Gauges and which ones?

[Pike]

I've read a lot of posts suggesting guages with an install

Air / Fuel Ratio
N20 PSI
Fuel PSI

For those of you that have those, which ones did you get (or do you suggest?) where do they hook up and what do you need to make them work. Links to vendors are appreciated (since shopping with jegs and summit is like looking for a needle in a haystack).

PS = Is it true autometer is crap?

[John_D.]

<blockquote>quote:</font><hr>Originally posted by Pike:
For those of you that have those, which ones did you get (or do you suggest?) where do they hook up and what do you need to make them work.

PS = Is it true autometer is crap?<hr></blockquote>

I have a electric fuel pressure gauge. It's from the autometer phantom line. A search on fuel pressure gauge, or phantom, on jegs or summit should turn up a short list of part numbers and descriptions. The fuel pressure gauge works great. (I also got the vacuum/boost gauge from the autometer phantom line, and it works great too, so no complaints on autometer gauges from me.)

I had to tee off the schrader valve, one outlet for the fpss with the nitrous kit, the other outlet for the fuel pressure sending unit. I had to get a brass tee in order to do this, I just prowled around in the fittings box behind the counter at Advance to find something that would fit. (I did bring in the three different pieces, so I could tell what would work for sure.)

Then a wire inside the car to a box, also a hot wire, and a ground wire. A couple of wires to the gauge, from the box. And a wire from the fuse panel to the light in the gauge, so it would be lit up when the instrument panel lights were one.

The fuel pressure gauge was good to confirm the bypass jet and line were working correctly on my dry kit after I got it installed, and to diagnose a miss on top end when I ran a bigger shot (I was losing fuel pressure when I went from an 85 to a 130+).

___________________________

I have an NOS nitrous pressure gauge mounted on the bottle. So far I've only used it to see what my initial pressure is (around 750...), which tells me I need a bottle heater. I bought it at a local speed shop when I was getting the bottle filled.

It would be interesting to see what the pressure drops to immediately after a run, and to see how quickly it bounces back if I had a heater.

It came with everything needed to hook it up.
_____________________________

Oh, get some teflon paste, you'll need it for the nitrous kit connections anyway.

[Pike]

Perfect, Just wanted I wanted to know (and then a little more [img]smile.gif[/img]

[12secondv6]

My chevelle and bird has autometer.
A lot of my fellow racers run autometer, I've never had any problems.
As for guages:
nos psi guage (came with the kit)
autometer air/ fuel ratio guage
autometer fuel psi guage
b&m tranny temp guage (broken, soon to be replaced by autometer)
Chevelle has autometer oil psi and water temp

As for wiring, ask anyone, I'm useless with it [img]smile.gif[/img]

[Pike]

I've been reading through some of the old posts (yep thats right - I DO use the SEARCH function! HA HA!) and have read a few things that hint that an EGT (Exhaust Gas Temp) is a better way to tell A/F ratios.

If this is true, how so and how would you read one? (It's nowhere near as easy as the ol rich/lean needle pointing the way)

[John_D.]

<blockquote>quote:</font><hr>Originally posted by Pike:
...have read a few things that hint that an EGT (Exhaust Gas Temp) is a better way to tell A/F ratios.

If this is true, how so and how would you read one?<hr></blockquote>

I've read some things here and other places. EGT is supposed to be very accurate. However....

Depends on where you mount it. It's conceivable you can monitor individual cylinders, and see if one runs leaner than another. Likewise, if you only monitor one, it could be the rich one. Or the lean one. So you would be tuning the whole engine based on one cylinder. I think the recommendations I saw were around 2-4 inches from the exhaust port. Which pretty much means measuring only one cylinder. (assuming you have headers, since you probably don't want to penetrate the casting on a manifold.)

You can measure further downstream, in the collector, and get a good average for that side, just like the stock o2 sensors do. The sensor supposedly responds differently though, because it is gettting hit more often with hot exhaust gas pulses (three or four instead of just one). Also one missing cylinder can cool it down.

It takes a certain time for the egt to respond to the exhaust. So a short run may not tell you the true temp. Likewise, a longer run can build a lot of heat in the sensor, and you won't see the variations at different rpms as you're shifting, so you may not see a lean condition on top end as you run out of fuel...

You will need to figure out the optimum temp for your engine. There are ranges that correspond to different a/f ratios, roughly. But all the things I've read lately point out that different engines may like 200-400 degrees difference from one another, it takes several dyno runs to figure out what temp your engine likes best.

I just went with the stock o2's and an autotap, since there was some good info on here about what ranges to shoot for. EGT got too complicated for me...

[ December 26, 2002: Message edited by: John_D. ]</p>

[12secondv6]

<blockquote>quote:</font><hr>Originally posted by Pike:
I've been reading through some of the old posts (yep thats right - I DO use the SEARCH function! HA HA!) and have read a few things that hint that an EGT (Exhaust Gas Temp) is a better way to tell A/F ratios.

If this is true, how so and how would you read one? (It's nowhere near as easy as the ol rich/lean needle pointing the way)<hr></blockquote>


EGT's aka pyrometer guages
You and John are correct.
This is a much better way buuut tere are some things that must be understood (and I'm still learning with this)

Best location, on average, is 6 inches from the exhaust port on the block. But this only monitors the left or right bank of cylinders.
The best way is to drill and tap each primary tube (per cylinder) approximately 6 inches from the exhaust port on the block and run 1 guage per cylinder to monitor each cylinder's combustion temp. This will show poor running cylinder's, poor combustion, potential problems, lean conditions etc.

I am planning on trying 1 per cylinder bank this winter and I am pretty sure the guages will be placed where the cd player is currently residing

I do not know what to expect but I'mlearning more and more on this.
They are not cheap though :(
Sigh, update will occur soon [img]smile.gif[/img]

[Pike]

Hey 12sec,

To save some money on those, you could probably run more than one probe to a guage or set of guages.

By looking at the pictures at summit, the probe is a simple 2 wire hook up (I'd think the input to the gauge would be the same). All you would need to make that work would be a guage (or guages) and then wire them all through a selector knob (~$10 at radio shack).

Then you could just dial in a particular cylinder to the guage and not have to buy six guages and wire ALL of them to six seperate guages (that would be confusing to me).

Just and idea. You'd still have to buy all the probes (which the expensive part) but it save you a little cash and wouldn't be hard to hook up.

(since you suck at wiring, I could draw one up for ya if you would like)

[edit]
I just did a search at Radio Shack this part (#275-1386) would be just perfect for that project. (maybe th3 past 4 years in navy electronics is paying off... :D )

[ December 27, 2002: Message edited by: Pike ]</p>

[12secondv6]

True, very true.
I'll talk to my shop about that.
In theory having one per cylinder is the best route but due to cost, increased of guages and wiring, and where the hell do you put 6 guages you have a very good idea
Most likely I'll have one per bank, but I'll talk to my shop about your idea, I like it

[tim haynes]

why do you need a nitrous guage.
how can it help you.

sure it tells you the amount going through , but why does that matter.

[Pike]

It's not a nitrous flow gauge but a nitrous pressure gauge. It's telling you how much nitrous is in your bottle thus you can run correct pressures at the track and know when to refill it.

[Arctc Wolf]

retarding timing will raise egt's and make it seem like ur running lean, and w/ nitrous, u usually have 2 retard timing somewhat, so I'd use a ture a/f ratio gauge and get new wideband O2 sensors to replace the stock sensors so u can get accurate readings from the a/f gauge.

[12secondv6]

<blockquote>quote:</font><hr>Originally posted by tim haynes:
why do you need a nitrous guage.
how can it help you.

sure it tells you the amount going through , but why does that matter.<hr></blockquote>
The nitrous guage indicated the pressure in the bottle, not flow

Correct bottle psi ='s good horsepoer
Typically I stage with 1100 psi, and purge to 1050

As for timing, i still run stock