2.2 S engine upgrade
 

Hi,
I have just started rebuilding 2.2 S MFI engine. While pistons and cylinders have to be replaced I started thinking about upgrading the engine.
What ways can I go ? I have read somewhere that changing pistons to 2.4 S may give some extra power without need of MFI Pump resetting .
Are there any other options ?
Thank you
Martin

Hi Martin,

In order to get to 2.4S from a 2.2S would require a change to pistons, rods and crankshaft.

That said, the fuel maps between both of them are pretty close. I have never tried it so I can't provide feedback for actual performance.

Alternatively, you can Bore out the cylinders to 85mm for new pistons or buy Nickies with a larger Bore than 85mm

You have a great base to work from.
Suggest 10/1 pistons on bored cylinders.
If your P&C s were good, going to a 2.4/2.7 crank and rods gives 10.3 cr
Going to 2.4 S pistons only gives you less than 8.5 cr because they are 8.5 on the long 2.4 crank.
Bruce

2.2 Sengine
 

It is hard to beat the 2.2S engine as it is the last of the high compression engines. The 2.4 S engine was 8.5 CR to satisfy the federal laws on fuel usage. You power band will stop around 6300 rpm where as the 2.2S will pull strong up to redline.

Thank you for your advice. I think I will stay with OEM spec.

As cool as it is to rev the little 2.2S engine, the 2.4 with increased compression and a more modern cam (Mod S or similar) is generally quicker and much easier to drive.

Actually, the 10.3 number theorized by changing the stroke is extremely misleading.
Over the years we've discovered that the 2.2 "S" (9.8:1) static compression is actually closer to 9.4:1. By changing the stroke the resulting static compression is closer to 9.9:1.

There's not really much you can do to get more power out of that engine. Perhaps as other have mentioned, MOD-S cams (Dema Elgin or DRC). If you really wanted a project, you could put the MFI on the shelf and go with an EFI setup that will net you a few extra hp.

Henry do you think one could run a single-plug 2.4 at 9.9:1 compression on California 91 pump gas? Maybe a little less compression just to be on the safe side? I've got a 2.2T built to S specs with the Mahle p/c's and have started thinking about using the 2.7 crank/rods and a modern cam like Mod-S for a power upgrade. Probably wouldn't go there if it meant having to twin plug it though. Thanks for any guidance.

9.9 on Cali street gas is marginal as a single plug. The issue is heat. If the heads get hot, it will detonate unless ignition timing is severely restricted.
Rich mixture, retarded timing and easy throttle trough maximum torque can mitigate the issue.

Edit: sometimes you can mitigate detonation by simply changing to a cooler spark plug.

Thanks...sounds like it'd be better to just shim the cyls and knock the compression down to 9.6 or .7? Any sense of what kind of power such an engine would make with mod-s cams?

With Mod"S" cams, 9.5:1 + compression and some modest porting this formula should product 180-190hp at the crank.

Our twin plug, 9.5:1, Mod "S", 2450 (70.4 x 86) with 40mm Webers have been dynoed at 180 RWHP.
Chassis dynos are dubious at best but the drivability and seat of the pants acceleration seem to quantify the numbers.