proven better.

CS-16 944 2V Best power band 3500-6800 rpm. 950 rpm
idle. .474 cam lift (IN & EX) with stock base circles for drop
in performance. Uses stock or 944 Turbo valve springs for
best results. Motronic chip must have rev limit raised for best
results. Up to 450bhp. Needs aftermarket engine
management, larger turbo, larger injectors, raised fuel
pressure, larger fuel pump. No equivalent competitors cam.

8SR/S3-14 944 2V for stock valve sizes or 8SR/277-14 for
larger intake valve Best power band 3800-6900 rpm. 900
rpm idle. .502 IN cam lift & .475 EX. with near stock base
circles. Uses race valve springs. Motronic chip must have
rev limit raised for best results. To 490bhp with race exhaust,
larger turbo, larger injectors, raised fuel pressure, larger fuel
pump. Needs custom Motronic chip or aftermarket engine
management. No equivalent competitors cam. Used where
lift is un-restricted but racing cam is allowed.

B13/8SR-14 944 2V Best power band 4200-7200 rpm.
1000 rpm idle. .537 IN cam lift & .502 EX. Modified intake
hydraulic lifters required and longer intake valve stems or
lash caps may be required depending on tip height. Race
valve spring & retainer package required. Motronic will not
work. Bhp available depends upon tune of engine. No
equivalent competitors cam. Used where lift is un-restricted
but racing cam is allowed. Power up to 625 bhp.

304M2/280M-14 solid lifter for 2V 944T. Best power band
4700-8200 rpm. 1200 rpm idle. .595 gross cam lift IN, .526 gross EX. Race solid lifter, valve spring & retainer package required. Motronic will not work. Bhp available depends upon tune of engine. No equivalent competitors cam. Used where lift is un-restricted but racing cam is allowed. Best results with unrestricted intake, fully ported cylinder head with larger valves, racing turbo header, racing turbo.
N7/N9 4V Near stock, S, S2, 968 cores .437 lift IN, .385 lift EX Stock lifters OK, Stock valve springs.

N11/N9 4V More intake lift and duration than N7/N9. S, S2,
968 cores. Recommend S valve springs. Peak power near
7000 rpm. Dry sump recommended

277/N11 More intake lift and duration than N11/N9. S, S2,
968 cores with welded intake. Recommend race valve
springs. Peak power near 7400 rpm. Dry sump highly
recommended.

N13/277 More lift and duration than 277/N11. S, S2, 968
cores must be welded. Race valve springs required. Peak
power at or near 8000 rpm.

333pg333

lol...as opposed to a pushrod V8...

FullThrottle64

I'm not an expert, so please explain if I'm missing something, but:

Why wouldn't an increase in valve timing overlap change back pressure? In a NA application, isn't overlap used to pull fresh charge into the cylinder by reducing the backpressure?

Dougs951S

Pauly is your cam grind similar to the B13 profile? If so that is a mighty big cam on a street engine! I'd love to cam my car but dont want to make it any worse to drive on the street than it already is. Its kind of treading the thin line between bearable and too race for daily use.

lee101315

Technically, more exhaust volume in the same pipe per minute gives you more pressure.

Realistically? A cams affect on back pressure is not worth considering. Itd be like considering the time youd save swimming a lap by shaving of all of your body hair.

Paulyy

A bit hard to tell. I haven't been beyond 6700 rpm and the power was still climbing.

Paulyy

The only time the cam will create more backpressure is if you've reached the flow capability of the exhaust housing on your turbo and therefore you won't gain any power.

TurboTommy

Back pressure is created in the exhaust system, at some point after the exhaust port.
Cams don't change back pressure (unless, like somebody already said, the exhaust system is a little bit too small to begin with), but they are sensitive to back pressure.
So, there is a relationship there.
More accurate: back pressure affects the cam selection and how good it will work