KSpec

I just wanted to know if I got a set of 240-255 degree cams that my internals would hold up. I couldn't find the information on a search. If I do this kind of upgrade are there other complementary upgrades I will need as well such as a fuel regulator? Would I need to have the car tuned?

thanks...

MechaniX_034

Valvetrain...

Red

You won't break "stock internals" until about 220 wheel horsepower, and because these motors can't rev to save their lives, anything short of a full-race cam won't hurt the stock valvesprings/retainers/locks/HLA's either.

Random

for the Beta I, If they use extreme lift (.350 or higher) upgraded valve springs would probably be required, as the stocker v-springs could fatigue at lifts that large.

For the Beta II, .375 lift before replacing the springs.

Listing the cam duration, we need to know is that 240-255 duration figure 0 to 0 or .050 to .050? It makes a big difference.

KSpec

Ok, I will try to find out...or maybe you already know. I want to order the HDK cams, and maybe you already know the lift, also you could tell me if I would require it for the RPW cams, since those and the HDK ones are the only available directly through a reseller. Thanks...

BV1

Could someone give an indepth explanation on how the degrees duration benefits HP. I understand that the longer the valves are open the more air is drawn in, but are not our modified cars very near 95% volumetric efficency? And why does it royally screw up the idle?

Just trying to understand,
-Steve

Denisst99

Steve,
cams with more duration will leave the valves open longuer creating more overlap (moment when BOTH intake and exaust valves are open) longuer duration will also reduce engine power at low RPM's now you know why large cams affects idle
Basic rule of thumb, more duration means more rev
(engine will lost some power at low to mid range and will gain power at mid to high range)
More lift genrally means more torque if the cylinder and intake system can flow enough to let the extra air enter the engine)
It'S a very basic explanation but it should help you

Denis

MechaniX_034

Dude you don't replace the springs, seats, retainers and valve locks when you install higher-lift cams!?

Random

See below....This info comes straight from RPW.

The RPW has 3 "stock" cams (cams they keep in stock) and they can custom make any spec you want.

For the Beta I with HLA's
Stock Intake Cam
200 duration (0.050" to 0.050") .347 Intake lift

RPW Stage 1 (no springs required)
224 duration (0.050" to 0.050") .348 Intake lift

RPW Stage 2 (upgraded springs required)
235 duration (0.050" to 0.050") .375 Intake lift

RPW Stage 3 (upgraded springs required)
240 duration (0.050" to 0.050") .425 Intake lift

Beta II with shim lash adjustment
Stock Intake Cam
199 duration (0.050" to 0.050") .310 Intake lift

RPW Stage 1 (no springs required)
214 duration (0.050" to 0.050") .335 Intake lift

RPW Stage 2 (upgraded springs required)
222 duration (0.050" to 0.050") .351 Intake lift

RPW Stage 3 (upgraded springs required)
236 duration (0.050" to 0.050") .353 Intake lift

RPW reccomends upgrading of Intake Camshaft only on all models up to Stage 3 cam because exhaust camshaft profile is already too large for vehicle and larger gains found modifying intake camshaft only. Going larger than Stage 3 intake camshaft decreased driveability a lot and is recommended for race cars only

Exhaust Camshafts are available in larger grinds on special orders only and RPW is not responsible for any horsepower losses when fitted with any of the above camshaft grinds.

edit
Some of you are probably wondering why the HLA equipped cams are so different than the Solid Shim cams. The answer is really rather simple. The HLA's get "squished" by the cam as it goes to open the valve. As such, they 'eat up' some of the valve open duration, and some of the valve lift distance. The HLA fills up with oil again as the cam bump receeds, keeping everyting nice and adjusted. The Solid shim lash adjustment doesn't have any "give" to it, and as such, the cam profile doesn't have to be nearly as radical to achive the same "actual" valve lift and duration vs the HLA equipped "squishie" valve train.

KSpec

RPW Stage 3 (upgraded springs required)
240 duration (0.050" to 0.050") .425 Intake lift

Ok, so why doesn't Shark Racing sell the upgraded springs for these cams? It would make sense to be able to get the appropriate springs with the cams we order.