How beneficial is headwork...

[cK]

... on the 172 engines?

Don't give me "how long is a piece of string?".

I was just wondering if many have had it done and what kinda gains they got?

Thanks

 

[Fred@BTM]

you won't see massive gains, its like everything on the F4R

spend £'s and get f**k all out of it

still worth doing

 

[cK]

Why is it still worth doing then?

From the very beginning I said I would get the headwork done but have done other things before this.

Obviously with a remap afterwards...

 

[Fred@BTM]

you have to spend serious cash for tiny tiny gains on the F4R's thats the way it works

hence still worth doing!

 

[haitch]

ive had headwork done by Ben & im sure he can better explain the advantages of it, cant say on its own how beneficial it is but with the other mods the car has good torque, peaking at 4.5k, always feels like its straining at the leash, cable throttle is probably next for me after a few track outings ;-)

 

[cK]

Mine already has cable throttle and is producing 195bhp without headwork. You definately think its worth spending the cash on? How much was it roughly when Ben did it for you?

 

[BenR]

Its beneficial, but like i've said, i've not seen any great work from others. The head comes CNC'ed from the factory. The great part about this is repeatability between all the heads that come out of the factory, irrespective of casting. The bad part is that renault didnt get the design quite right.

It takes alot of work but very little material removal (renalt already took too much out), and from what i've seen from others its basically a cleanup of the cnc marks. About 80% of the flow gain is from the valve seat work and bowl work.

This is a full rework, without chamber work, to a spec simiar to what a sprint/clubman racer would require.

Cyan line is std intake
Red line is Std Exhaust
Blue is modified Inlet
Green is with Modifed exhaust

Max measured lift is 0.48" or 12mm, but as you can see flow curve continues.

Inlet there is a 12.5% gain in flow with ZERO flow loss at any point in the curve, normally the average porter will loose flow below 0.28" as they honk it out to gain peak lift flow.

There is MASSIVE 26.5% gain on the SMALLPORT 182 head exhaust port.Ex/In flow ratio is now a healty 91.8% ratio average, peaking at 99.5% @.24".

 

[Fred@BTM]

gotta love the Rushworth

 

[timdog]

Ben, Check your email. I've sent you some thoughts on the flow figures and some of my pfa data.