H22a8 head on h22a5 bottom end?

Therealjj91 · Post by **Therealjj91** » Tue Sep 17, 2013 3:58 pm

And did I read somewhere that if you got a type s ecu you could unlock the 217bhp?

Post by **Merlin** » Tue Sep 17, 2013 4:26 pm

That wouldn't work. You can get more grunt out of it by getting a tunable ECU like this http://www.ludegeneration.co.uk/prelude ... t3567.html

Although the lower compression of your a5 pistons will hold you back.

It it thought that a stock a8 (whole engine) should make more power than it does since it has much of the same specs as an ATR or Prelude Type-S engine. Tuning it would yield some more power.

Therealjj91 · Post by **Therealjj91** » Tue Sep 17, 2013 4:33 pm

Yeah tuning it was going to be my last modification that I was going to do after I had done everything else, so are the pistons in the bottom end then? And will I see a power increase after fitting the a8 engine even before a tune? Thanks for all your help btw

Post by **Merlin** » Tue Sep 17, 2013 4:41 pm

The power difference between a stock a5 and a8 is only 12 bhp anyway so you probably wouldn't notice.

Comparing stock engines It's the combination of the sight increase in power and different gearbox which makes the a8 accelerate faster than an a5.

Therealjj91 · Post by **Therealjj91** » Tue Sep 17, 2013 4:43 pm

Hmmmm I don't know what to do lol

Therealjj91 · Post by **Therealjj91** » Tue Sep 17, 2013 6:06 pm

There's someone on here selling ATR pistons would it be worth while fitting them and the a8 head at the same time? Would that be easier for the mechanic since the engine will be out any way?

mercutio · Post by **mercutio** » Tue Sep 17, 2013 11:00 pm

might be cheaper waiting on a complete a8 buddy because If your gonna put the pistons in your engine that is pretty much a full rebuild so you will need all gaskets may as well do the cambelt waterpump balance belt new piston rings with labour you wont get much change out of £1200

Therealjj91 · Post by **Therealjj91** » Tue Sep 17, 2013 11:55 pm

Yeah you're right I'm probably getting too ahead of myself lol I don't have that sort of cash lying around anyway, my mechanic is pretty good though charging me £150 to install lightened flywheel and pulley

mercutio · Post by **mercutio** » Wed Sep 18, 2013 8:21 pm

that's not bad at all buddy

Post by **SPYDOR** » Tue Oct 08, 2013 11:35 am

Just noticed this thread and thought I would add that I seem to have the H22A5 block with an H22A8 head in my 5th Gen. My car is listed as a 197bhp H22A8 model. I have never been sure whether the normal H22A8 engines used A5 blocks or if there was a different A8 block.

Looking through my service records, the first owner complained about a lack of power at about 15k miles and Honda performed a short engine rebuild or something, so this could be responsible for the different parts in mine.

Anyhoo, its been running strong since I bought it in 2007/2008 and old dyno charts show it has the power of an H22A8 so no complaints here!