924Board.org

[931Owner]

Folks

Has anyone tried modified cams from this crowd?
And are these kinds of specs helpful?

Thanks


VALVE DURATION DURATION
LIFT @ 0.050" NUMBER

.517/.517 257°/257° 233°/233° Very broad power range for hot street engines with carburetors or stock fuel injection.

.517/.517 267°/267° 243°/243° Good mid and upper end performance for street, rally, etc. Use with carburetors or modified injection.
_________________
1980 Turbo
-too many cars and too many motobikes

[Dutch924-racer]

I have had the 257 cam, don't expect to much of it. I wouldn't buy it again for the money.

By the way it is only suitable for an 924 NA not for turbo !
_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

[gegge]

Why is that?

I´ve got a a 268/268° in my 931. The duration is measured @ 0.022" and got 12.2mm lift. LSA is 112°.
_________________
Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs

[Dutch924-racer]

For tuning turbo's you need different intake/exhaust duration, see:

http://www.integralcams.com/924.htm
_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

[gegge]

Not neccessary, that is just one way to compensate for the bad intake flow in relation to the the exhaust. The stock flowbalance is biased to the exhaust and if you solve that by port the intake only the problem is gone. Could be that the smaller exhaustduration is required due to high backpressure - small turbinehousing, old cat or stock mufflers?

The stock cam is rather hot for a turbocam at 255 deg on both - intake and exhaust, but with an old profile. A 267 cam on a turbo will shift the powerband another 1000rpm compared to a NA, expect max hp at 6500-7000 rpm. Difficult to recommend a cam - need more information about the engine.
_________________
Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs

[931Owner]

Thanks guys.

I was just curious about after market cams. I may be mistaken but I believe I read somewhere that the cams were the same for 924 & 931.

I have a 80 931 and I was just wondering what would be the best way to get more power and usually a cam is a way to get more power. I am a novice in that all I do is fix my own stuff but don't know anything about modifying an engine.

Usually, it's intake and exhaust that gets modified or improved first then move on to things like intercooler, cams, turbo, flywheel, suspension. Some kind of modification road map may come in handy?
_________________
1980 Turbo
-too many cars and too many motobikes