TU5JP4 mods, JP4S inlet, J4 cams etc.

[bifrogifro]

Currently have a J4, JP4 and JP4S. I'm scrapping the rust bucket C2 Code so taking a few parts from the JP4S.

Does anyone know what power is to be expected from a JP4 with either JP4S or J4 cams and JP4S alloy inlet manifold? If the J4 cams are more worthwhile, what other valvetrain components would it be prudent to swap over too?

Is remap a necessity?

Cheers

[VeiRoN]

Best cylinder head is the JP4,to use with J4 cams as they are a bit better than JP4S but really really benefits from upgraded cams,C2 inlet only gives you around 4-5hp.

Reuse valve train from the Saxo as it is stronger,not really worth to pay 300-400£ for a remap with just those mods to be honest.

With just those I would say around 130hp,you really need to buy some more aggressive cams (probably need cutouts on the pistons for decent power),a good induction kit (forget buying from UK,the proper ones are only sold elsewhere),and a bigger diameter exhaust without restrictions (again kits are sold outside the UK),after this pay a visit to Chipwizard.

It's not going to be cheap,I spent 4k to get 166hp,and paid no nobody as I done the work myself apart for the remap and doesnt even take into account possibly upgrading to itbs or the new inlet manifold I just bought, it's worth it as it puts a smile on my face evertime I drive it but just keep in mind you need some £'ss.

[bifrogifro]

Thanks for the info.

Regarding induction kit/aftermarket exhaust, would you recommend any particular manufacturers?

Also, is there any benefit to be had from swapping ECU's?

[VeiRoN]

Originally Posted by bifrogifro

Thanks for the info.

Regarding induction kit/aftermarket exhaust, would you recommend any particular manufacturers?

Also, is there any benefit to be had from swapping ECU's?

Check PSA Evolution,no benefit from swapping ECUs as far as I know.

[MartinObviously]

Originally Posted by bifrogifro

Currently have a J4, JP4 and JP4S. I'm scrapping the rust bucket C2 Code so taking a few parts from the JP4S.

Does anyone know what power is to be expected from a JP4 with either JP4S or J4 cams and JP4S alloy inlet manifold? If the J4 cams are more worthwhile, what other valvetrain components would it be prudent to swap over too?

Is remap a necessity?

Cheers

the crucial thing on these engines, is to make sure the inlet cam and the intake manifold match.

If you're using a J4 plastic manifold, you MUST use the J4 inlet camshaft.

The plastic J4 manifold has better performance for intake temps too.

This isn't about peak power, this is about resonance. You'll have a much more consistent power across the board with these items matching. It's just not worth the hassle mixing and matching.

For the record, my standard j4 engine went from 122hp to 138hp in a short dyno session. Still probably a bit more to be had. That's simply with an old 4-2-1 raceland, with janspeed cat converter and system and a cone filter.

In short what I'm saying is if you fit the C2 manifold and cams, you will gain nothing.

By all means, feel free to swap over the complete engine, the valves are a bit different. There's a bit more torque in the mid range with the JP4S engine. This won't net you more hp though as it doesn't make the same power at high rpms but it's a better engine overall in terms of overall power output.