F7R vs F4R

[Djw Dave]

Im interested in the technical merits of both these engines for tuning to a higher power level

i know the F4R makes more power in stock trim but how capable are both engines given the same mods

say for instance, stock heads, 285in/275exh degree catcams or similar, throttle bodies, properly designed exhaust manifold and well mapped DTA or similar

im assuming that as long as both engines have similarly good cylinder heads that they will produce similar power in that state of tune? 230bhp?

what are the bottom ends like for both engines? stock rods good for 8krpm? piston design?

there seems to be a shortage of tuning parts for the F4R (no forged pistons for instance?) is this the same for the F7R?

Any info would be great!

Cheers

Dave

 

[theduck]

i thought the f4r was more tunable? i maybe completely wrong though

 

[BenR]

F4R breathes better in std trim, F7 wont touch it.

Bottom ends are basically the same, pathetic piston design (5cc dish), but the F4 is manufactured better.

There are plenty of forged parts, but none of them i rate high enough to bother talking about....apart from arrow and carillo rods.

Zero decent pistons about....for now

 

[Djw Dave]

so given the above specs what power outpous would you be looking at from both engines? i know u cant give an exact figure but what ballparks are we looking at?

to give an example £2.5k spent on a Vauxhall XE lump would gain you some throttlebodies, exhaust manifold and mappable management and would see you around 190-200bhp with nothing more done apart from some uprated rod bolts. Cams and headwork can take that engine all the way to 300bhp (with the obvious upgrades to the bottom end as things get up the power levels)

what im asking is that if you took both motors and fitted the same throttlebodies, exhaust and mappable management what kinda power levels would you be looking at? and similarly how much power would be attained from some more aggressive cams? obviously you;ll start getting flow issues as the power level climbs but i'd just like an idea as to what they can do

cheers

 

[Fred@BTM]

adams 16V - 216bhp F7R (megane head) = £5K or there abouts i think

 

[White16valver]

Ouch.

But it is rapid!

 

[BenR]

With a mild build consisting of bodies, cams (of durations you specified), manifold and std long block. I would put the F4 at about 225-230 and the F7 at 200-210.

All out, you'll max the F7 at about 280-290 and the F4 at a tad over 300, but just remember it takes a SERIOUS amount of work to get any 2ltr near the 300bhp level, bar some super 4 pots.

F4 is better, period.

 

[MAXIBOY]

dont wossner now make decent forged clio pistons just got a set of 7.5 forged turbo pistons from them

 

[BenR]

i guess the operative word ther is decent, i wouldnt rate them as 'good'.