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172 Vs 197 cylinder head



scruffydubber

ClioSport Club Member
  RS CUP
I've seen it mentioned on here the 197 head is a better design then a 172/182 head.

So question to the people who have compared them what is better about the 197 head, ignoring the manifolds.

I'm thinking along the lines of a 172 running itbs (jenveys not direct to head) it would be relatively straight forward to make the change. Drill and tap the extra hole for the idler/tensioner, 197 jenvery manifold. Dephaser, cams all swap over.

Ignoring the lower compression for a moment due to the increased combustion chamber volume, what gains could be expected once the setup is mapped correctly.

Thanks
 

Luke_Exc

ClioSport Club Member
  V6 255, 172 cup, ph1
Same dyno, my car (standard ph1 engine with 197s and obx bodies) and chip's car (197 head and internals, AT power bodies), I made 6 more bhp. There can't be much point in the expense of doing it for that sort of 'gain'.
 

scruffydubber

ClioSport Club Member
  RS CUP
Same dyno, my car (standard ph1 engine with 197s and obx bodies) and chip's car (197 head and internals, AT power bodies), I made 6 more bhp. There can't be much point in the expense of doing it for that sort of 'gain'.
That's good feedback thanks.

I have some 197 pistons that I planned to fit to a 172 anyway. Sticking with the 172 head I could well make a similar gain due to the higher compression.
 
A mate of mine made 224bhp with 197 cams, 197 pistons, 197 valves and valve springs, RS2 inlet and a 172 ph1 head with a bit of porting

He's going for bodies this year and has them nearly ready. Chris at EFI said it was the healthiest he's seen a simple NA F4R make power wise, not bad for an engine chucked together by a 23 year old🤷‍♂️ it might not make more power on bodies but it will pick up some sweet sweet noise😂
 

NorthloopCup

ClioSport Moderator
197 head has a better combustion chamber design and also the inlet ports are in a different position. They make bigger power significantly easier when they’ve been accompanied by the correct mods.

I made 230bhp using R3 maxi internals, mildly ported 197 head and the 197 inlet.

Show me a 1*2 engine that would do those numbers on a standard head/inlet combo with the same supporting mods.

45’s on a 197 head is pretty pointless as well. These engines are hungry when it comes to induction.
 

scruffydubber

ClioSport Club Member
  RS CUP
A mate of mine made 224bhp with 197 cams, 197 pistons, 197 valves and valve springs, RS2 inlet and a 172 ph1 head with a bit of porting

He's going for bodies this year and has them nearly ready. Chris at EFI said it was the healthiest he's seen a simple NA F4R make power wise, not bad for an engine chucked together by a 23 year old🤷‍♂️ it might not make more power on bodies but it will pick up some sweet sweet noise😂
That is mighty impressive. I much prefer I well thought out lower budget build then just ordering a load of aftermarket parts.
I was planning a spec along these lines, which then got me thinking about the 197 head. Only problem is I would lose the lower cost option of raising compression with 197 pistons.

It would be great to see the back to back of this with phase 1 vs phase 2 vs 197 head.
 

scruffydubber

ClioSport Club Member
  RS CUP
197 head has a better combustion chamber design and also the inlet ports are in a different position. They make bigger power significantly easier when they’ve been accompanied by the correct mods.

I made 230bhp using R3 maxi internals, mildly ported 197 head and the 197 inlet.

Show me a 1*2 engine that would do those numbers on a standard head/inlet combo with the same supporting mods.

45’s on a 197 head is pretty pointless as well. These engines are hungry when it comes to induction.
Sounds like the further you go with the spec the more benefits you get with the 197 head.

Interesting PMS modify the 172 combustion chamber for there custom pistons. I guess the better 197 combustion chamber will allow for a better designed high comp piston.
 

NorthloopCup

ClioSport Moderator
Sounds like the further you go with the spec the more benefits you get with the 197 head.

Interesting PMS modify the 172 combustion chamber for there custom pistons. I guess the better 197 combustion chamber will allow for a better designed high comp piston.
The valves are also unshrouded a bit more than the 1*2, but it’s a minimal amount. Every little helps though.

Yeah that’s got to tell you something hasn’t it. No one changes things for no reason, and it’s also worth noting, Renault were at the time of the 197/200 involved in f1. Some of the things they learnt in f1 did find their way down the pecking order to the mk3 Rs. The better cylinder head to have is off the 832 engine as well for reference. 👍🏻
 
  Clio Sport 2 172
Clio 3RS 197 head is very good, it's the best way to do 250KM+ engine spec. On the flowbench you can compare the serial cylinderhead from Clio 3RS with the serial cylinderhead from Clio 172.
F4R porównanie.png
 

scruffydubber

ClioSport Club Member
  RS CUP
The valves are also unshrouded a bit more than the 1*2, but it’s a minimal amount. Every little helps though.

Yeah that’s got to tell you something hasn’t it. No one changes things for no reason, and it’s also worth noting, Renault were at the time of the 197/200 involved in f1. Some of the things they learnt in f1 did find their way down the pecking order to the mk3 Rs. The better cylinder head to have is off the 832 engine as well for reference. 👍🏻

I see thanks. I wonder if the 172 head has room to modify the combustion chamber to increase unshroud the valves. If possible I wonder if the combustion chamber ends up as a similar volume to the 197 heads. I find it quite interesting, I might try and pickup some heads cheap to compare.

Do you remember what compression you ended up at on your engine?

Clio 3RS 197 head is very good, it's the best way to do 250KM+ engine spec. On the flowbench you can compare the serial cylinderhead from Clio 3RS with the serial cylinderhead from Clio 172. View attachment 1514527
That's great data thanks.
Do you remember if this was a ph2 head or ph1 with the large exhaust ports?

I wonder how a modified 172 head compares to a standard 197 head. And how a modified 172 head compares to a modified 197 head.
 
  Clio Sport 2 172
That's great data thanks.
Do you remember if this was a ph2 head or ph1 with the large exhaust ports?

I wonder how a modified 172 head compares to a standard 197 head. And how a modified 172 head compares to a modified 197 head.

I compared standard ph2 to 197 head both with small exhaust port. If I dont forged I will show you after weekend when I come back to work compares of modified and standard heads.
 

gambit

ClioSport Club Member
  182 Trophy
Watching this closely as would like to one day do ported 197 head and cams with forged f4r bottom end on a maxed out Rotrex setup. Just need to justify the work involved in the 197 f4r832 head.
 

Touring_Rob

ClioSport Club Member
Thats a shame, he added a lot of great info. When Siri first came out I had an old SV650, for some reason Siri would have a V-Twin melt down and pocket call him, happened 4-5 times. Don't really know him well enough to call up and ask how he's doing!
 

Luke_Exc

ClioSport Club Member
  V6 255, 172 cup, ph1
Thats a shame, he added a lot of great info. When Siri first came out I had an old SV650, for some reason Siri would have a V-Twin melt down and pocket call him, happened 4-5 times. Don't really know him well enough to call up and ask how he's doing!
Go test ride an sv650, you can call without being creepy.
 
  Clio Sport 2 172
bugger just looked up honda k series and a stock k20a flows more than a cnc f4r 832 on an sf600 flow bench. However only 5% difference
Yes, but K20 have bigger valves 35mm on intake, this F4R832 head still have 33,50mm intake valves.
 
  Renault 5
A mate of mine made 224bhp with 197 cams, 197 pistons, 197 valves and valve springs, RS2 inlet and a 172 ph1 head with a bit of porting

He's going for bodies this year and has them nearly ready. Chris at EFI said it was the healthiest he's seen a simple NA F4R make power wise, not bad for an engine chucked together by a 23 year old🤷‍♂️ it might not make more power on bodies but it will pick up some sweet sweet noise😂
is all the valve terrain interchangeable from 197/200 into ph1 172 heads???
 

gambit

ClioSport Club Member
  182 Trophy
Nice one!
I’m in the process of setting up 197 cams, valve springs, retainers and collets in a ported 182 head.
Keeping the 197 head for some big plans on my other build.
 

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Coops Mk1

ClioSport Club Member
  Lots of Scrap...
That is mighty impressive. I much prefer I well thought out lower budget build then just ordering a load of aftermarket parts.
I was planning a spec along these lines, which then got me thinking about the 197 head. Only problem is I would lose the lower cost option of raising compression with 197 pistons.

It would be great to see the back to back of this with phase 1 vs phase 2 vs 197 head.

Some of them are just solid engines, my bone stock internally 172 phase 1 engine with just 197 cams and injectors and an rs2 inlet made 212.
 


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