Boosted 172 help

[Radugns]

For my second engine rebuild I want a turbo conversion. I know it would be simple to just add a meg 225 engine, but this is not what I want.
I think I have some options here:
1st: use all 225 internals, like pistons and head. this will drop the CR and the head accept 225 manifold.
2st. use the 197 head on the 172 block with 172 pistons. this also drop a little the CR, I think a little under 10:1. But does this accept de 225 manifold or need custom one?

The engine will be fully rebuild, so there is no problem to swap parts, they will be disassembly anyway.
3rd: use the 197 head and build a forged engine. Get the 9.5:1 CR and because of the 197 head could run higher boost. But I want to keep it a little under 300 due to jc5 box.

For me if can be used the 197 head with 225 manifold would be the best, because it looks good and also provide the power I need.

Thanks,
Radu

 

[scotiamr2t]

use the megane head gasket and it will allow you to keep the rest of the block and head as per the standard clio 172/182

 

[NorthloopCup]

225 inlet won’t fit on a 197 head as the ports aren’t the same. Bolt pattern is the same though.
Turbo manifold will fit on any f4r though

 

[Radugns]

225 inlet won’t fit on a 197 head as the ports aren’t the same. Bolt pattern is the same though.
Turbo manifold will fit on any f4r though

So no really need 225 head, I can use 225 manifold on 172 head?
If so, forged internals and keep the 172 engine.

 

[NorthloopCup]

So no really need 225 head, I can use 225 manifold on 172 head?
If so, forged internals and keep the 172 engine.

Yes mate, you can use the exhaust manifold on a 172 head if that’s what you’re wanting to do.
The 172 inlet manifold will most likely foul the turbo on a 225 manifold, so you’re better off getting a log manifold. Gives more scope for turbo choice as well with a log manifold.

 

[Radugns]

Yes mate, you can use the exhaust manifold on a 172 head if that’s what you’re wanting to do.
The 172 inlet manifold will most likely foul the turbo on a 225 manifold, so you’re better off getting a log manifold. Gives more scope for turbo choice as well with a log manifold.

Maybe the easy way is to put the 225 head, but did not know what forged pistons to get. I think the combustion chamber is bigger than 172.

 

[NorthloopCup]

Maybe the easy way is to put the 225 head, but did not know what forged pistons to get. I think the combustion chamber is bigger than 172.

Dunno mate. Not something I’ve looked into.

 

[bloke]

i'd use the standard head over the 225 head all day long. 197 head is better though.

197 head and megane pistons or 197 head, 172 cams and 225 or 250 headgasket. you can use the megane exhaust manifold and turbo but you need to cut the neck off the turbo and turn it 90deg.

 

[Radugns]

So if I have a 197 head is better to use it on the 172 block instead of 172 head. And about the manifold, it will fit OK on the 197 head ports?

 

[bloke]

Turbo exhaust manifold will fit it fine. Run the 197 inlet. Chamber is bigger on the 197 so that will drop your cr slightly and if you use the meg gasket that drops it again. The 250 gasket is thicker than the 225 as well so you've got three gasket choices.

 

[Radugns]

For now I have:
-225 pistons
-197 head and inlet
-turbo manifold

But what about cams? 172 or 225 ones? I am sure 172 are common, but if needed I will go for 225 ones.

Thanks,
Radu

 

[bloke]

172/182 cams if you want power.