So my Defi mechanical boost gauge finally came in, and I got it installed. And guess what? It displays a different boost value than my GReddy EBC. I'll be damned.

On my EBC's "LOW" setting, which is set to boost for 17-18psi, the Defi gives me 21psi. On the "HIGH" setting, which is for 19-20psi, the Defi displays 25 psi.

I am more inclined to believe the GReddy is wrong here. Both are hooked up to the same source, so I don't know what the hell is going on. Is my GReddy unit f*cked?

I'm ****ting on myself already though, in fear of the fact that I may have been boosting 25psi for the past two months. F*CK! Any ideas?

 

i would think the gauge might be off

 

if ur running 91 octaine ur guages are ratarded as the car wont boost over 20 safely constantly. the engine will knock or it will missfire or whatever u call it.

 

It's 93/94 octane. Depends on what I feel like paying for at the time I get gas...

I suppose it is possible that the gauge might be off, but since it's mechanical and not electrical, I don't see it as likely to be at fault.

C'mon people... any more ideas here?

 

Did you use a "T" fitting or a "y" fitting? I had a bernouli affect (fast moving air across a 90 degree creating a slight vacume) when I ran dual boost gauges before. Is the Vac on the Defi greater??

 

I have a Y fitting from the intake manifold leading into the car. That fitting came with the EBC.

Inside the car, the line is split again using a T. This fitting came with the boost gauge. It is really really odd.

The VAC seems to be reading about -10 inHG. On the GReddy, it gives me some ridiculous number like -60~-80. I have no idea what the number is supposed to be. When it read boost, however, it reads 190 as 19.0psi. I have no idea what units the -60 is supposed to be in...

 

Do the conversion its mm/Hg get another "y" and try that. I would really want both spliced near the manifold not way away from the source

 

Is there a particular reason to use "Y" over "T"?

AdvanceAutoParts only seems to sell T fittings. Also, my EBC uses a T fitting to tip into the BOV line. Will that make a difference as well?

As for units, it might be mm/Hg, I'm trying to recall what it is off the top of my head. Sorry 'bout that.

 

Its not your fitting and the chance are that the defi is correct. adjust it and move on...its fine

and on 91, it still would have been fine, the car's ecu is has plenty enough control to pull out enough timing....theres nothng here to stress over.

 

I find that when the car is off, the Defi reads 5psi, not 0. Is this a problem?

 

Your Defi is 5 psi off....no question in my mind! If it was reading 5 psi when you pulled it out of the box you should have sent it back for a new one. In any case, if it is new it should be replaced by Defi at no cost to you.

Keith

 

Yeah, I just called EDO performance, the distributor here in the US for the D-gauges. As it turns out, there was a bad batch shipped from Japan! Apparently I'm not the only person that's been having these problems... anyway, thanks for the help guys.

 

Within the large shipment of D-gauge black boost gauges we received recently, we do have a few bad gauges. We're working very closely with Defi Japan to address these issues as quickly as possible, and hopefully we will have them ship replacement gauges directly to customers so there's less of a wait.

The quickest way to help us go through the replacement procedure is to fill in the RMA (Return Merchandise Authorization) form Available Here , and fax it to us. We will follow up with an email, and direct the request to Defi Japan within the same day.

If you have any question on return policy, or anything regarding Defi Products in general, please send me a email at benliong@edoperformance.com

 

yep if you were boostin 25 you would have a CEL for overboosting, and a hard head jerking fuel cut at 25 psi.