F4r engine design

[Stu_182]

Why did Renault decide to make the inlet manifold go back over the top of the engine and have the tb at the back away from cool air? Why didn't they use a similar design to the jms intake? Any obvious reasons? Only thing I could think is it would get in the way when doing an oil filter change but the current set up needs removed to do spark plugs.

Any thoughts?

 

[Trainerbrow]

Because they are french and therefore retarded

 

[The Boosh!]

I'm guessing it was to keep within certain regulations and also to meet certain marketing/selling criteria. IE insurance group/emissions etc

 

[sideways danny]

f4r is like a dirty girl. it likes length

 

[mwn11]

LOL that made me laugh!

 

[Jamie86]

f4r is like a dirty girl. it likes length

Does width matter as well?

 

[sideways danny]

serious answer or "i'm a dirty little filthbag IRL" answer??

 

[Ant@BackyardRacing]

runner length i would say. couldnt really have the same runner length without going over the top of motor.

general rule of thumb is short/fat runners give better gas flow (i.e high rpm hp)
long/narrow runners give higher gas speed (better for low end torque, and thus drivability)

same goes for throttle body sizing, plenum volume

 

[Gaz_]

so with these front mounted intakes (jms style) are we losing low down torque?

 

[Jamie86]

serious answer or "i'm a dirty little filthbag IRL" answer??

Nah I get the basics of engine tuning.. so dirty filthbag please! lol

so with these front mounted intakes (jms style) are we losing low down torque?

Take a look at graphs.. You wont be losing over standard setup I wouldn't of thought..

 

[Ant@BackyardRacing]

well i suppose its possable if the stock item is poor, but i would be supprised.

i cant see how to increase gas speed, whilst also increasing flow...


same goes for cams, you generally loose somewhere to gain somewhere else,

 

[Gaz_]

Thats my thinking, to gain one, you lose the other. It must be advantageous for this engine as its still used in the 197/200, but with a better entry angle for the TB as the air is fed in smoother.

 

[Jamie86]

Ok put it this way i'm willing to bet that any loss will be under say 2000rpm so not noticeable.. other than maybe needing more revs to pull away..

Anyway I haven;t looked into JMS kit so really have no idea!

 

[sideways danny]

the thing that's often forgotten is there's more to it than full throttle. Where you will most likely lose out is part throttle driving at or under 50% throttle opening, where you'll spend most of the time around town