2.5E port size?

[rads]

I'm just finishing off my build list and could do with some recommendations for port sizes.

The car is a 911T and is mostly hot street use. So far I have the following:

86mm 9.5:1 Pistons
E cams
MFI pump has been reworked to E spec
I'll be using T stacks until I can afford and get E ones (or find them!).

So the question is, what size shall I open up the ports?
Should I open the throttle bodies to 34, Intake 34, Exhaust 34? or 32 all round like an E or something different.

I really want to keep the torque in lower rather than peeky power of an S.

Any input would be great as I need to tell my machine shop soon!

[Steve@Rennsport]

Rads,

T & E engines use the same size ports, valves, throttles & intake stacks; only the cams and MFI pump varies.

If you want to retain maximum torque & throttle response, keep the heads stock.

[rads]

Originally Posted by Steve@Rennsport

Rads,

T & E engines use the same size ports, valves, throttles & intake stacks; only the cams and MFI pump varies.

If you want to retain maximum torque & throttle response, keep the heads stock.

Thanks for getting back to me Steve.
I've measured my intake and TB's and they are 29mm, I thought E's ran 32?

[Henry Schmidt]

Originally Posted by rads

Thanks for getting back to me Steve.
I've measured my intake and TB's and they are 29mm, I thought E's ran 32?

I assume (86mm /2.5) that we are talking about a 72-73, 2.4 T.
You are correct, T and E have different throttles, ports and stacks.
The T has 016 stacks, the E has 014 stacks and the S 012.
The ports are as you elude. 28/29 vs 32 for E vs 36 for S. The throttle housings match at the port.
The engine (86x 70.4) is actually a 2.45. I build them all the time. This engine likes to breath.
My recommendation is to port it to 36mm, run E or S stacks and match the throttle housing to the port, 36mm.
I would also take the E cam and have John @ DC cams grind them to Mod Solex. You can do this on E cams very easily.
The results will be a great little engine that will make good torque and great horse power all the way to 6400+. It's a fun engine to drive.
We have the stacks in stock, can modify yours (bore them out) and modify the throttle housings with an incredibly quick turnaround.

[Henry Schmidt]

Almost any size you want, quick and easy . Generally within two weeks.



We can even repair damaged plastic stacks, within reason.......

[rads]

Thanks Henry. You are right about the 2.45, they P&C's came from you.
I Will have to have a think of what to do now, as the engine you mention sounds great but, my budget is tight and didn't really want to spend more on cams.
Good to know about the Stacks, I should have got you to pop a couple in the package you've just sent me with the 4 rib oil pump!

[jpnovak]

Henry your wine shelf needs to be restocked.

[kenikh]

Mod Solex, 36mm ports and stacks, cam timing slightly advanced, ZOOOOM.

[Trackrash]

FWIW. I have a SS 2,5. 66 stroke 90mm P&C. 8,5 CR. I'm running E cams with Webers.

I ported my heads to 35mm intake and exhaust. Great running motor. I can hit the 7300 rpm limiter in second gear and the motor is still pulling.

If you want a real screamer, I would use S cams with 35 to 36 mm ports. Depends if you want lots of top end for a track motor.

[rads]

Originally Posted by kenikh

Mod Solex, 36mm ports and stacks, cam timing slightly advanced, ZOOOOM.

I read a post about it being difficult to get the DC30 and MFI pump to work, thus my switch to an E Cam for safety!

[rads]

So if we assume that I stick with my E cam for now, is the general consensus 34mm, 35mm, 36mm!?

[356RS]

34mm if your keeping the E cams.

[Henry Schmidt]

Originally Posted by rads

So if we assume that I stick with my E cam for now, is the general consensus 34mm, 35mm, 36mm!?

If you are truly struggling with .080'"in your decision process, make the best compromise.
Port the heads to 36mm and port the throttle bodies to 34. This transition can even help the control intake pulses. The difference is minor but if you decide you want more top end, all you do is convert (bore) the throttles and change the cams .
No need to remove the heads to enhance your performance.

[rads]

Thanks Henry and everyone, I think I have a plan!