bshaw

So you're saying 14.7 at WOT with a supercharger is a bad idea?

ViribusUnits

Did you not pay attention to Lag?

Anything over about 12.5:1 is BAD!

You want it to be between 11:1 and 12.5:1. There is no way for a narrow band O2 sensor to tell you that. It's that simple.

Most of the narrow band O2 sensor kits come with a multitude of lights, of the 3 colors. The 3 colors are all that the O2 sensor tells you. The rest of the lights are nothing but a pretty marketing trick.

2V4V

Bill,

Yup, WBO2 is the only really accurate way to know your AFR.

As cheap ($349) as an accurate meter is now, you really should have one.

If you need fuel rails to hold larger, cheaper later style injectors (non-hose type) I have them on the shelf now. I also will have a replacement -8 AN hardline solution from the tank forward in the next few weeks.

Yes, you need more fuel for more than ~500 RWHP than the factory system can provide for any MY. The 84s need some upgrades past about 6 psi to keep mixtures where you want.

Greg

bshaw

That was meant toung-in-cheek. C'mon guys, this is the THIRD time in this thread this particular BFO has been stated. Yep, we're all in agreement here. 14.7:1 and WOT and 5 lbs of boost is bad. I'll be sure not to go there. Now relax everyone, enjoy the ride!

bshaw

Yep, once again we're all in agreement here. The WB02 is a much more accurate way to measure the AFR. That's why I bought one. That doesn't mean the zirconium based switching O2 sensor is useless though, just not as accurate once you get out past the knees.

Thanks for the offer on the fuel rails, I'll keep that in mind. You are correct in your statement that the '84 needs bigger injectors to get much past 350 hp. You can increase the fuel pressure to gain more fuel flow, but at some point you just run out of pulse width. Nissan 280ZX Turbo injectors (32 lbs/hour) will fit my '84 with the stock fuel rails, I'm headed that route now if I can verify that they're low Z.

bshaw

I didn't get a chance to check my fueling table change last night, it was getting late so I just burned a new EPROM, made sure it would start, saw it was running richer at idle, and quit for the night. This morning I have the 9th light on my AFR meter flickering on, so the fuel at WOT did get fatter.

I know, I know, I can't say by the LEDs if it is 11.8 or 11.7. What I can say is I am a long way from 14.7:1 at WOT, and a little bit farther away than yesterday. I'm going to do some plug cuts again at lunch time today just to be sure. Regardless of what the O2 guage says, the best way to know what's going on in your cylinders is to look at the plugs.

Gretch

Bill, nice looking bracket and the idler pully design looks good. How do you index the idler pulley adjustment to tension the belt? I can't tell from the picture if there is a adjustment mechanizm, or if you just set the tension with some leverage on the pulley while at the same time, tighten down on the locking nuts.

The discussion surrounding aluminum vs steel brackets left a couple of impressions on me. The first was the metal fatigue, vibration differences, and the second was the coefficient of expansion differences. I will be very interested to see how your bracket holds up.

Please tell me more about your intercooler. In your install I don't see where it is fitted. It is an air to air unit. so I am interested in how you will run your plumbing between the blower and the intake manifold to fit the intercooler.

Question for the guys running the wide band O2 sensor: Do you install that in addition to the stock sensor? where and how do you do this?

bshaw

To tension the belt I put a 1/2" breaker bar in a square hole in the bracket and torque. The intercooler fits behind the front grill, in the very front of the car. The plumbing goes through the fender, where the headlights used to be. Obviously, this is not for your normal street 928s :-)

The WBO2 is getting it's own bung welded into the headers on my car. Unless you are running some aftermarket engine controller that is designed for WBO2 you will have to run the zirconium based switching O2 sensor also. The outputs of the switching O2 sensor and WBO2 are not compatable. Mine gets fed to a spare analog input on the '749 to get digitized and is reported in the ALDL data stream to the laptop for data logging.

BTW, a while back when you first reported getting yours on the road I asked how your intake air was plumbed but didn't get an answer. Would you mind sharing a pic or 2 of the intake side of your SC?

Gretch

Sorry, I surely must have missed your question, cause I would not likely pass up an opportunity to show off my install. I will post what I have and explain as I go. Below is the air cleaner end of the plumbing. (Nicole, save your comments, I am not interested...) This piece is installed behind the drivers side headlamp.

Gretch

This is my gratutious advice...........get yours installed.

Gretch

Here, you can see part of the air box on the front of the blower, aluminum fabricated. It attaches to a 4" hose (gray ribbed in the picture) that drops straight down between the fan fames, to the bottom of the radiator frame and then runs along the bottom of the radiator and into the front fender behind the headlight

Gretch

I only have one more picture, It is hard to see the details but it is a good rendition of the results.....

bshaw

Ahhh - fabricated AL air box... that was what I was wondering about at the time. I used a Vortech part, cut it, flipped one end 180 degrees and fiberglassed it back on. It fits nicely with a little 'S' bend to get the air from the driver's side fender well.

Yours is an iron bracket? Bolted to the water pump? The little bit of it that I can see looks generally like mine. Guess that would figure since Tim started with the FAST kit and made his improvements from there.

Stock V-drive PS belt, alt belt in stock position, so the crank pulley has been modified from the FAST design also. Interesting...

bshaw

Nice, Tim should be giving you a commission!

Lagavulin

I'm sorry Bill; you are using a different gauge than I, and thus the confusion on my part. The air/fuel ratio reported by my WBO2 when my gauge shows two yellows from the first green is high 13's, 14:1.

As others noted, get your WBO2 installed immediately as it's your most important gauge with a supercharged car since the air/fuel ratio is so important. When installed, you will know the EXACT air/fuel ratio, unlike a narrow-band one.

The recommended location for my WBO2 sensor (..Bosch VW part) is as far away as possible from the head since it does not like to heat up above 800 degrees. Again, yours may be different, but I just want to exhort you to check with the manufacturer's recommendations, which may very well be right on the header as you plan.

Currently I am running only the WB, and I welded another bung right in front of where the resonators used to be, and run the WB there. I plan on installing a 'stock' NBO2 in the stock location, and use it to drive the ECU versus the WB. Of course, the WB will still be used to report and log the air/fuel ratio.