Are Adjustable Cam Gears Worth It! - Fuelly Forums
Go Back   Fuelly Forums > Tech, Troubleshooting and Repair > Experiments, Modifications and DIY
Search Today's Posts Mark Forums Read
Thread Tools Display Modes
Old 12-15-2009, 06:05 PM   #1
Registered Member
Join Date: Oct 2007
Posts: 211
Country: United States
Are Adjustable Cam Gears Worth It!

It has come the time to change my timing belt, since I have a Focus there are all sorts of goodies to make my car go fast and get really bad gas mileage, that is until I saw a pair of adjustable timing sprockets. Would the mileage improvements be worth the investment to have the ability to retard my intake cam a couple of degrees?

GasSavers_Scott is offline   Reply With Quote
Old 12-15-2009, 09:00 PM   #2
Registered Member
Join Date: Oct 2006
Posts: 615
Country: United States
Go for it. Cam gears will let you move the power around and put it where you want. I'd recomend advancing the intake cam for more low end power, which will let you shift sooner and keep the revs low.

OTOH retarding the intake cam might provide an Atkinson-cycle type of benefit during steady cruise. The only sure way to find out is to try it and see.

Dave W.
DRW is offline   Reply With Quote
Old 12-16-2009, 07:16 AM   #3
Registered Member
GasSavers_BEEF's Avatar
Join Date: Apr 2008
Posts: 1,831
how much of an investment are they?

hard to say if the advantages are worth it without knowing the initial investment.

I do like the idea of experimenting with timing
Be the change you wish to see in the world
--Mahatma Gandhi

GasSavers_BEEF is offline   Reply With Quote
Old 12-16-2009, 10:26 AM   #4
Site Team
Join Date: Dec 2006
Posts: 652
Country: United States
I have an adjustable cam gear in my 455. I got it so I could index the cam, not as a tuning device.

However, one time I decided I had too much high-end power, and not enough low-end torque. So I advanced the cam 4 degrees.

Well I didn't pick up an low-end torque, I did lose high-end power, but I did gain about 4 MPG. That was when I was getting almost 20 MPG in my daily driving (probably mostly 18 or so, to be fair.)

But power was too far down, so I didn't leave it there.

I sure would love on-the-fly adjustable cam timing...

Think you are saving gas? Prove it by starting a Gas Log, then conduct a proper experiment.
bobc455 is offline   Reply With Quote
Old 12-16-2009, 11:26 AM   #5
Registered Member
i-DSi's Avatar
Join Date: Nov 2009
Posts: 179
Country: United States
Hi all,
When I was a student I remember reading a thesis from two students who wanted to test different positions of the camshaft. I remember the vehicle was a small Fiat, with a small petrol engine DOHC, carburettor.
They could not adjust the camshaft while the engine was running, but they could very easy just change it a few degrees. After each adjustment they put the engine on a dyno and measured torque, BHP, fuel consumption and emissions on a range of RPM's and engine load.
Very interesting conclusion: NO gains could be achieved, on no matter what field when you only adjust the camshaftposition.
On engines developed by R&D-departments with variable camshafts everything is adapted to go with it (fuel mixture, ignition timing, EGR, expected lambdavalue, drive by wire throttle housing,...).
I know e.g. the variable exhaust camshaft on a European Honda TypeR's main function is EGR. They did not had to install a classic EGR, but by delaying the closing of exhaustvalve you suck in some exhaust gas....there's your EGR.
A question raises: aftermarket camshafts have most of the time only one goal: more power by more valve overlap and higher valvelift. If this is the case I would definitely not do this.
Based on this (limited) info I would not go for this modification.
i-DSi is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
K&N Air Filter bowtieguy For Sale 2 08-14-2009 01:18 PM
Multiple fillups per day - broken mathrock Fuelly Web Support and Community News 10 09-10-2008 01:02 AM
new used car dillema lunarhighway General Fuel Topics 6 03-03-2008 02:35 PM
A Alternative to gas saveing Possum on brick General Fuel Topics 8 10-26-2007 09:17 AM
92 Civic 1.5 engine work with CRX? UfoTofU General Fuel Topics 4 10-08-2006 05:50 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -8. The time now is 11:52 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.