993 increase intake airflow

[porschke911]

Found some info about 993 intake only being good to 215hp and 6500rpm. Some mention of 996 GT3 intake to get more air. What all is involved in this swap or is there a way to get more air through a 993 intake?

[Trackrash]

Not sure where you got that info since the '96 ROW 993 had 300 hp.

Maybe you meant 315hp?

[Bill Verburg]

Originally Posted by porschke911

Found some info about 993 intake only being good to 215hp and 6500rpm. Some mention of 996 GT3 intake to get more air. What all is involved in this swap or is there a way to get more air through a 993 intake?

You need to be more selective about the info you believe
A stock 964 is 250hp @6100 either an al or later a plastic intake
a stock 993 nvr is 272hp @6100 plastic intake
a stock 993 vam is 285hp @6100
a stock 993RS(also a vram) is 300hp@6500 vram al intake
a stock 993 Cup which uses the nvr intake is 320hp 6500

We regularly see 300+ from modified 993 3.6 & 320+ from modified 3.8 all using stock injectors

Which brings up the real limiting factor
stock 3.6 used 1 of 2 different injectors
964 use 195 cc/min injectors
993 uses 235 cc/min injectors

once you get to around 320hp you want 32 cc/min injectors because the stockers are running at 100% duty cycle

Besides the injectors the rpm is the next obstacle, stock crank is only good to 7k max, after that you need a GT3 crank and oil pump

[porschke911]

Sorry. Typo. I did mean 315hp. I am currently at the 320hp mark. Injectors are not running at 100% as steve wong leaned out the mixture above 4000 as it was running 11:1. In trying to figure out the route to get even 10% more power. I read all the time about people getting 400+ out of a 3.8. 350hp would be nice out of my 3.6

[Bill Verburg]

Originally Posted by porschke911

Sorry. Typo. I did mean 315hp. I am currently at the 320hp mark. Injectors are not running at 100% as steve wong leaned out the mixture above 4000 as it was running 11:1. In trying to figure out the route to get even 10% more power. I read all the time about people getting 400+ out of a 3.8. 350hp would be nice out of my 3.6

To get that kind of power you need to raise the rev limit, and use hotter cams, As i said for those motors you build from the crankshaft out

[porschke911]

John Dougherty said he wouldn't recommend any hotter cam than the 993SS for street use. Guess I should have done more research. Even Steve Weiner told me my cams are done by 6000 rpm so there was no need for me to work on increasing the rev limit of the engine. What would be a good cam that can breath up to at least 6500rpm?

[Bill Verburg]

Originally Posted by porschke911

John Dougherty said he wouldn't recommend any hotter cam than the 993SS for street use. Guess I should have done more research. Even Steve Weiner told me my cams are done by 6000 rpm so there was no need for me to work on increasing the rev limit of the engine. What would be a good cam that can breath up to at least 6500rpm?

JD & SW are right
w/ hyd lifters RS cams w/ mechanical SS are the happiest cans you can use w/ a stock intake, enginemangement and bottom end, rpm limit is still high 6s maybe 7 if you at least upgrade the rod bolts

[jluetjen]

I wrote this (ulp!) 12 years ago, and it contains a lot of information that I learned about camshafts in general, and in regards to air-cooled 911's specifically.

Camshaft Selection -- First Draft

It might answer some of your questions.

[Bill Verburg]

W/ CIS and Motronic fual management cam selection is limited to those w/ little or no overlap, the more overlap the more intense the intake manifold reversionary oscilations which upset those two types of fuel mangement, If you go to carbs or ITBs w/ some form of electronic management then the limiting factors become valve clearance and rpm restrictions