How da ya like that 2.4E w/ 2.2E pistons & cams?

[Brent Seidel]

I have been looking to upgrade my 2.2T.

Looking at Wayne Dempsey's book How to Rebuild & Modify 911 Engines, one of his recommended upgrades for the 2.2 is to transplant in the 70.4mm crank (2.4, 2.7) and run with 2.2 E pistons, & E cams.

Suprisingly, he states that the engine will run fine on pump gas without twin plugs.

Anyone have any experience with this configuration?

What kind of HP & torque could one expect?

[joetiii]

I don't have personal experience with upgrading a 2.4, though I understand the bump in compression from the 2.2 pistons is only a little noticeable. I was reading Bruce Andersons book the other day which stated the 2.2 pistons don't necessaruly give you the same compression as in the strait 2.2 engine. 3/4 point bump maybe??? Certainly in the realm of single plug capability.

The biggest bang for the buck is the cam upgrade and some port work on the heads. Here's an article on cams & flow. cam selection

I think the limiting factor on a T engine is the bottom end. There are those on this post who can chime in and let you know how much performance & durability you can get from this configuration.

[samjepperson]

I was curious on the same thing. Instead of "upgrading" to 2.2S pistons and porting the heads I thought that changing out the crank/rods would make sense. Looking forward to hearing what people say.

Sam

[Brent Seidel]

Joe,

The key item I neglected to mention was the anticipated compression for the stroked 2.2E is 10:1

A factory 2.2E (66mm crank) produces 9.1:1 compression (155hp)

Installing the 2.4E crank (70.4mm) increases compression to 10:1 and displacement to 2.4

The factory 2.4E produces 8.0 compression (165hp)

Installing the 2.2E pistons increases compression to 10:1

In either case the finished product is a 70.4mm crank with 2.2E pistons in 84mm cylinders with E cams producing 10:1 compression (???hp)

The power increase must be significant.

But, it'll be interesting to hear just how friendly it is.

[joetiii]

Originally Posted by Brent Seidel

Joe,

The key item I neglected to mention was the anticipated compression for the stroked 2.2E is 10:1

A factory 2.2E (66mm crank) produces 9.1:1 compression (155hp)

Installing the 2.4E crank (70.4mm) increases compression to 10:1 and displacement to 2.4

The factory 2.4E produces 8.0 compression (165hp)

Installing the 2.2E pistons increases compression to 10:1

In either case the finished product is a 70.4mm crank with 2.2E pistons in 84mm cylinders with E cams producing 10:1 compression (???hp)

The power increase must be significant.

But, it'll be interesting to hear just how friendly it is.

So if I understand correctly, you've basically got a 2.4 that make 2 more points of compression over a stock. I think 1 point of compression is worth just under 3% more HP so 2pts is probably around 6% more than a stock E. Not huge numbers, but the E cam will make for a nice shove in the seat.

I defer to Wayne on usability of this configuration on street gas.