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Discussion Starter #1
Hello,

Does anyone have any detailed pictures of the stock FN2 cams and the FD2 cams, also any details of what makes them different. I have seen some owners get great gains from the FD2 cams, I am just trying to work out why, and what the difference is between the two.

Many thanks
 

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I'd assume the FD2 cam lobes have a more aggressive profile amongst other things, possibly lighter.
 

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Hello,

Does anyone have any detailed pictures of the stock FN2 cams and the FD2 cams, also any details of what makes them different. I have seen some owners get great gains from the FD2 cams, I am just trying to work out why, and what the difference is between the two.

Many thanks
Dont quote me on this however I think its mainly the lift and duration of the cam profiles thats different. The FD2 allow the valves to stay open longer to allow for more air and a higher compression? Im not 100% ure so dont quote :D

Best listen to someone with alot more knowledge than me :D
 

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Discussion Starter #4
Dont quote me on this however I think its mainly the lift and duration of the cam profiles thats different. The FD2 allow the valves to stay open longer to allow for more air and a higher compression? Im not 100% ure so dont quote :D

Best listen to someone with alot more knowledge than me :D
Dont think changing the cams can have affect the compression ratio but I could be wrong.

Im guessing the cam lobes on the FD2 are different shapes hence opening valves differently but wanted someone in the know to confirm this and show me a picture.
 

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Discussion Starter #6 (Edited)
ring paul at tdi?
I better not, if he gets one more email or PM from me he might explode! lol There are plenty of well informed people on here who will be able to help.
 

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my guess is the rsp cam does not have engraved rings that you'll find only on "PRC" cams

my buddy Katman's pic see the circled engraved rings on the left


so far I have composed this list :popcorn:
the fn2 CTR has its own unique part numbers
14110-RSP-G00
14120-RSP-G00

the fd2 CTR supposedly runs
14110-PRC-020
14120-PRC-020

the usdm 05-06 dc5 k20z1 runs
14110-PRC-030
14120-PRC-030

I think the original (early) jdm k20a ep3 & dc5
14110-PRC-000
14120-PRC-000

original k20a2 usdm dc5 rsx-s DC5
14110-PRB-A00
14120-PRB-A01

'06+ usdm Civic Si k20z3 Fg2 (coupe) Fa5? (4dr?)
14110-RRB-A00
14120-PRB-A01

'06+ tsx k24a2 CL9
14110-RBB-A00
14120-RBB-000

'04-'05 tsx k24a2 CL7
14110-RBB-000
14120-RBB-000

the tsx has the largest exhaust cam (primary aka non-vtec & vtec lobes)
the '06 tsx has the largest intake cam (primary) its believed the vtec is the same exact vtec lobe as the PRC type r cams
 

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I'm no expert but in terms of engine performance there are 3 variables that a camshaft can provide:

The length of time the valves stay open to admit/expel fuel, air and exhaust gasses
The height the valve open to (obviously higher lift allows gasses to enter and leave more rapidly);
How rapidly the valve lifts from its closed to open position.

I imagine that compared to FN2 cams, the FD2 cams provide a bit more lift and duration and they may also be a bit more aggressive (ie more rapid opening) in their operation
 

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Discussion Starter #11
Thanks Gass, which one on the top picture is exhuast and which is intake? I can go from there and match them to the FD2 cams
 

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I think Lou at TDI has measured the lobes and has the specifications - If hes in a good mood, this thread might prompt him to share... hint
 

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Ash, the top pictures are of my FN2 cams ,so i will have to take a photo of each one again to confirm which is inlet and exhaust!

Leave it with me

Matt ;)
 

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The difference is in duration. You won't measure anything different even with a vernier. You need to rig them up with a dial plate and dti.
A lot of aftermarket cams give many alternatives but the difference is measured in duration only. Longer being the more lairy. Check out the HKS options for say a Supra or GTR and you get the idea. ;)
 

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Discussion Starter #15
My cams, roll on next week :
 

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Discussion Starter #16
Ash, the top pictures are of my FN2 cams ,so i will have to take a photo of each one again to confirm which is inlet and exhaust!

Leave it with me

Matt ;)
Just worked it out, bottom one is exhuast, top is intake
 

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CR

BTW changing the cams will not alter the CR

And FD2R cam are slightly more aggressive than out stock FN2R cams

I changed my stock FN2R cams to 07 TSX cams and I managed to extract 10WHP from it

But now I am on a complete different setting K24 Setting;)
 

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BTW changing the cams will not alter the CR
You may be surprised, but that isn't strictly true.

The compression ratio can be thought about in two ways. There's the "static" compression ratio which is calculated form the swept volume and clearance volume, then there is the "effective" or "dynamic" compression ratio which is what the engine actually "sees".

The effective or dynamic compression ratio can change significantly accoring to the opening period of the valves (camshaft duration). In principle, the longer duration camshafts you have the more the effective compression ratio will drop, hence there is a need to raise the static compression ratio to compensate.

Hope this helps :)
 

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You may be surprised, but that isn't strictly true.

The compression ratio can be thought about in two ways. There's the "static" compression ratio which is calculated form the swept volume and clearance volume, then there is the "effective" or "dynamic" compression ratio which is what the engine actually "sees".

The effective or dynamic compression ratio can change significantly accoring to the opening period of the valves (camshaft duration). In principle, the longer duration camshafts you have the more the effective compression ratio will drop, hence there is a need to raise the static compression ratio to compensate.

Hope this helps :)

With this you may now quote my first post :D
 
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