911S Heads Paired with 911E Cam Shafts

[M491]

I wanted to ask your kind advice, please, because I want to be sure I do not make any mistakes in rebuilding my 2.4 engine. Your expert advice would be highly appreciated.

What do you think of the combination of 2.4 911S pistons and cylinders, whose lower compression ratio will allow the use normal pump gas, freshly made E profile cam shafts, and 911S spec (36mm intake ports), with 2.2 911S stacks and throttle bodies? Would the use of E cams on an otherwise S-spec engine allow for more useable torque than I would get with S-cams? Thanks.

[tfiv]

I would think the large ports would compromise the torque you are trying to gain with the e camshafts. 2.4Ss have plenty of torque, why not just use S cams? Especially considering you have some fairly valuable S pieces accumulated.

[M491]

I may just have to do that! Thanks.

[super9064]

I agree, use S cams, lack of low end torque was a issue with the lower displacement S's mostly the 2.0, by the time the motor had grown to 2.4, slogging around town in traffic was much easier.

[gled49]

I tried to cure a midrange lean condition in a T by using an E pump. Didn't work very well. would recomend sticking with cook book recipe. S heads, S cams, S injection. Compression not as important. Gordon

[Scott Clarke]

My short stroke 2.5 has E cams with S ports and S MFI throttle bodies and stacks. It seems to work quite well. It bounces off the rev limiter (7100 rpm at the moment- I am going to switch out the rotor for a 7300 rpm unit) in first second, and third. It pulls cleanly from 2500 rpm. Power does taper off above 6500 rpm, but it is still pulling nicely. MFI pump is an E unit with the silver internal screws turned all of the way in, and a shim under the barometric cell. My understanding is that the ports on these motors are on the small side. I decided that the 2.5 configuration waranted the larger ports. Plus, I can now change the cams without pulling the heads, something I am contemplating.

John Luetjen, active on the Pelican board, has put a lot of thougth into this issue and has done a lot of research. I'd do some searches over there, and contact him if you still can't decide.

I will say that it is nice having a motor that allows me to be occasionally in the wrong gear without much penalty.