spiller

I remember reading something a while back about upgrading the stock camshafts to cup car cams, thus doing away with the variocam. What would be the advantages and disadvantages of this and is there much to be gained from a performance perspective by using the cup car cams?

My car is already fitted with every bolt on intake and exhaust mod possible (IPD plenum, 997 TB etc) so just considering other potential upgrades that don't involve opening the motor.

32krazy!

you have to pull the motor to get to the cams so base it on doing a build while its out. you can have the cams reground for more lift and duration while retaining the variocam as well

spiller

Is the variocam better to have than the motorsport items?

32krazy!

thats a difficult answer. i tend to think of it as a solid lifter type of setup without variocam. there are adjustments that have to nbe made to keep everything in spec. i think you also will have to change cam housings as i dont think the intake cams fit. it can be done but its a lot of work for stock ported heads and internals

AudiOn19s

This is an interesting topic and one that doesn't get much discussion here.

I'm not sure I've seen cams done on a stock displacement build but the Sharkwerks 3.9 cars rev to 8800 and they aren't doing that on the stock cams. I'd call up sharkwerks and see what they have to offer if you really get serious about this.

Charles@dundonmotorsports

The biggest overall issue I have seen with cams on a stock ish 996 gt3 is

1) the heads do not flow as much as 997
2) the intake manifold is tuned for a lower RPM range and for a much earlier peak hP

both of the above cause power to fall off quickly from peak like it does. Installing intake cams may make more power but trying to get it to rev higher AND make more top end power and carry out is going to need atleast the 997 intake manifold setup....which is not 100% bolt on.

i have not seen anyone (or myself) install 997 gt3 street cams in a 996 as you need the cam actuators as well so it can get pricey. But I bet 997 intake cams could make 10whp with supporting mods but that gets expensive.

I think there is 1-2 companies that make drop in cams for 996 gt3 with VTC

dual cams

@Charles@dundonmotorsports.

How difficult is to setup the 997 intake manifold and I was told that the DME will need to be retune.

Also what you you suggest with street/track 996 GT3 without internal mods with 997 manifold and center exhaust setup?

Charles@dundonmotorsports

the 997.1 intake manifold is not extremely difficult to do, however there are a few items that will need to be addressed.

1) The 997 center plenum will hit and interfere with the 996 gt3 oil filter console housing
-If you use the 997 oil filter console, you will need to make adapters to use the 996 oil temp and pressure sensors, or weld bungs on to use them.
-you can modify the stock plenum to clear the oil filter housing, but it is a little work and know how to do it.

2) the 997 intake manifold will have slight interference with the 996 oil cooler bleeder outlet hose, either modify or purchase a 997 oil cooler

3) the 997 manifold has 2 flaps. Either only use the large flap and wire the small flap open, or run another solenoid and wire to the DME
-The stock 996 gt3 dme flap map is setup to run dual flaps already, just need to run the wire and then modify as needed in the map.
-I usually just lock the small flap open or remove the flap itself

4) yes the tune will need to be modified. The torque peaks and troughs are now different which requires a remap of the timing curve.
- I have done this before with a few variations but it really does matter what manifold you are running as well as what exhaust.

5) the 997 manifold will require a few small other items.
-oil fill hose brackets
-997 sec air bracket (if you want to keep it)
-brake booster hose comes from the manifold (either weld a bung on the plenum or add the 997 vacuum pump)
-vacuum lines will need to be modified slightly as the 997 uses the vacuum pump for supply and the 996 gt3 comes off the rubber boots
-will need a 997 T/B and intake boot.


It is a lot of work for some gain, but i have not done just a manifold swap.

There are a lot of good mods to do and items to change to make more power, most of them require upgrading the cylinder heads and up.

997 heads
997 cams (and adjusters) or aftermarket cams
997 intake manifold, 3.6, 3.8RS or dundon plenums on 3.6
Dundon 996-3 dual exhaust or Dundon 997 headers and center exit.

The above makes about another 60whp at about 8000rpm and pushes peak power to around 8000... on a stock 996 gt3 bottom end.

All of these options require a tune however.




Other option is to purchase a Dundon 996 Gt3 dual exit exhaust as many consider it the best mod to their 996 Gt3. I am building one for a customer now and am trying to build 2-3 more at the same time.