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Cat Camshafts
- Thread starter portal172
- Start date
M
mini-valver
He must be pretty deep by now though?? 
ClioI Ph.3 1.6 16V
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.
The newer K7M-760 engine in the Megane Mk.2 (113hp) has 40° cam-shaft angle for the phaser (that´s 80° crank-shaft....
), but all phases of the RS have 16° as Ben said.He must be pretty deep by now though??
It ain't bad to accept that you might be wrong...
In this case i am,the vvt valve has the same part number,i checked it my self.:dapprove:
But i still think that 730-732 and 736 engines have differences...
I'll have to make a better search to get 100% sure...
you sure your not talking about the 738? The 736 is the phs2 RS.
The 182 has the RS inlet manfold and a 4-2-1 ex manifold.
All stages have revised engine management and mapping aswell.
i've always found the MK1 RS to have the best drive, but the cylinder heads on them tend to be best on the earlier cars.
The 182 has the RS inlet manfold and a 4-2-1 ex manifold.
All stages have revised engine management and mapping aswell.
i've always found the MK1 RS to have the best drive, but the cylinder heads on them tend to be best on the earlier cars.
No,no i know about the 182's 738 engines...
I'm talking about 736,the next generation of the 730-732 which had the same 4-1 exhaust manifold but the throttle body was "by wire" and not mechanical like the first generation of the RS 172.
The only think that might make so much difference is the ECU(like you said) but again,it seems quite big only from a better remmap...:dapprove:
On the other hand you got a much better airbox at phase II than the round airbox of phase I,better design at the catalysts...
Riddle isn't it?:S
I'm talking about 736,the next generation of the 730-732 which had the same 4-1 exhaust manifold but the throttle body was "by wire" and not mechanical like the first generation of the RS 172.
The only think that might make so much difference is the ECU(like you said) but again,it seems quite big only from a better remmap...:dapprove:
On the other hand you got a much better airbox at phase II than the round airbox of phase I,better design at the catalysts...
Riddle isn't it?:S
i always felt the phs1 was better. It had a 2 better designed cats on the early ones that then got replaced with cheaper items. The cylinder head is miles better, the throttle body is slightly larger, the airbox has a larger filter area.
And they always seemed fastest despite slightly longer ratios.
And they always seemed fastest despite slightly longer ratios.
I didn't know about the throttle body,honest...
Reffering to the airbox,phase II airbox is much better...It has much higher efficiency than the phase I.
Simmilar airboxes are used in supercars.
As for the ratios,the wheel is almost the same,the final drive makes the difference...
The good thing is that phase I is slightly lighter than phase II and with better aerodynamic design,as far as i know.
Reffering to the airbox,phase II airbox is much better...It has much higher efficiency than the phase I.
Simmilar airboxes are used in supercars.
As for the ratios,the wheel is almost the same,the final drive makes the difference...
The good thing is that phase I is slightly lighter than phase II and with better aerodynamic design,as far as i know.
ClioI Ph.3 1.6 16V
I didn't know about the throttle body,honest...
Reffering to the airbox,phase II airbox is much better...It has much higher efficiency than the phase I.
Simmilar airboxes are used in supercars.
...
From filter area point of view I think Ben is right. I wondered allways why the air-box of the R25 V6 (or better known as "cup air-box") with it´s single inlet with 100mm diameter brought that big increase in ph.1 models compared to the original ones with 2x60mm, I think.
(p.s. some edit of my posting before: I meant K4M-760 and not K7M-760...)
In my opinion phase 2 airbox is less restrictive because the filter is vertical to the airflow compared to the phase 1 which is round so it is a little more difficult to create kind of a "ram effect" due to turbulence because of the shape of the airbox...
I might be wrong but that's how i think of the whole design of that system...
I might be wrong but that's how i think of the whole design of that system...
No,you are right ,there is no way that a proper ram effect can be made because the air speed is very low so the pressure inside the airbox will never be in such high levels to create an effect like that...
But in some cases when the OEM airbox is modified correctly,it has quite a difference compared to another one which is completely standard.
,there is no way that a proper ram effect can be made because the air speed is very low so the pressure inside the airbox will never be in such high levels to create an effect like that...But in some cases when the OEM airbox is modified correctly,it has quite a difference compared to another one which is completely standard.
No,you are right
But in some cases when the OEM airbox is modified correctly,it has quite a difference compared to another one which is completely standard.
There is zero ram effect in the OEM airbox even if modified, the nature and complexity of 'ram effect' does not permit its use on a clio.
ClioI Ph.3 1.6 16V
Look in that document:
http://home.vrweb.de/~seegi/Pics/staudruck.doc
I calculated the theoretical ram air effect. It´s in german, but with the international abbreviations I used I think it´s understandable.
As you can see, it´s not much....
http://home.vrweb.de/~seegi/Pics/staudruck.doc
I calculated the theoretical ram air effect. It´s in german, but with the international abbreviations I used I think it´s understandable.
As you can see, it´s not much....
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trust me, even at those speeds you will not generate any positive pressure.
And an engine will never run out of air.
I once read an article that demonstrated at about 160mph you can generate, with a perfect ram air system (which is highly complex) about 0.3psi, and to generate a single psi you would have to do about 320mph or something similar.
This is due to the manifold design and pressure waves, thus allowing the volumetric efficientcy to rise over 100%. so in reality its not like a turbo just utilising pressure waves to their advantage.
http://www.pumaracing.co.uk/POWER2.htm
Nick
Fred both Ben and Oliver are right,i have a friend who works at a research center of a university and he had a whole research on that subject.
He told me exactly the same thing like Ben and Oliver,that by normal "car" speeds(meaning 120-140mph) in a perfectly designed ram system,the pressure won't exceed 0,2 psi...
My question is although by theory ram air does not exist due to small air speed,why in many cases a fat pipe that faces to the front of the car has much better results than every other system?
He told me exactly the same thing like Ben and Oliver,that by normal "car" speeds(meaning 120-140mph) in a perfectly designed ram system,the pressure won't exceed 0,2 psi...
My question is although by theory ram air does not exist due to small air speed,why in many cases a fat pipe that faces to the front of the car has much better results than every other system?
ClioI Ph.3 1.6 16V
You are right, but you have this effect only in small rpm area, where the single tubes of the manifold are in perfect resonance.
ClioI Ph.3 1.6 16V
...
My question is although by theory ram air does not exist due to small air speed,why in many cases a fat pipe that faces to the front of the car has much better results than every other system?
You have to differ between charging (generate a pressure in the intale manifold that is higher than the ambient pressure) the engine by the ram-air effect and the decrease of pressure losses by the ram-air effect.
Exactly and this is usally done at about 3000rpm where you use the car most. Thats another reason why i think they use the intake valve on the clio - would be interesting to compare 2 dyno runs one after the other.
Nick
i gaurantee that 100% VE is not achieved at any point on the new engine, especially not at such a low RPM. Sure resonant tuning will help, but with a fixed inlet length its going to be in one area, but its not going to help being low rpm VE anywhere near 100% simply due to the fact the velocity which plays a much larger importance, is nowhere near high enough.
Fred both Ben and Oliver are right,i have a friend who works at a research center of a university and he had a whole research on that subject.
He told me exactly the same thing like Ben and Oliver,that by normal "car" speeds(meaning 120-140mph) in a perfectly designed ram system,the pressure won't exceed 0,2 psi...
My question is although by theory ram air does not exist due to small air speed,why in many cases a fat pipe that faces to the front of the car has much better results than every other system?
Because pressure variences underbonnet and outside the car. As airflow is not equal under the bonnet as it is over the car, then it will generate a lower pressure average.
The most efficient and common place for modern racecars to take high pressure air from is at the base of the windscreen.
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