Cat Camshafts

[sthom]

The S1600 is a pretty well known spec and it is not overly hard to work within the restraints of the FIA regulations, the cars have a max build cost of US$100,000 for everything.

We have a K4M powered car comming in in the second week next month to try out a few new items, so it should be pretty exciting for you K4M owners once its done......its not some boring air filter and ex jobbie.

Ben don't forget about us,we are waiting...

 

[BenR]

the car comes into the workshop in about a week.

 

[mini-valver]

*rubs hands*

 

[Clio172-DK]

from Renault (clio 172)

Engine F4R 730 -732-734-736-738:

234 deg. inlet, lift 41,5 mm

225 deg. exhaust, lift 41 mm.​

 

[sthom]

What exactly are these numbers?

 

[kd rs1]

OEM cams?
I ordered 5502423 cat cams for my 172 without VTT:evil: .

Santa tell my mechanic too hurry up ...

 

[BenR]

why without vvt?

 

[sthom]

Probably because he is not going to use high compression pistons so there won't be enough space left in the combustion chambers to let the valves travel free without hitting a piston while they are opening...:dapprove:

 

[BenR]

Then why run such a high duration cam on a stock bottom end that cant take high rpm?

Seems counter productive.

 

[sthom]

I agree with you Ben...:dapprove:

 

[BenR]

another example of greedy eyes or 'if big is good, then bigger is best'

 

[kd rs1]

Greedy?
Tell me why should use VVT with high compression pistons, uprated con rods?
Polution, more down grunt :rasp: . bah

 

[BenR]

he said you werent using forged pistons?

greedy eyes is a saying, eyes bigger than your stomach etc.

 

[sthom]

VVT is not only for pollution but to make the engine produce more power to the whole range than having only power at high revs...

So unless you are going to use a close ratio gearbox which won't let the rpm fall more then 300-400 rpm at every gear change,then by selecting a set of cams like that will make your car much slower than another one that will have slightly lower max power but for a much wider band through the rpm range.

That's exactly what Ben ment when he said "The bigger,the better" is not always the best...:approve:

 

[2FST4U]

Thanks Ben! Now to figure out a plan to sneak out 600 pounds without the mrs knowing.

lmao if you find away to do that tell me rofl!

 

[Andy_J]

i guess thats meant to be 3000-4000 not hundred..

 

[sthom]

i guess thats meant to be 3000-4000 not hundred..

Andy if you are talking about the rpm drop at every gear,i meant 300-400 not 3000-4000.
All racing gearboxes have very close ratio due to very small power band.
The cams that kd rs1 chose are entirely race cams so it won't be a good combination to keep the standard gearbox...

 

[Andy_J]

ah right, i thought u meant fall below 3-4krpm..

 

[BenR]

the vvt in the clio is very crude and only operates as a defined switch at 1450rpm, so it is not variable across the whole rpm range. It does very little for torque or power.

 

[sthom]

Yes,i know it is not variable through the range but RS 172 phase 1 and RS 172 phase 2 have much difference when compared through the low-mid range,because phase 1 has only 18 degrees VVT when phase 2 has almost 40.

Of course phase 1 has wilder cams too but the difference is not so big...

 

[BenR]

ph1 & 2 172 and 182 all have 16 degree advance.

 

[mini-valver]

So the vvt has nothing to do with the '5k kick'??

 

[BenR]

nope

 

[mini-valver]

Where the hell does that come from then? What is the point in the clio VVT, any advantages?

 

[BenR]

search......done to death, or just wait till you see me.

 

[mini-valver]

I'll wait, the search on here takes forever!

 

[jph172]

OEM cams?
I ordered 5502423 cat cams for my 172 without VTT:evil: .

Santa tell my mechanic too hurry up ...

Id be to know how you plan to make this run on any engine management system- mine were the 421,s and they caused serious problems even with an aftermarket ecu your looking at major work i.m.o
Unless im out of my depth here and your not going to be using ur car on the road?

 

[BenR]

i assume if he's running forged pistons then the management system isnt staying OEM.

 

[jph172]

Jus thought id ask. You guys kind of lost me on the 2nd page! lol
But even still could you really use that sort of set-up in an everyday driving car?
Would it produce much more power?

 

[BenR]

you could build an engine with a powerband that was usable on the road and everyday, with reliability, but i'm not sure most people would spent the money required.

 

[Fred@BTM]

Yes,i know it is not variable through the range but RS 172 phase 1 and RS 172 phase 2 have much difference when compared through the low-mid range,because phase 1 has only 18 degrees VVT when phase 2 has almost 40.

Of course phase 1 has wilder cams too but the difference is not so big...

eh?

 

[sthom]

ph1 & 2 172 and 182 all have 16 degree advance.

All the phase II RS Clio's have almost 40 degrees VVC.
If i remember well it is 36 or 38.
Only the phase I RS 172 had 16.

 

[Fred@BTM]

who told you that!

 

[BenR]

:S

 

[sthom]

A friend of mine has very good relations with Oreca company in France who used to prepare the original Renault Sport Super 1600 Clio's...

I don't think that they could be wrong about that.

 

[Fred@BTM]

well they are!

 

[BenR]

sounds like they are.

 

[sthom]

Take a look over here...

http://www.oreca.fr/index.aspx?langue=2


I cant say for sure that there is no way that they might be wrong but i know for sure that the VVC valve in phase I is different(part number code) compared to phase II which in 172 and 182 is exactly the same.

 

[BenR]

The phase shifter part number across all CB chassis 172's are the same.

If tehre was 40 deg advance then the vvt logarhithmics would have to be a whole lot more complex than 'on/off'. Not to mention is a pretty apalling gain for the work done........i.e zero.

They are not 40 deg advance

 

[sthom]

A friend of mine who also owns an RS 172 phase II,went to a Renault dealer to buy a new one because the older one was stuck,the dealer(who probably used Dialogys) told him that it is completely different...

Anyway,that is not a problem(i might be wrong),i can check it my self too because i have and an 732 and an 736 engine so by Tuesday you will have an answer!