Goldstein

Reason Im asking is my pully is covered under a third party warranty but I wont have $ for the tune until a month or so. Can I put an upgraded pully on with the stock ecu tune temporarily?

efiftyfizzle

Yes you could, but you won't get the full potential out of it until the tune is done.

viren.89

I think you can , but you will only reap the full benefits of it once the ECU is tuned and set up according to the new pulley.

Oh snap, yeah what he said ^^^

chawkins2001

If you do that, I would get a a/f check. Colder weather coming in, plus more boost without a tune is looking for trouble.

Goldstein

thanks guys. yea i figured it wouldnt add too much power if any. just wanted to make sure it wont mess with the car.

berti_00

Just dont beat on it... should be fine

efiftyfizzle

Well, going with what Chawkins said... the weather is getting colder and your supercharger is going to put in more work. Your engine is made for a certain amount of boost and a different pulley size is changing that boost level. I wouldn't run a different size pulley without a tune for too long. You're essentially changing something on the motor without "telling" it that it has been changed. The whole point of the tune is to adapt the motor to the new changes.

Hulk

Spoke to a tuner about this and the ecu will adapt to a certain point but don't beat on it, on this point, sneakneon has a thread where he went to a 180mm with some other mods and went to the track and he was fine but that is an extreme situation lol

PACougar

Don't go wot and don't drive it hard and you'll be fine.

Manuyc

Yeah be careful not to blow gasket

groove66

well the issue that arise from the smaller pulley would be an increase of boost. may 1-2 psi. Along with getting colder the air(which is good)it is going to help your IAT's big time for the time you drive without tune..

Most ecms have about a 7-10% correction factor if not more. And i would say that a 1psi increase in boost pressure is not gonna hurt anything.. are you gonna get max effort out of it without a tune ...NO. is it gonna run just like it did before? you bet

most Manufactures have the correction factor to aid in vacuum leaks and still make motor run clean..

Correction--- your ECM is tuned for a certain amount of boost not your engine. if it was the engine people would be building their motor everytime they change a pulley.

the motor won't even notice the pulley change until max boost is reached. but under normal driving conditions it should be the exact same as stock pulley.

air enters motor motor through intake/ MAF sensor senses the air coming in and calculates the air mass. by changing the pulley you are not changing the air mass that come in the motor untill full boost is reached.
therefore making the engine run just the same as before with stock pulley

efiftyfizzle

Your correction is right... my words came out wrong I meant to say stock ECU not engine.

DVC

Search for a post regarding Hennessey upgrading a crank pulley back in the day on the stock tune. Very interesting read.

Goldstein

Okay so I put 2000 km on the motor with just the pully. On my way to get the tune done The car finally reacted, Engine light came on with a code for the MAF sensor, Forgot if the mechanic told me it was either Too lean or too Rich.

berti_00

You are a brave man

AKnight55

You could have just gotten an EC tune for $300 on black Friday.. I would think you could have afforded that.

berti_00

cant really beat that

Manuyc