EGT temps or A/F meter

[King Salami]

Guys - I've seen a few posts on this issue, but I'm trying to get the definitive word (is there such a thing) on this issue.
I'm just starting to mod my DSM. I plan on upgrading the stock exhaust & fuel pump soon, but I'm going to install instrumentation first. I'm going with a boost gauge, but I'm undecided on whether to go with a A/F meter or EGT gauge. As I understand, the EGT is a more accurate way of protecting your engine, but...
I've seen people posting "danger zone" EGT temps anywhere from 900 degrees to 1700 degrees. Is this Farenheit vs. celcius? Can you guys give me normal "safe" EGT limits.
Will the EGT detect a dangerously lean condition more accurately/sooner than an A/F meter?
Thanks!

92 Talon TSi AWD - free mods, K&N w/ moded air box, fuel pump rewire

 

[candela]

IMHO an egt will give you more accuracy to tell how your motor is doing. The only way I would choose an a/f over an egt is if it was a wide band o2(very expensive and don't last long). I dont know about that 900 degree stuff being danger zone. Just cruising around here Im usually at about 1000-1200 F. After a quarter mile pull while in 4'th it will peek at about 1400, which I could probably go a little highe safely. I know some who run pretty lean and hit like 1600 all the time at WOT. When idling its really low at like 800 or so, not to sure. Any a/f meter you get is a good tool to have just not for tuning...because they aren't very accurate at WOT. Plus w/ those free mods, k/n and a rewire your car should be unning very crisp.

 

[candela]

I think on vfaq.com there is an expicit graph of the differences between the two. If I remember correctly you can swap out everything...but youll have to check

 

[dsmtrance]

I've seen people posting "danger zone" EGT temps anywhere from 900 degrees to 1700 degrees. Is this Farenheit vs. celcius?

Yes. 900C and about 1650F is where you want to be at redline w/ little knock and good timing to maximize output. 500C at idle is about the norm from what I've seen.

Will the EGT detect a dangerously lean condition more accurately/sooner than an A/F meter?

To an extent. It's just more accurate and tells you more "vital" information...as in, your engine's about to melt IMO, get the EGT and then get a Jumptronix A/F gauge. OR, if you want to really do something good for your car get a pocketlogger setup!!! I have the GReddy EGT, Jumptronix A/F AND the pocketlogger and they all work well together.

 

[candela]

i posted in the wrong one my 2nd post... sorry guys it was ofr someone asking about blocks,...

 

[AWDSOME]

How about the Greddy Air/Fuel gauge? Is that a worthwhile option. I know it has an 02 sensor, but is that the same as a wideband 02 sensor. The only problem I would think it would have is that you cannot get a good ratio by RPM since it can't be read to a computer or datalogger.

I guess overtime you could smooth it all out, but there has to be a better way.

 

[gvr4#1372]

I would say both of them if you can, That way you have the correct Temp and also you can see the mixter as well....

 

[Violater101]

My advice would be by the EGT gauge, then later on buy some type of logging device and read your A/F that way. The only good A/F is a wideband imo. You can pick up a jumptronix for relatively cheap as well when or if you buy an A/F gauge

 

[King Salami]

Thanks for the info!

 

[L2RTSiAWD]

Yes I have a greedy EGT and it's great much better than the A/F gauge I had. I basically wanted money on it so now I warn everyone to spend the money on an EGT.

Later,

 

[96TalonAWD]

Thats right an EGT is more precise!! i have a autometer A/F gauge sorry people but for some reason i just cannot spend like $140 on a gauge plus installation is a project. how well does a pocketlogger warn you of lean condition, you plug it while driving??

 

[L2RTSiAWD]

It can't warn you of a lean condition. that's what the EGT is for. The logger can show thru the RPM range where you need to add or subtract fuel.

Later,

 

[Sgt Turbo]

Originally posted by Violater101
My advice would be by the EGT gauge, then later on buy some type of logging device and read your A/F that way.

EXACTLY! This is the way to go. I would only add that I would stay away from the VDO EGT probe, it reads too slowly for tuning purposes, I know I have one. You will eventually find that you will only use your EGT gauge for a "reality check" and your logger for the majorlty of your tuning.
I do have a A/F gauge, and I can honestly say I never, ever look at it.

 

[candela]

You car looks ery nice SGT!!!

 

[Sgt Turbo]

Thanks

 

[Enigma_Man]

Yeah, from what I've read, the only real way to accurately measure air/fuel ratios is with a wideband O2 sensor, which are pretty expensive.

A regular Air/Fuel gauge you pick up somewhere isn't going to be Wideband O2. It reads the signal from the stock O2 sensors that are used, which is essentially a digital switch that operates around 14.3 or so air/fuel ratio (perfect for low-power fuel economy driving) When your car is at WOT, the engine calculates how much fuel is needed based on air through the MAF (or whatever) and then just hopes it is right It runs much richer at WOT, so the stock O2 sensor is not accurate. To get a wideband O2 gauge, you need the special O2 sensor, a special electronic hookup for it, and some sort of gauge to read the output from that (a regular autometer or whatever gauge isn't going to be calibrated for it, without more supporting electronics). They run into the many 100's of dollars. There's a DIY kit out there for about 200, methinks.

The EGT gauge would be a good sorta like "danger" meter. As in, you probably wouldn't want to tune directly off of it (IE, go lean until it's running hot), but it will let you know if when you do something based off other gauges (or loggers) you went too far.

None of this is from experience, btw. So if I'm full of shat, please let me know.

-Jesse

 

[SPEEDY]

I agree about getting the egt first. On a side note, you can always do the blue wire mod on a S-AFC to read your air/fuel mixture in volts, just like the jumptronix meter. It's just a little harder to read because of it's smaller size.

 

[fast_talon]

I have the TRE probe and is very fast.

 

[SPEEDY]

Originally posted by fast_talon
I have the TRE probe and is very fast.

I plan on getting the TRE probe after my GReddy probe dies out, but how is, or what do you mean by the TRE probe being faster, exactly? Does it Come up to temps faster or something. I'm not to sure. THANKS!

 

[IPT]

Get the EGT gauge first. To monitor your A/F get some sort of a digital volt meter so you can watch it.

Some Turbo timers have o2 sensor A/f meters, pocket logger, Jumptronix, Blue wire mod on an AFC, ect..

 

[fast_talon]

TRE probes react faster to temp changes. It will display on your Greddy EGT much faster then most other probes.

 

[SPEEDY]

Originally posted by fast_talon
TRE probes react faster to temp changes. It will display on your Greddy EGT much faster then most other probes.

Thanks for the info!

 

[tsibribri]

is the probe that comes with the autometer egt guage good or will i need another one?

 

[candela]

What do you guys think of the temperature difference between the #1 and #4 runners? Do all of you have taps in the #1. When I bought my car it was tapped in the #4, and I have been told that the #1 or even #2 is better(hotter).

 

[Moorepwr]

I believe that #1 gets the hottest. at least my friend told me his does in his 1g.