XU7 upgrades

[Mart_n 0]

Hello, I'm new to this forum. Sorry if the topic I'm about to ask was already answered some time ago. Up start I'd like to state that I do not own a 205, but a 306 Phase 3 XS Trim.

 

It has the XU7JP4 under the hood. I use the car as my daily and plan on keeping it. I'd like to add a bit of power though, i'm looking for a compromise between fuel-economy and more mid to top range power. I've already done some research and came up with replacing the camshafts for the ones found in the XU10J4R (2.0 liter / easier and cheaper to find than the ones from the GTI6). And also changing the intake manifold together with a throttle body for the XU10J4R one. 

 

What I want to ask you all about is your opinion, regarding the mods I've mentioned. If it's worth the hustle or if there might be a better way.

 

Also, I've thought about replacing the stock log-type exhaust manifold with a copy of XU10J4RS 4-to-1 one. But I can not find any exact measurements of it. I plan on welding it myself and adapt the mounting points to fit my engine-block. 
Could anyone please post any measurements of the XU10J4RS exhaust manifold?

 

Thanks a lot
- Martin

[welshpug 1,657]

loads of info there for you.

 

regarding changing the cams and manifold the easiest route is to just bolt the RFS manifold and downpipe straight on, and swap the complete RFV head, the ports are larger.

 

this might get you near the 135 bhp of the RFV, and be about 20kg lighter, but only if you can find someone to map the original ecu or change the ecu to an aftermarket one.

 

if budget is a constraint then honestly just dropping in a complete RFS(gti6) engine and loom assembly in direct will be far less work and money for the bhp gain.

[Mart_n 0]

Thanks for the advice. I've already thought about swapping the heads for the RFV one. But from what I've noticed the bore of LFY is 83mm and the bore of RFV is 86mm.

I don't think that they would fit at all, but please correct me if I am wrong.
And regarding the RFS exhaust manifold, they are not easy to find in my part of the world (Slovakia), let alone cheap. But yes, it might be cheaper to just import it from another country than welding it all from scratch.

But I've seen many RFV ex. manifolds for little money (like 15€), would that be a more viable option?

 

When it comes to mapping the original ECU (I have a Sagem SL96), I'd just swap that out all together with Speeduino, I am quite handy with this stuff so that wouldn't be much big of a problem.

[welshpug 1,657]

Rfv and lfy exhaust manifolds are the same, so no point in swapping those!

 

Heads should swap fine, the chamber is smaller than the gasket, I can check tomorrow  however  as I have all 3 types.

[Mart_n 0]

13 hours ago, welshpug said:

Rfv and lfy exhaust manifolds are the same, so no point in swapping those!

 

Heads should swap fine, the chamber is smaller than the gasket, I can check tomorrow  however  as I have all 3 types.

Yes, that would be great if you'd checked.

What I meant by them not fitting is, that I am a bit worried regarding the head gasket interfering with the combustion. Not really sure which one should I use, I'd suppose the RFV one.
Has anyone actually done this?