Topic: Retarding Intake Camshaft -- bad idea?

I am refreshing the Mazda KL 2.5 V6 in the racecar, and I am thinking about advancing the cam timing to move the powerband up the rpm range.  As I see it,  the car is pretty much over 4,000 rpm all the time,
with a 5-speed manual, you are going to downshift if it gets much under that when racing.

The KL engine has about 170hp, there is the KLZE japan version which has 200hp, it is reported
to have a bigger intake cam and peaks at a higher rpm.  So I am thinking I can pickup some more power if I make the cam more like the KLZE and retard it, and peak the hp rpm at 7k instead of 6.5k.
This mod is essentially free, just some time to modify the timing pulley.
I suppose I am jealous of the Variable Valve Timing engines and will just go right to the high rpm setting.

Now I know some might say the last thing we need is more hp in Lemons, a bigger fuel tank instead...but some more top speed in the straights makes passing easier, and that can be helpful.

Or its a waste of time?  what  you think?

Re: Retarding Intake Camshaft -- bad idea?

You're going to do it anyways, right?

That guy

Re: Retarding Intake Camshaft -- bad idea?

DirtyDuc wrote:

You're going to do it anyways, right?

lol, Probably not going to do it.   Once I get my engine dyno setup, then I can see if it helps, but so far it has not been done on this engine, so no guide how much is best.

Also it has the 1.8 engine computer and 1.8 intake manifold which is setup wrong for a 2.5,
so just fixing that will make more difference I think.

Re: Retarding Intake Camshaft -- bad idea?

you could probably make some HP by porting some... 170 for a 2.5 is pretty good. also removing all the emission junk should have picked up a few HP. spinning any engine 7k for 6+ hours is never a good idea.

"get up and get your grandma outta here"

Re: Retarding Intake Camshaft -- bad idea?

I am just going to swap in the junkyard motor for now and refresh the old one later, so not going to tear into it and just do the intake manifold, which is reported to pickup 10hp.

Re: Retarding Intake Camshaft -- bad idea?

what are you running the 2.5 in?

I'm thinking of putting one in my festy.

88 Festiva  -  Damn Tree!!!
"We Are Not Really From Iran" Festiva  -  Motor and Trans to be anounced

Re: Retarding Intake Camshaft -- bad idea?

fitsbain wrote:

what are you running the 2.5 in?

I'm thinking of putting one in my festy.

Mazdamaro, a mx-3, check out my new video on the manual rack conversion,
https://www.youtube.com/watch?v=EpJPmWp4afE

Re: Retarding Intake Camshaft -- bad idea?

I swapped a 5.9L Magnum (Chrysler) EFI motor into the Mirada a few years back. After the first race with the new motor, I decided to replace the timing chain set. When I picked up the new timing set, I notice there was an option to run the cam at -4°. Since it was a stock truck cam, I decided to give it a go.

Wow...

Yes, retard the cam timing.  :-)

The Pentastar whisperer