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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?
 
Ignore the colour of the injectors, early 225s tended to come with the brown injectors, and R26 with the blue ones. No difference from my knowledge though in the two colours.
 
been a while since I cross referenced parts, if you could pop over the vin number I could take a look.

From memory the 170 and the others (205/225/230) had different pistons and cams, possibly the rods internally.

Then bolts on like injectors (possibly) and turbo are different (smaller) on the 170
 
been a while since I cross referenced parts, if you could pop over the vin number I could take a look.

From memory the 170 and the others (205/225/230) had different pistons and cams, possibly the rods internally.

Then bolts on like injectors (possibly) and turbo are different (smaller) on the 170
Hi Adey, here is the vin number bud. VF1BM2RR640136867...
This has the F4R776 engine in it.
 
On another note...FUELING!!!! anyone tried increasing the fuel pressures on the Megane 2's? I know they run on +- 3 bars pressure. Easiest way to overcome fueling issues is to throw in a set of 630cc injectors right?
 
I'm sorry to bring up the subject but I plan to transform a 165 into a 225. 😗
I checked all the part numbers, the only differences are on the pistons and the head gasket.

Engine block, crankshaft, connecting rods, cylinder head, camshafts are identical.

The difference seems to lie mainly in the reduction in volumetric ratio obtained by the cylinder head gasket and the pistons.

If you have more information on the differences between 165 and a 225 I'm interested, I will tackle the project shortly
 
Few years ago I struggled to find a R26 engine as I blew an old motor. Spoke to @Adey about it and he said that theirs slight differences with internals (cams,pistons,head gasket etc) and when I found a cheap 170bhp engine and stripped it down ready to forge I found that he was correct and all the part numbers were different from cams to pistons. You can push the 170bhp engines but after being on EFI’s rollers, Chris mentioned that there could be a slight difference with the head aswell as he struggled to get 350bhp out of it like what my old R26 engine was pushing.
 
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I'm really surprised because I searched with the part numbers on catcar.info and I only found a difference on the pistons and the head gasket.

Before starting the assembly I need to know if it is ok otherwise I am looking directly for a Megane RS engine.

I'm looking to get reliable 250hp for a track car.
 
I'm really surprised because I searched with the part numbers on catcar.info and I only found a difference on the pistons and the head gasket.

Before starting the assembly I need to know if it is ok otherwise I am looking directly for a Megane RS engine.

I'm looking to get reliable 250hp for a track car.
don’t always rely on everything you read on the internet 👍🏼
 
This is why I went to check the spare parts references. 🙂

According to the forums there are so many different versions. 🥲

According to you, who knows the engine well, do you think it is possible to get 250hp out of a 165? (with 225 turbo and head gasket)
 
I've documented some of the differences somewhere, with part numbers.

tbh pushing any old engine may highlight weaknesses. Id send it to 250 and see what happens lol. Pistons and higher comp ratio may even help at that power level and keep it a little more responsive.

If it were me, id slap a r26 or 250 turbo on it, some new r26 injectors and tell the person mapping it to keep the torque down

If you want solid reliability id build it.
 
165 piston 8200914513
225 piston 8200264972

165 rod 7701478497
225 rod 7701475350

165 head 7701475605
225 head 7711135943

though this is only as good as me writing them down and the info I could find at the time. I think they all had the same inlet cam but maybe differences in the exhaust cam. been a while since i looked them up.

Id slap a few parts on the 165 engine and go to 250 with no issues personally. But that said, any time you push an engine there are risks, as long as you accept that (y)
 
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