high comp engine help

[mattyealam]

any one running one/built one on here if so what rods are you running thanks matt

 

[Fernandez]

You'd be wanting these....

http://www.engine-dynamics.com/EngineComponents/pid307/cid111/EngineDynamicsForgedConRodSetWithARPBolts.asp

If you are using the high comp"Maxi" pistons then you will need to ensure that you get the right rod as the normal forged rods that are available are too wide at the top, the linked rods above will fit

 

[mattyealam]

I'm running wossner 83mm so yer they have to have the 21mm small end width

 

[ben_r1]

I ran Wossner high comp pistons with custom valve pockets on OEM rods with ACL big end bearings and ARP bolts.

Was told by TDF if its not forced induction the only other limiting factor to rods is RPM and OEM items are good up to 8000rpm, which is where my limiter was and never had a problem.

 

[Fernandez]

You could always go for solid lifters and the catcam followers. The head does need some work for them to fit but CatCam reckon you can then get around 11,000 rpm

 

[GrumpyTwig]

You could always go for solid lifters and the catcam followers. The head does need some work for them to fit but CatCam reckon you can then get around 11,000 rpm

:jump1:




I guess there would be a series of other factors limiting the engine power as well though beyond 8krpm sadly

 

[Fernandez]

Appologies but that should be 9K, sure I read somewhere 11

Cat Cams launches Renault F4R finger followers for high rpm usage* Belgium based high performance valvetrain specialist Cat Cams NV is pleased to announce a replacement finger cam follower package for the highly popular 2.0-litre, 16-valve Renault F4R engines as used in the Clio 172 / 182 / 197 and 200 models.

In standard form the original RenaultSport valvetrain limits the F4R’s power output to around 260 bhp and 7800 rpm, because the standard roller finger followers are a known weak point and are not designed for prolonged high engine speeds. Therefore Cat Cams decided to redesign the F4R’s valvetrain following extensive CAD examination of various layout options.*

Cat Cams settled on using new, bespoke finger cam followers that feature sliding contact. To ensure that these followers remain aligned on the valve top, the original RenaultSport F4R hydraulic lash adjusters are replaced by Cat Cam’s solid inserts, which are connected and locked by a common shaft. This shaft also acts as the rotation axis to make it impossible for the cam follower to leave its pivot. The exact geometry for the new sliding finger followers was determined using Cat Cams’ dedicated in-house software for detailed motion analysis, while Finite Element Analysis (FEA) software was used to optimise strength, stiffness and weight.

Main target parameters included: system clearance for 15mm valve lift, and a 40mm contact diameter for the virtual equivalent bucket tappet. Finally, a default range of cam profiles was developed, again using state-of-the-art cam design software that is continuously being developed on the premises since 1998.* With the new Cat Cam’s set up, the valve clearance on the F4R motor is set using lash caps with an extra long 4mm skirt sliding over the valve tip, and dual valve springs (manufactured by PAC Racing) with lightweight steel retainers and spring seats complete the kit.

Installation of the Cat Cams F4R finger cam follower setup requires a slot be machined in the cylinder head between the spark plug hole and the cam bearing, simply to provide the required clearance for the connecting shaft.* Ken Stessens, responsible for cam design and product development, testifies from own experience: "A simple manual milling machine with tilt table, a bullnose tool and 2 hours of hassle-free labour is all it takes to install the new cam follower hardware." Once the Cat Cams RenaultSport F4R engine finger cam follower setup is installed, the high rpm potential of the engine can be fully realised and the valvetrain ceases to be a weak link.

This theoretically endows the F4R motor with 9,000 rpm / 300 bhp plus potential when built using upgraded forged crankshaft, connecting rods and pistons.* Interested parties should please contact Cat Cams UK for more information and pricing on the RenaultSport F4R finger cam follower upgrade and associated cam profiles.*

 

[Chrisgti6]

I thought the bore/stroke ratio wasn't ideal for high revs on the F4R. Isn't that the reason the honda boys etc can extract power much easier than us?

 

[Foxspeed]

I thought the bore/stroke ratio wasn't ideal for high revs on the F4R. Isn't that the reason the honda boys etc can extract power much easier than us?

might be on earlier engines but most of the honda stuff is similar to the renaults in that they are slightly under square dimentions...

easy enough to do an average piston speed calculation

 

[Chrisgti6]

I had it in my head that the k20 engines were square?

 

[Foxspeed]

I had it in my head that the k20 engines were square?

well it seems they are 86x86.... for some reason i always thought they were slightly undersquare! maybe i got it confused with the 1.8 maybe

 

[Foxspeed]

I ran Wossner high comp pistons with custom valve pockets on OEM rods with ACL big end bearings and ARP bolts.

Was told by TDF if its not forced induction the only other limiting factor to rods is RPM and OEM items are good up to 8000rpm, which is where my limiter was and never had a problem.

wonder why simoxmino bent con rods.....

 

[mattyealam]

Ben did you have the std rods machined for acl bearings I'm sure those are tabed and std rods aren't thanks Matt

 

[ben_r1]

Ben did you have the std rods machined for acl bearings I'm sure those are tabed and std rods aren't thanks Matt

To be honest i wouldn't know mate the engine was specced and built in my absence. Mine did 3 trackdays with an 8000rpm limiter and never had any issues, one even on 97 Ron fuel by mistake lol!

 

[mattyealam]

Just out of interest wat sort of power did it pull on matts rollers

 

[ben_r1]

196bhp in standard form with Cat 402s
215bhp with ITBs and Cat 402s
220bhp with longer trumpet ITBs and Shricks
230bhp with forged high comp pistons, long trumpet ITBs, Cat race cams and VVT delete.