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F4R774 & F4R776 - whats the difference?

DennaGT175

New Member
Hi guys, please can some light be shed on the two above mentioned engines...my reason for wanting to know is because i have the Megane 2 ph2 GT with the F4R776 engine which i believe has 170bhp. I want to know if the Megane 2 225 with the F4R774 engines are internally the same or are there any similarities...
I am busy building my GT now and have removed the cylinder head and found that there is a noticeable difference in head gasket thickness - roughly the 774 head gasket is double the thickness than the 776 indicating that the compression ratio is lower on the 774 to compensate for the higher boost. So in terms of the rods and pistons, are there any actual differences with those parts between the two engines and are there any other hardware differences, cams, etc,?
I know the turbos are different, the 776 having a 10T tutbo and the 774 having a 14T turbo, as well as the injectors are different having the colour "blue" on the 774 engine and "brown-ish" on the 776 engine.
So, having said all that, can the 776, with the head gasket, turbo and injectors from a 774 engine work well in producing 225bhp? if not more, with a decent map?
 
Ok nice, thanks everbody for your answers. 🤗
@Adey It was a bit late yesterday night, i didn't realise that you are the guy with the Twingo on Youtube 🤣

Thanks Kimbe too for sharing details.

if you want I can list all the spare part references, maybe it can help someone?

To my opinion, a 165/170 engine with 225 piston and rods can handle about 250/260hp (same as Mégane 225 with remap), if you want more, you have to use piston and rods from Mégane 250/265/275. Of course with good turbo, injectors, engine management ... ect.

I'm gonna have the engine on tuesday, during the next month i've planned to rebuild it. I will document what I find 🙂
 
Hi,
I take time to compare all the parts number, maybe this can help someone. 🙂
I used catcar.info, i mentioned the original OEM numbers, not the remplaced one. To my opinion it's the most accurate, because if you buy an used engine, the parts came from factory, not from aftersales.
I compare F4R 774 with F4R 776 (Mégane / Scenic 2) and F4R 764 ( Laguna 2)

53345702575_be0eccfe29_o.webp
 
Hi,
I take time to compare all the parts number, maybe this can help someone. 🙂
I used catcar.info, i mentioned the original OEM numbers, not the remplaced one. To my opinion it's the most accurate, because if you buy an used engine, the parts came from factory, not from aftersales.
I compare F4R 774 with F4R 776 (Mégane / Scenic 2) and F4R 764 ( Laguna 2)

View attachment 215716
I mean, what we’ve just said is totally different to this but believe what you will 😂
 
I mean, what we’ve just said is totally different to this but believe what you will 😂

I know, sorry 😂
I also ask a french facebook group, it's quite funny because 4 people replied to me :

2 guys says : it's the same engine
2 guys says : it's completly different

I prefer to get the information UK forums ou groups, you go further in the modifications than the French people 😂
Few years ago, cliosport.net was a gold mine to mod ours Clio 172/182.

That is gold. Thanks @yabx172

Just to add is there any chance you could copy + paste the excel sheet into the post? It will help people find it rather than the image

I can of course !
the image is easy to read, but words are better for SEO 😁

PartF4R 774 (225) - CM0MF4R 776 (165) - EM0WF4R 764 (165) - BG0S
Engine block770147851077014785107701479257
Crankshaft820003783682000378368200037836
Rods770147849777014784977701478497
Pistons8200264983 (B ) 8200264983 (C)8200914513 (B ) 8200916586 (C)8200914513 (B ) 8200916586 (C)
Rings x4770147472577014747257701474725
Cylinder head770147560577014756057701475605
INT Camshaft820003804282000380428200038042
EXH Camshaft820091110382009111038200911103
INT valve770147428777014742877701474287
EXH Valve770147310177014731017701473101
Rocker arm770010755677001075567700107556
Valve lifter770010755577001075557700107555
Spring valveNo part number ( ??)82000776568200077656
 
I know, sorry 😂
I also ask a french facebook group, it's quite funny because 4 people replied to me :

2 guys says : it's the same engine
2 guys says : it's completly different

I prefer to get the information UK forums ou groups, you go further in the modifications than the French people 😂
Few years ago, cliosport.net was a gold mine to mod ours Clio 172/182.
There’s 100% difference between the internals of these engines. There’s even differences between 225 engines and r26 engines as they use different exhaust cams. When @Adey sent me this (picture below) I checked them against my old engine’s and they matched up however when I checked it against the 165bhp engine I had, they were completely different. And again, when I had it mapped, Chris at EFI Parts mentioned it was detonating sooner so had to come down from 24psi to 18psi of boost possibly due to the fact the combustion chamber on the head was difffent to my old r26 head.
2A02F100-2222-4EE8-90B4-49FF2E11D190.jpeg
Again, don’t always believe what you read on the internet…
 
I trust you, I'm sure there's a mystery to be solved 😁

Indeed, with the CM2H mine type the exhaust camshaft is different. Even if it's still an F4R 774 engine. (I haven't checked the other parts)

Out of curiosity I compared a Laguna 170 (F4R 786 same pollution level as the Mégane R26), it is different in fact, I also went to check on the 2.0 TCe 180 and the latter has an exhaust camshaft identical to the 165/170, but it is the intake camshaft that changes.

In short, a hell of a mess.

What I remember is that a 225 is less easy to optimize than a 230.
I am convinced that it is a matter of depollution standards

Euro 3 until 12/2005 = 225 with CM0M or CM1M type
Euro 4 from 01/2006 = 230 with CM2H type

I'm pretty sure that the point
 
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Wow, sorry, third message but i read a bit too fast (it's not my language ☺️ ), now I completely understand what you are explaining to me.
Even with the 230 internals the engine never managed to put out as much power as the original R26 engine.
 
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