Honda K20Z4?

Any of you chaps know if a K20Z4 engine is essentially the same as an A2?
I know it has DBW throttle but are the internals the same etc?
Cheers :slight_smile:

Some conflicting info on there…so is the Z4 considered inferior to the A2?
More confused now!

Z4 is the better engine…

I not so sure about the Z4 being better?

From memory in the LOT Class C days they were to avoided. DBW was an easy fix, but recall there something about an engine mount position being slightly different and less strong rods? Think someone on here had one last 2 laps of Spa on a 3 day race weekend.

What John said …^^

This thread maybe more helpful.

Maybe that’s because they are harder to fit in if your trying to put in a car that’s had a A2 in it John, the one at Spa could off just been a bad engine or low on oil, etc.
The engine mount position is the same, but the sump is deeper by about 30mm you also have to either change the inlet manifold or modify it
also there’s alot of modification to be made to the water system but like anything you can make it fit.

The other question is it as good as an A2 engine Now that a can of worms, but all I can say is i’ve won a championship with the Z4 engine in my car.


Don’t forget that class C allowed forced induction, and many rods were spat out when they were. There were plenty of people had issues when they were being raced with SC’s fitted to the later engines, a long way from a one off.

Your point about being harder to fit is partly my point. If you have a kit for an A2, then need an engine quick for an event, and all you can get is Z4, then you’re in for a bit of a surprise when the cooling system/undertray/etc don’t fit.

Reading some more it sounds like if you’re going SC then early engine standard or late engine and rebuild; if you’ve already got a early fitting kit, staying early engine saves some/lots of pain; if you’re going NA only and from scratch, doesn’t make a huge amount of difference. About right?

Good effort on your car and your result Tony. What’s the spec of it this year?