destroking engine. any ideas on how to reduce 2.2l down to 1 or 1.5l
 

Hi all,
Well i am stuck with a 2.2l engine, i have done plenty of modifications but the limiting factor is starting to be the engine itself. A 2.2l has much more power than i need. I toyed with the idea of deactivating the cylinders but the balancing and infrequent power makes the engine vibrate and generally doesn't ride very well.

So short of changing the whole engine the only other thing i can think of is to destroke the pistons which i believe involves changing the crank shaft. It sounds like a very difficult job so it may not even be workable but has anyone ever done this. I am wondering if i can just get a crank shaft from another car which will work for my mazda 626 91. also how hard it is to change the crank shaft.

if anyone else has ever tried to get the engine itself more efficient i would be interested to hear what has been tried. I have already heard of changing the cam shaft, piston coatings and lean burn.

thanks

just swap the motors if its that bad for you

If you change the crankshaft you would have to change pistons and/or rods also to maintain a proper compression ratio. You`d basically be rebuilding the bottom end.

I`m not sure what side effects would result from going to a radically over-square (large bore, short stroke) configuration. Fuel/ignition might need to be retuned to realize any gains in efficiency. (more spark advance?)

If you continue to use the existing intake then it would still be tuned for the same power level (and would be suboptimal for the low-rpm or low-load conditions that I assume you are favoring). In the Italian market, BMW sold (for tax reasons) a destroked (2.0L) version of the 2.3L e30 M3. It lost some torque but peak power remained pretty close, while moving to a higher RPM (192 at 6900, originally 200 at 6750)

If you feel the displacement is too large, how about going to taller gearing?

Another aussie..! :p

You can change to a smaller engine (which would be the second cheapest way), but the easiest and cheapest way is to just sell the 626 and buy something with a smaller engine.

If it has to be 4 doors, look at Toyota Corollas otherwise get a Starlet ($1500) like me.

If I had my time again, I would have tried to find a 'Lean-burn Civic' though I'm not sure these made it to Australia

You can destroke that 2.2L to whatever you want, except the cost would be ridiculously stupid and then the cylinder head ports would be too big for the reduced capacity, thereby reducing volumetric efficiency and then the cam timing would no longer be optimal either, the list goes on and on....

Putting it bluntly, get a different car.

:)

Getting a different car would also be a convenient way to get a stick shift. And a 144V starter motor. ;)

+1 for a wise suggestion. A cheap way to do this is to put larger tires on the drive wheels.

I agree on all the suggestions besides trying to destroke 50% of the displacement of the engine :thumbup:

It's going to be easier to swap engines. Destroking yours is a lot of work, and without re-tuning the intake manifold, cam and such, you'll lose pretty much all low-end torque, leading to no gains in FE, but a loss in power.

If you want to keep the same car, your best bet is taller gearing. A large engine with lots of low-end torque kept at low rpm will do just as well, or possibly better in some cases, than a smaller engine revving higher to do the same work.

Thanks for all the replies,
I was expecting it to be too hard / easier to buy a new car or new engine so its good to hear other people believe the same thing.

I would love to sell my car and get a new one that is more efficient to start with but i am not sure i would be able to sell it at this point (the front end was crumpled in on one side i bashed it out with a hammer so doesn't look too good) and i am enjoying the idea that i can do whatever i like to the car because if i stuff anything up ill just write the car off and get a new one. I am also interested to see how far i can go with a car that has started off being average for fuel efficiency.

regarding taller gearing, i have already started a previous thread on this and apparently it is very difficult to modify the gearing of an automatic transmission. However I do work with a guy that used to design automatic transmissions so i do plan to hit him up for some ideas.

You don't really want to destroke the engine . Forgetting about that ECU, intake, exhaust would be out of tune.
Destroking generally will move power and TQ up in rpm. thats not what you want for eco plus I doubt you get it much lower than 1.9-2.0 with stock OEM parts .

So either try higher gearing or replace with more modern small engine .