Im not here to scare you guys, but I need to give you the heads up.

Last year I ordered tunes from BRENSPEED (87 89 93) I had an MMR intake with TBS and an exhaust.

I loaded the 93 tune and everything seemed great. The car ran nice and had good responce.

NOW, a year later, I installed a wideband air/fuel gauge.

I took the car out for a run and I was seeing 14.8 to 15.1 at WOT!!!!! NOT GOOD. The air/fuel was wayy too lean at WOT. Should be in the low 13s...Like 13.3 -13.8 is OK.

I called up Brenspeed and like usual they (Dave) was very helpful. He told me to richen it up 6% and take it for a run. The numbers wentfrom low to mid 14sbut that was stillkind of lean. Iwent back and tuned it to 14% richer and the air/fuel went to low to mid 13s...about where I wanted it.

He also had me compare my stock tune to Brent's original 93 tune for my car. With the stock tune I hit 12.7 and with the 93 I hit 15.1!! So for now im running the 93 tune 14% richer (MAXED OUT on the tuner).

Brent is going to rewrite my 93 tune and e-mail it to me so I get my adjustability back.

The power down low feels similar, but after I richened it up my top end greatly increased. My factory tunes top end was better then the 93 tune before I fixed it.

So my point here is that I LOVE WIDEBANDS AND EVERYONE SHOULD HAVE ONE, you just cant trust any mail order tune...and please check to make sure that your tune isnt making your car run too lean!

 

interesting......thanks for the heads up. this mental note will be well kept.

 

and what is the easiest/cheapest way to check this?

 

Well I can think of 3 ways...and none are easy and none are cheap.

1. Get a wideband 200+$$ plus install.

2. Go to a dyno 150+ for 3 runs by me.

3. Play with you tuner and see if your car runs better (guessing)....soooo?

 

you should start a post in the general s197 section more people can chime in on this. i am a bit concerned now

 

will do

 

Not surprising at all....

I posted this info way back in spring of 2005... The MMR intake says it doesn't require a tune and while it doesn't trigger a CEL, it will in fact really lean out your car... Especially if you add a tune...

 

But to a 15.1??? I ran it with the stock tune and it never went above 12.7...?

EDIT: Now that I think about it, with the stock box the AFR is probably in the 11s. So Brenspeed sent me a tune for the stock mass air size but did not account for the car already be leaner. Instead of hitting their target 13s they put me at high 14s...Maybe I should let them know this info for future reference.

 

I had kind of a similar experience with my original B am A 87 performance tune; it dyno'ed at high 13's to low 14's with an AFE stage 1 intake. The tuner said it was dangerously lean and should be in the high 11's/low 12's. Since then I installed the X-Charger with the canned tune and it was way rich, which was preferable to too lean. I had it dyno tuned and it's now at an ideal 11.9; moral of the story is get a dyno tune!