I'm about to kill myself for being so dumb and not using traditional testing methods like a "Control" car.

As most of you have heard me b1tch about, my vacuum and boost have never read what they should....right now 17Hg at idle, 8PSI at full boost with a 3.12" Pulley on the V1.

I've tried 3 different gauges, all sorts of removing of parts and replacing gaskets, blah blah blah.

Well - I finally got up to 17PSI recently. It's minimum of spec - but hey - better than the 13 I had when I started this quest.

So today I plugged a cheap diagnostics gauge into the car. Hmmm....19Hg. Strange....

I'm thinking "Well, I've had 3 dash mounted gauges, and they all read 13-15Hg, except for recently, where I fixed a slight EGR leak (17Hg)....so this cheap-o gauge must be off."

Then as a control I plugged it into my friend's pretty much stock (Y-Pipe and HAI only) 96 I30.

21Hg.....only 2 HG more than I have right now...

So then I plugged it into maximase86's 2nd Gen. - 20Hg!

So can it be possible that ALL 3 in-dash (2 Autometer, 1 ISSPRO) guages were (and are) reading bad? I replaced all the lines and wiring and hardware each time....

 

last night I went out trying to make more videos and so on, I ran another 350Z more like playing with him, after that no more cars to play with so I decided to punch the car and look at the boost gauge. My belt has some alright tension on it, and in 3rd gear right at 6600RPMs I hit 10PSI, so I am hitting full bost right at redline and I have a V2. With the pulley you have on there at redline you should be seen 10.5PSI, thats what Matt was boosting when he had his V1, so your goal is 10-10.5PSI

 

Exactly.

I already know that.

The strange thing is that I show low vaccuum and boost on 3 different dash gauges and 1 diagnostic gauge over the last 1 year.

But now this gauge shows me as being very close to spec (in vacuum). And it shows normal (not optimistic) readings on 2 other "stock" cars.

So it could just be that ALL those gauges were bad.

I'm going to get yet another diagnostic gauge and test that on a control car and my car again.

I think what's going on is that there's a kink or leak in the plastic line going to my in-car boost gauge, so it's reading low vacuum and low boost.

Maybe I'll also take this diagnostic gauge and tape it to my windshield (it reads boost as well)

If that's the problems, that owuld be whacked, since I eliminted the boost gauge awhile ago as being the problem because I replaced it - twice.

 

ian , does anyone else around you have a boost gauge in there maxima?

that way you could check the diagnostic gauge with another gauge inside the "test" car

 

if someone can let you borrow a boost gauge you can ghetto rig it to the windshield if worse comes to push and then you know for sure. Now the Hg's I get about 16-18Hgs most of the times is around 16 or 17. I use to see more vacuum in the 19's but after the MEVI install it went down maybe one or two Hgs

 

Well, it gets stranger....

I pulled the gauge and hard-lined it using a rubber hose onto the plastic line going into a connector then going into a larger piece of hose hooked directly onto the gauge.

Turns out that my vacuum gauge was leaking air with that cheap metal crimp thing on there:



Well, that looks great!

So I was all psyched thinking that because it was leaking, it would leak vacuum and boost.

WRONG. I'm not hitting anything over 7.5-8PSI with a 3.12" Pulley. My HP numbers (275hp, 243tq with a 5spd and MEVI) show this also. If the belt were slipping inaudibly, I would have seen that on the Dyno also. And this is my 3rd belt....

SO I took the diagnostic gauge (which reads boost also) and plugged that straight into the manifold and ran a hose to the cabin.

I had my friend hold onto it while I boosted on the freeway.

7.5-8PSI.

SO the gauges are reading fine now - both of them.



(Remember, I also had the Smoke-It leak detector procedure done. If there's any kind of leak, it will find it. (cool piece of gear) There was one small one which is now fixed, and no leaks anywhere else. The charge piping was tested also, and is 100% sealed, and none of this makes any sense.

Looks like the blower really has been the problem the whole time? Maybe time for a rebuild?

Or maybe a swap? WIll the V2 Blower fit on a V1 bracket?

IanS

 

Now keep in mind I have done neither procedure, and am only running off what I've "heard."

I've heard:

1) You can have the blower rebuilt by vortech back to spec as a V1.

2) You can pay extra dollars and have it rebuilt by vortech back to spec as a V2.

I'm assuming what I heard about #2 means that it will be in the same housing and therefore fit on the same bracket. If it's bugging you so bad, go #2. Frankly though, 270ish HP isn't bad for a supercharger. The most you're going to get without redoing your injectors is 300-325ish. You need to jump on the turbo wagon

 

Injectors are on the way, Nitrous is sitting in the basement, and Aquamist soon.

(But I may just sell the N20 to pay for the rebuild and get a 2.87" Pulley)

That's the reason I'm re-visiting this issue - I want my car at 100% before I push another 50hp into it.

IanS

 

Tok off the charge piping today and re-checked all the seals (like at the MAF and all connection points).

It looks great. BOV is only releasing under vacuum...(HKS SSQ - it can't physically release under boost).....everything is fine.

But still only hitting 6.5-7.5PSI with the 3.12" Pulley.

Vacuum is now at 20Hg - perfect - "Smoke-IT" test shows no leaks anywhere.

Anyone have any ideas other than the blower needing a rebuild or any confirmation on how it oculd be the blower before I send it in for a rebuild?

Thanks,
IanS

 

Dirty air filter, maybe? Have you tried boosting with the air filter removed, just for sh*ts and giggles?

I'm trying to think how a blower rebuild would make a difference in boost pressure. I guess if the seals are really bad then air can leak out past the bearings and into the oil drain pipe. It's hard to imagine so much air leaking that you lose 2-3 psi, though.

Have you pulled the blower housing off and looked at the condition of your impeller blades? Or maybe there's a redrag stuck up inside it.

And you're absolutely sure your belt is not slipping? The way I could tell mine was slipping was it would get up to about 8 psi and then drop back to 7 psi and stay there to redline.

 

From my understanding, when you blow your seals you get oil puddles on the in/out ports on the SC. I made sure to check yesterday when I had the piping off. Dry as a bone. I also cleaned the air filter pretty well at that time. I'll try removing it anyway and seeing what happens - because it's an idea...may as well try it.

I'm sure the belts not slipping. If it were, it would show prety well on the Dyno (especially with 3 PSI) and also the needle would jump a little more when boosting (like you said). It's not. I checked belt tension yesterday, and it feels pretty tight. (Gatorback Belt)

Checked the impellar when I had the SC off a few weeks ago when I went to the 3.12" - it loked fine.....but maybe there's something I can't see.