It seems like people go through an awful lot of work to turbo the small A12 with its small intake ports, etc.
I have an A12 that needs some work, but I can also get an A14 for free that is in good shape. I may go the turbo route, but right now I'm just curious.

For racing a blown A12 can compete in classes where a blown A14 or A15 would be too big, I think its an under 2 litre class thing.

They would be using an oval port head though.

Quote:Grab the A14 with both hands as it will never be cheaper than that & it will cost the same to turbo either one.

For street use, it makes no difference which engine you use.

A12's rev harder due to shorter stroke and are very pleniful and very cheap if not next to free. A14's and 15's are getting quite dear now...as expensive as an SR20 to buy and if you get your fuelling wrong it less heartache on the back pocket to get another A12

I agree with the racing classes the A12 is a bit more flexable. But i would say the main reason is the cost. cheap and available everywhere. I know that in my street car i would much rather have a tuff A14/15 than a baby A12. If you can get a motor for nothing and upgrade at the same time then you cant go wrong.

sundat, let's see some good pics of your coupe!

i've had all three

i would say for street a15 is best by FAR, even over an a14

it has the low down torque so any lag is no issue

plus its more reliable because you can make the power lower and dont need to rev it out to go fast

Quote:

I will post pictures up soon. Right now the car looks a bit rough (planning to touch up the paint shortly) and I'm without a digicam.

But i was able to get my VW rabbit Bilstein front strut inserts installed two weeks ago (required custom spacers and machining of the top nut) along with some coilovers. 13x6 jellybeans with 175/50/13's should also be going on as soon as I mount the tires and lower the rear.

Its amazing how much better the car handles with just the bilsteins and stiff coilovers I'm using 280 lb/inch springs with a soft helper spring- which is too stiff for daily driving but I actually drove it all the way from norcal to socal last weekend and I survived.

I also machined my caster rods .600 of an inch, to allow four degrees caster, which really helped the cars stability on the freeway. I highly recommend it.

Back on topic, It seems like the a14/a15 engines are more common than a12's in the US. I'll probably be using the A14, donated by my uncle from a b310 he's junking.

Sidedraght is right on the money.
In all circuit racing and hillclimbs that I've seen the rules for, a turbocharged or supercharged engine has a engine capacity multiplication factor of 1.7, and most engine capacity classes (ie 2000cc) will accept capacities within 2%. That make a 2040cc engine ok for the under 2L class.

So, to be competitive you want to be just under 1200cc for the 2L class or just under 1800cc for the 3L class.

1200cc x 1.7 = 2040cc (under 2L)
1800cc x 1.7 = 3060cc (under 3L)