PDA

View Full Version : Clio Maxi cylinder head



Yanoo_
16-12-2010, 00:45
Has anybody got any information on Clio Maxi cylinder head? It was a modified Williams CH or Megane one? Inlet port and valve size, camshafts etc ? I'm curious, any info would be great.

n9kie
18-12-2010, 12:16
how much power did the clio maxi have?

Wobba
18-12-2010, 13:40
I think it was about 255 bhp at 8800 rpm.

zmaster2k
18-12-2010, 14:08
we need details tbh!

Tommo
18-12-2010, 14:16
http://www.rallye-info.com/carspecs.asp?car=320

robi1000
19-12-2010, 21:25
What do you want to know?

Heads came with equalized chamber volume which was around 46 ccm. Valve seats were made of bronze beryllium. Valve guides were bronze. Valves and retainers were made from titanium. Solid lifters were used with stronger springs.

Yanoo_
20-12-2010, 14:27
What do you want to know?

Heads came with equalized chamber volume which was around 46 ccm. Valve seats were made of bronze beryllium. Valve guides were bronze. Valves and retainers were made from titanium. Solid lifters were used with stronger springs.

Thanks Robi! I'd like to know the valve size and inlet runner diameter and especially the cam specs. I read somewhere years ago that Colombo and Bariani camshafts were used in the Clio Gr.A (and perhaps in the Maxi aswell). Is this right?

robi1000
21-12-2010, 00:14
I don't know exact runner diameter, but AFAIK it was almost standard. Most of the changes were in valve throat area. I'm not sure about valve size. I don't have exact cam spec, but I can tell you that maximum lift was in the crazy section (around 15mm!!) and about 4,5mm! at TDC. Duration was probably around 280 deg.

I don't know if Maxi also used Colombo&Bariani, because engines were built by Sodemo and they have their own machines and can make custom profiles. On the other hand this is really expensive and it could also be an off-shelf item.

cliorod
21-12-2010, 02:12
Colombo&Bariani,
These cams were used in the Diac cars :wink: or at least were supported by them.I sold a pair of race camshafts from this company,to a guy in France about 18months ago ~~ Made £450 on Flebay :lol: :lol:
Rod

MAXIBOY
21-12-2010, 02:18
maxi's had williams spec heads port size and ran 280bhp ..

n9kie
21-12-2010, 08:10
maxi's had williams spec heads port size and ran 280bhp ..

So if they used the same heads where did all that extra power come from??

dkrevs
21-12-2010, 08:47
So if they used the same heads where did all that extra power come from??

High lift and duration cams, ITB's, high compression and blueprinted BE...
IIRC, MAXI had from 260 to 280HP depending on the settings, stage,...
Heads that are used in Williams or Valver are actually Gr.A or MAXI spec, because of homologation purposes. For Gr.A homologation head had to be stock, that's why they put heads with such big runners in road cars.

robi1000
21-12-2010, 09:52
So if they used the same heads where did all that extra power come from??

High lift and duration cams, ITB's, high compression and blueprinted BE...
IIRC, MAXI had from 260 to 280HP depending on the settings, stage,...
Heads that are used in Williams or Valver are actually Gr.A or MAXI spec, because of homologation purposes. For Gr.A homologation head had to be stock, that's why they put heads with such big runners in road cars.

Even in Gr.A you can't change port diameter where inlet starts, that's why they are so big on Valvers/Williams. If we focus just on the head casting, additional power came from work done in valve throats and smaller head chamber (higher compression). Most of the power came from cams and of course revs. That's why bottom ends were balanced and used very light slipper pistons. Rods were also a bit longer to make rod/stroke ratio a bit better. There's also another million things that they changed, but things above are main ones.

bbaazz-08
27-12-2010, 21:50
so what are you talking to build one of these spec engines?

lightened and balanced bottom end?
stronger rods
what about forged pistons?

what compression ratio di it run?

i would love to here that engine on its itb's at 8k

robi1000
27-12-2010, 22:32
so what are you talking to build one of these spec engines?

lightened and balanced bottom end?
stronger rods
what about forged pistons?


Depends on the evolution, but later engines are very far from stock BE. Completly redesigned waterways for improved cooling, different oil flow due to the solid lifters and more oil needed for bearings. Crank with different journal size and stroke. Longer rods and slipper pistons with different compression height. Nikasil coated bores...

In short, a lot more then just forged rods and pistons.



what compression ratio did it run?


12.5:1



i would love to here that engine on its itb's at 8k

Just be patient... :lol:

robi1000
28-12-2010, 00:31
Until then, here's one vid for you. Maxi roaring at 8k:

http://www.dailymotion.com/video/x25z6v_course-de-cote-de-soisson_auto

:D

bbaazz-08
28-12-2010, 12:38
i want a go :(