Wich 4 guages are essential?

[definitiveno]

So far i ordered just a boost guage and a trans temp guage (built automatic). I will put them into one of the autometer dash pods to keep them out of the way and stock looking as possible. The only two other units I was thinking was an aem wideband hooked up to an air fuel guage and an apexi turbo timer wich also shows volts. Not sure where to put the timer but I supose the air fuel would go in the pillar if I had to.......... hmmmm or maybe the ashtray .... Not sure yet


Any thing else that you would get and why you feel it is a necassity, post it up?

 

[definitiveno]

Again, I will be using a wide band to moniter for lean mixtures.

 

[HighPsi92GST]

lets not turn this thread into a discussion about dsmlink please...

 

[psychlow]

Air/fuel mixture hardly has much influence on EGTs as it is.

Uhm... sorry, but WTF?

EGT is a DIRECT relationship to A/F (within certain values).

In gasoline engines (not diesel, mind you):
Rich = lower EGT
Lean = higher EGT

Yes, you'll get hotter EGTs if you get timing retard due to two reasons - one, because more of the combustion will still be taking place when the exhaust valve opens, wasting energy. If you think that just straight A/F doesn't affect EGT much, though, try tuning a car with no knock sensor, lean it out to less than stoichiometric, and see how it affects EGTs.

EGT - Exhaust Gas Temperature
Usually refers to a gauge that displays the temperature perceived by a sensor that is either mounted on the outside of an exhaust manifold/header/etc. or via a probe that internally protrudes into the exhaust path. As fuel leans out, the exhaust temps increase. Likewise, as fuel richens, the exhaust temps increase.

 

[guitarXgeek]

Uhm... sorry, but WTF?

EGT is a DIRECT relationship to A/F (within certain values).

In gasoline engines (not diesel, mind you):
Rich = lower EGT
Lean = higher EGT

Yes, you'll get hotter EGTs if you get timing retard due to two reasons - one, because more of the combustion will still be taking place when the exhaust valve opens, wasting energy. If you think that just straight A/F doesn't affect EGT much, though, try tuning a car with no knock sensor, lean it out to less than stoichiometric, and see how it affects EGTs.

Well duh, in conditions of extremely lean AFR, then yes of course the EGT will go up. That is my whole point. But by the time your lean-as-hell AFR has a significant effect on EGT, you've probably already done quite a bit of damage. EGTs are an indirect correlation with AFR. Why, you ask? Let's say you're running a bit on the lean side. This of course causes quite a bit a knock, which your knock sensor picks up. The knock sensor tells the ecu to pull timing to help control the detonation which in turn raises EGT. Now, if your AFR skyrockets then of course your EGTs are going to go up! That is common sense.

I guess the fact that karbon said that an EGT gauge was a must-have while a WBO2 is a nice-to-have irked me quite a bit. WBO2 > EGT. If you can argue that, I'll give you not one, but TWO cookies

 

[psychlow]

WBO2 > EGT

Agreed.

Well duh, in conditions of extremely lean AFR, then yes of course the EGT will go up. That is my whole point. But by the time your lean-as-hell AFR has a significant effect on EGT, you've probably already done quite a bit of damage. EGTs are an indirect correlation with AFR. Why, you ask? Let's say you're running a bit on the lean side. This of course causes quite a bit a knock, which your knock sensor picks up.

Yes, the fact that we have knock sensors and ECUs that control timing makes the difference more dramatic. But, as I said, try leaning out an A/F ratio on a car without an ECU or knock sensor. EGTs will go up, with no change in timing.

There's a reason we don't all run at an 14.7:1 while WOT. Why do you think detonation occurs? It's a product of the increased heat created by the lean condition. If you ignite a 14.7 atomized gasoline mixture in open air, it will not detonate. Likewise, if you compress it to 120-165+PSI at room temp and then ignite it, it still won't detonate (this is why we can get away with it all the time at part throttle - the cooling system is able keep up with the heat and prevent the cylinders from reaching detonation range).

It's when you try to ignite that same mix in an engine that's cylinders are overheating from a too-lean A/F that you get detonation.

My point is that EGTs have a direct impact on A/F. You can see in increase in EGTs by leaning out the mix without detonation occurring. Hell, if you take a DSM to 10:1, record EGTs, and then back it down to 11.5:1, you'll see an increase in EGT, without knock. If you do it with an SAFC, it'll usually STILL go up, even though the timing ADVANCED.

(Personally, I just tune using the knock sensor and a logger, then I find out where I'm knocking and richen it up a few % for a safety margin, and I make it a habit to read my plugs often. That's just me, though. Other people enjoy throwing down $800 to tune that last 10HP and 2MPG out of it.)

I agree that a logged wideband O2 is a better tool for tuning. But just knowing your A/F isn't going to tell you much if your intercooling sucks and you're detonating because you're heatsoaked, either. Using a knock sensor, an EGT, and a WBO2 all in concert is the only way to tune to the edge and KNOW that you're absolutely on - WBO2 and knock being the second-best option.

Sorry this went a little long winded. To sum: EGT gauges can still give you a decent idea of what's going on while driving, though, at less than half the price of a WBO2. The reason I chose to post about this is because it seemed as if you were conveying that EGTs were worthless to measure as far as monitoring the engine, and to also chime in about the direct correlation between A/F and EGT.

 

[guitarXgeek]

Agreed.



Yes, the fact that we have knock sensors and ECUs that control timing makes the difference more dramatic. But, as I said, try leaning out an A/F ratio on a car without an ECU or knock sensor. EGTs will go up, with no change in timing.

There's a reason we don't all run at an 14.7:1 while WOT. Why do you think detonation occurs? It's a product of the increased heat created by the lean condition. If you ignite a 14.7 atomized gasoline mixture in open air, it will not detonate. Likewise, if you compress it to 120-165+PSI at room temp and then ignite it, it still won't detonate (this is why we can get away with it all the time at part throttle - the cooling system is able keep up with the heat and prevent the cylinders from reaching detonation range).

It's when you try to ignite that same mix in an engine that's cylinders are overheating from a too-lean A/F that you get detonation.

My point is that EGTs have a direct impact on A/F. You can see in increase in EGTs by leaning out the mix without detonation occurring. Hell, if you take a DSM to 10:1, record EGTs, and then back it down to 11.5:1, you'll see an increase in EGT, without knock. If you do it with an SAFC, it'll usually STILL go up, even though the timing ADVANCED.

(Personally, I just tune using the knock sensor and a logger, then I find out where I'm knocking and richen it up a few % for a safety margin, and I make it a habit to read my plugs often. That's just me, though. Other people enjoy throwing down $800 to tune that last 10HP and 2MPG out of it.)

I agree that a logged wideband O2 is a better tool for tuning. But just knowing your A/F isn't going to tell you much if your intercooling sucks and you're detonating because you're heatsoaked, either. Using a knock sensor, an EGT, and a WBO2 all in concert is the only way to tune to the edge and KNOW that you're absolutely on - WBO2 and knock being the second-best option.

Sorry this went a little long winded. To sum: EGT gauges can still give you a decent idea of what's going on while driving, though, at less than half the price of a WBO2. The reason I chose to post about this is because it seemed as if you were conveying that EGTs were worthless to measure as far as monitoring the engine, and to also chime in about the direct correlation between A/F and EGT.

I guess my point is that it really isn't needed on our cars, specifically. Tuning a N/A car to close to stoich (which they don't even do) is a completely different thing When do we ever go over ~12.5:1?? And even that is race gas territory. The margin of AFR on our cars is so small that EGT would just barely be effected if you're running too lean/rich. Yes, EGT would go up or down, depending on how rich/lean you are, but honestly how much do you think it will change? Anything significant? Probably not. Since our cars DO have knock sensors, we'll know that we're knocking and have timing pulled because of it WAY before the EGTs are directly affected by the lean AFR.

Otherwise, I pretty much agree with what you're saying. I just don't see an EGT being entirely necessary or even applicable in our case. Honestly, its just a personal preference. I don't feel the need to spend money on it, but other people may. Freedom of choice is awesome