Hello All!

Do you really need to change plugs when you install an aftermarket pulley?
What would happen I you do not go to colder plugs?

The cost of the plugs isn't that big of a deal, I just want to understand why

 

Colder plugs will be helpful to avoid detonation. You do want to switch to colder plugs.

 

It may not be a rush item to change em, but they definitely do make the engine smoother.

 

i dont think you need em at all, i mean u could change em if u wanted too. I have a 16% on my car and the car runs real good with out em. and the car see's redline daily .

 

I'm sure you know that the Mini ECU will automatically retard timing and dump more fuel if detonantion is detected. You won't really hear any detonation.
I'd bet your Mini will run even stronger @ higher RPMs with colder plugs

 

Can somebody explain how you know which level of plug to pick? I've been reading plug sites and they vary, but most say you need at least +50hp in mods to need a colder range. I'm running a 15% pulley, BMP CAI and plan to do an exhaust. I'd say I'm approaching 20-25 extra hp... so why do I need colder plugs? I have a stock ECU running 39.

I haven't lost more than 1mpg since the pully & CAI.

I've just bought (not yet installed) some NGK iridiums... I figured a step up would help, but they are stock range, I believe.

 

Oh i know its not detonating, im just saying that my car feels strong as it is with out the colder plugs. Maybe one day ill slap them in and see if it makes any difference.

 

My point is... It won't detonate... the ECU will see to that. You could, however, lose some hp is the ecu has to retard timing/dump fuel.

NekoWoman: Denzo or NGK Iriduims OK. I went with the Denzo 22's (see sig)

 

Ditto.

Ditto.

 

I'm going to take the plunge into an Alta 19% pulley within the next couple of weeks and I was wondering if I should delay installation until I buy colder plugs (IK22's) or just install the pulley and put the plugs in whenever I get them...

BTW, anyone know what the cheapest place to get the Denso IK22's is? Thanks

 

If your set on making the 19% jump, I would definately wait until I had the IK22s in hand so they could be installed at the same time as the pulley.

 

How long will it take the ECU to figure out the plugs have changed?

I always felt immediate differences after flashes and then after about 500 miles the car would settle back down (usually going back to old, bad habits like cold start or yo-yoing)

 

Actually, the ECU won't really know (or care) that the plugs have been changed. The only thing the ECU will know is the knock sensor is no longer telling it to take action for detonation.

 

Correct me if I am wrong, but doesn't the JCW Tuning Kit include colder plugs because it also includes a ~14% reduction pulley and bigger 380cc injectors?

 

That sounds right to me. I know the JCW cars do have different plugs than other MCS. It stands to reason that this could be the reason.

JCW owners?