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General Forums => VW Club Corner => Topic started by: berliner on March 23, 2009, 08:01:24 AM

Title: rods
Post by: berliner on March 23, 2009, 08:01:24 AM

I'm putting together a 2275 and the con rods I have are 5.5 which will mean spacers and a wider engine.If I use 5.4 rods how will that affect the engine's performance?I'll be having compression around 8 and the cam is more for bottom/mid range rather than real high revs.

Title: Re: rods
Post by: Bruce on March 23, 2009, 08:36:23 PM

The shorter rods will cause higher piston speeds.  Higher piston speeds will make the engine pull more air in, so at lower rpms, your engine will make more torque.
The downside is that the rod angle is greater, so you will see more cylinder wear.

Title: Re: rods
Post by: jim martin on March 23, 2009, 09:13:07 PM

what cam and carb size ?
if you run a full skirt piston such as a cima with a larger wall clearance you will be ok ,id run shorter myself  ;)

Title: Re: rods
Post by: berliner on March 23, 2009, 10:17:07 PM

The cam is Engle fk41,duration240. C.B. performance fuel injection.

Title: Re: rods
Post by: jim martin on March 23, 2009, 10:56:24 PM

yep thats a low rpm'er ,i don't think excessive cylinder wear will be a problem, i can't remember what cima stock is out of the box.id say run between 0.003-0.004

Title: Re: rods
Post by: berliner on March 24, 2009, 08:10:38 AM

Thanks for the info.I'm looking for decent power and drivability on the street,so I think this should do it.

Title: Re: rods
Post by: egspot on March 24, 2009, 08:41:06 AM

Quote from: berliner on March 24, 2009, 08:10:38 AM

Thanks for the info.I'm looking for decent power and drivability on the street,so I think this should do it.

My 2165cc motor has the FK41 and stock rods. I probably peak at around 5500 rpms and I would think that that would get me 100-115 hp at the wheel. Power is plenty and I can not hardly ever go for it . It realy come alive whe i need to go up Boundary road and have to find my own lane to get away from those other cars.

Title: Re: rods
Post by: berliner on March 24, 2009, 05:44:11 PM

That's good to know,you're the first guy I've heard from that's using that cam;my son wanted to put in something wild but I wouldn't go for it;when he inherits the car he can do it!What's the length of a stock rod?

Title: Re: rods
Post by: Bruce on March 24, 2009, 06:09:17 PM

stock rod is 137mm.

Title: Re: rods
Post by: egspot on March 24, 2009, 06:11:43 PM

Quote from: Bruce on March 24, 2009, 06:09:17 PM

stock rod is 137mm.

What he said/wrote ( mine are in inches .) ;D