OK I had a vafc2 on my 2003 s2 and i got it tuned and it put down 215 whp i was very happy was alot quicker so a buddy of mine was selling the aem ems i bought re-tuned it with the ems and the tuner only got 203whp and the only things i did in between was go with 17in wheels but lighter and wider tires all around could that be possible to loose that much power or should i go to another tuner

 

I say go to another tuner. An EMS has way more tuning features than a VAFC II, and should be able to put out quite a bit more power if tuned right.

 

that's what i thought but the thing he told me was cuz i went with bigger and wider tires that's where the hp lose came from that's not true right

 

How do these tuner places make money lol. Definitely go to another place! Tuner sounds like a moron who obviously has no idea how to tune an AEM EMS.

 

Depending on the type of dyno. If you went to 17" rims with wider tires, you have more loss from overcoming inertia and more loss from friction. Technically, you probably did lose about 10 horsepower from going with bigger rims and tires.

 

It is definitely a very poor tuning job not because of going with wider tires.

 

Right. It must be that. Because adding more weight for the engine to turn yet putting it on the same dyno never lost anyone horsepower.

Go ahead, run 25 psi in your tires then run 40 psi, watch 40 psi make more horsepower every time.

Fact is, you move the weight further from the center, you make it harder to turn. You make your wheel larger, you gear the car down. You make the wheel wider you get more friction loss.

My buddies car with flashpro and intake/exhaust dyno'd 183 whp. It's a civic. He has 18's on the car, every other person i've tuned running stock rims made 190-195 whp.

it absolutely does affect how much power you put to the ground.

 

I would still guarantee any amount of money a properly tuned aem ems will still make more power than the vafc even with 20's on it lol.

 

Was it on the same dyno? Weather similar?

 

Yes OP, give some more details. What kind of dyno was it?