7A block and pistons + AAN

[shone190]

I have URquattro with 7A block and pistons, everything else is from AAN engine. My question is, do I need to change this block and pistons for one from turbo engine or not?

Engine is working great but I have plans for bigger turbo, injectors, IC... to get about 400HP, so I need to know is it cappable (block and pistons) for that power?

Thank You very much in advance.

Best regards.

[driftin jo]

The compression ratio of the 7A is your problem, you really need low compression pistons
and probably stronger rods but it is probably cheaper to just find a turbo engine instead as the standard ABY AAN will do 400hp standard no problem.

[shone190]

Is this better and cheaper solution?

http://www.034motorsport.com/engine-components-audi-i5-head-gasket-compression-dropping-multi-layer-steel-audi-cyl-p-114.html

[Zoig]

"OEM quality, MLS headgasket with increased thickness to drop compression in all hydraulic-lifter 10v and 20v 5 cylinder motors with up to 82mm bore"

AFAIK 7A has 83mm bore.

[shone190]

"Will lower 7A motor to 9.4:1 (approx. the same as the AAN stock)"

How do they imagine this?

[shone190]

Here is complete Turbo kit for 7A engine: http://www.034motorsport.com/turboch...r-p-19679.html

I can see that there is "034Motorsport Compression Dropping Head Gasket to lower compression to 9.5:1 for optimal timing advance and safety", so they have appropriate gasket.

[Jamo]

Use that gasket at your peril do it properly http://www.s2forum.com/forum/showthread.php?t=44889

[prj]

Thicker gasket will mess up quench, so you might not get as much benefit as you think.

[shone190]

So what's the best option in this case? Turbo block and pistons?

[prj]

Pretty much...

You could also try 7M-GTE pistons, BMW 328i rods and getting the head professionally re-done plus the crank machined to fit the 328i bearings.
The parts would be very cheap.

[shone190]

Thanks for the info

What do You mean for current setup with this 7A block/pistons and chipped AAN ecu, it is safe to run this way until I decide to buy bigger turbo and other stuff?

[prj]

No, it's not safe at all, as with that CR it's probably knocking like crazy. And it is possible that when you open the engine, you will find a bad surprise.

[shone190]

Car is working perfect for about 5 years (about 30000km) with this setup, so I am wondering are there 7A block/pistons at all

[prj]

Well, AAN Motronic knock threshold maps are very low, so it is pretty good at surpressing knock.
But that means it is never really running the power that it should.

You can always take the head off and look how it is inside

[shone190]

OK, so conclusion is that I need to buy turbo block and pistons