hi i have a 1990 coupe quttro 7a that im tuboing

[MISTER T 1997]

yea why not?

[piotr]

I wish you alot of luck mate with your project.

[Error404]

You can’t use an MLS head gasket on a 7A block (Max 82.25mm bore. So the cheapest solution is as I suggest earlier in the thread - sleeve the block to 81.01 and use stock S2 forged pistons, H-beam rods and S2/RS2 sputter rod bearings.

You’d be best getting an S2 oil filter / oil thermostat housing so that you have the turbo oil feed and oil cooler I/O ports.
Alternatively you could tap the oil filter housing bolt and take a feed from that.
You also need to think about the turbo coolant feed and return.

You can’t use a 7A intake, it’ll occupy the space you need for the wastegate. Also the 7A throttle body will cripple the airflow.

As I said there a ton of details that all need solving and with S2 parts prices as they are these days it will be an expensive project!

[LHD_Kid]

yea why not?

I don't know what it is...

[MISTER T 1997]

s2 b3 the first s2 the one that is the same as my 7a

[LHD_Kid]

Ah, OK... 3B, but it isn't the same as your 7a...

There are differences, 3B to ABY, but essentially you can use a 7a cam cover with any of the OEM I5 inlets (3B, ABY, ADU, AAN)

[MISTER T 1997]

o realy i was told that the covers were different and it would not fit as i initially had planed on using an aan manifold
also i ment that it used a dizzy and leed and older tek the the newer aby engies

[LHD_Kid]

3B did have a distributor and leads, but it doesn't stop you from using the 7a cover. The problem with using the AAN manifold is rather the radiator placement...

Edit; but I think you have quite a lot of reading to do before you get to the stages of worrying about radiator placement...

[MISTER T 1997]

i did think that the rad would be an isue but its nice to know that the aby manifold will fit

[MISTER T 1997]

Some one offered me a s2 b3 ecu and wiring loom for £300 I am a bit hesitant on buying it as I don’t know how good a 3b ecu is my plan was to ether get a aftermarket one or a aan but it is quite cheap is the 3b ecu worth having?

[LHD_Kid]

If you use the 3B ECU, you are stuck using a distributor, also, any S2 genuine ECU, your choice of who to remap it is VERY limited

[MISTER T 1997]

So you recommend to go aftermarket but will my 7a loom be alright to mod or should I get a b3 or aan one?

[steve briance]

Before you start buying turbo components, getting machining work done and find yourself in the downward spiral of 'unknown other things' you need...

Consider throttle bodies and standalone ecu on your 7a.

You want to build something different? This WILL be different and dare I say it a bit more interesting than yet a other turbo charged 5 cylinder. You will end up buying a stand alone ecu whatever you end up doing but the big difference is that with a small custom manifold; you can bolt throttle bodies to your 7a AS IT IS assuming it is healthy.

You leave the compression ratio alone, the radiator stays where it is, the gearbox will thank you, it will sound amazing, rev happily, options for places to get remap done will increase with stand alone ecu and if you add a camshaft set would make well over 200bhp.

[steve briance]

The sound quality is not the best in this video but just listen to the noises this engine makes.

https://youtu.be/0MjthtT9vEQ

[steve briance]

Or this one

https://youtu.be/1na7EoxdtWs