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Discussion Starter #1
Boost gauge is one, obviously.

Would the other be an EGT gauge? Are there any out there that are less than $250?

I just purchased a dual gauge pod (couldn't find a single) and might as well fill the other pod in with another gauge but have no idea what I can put in there. I'd like to make sure both guages are of the same brand and look.
 
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Discussion Starter #3
auto meter just came out with one for under 150 and it comes with a probe too.
 

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EGT is actually the single most important gauge in any modified turbo car. I would definately recommend on with some sort of peak hold. And before the BS starts to fly, the ONLY useful place for an EGT is in the #6 runner.

-Mike

DefBringer said:
Boost gauge is one, obviously.

Would the other be an EGT gauge? Are there any out there that are less than $250?

I just purchased a dual gauge pod (couldn't find a single) and might as well fill the other pod in with another gauge but have no idea what I can put in there. I'd like to make sure both guages are of the same brand and look.
 

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Re: Re: 2 most important gauges for BPU Supra?

V8THIS said:
EGT is actually the single most important gauge in any modified turbo car.
How about a WB O2 sensor instead? :) I've personally seen A/F shoot to 14:1 and the EGT budge less than 10 degrees C. If we didn't have a WB we wouldn't have known to stop immediately. Makes me wonder if the EGT would save you in time. Good thing our engine can take some abuse.
 

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after speaking to some of the big supra poeple.. it seems that an EGT is really about as usefull as a narrow band o2(well. maybe a bit more usefull.. but not much)

lets say you are running 640c egts.. which is well below "a problem".
you hit and instant lean condition. spike to 16:1 AF.. and then drop back to regualr fuel.. your EGT wont even move.. but you could have just melted a piston.
Personaly.. IMO the 2 most importnat guages are Fuel pressure and wide band O2.
D.
 

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Re: Re: 2 most important gauges for BPU Supra?

V8THIS said:
EGT is actually the single most important gauge in any modified turbo car. I would definately recommend on with some sort of peak hold. And before the BS starts to fly, the ONLY useful place for an EGT is in the #6 runner.

-Mike

Do you mean I should mount EGT before turbo? Or in DP will be OK?
 
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Discussion Starter #8
Just beacause the probe you have sucks doesn't mean the information its gives is not important. A member here has a $1700 egt system that measures temps instantly many times a second. If you had that the info you get would be very useful.


While on the subject. I've wondered why we don't set up an egt gauge with a higher quality probe and a lower quality display. I think its Boost junkie that has the 6 egt sysmtem. If he reads this maybe he can tell us the name of the probe. Hus system has 6 egt probes(one in each runner). I would pay $500 for a single probe system in the #6 runner if it were fast and accurate.
 
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Discussion Starter #9
i agree with V8THIS, an egt guage is the single most important guage that u could purchase for a turbo car! i have one in my eclipse and it helps out tremendously! Boost is important but egt is just as important if not more. most who own a supra use a vpc along with a gcc which is great but i don't think with these 2 u could really get lean spikes, and even if u do it won't hurt if your only lean for a few seconds. the reason i say this is because the vpc and gcc, is a piggy back to the cars ecu which has a fuel map of it's own, so unless u do something stupid and try to lean it out than i don't think u would have a probelm but even then the ecu will try to adjust, at least this is what happens on dsm.
 

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I work on aircrafts and they all have EGT gauges. Even the piston planes have egt, no fuel air.
 

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Forget the relatively useless EGT gauge and get yourself a built-in wideband O2. I have a GReddy EGT gauge (with the probe in the collector centered directly under the turbine entrance) and also a $1750 Heraeus EGT monitoring system with a probe on each header runner. The Heraeus system is practically instant-reacting and makes the GReddy type gauges look silly in terms of quick and accurate temperature measurement. But even the Heraeus system with its quick reaction time is almost useless for careful tuning.

What you NEED to know is the AFR. I have an FJO wideband and I can tell you from extensive experience that you CAN NOT spot AFR variations with an EGT guage until they are extreme -- at LEAST one FULL A/F point, and that's if you can carefully control other variables such as length of the pull, fuel quality, etc. Also, you CAN NOT identify lean or rich spots in the RPM/boost range with an EGT gauge -- you can only get some vague idea of where the EGTs peaked over the course of the pull. And, what little info you can gather through EGT readings can only be done AFTER you have correlated the EGT readings that you get on YOUR car with AFR readings from a wideband O2. At the same AFR, EGT readings can and do vary from Supra to Supra by more than 100 C depending upon what type gauge you have, how and where the probe is positioned, the length of the pull, etc.

Here's one example (I have many, but here's a simple one): Recently on the dyno my car was encountering a lean spot in the 5500 RPM range. It would spike up into the 14+:1 range, with low-11:1 AFRs on either side of the spike. With a good bit of boost and an extended pull, 14+:1 might be enough to damage an engine, agreed? Okay. The EGT on the GReddy gauge peaked at 820 C on those pulls because the lean condition wasn't of long enough duration to give the gauge time to react. If one were going simply on the goofy 900 C Max EGT rule, we'd have thought that everything was just peachy. We tuned the spike out and got the AFR down to 11.5-12.0:1 across the high boost RPM range, and as a result EGTs in the collector went UP to 840 C. That's because the overall AFR was leaner, though the 5500 range was richer.

It is really unfortunate that so many people think they can get useful tuning information with EGT gauges. I just wonder how many engines have been blown due to this? No matter, people need to stop propagating the myth that EGTs are inherently useful for accurate fuel tuning.

Steve
 

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A WB O2 is not as expensive as everyone thinks either. You can get a DIY WB kit for ~$30 US. Get the sensor for ~$125 and then get a digital volt meter from Gadget Seller for $70 ($99 if you want the LED version). Grand total is $225 for a WB kit. Granted A/F isn't displayed voltage is so you just have to know how to conver from voltage to A/F in your head. That's what I'm doing, it beats an FJO unit. The reason I didn't get the Jaycar display for the DIY WB is that it is a beast from hell to assemble so I figured a simple DVM was my best bet.
 
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Ok, so you're essentially saying that the popular EGT gauges made by Greddy are worthless? They're not good for anything at all? I wish I would have known this before I just spent $200 on the thing this morning. :(
 

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So basically everyone should dump off their EGT gauge and buy get a wideband.

Who is going to get the group buy going on this?
 
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goddamnit....can we get some more opinions on this quickly? I need it soon so I can call up the place and tell them to hold my order of the gauge. Should I get a fuel pressure gauge instead? Oil pressure gauge?
 

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The FJO kit costs more, but offers some useful features that some people may favor:

The FJO is ready to plug and play -- no fooling around for 3 weeks and pestering every electronics-savy friend you know to get the thing put together. :)

The FJO offers data-logging capability -- a VERY useful function (I know, because I've done it with and without data-logging). It offers data-logging relative to RPM, as well as relative to 5-volt input (the latter could be a useful tool when compared to VPC output or throttle position sensor output). IF the DIY kit does not offer data-logging, I would be reluctant to buy it unless I simply could not afford the FJO. If I couldn't afford the FJO, I'd definitely go the DIY route because real-time display is far better than no wideband at all.

The FJO offers real-time readout of AFR (no converting required)

The DIY kit offers the following advantage:
It's less expensive.

I can supply the FJO kits at the group buy price, but they are still more than 2X the cost of the DIY components.

Steve

burnmacs said:
A WB O2 is not as expensive as everyone thinks either. You can get a DIY WB kit for ~$30 US. Get the sensor for ~$125 and then get a digital volt meter from Gadget Seller for $70 ($99 if you want the LED version). Grand total is $225 for a WB kit. Granted A/F isn't displayed voltage is so you just have to know how to conver from voltage to A/F in your head. That's what I'm doing, it beats an FJO unit. The reason I didn't get the Jaycar display for the DIY WB is that it is a beast from hell to assemble so I figured a simple DVM was my best bet.
 

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I'm not particularly saying that they are categorically "worthless" but I am saying that they are relatively useless for fuel tuning, and compared to a wideband O2, they are.... well... pretty useless. Once you know what the EGTs are on YOUR car at a given AFR and a given set of operating parameters, you can sort of use the EGT gauge to tell you if something has gone waay screwy with the AFR. But, if you have a wideband, you'll know just how screwy and you'll know much sooner than you will with the EGT gauge.

If you get a wideband, the EGT gauge will become much more of a novelty, as opposed to something that you try to use as a tuning tool. As is, I watch the wideband readout more than any other gauge in my car. I set the boost controller, and then only check after a pull to see what the peak boost was. Of course I watch the tach some of the time, but I keep a close eye on the AFR. Once in a while I'll check the GReddy EGT gauge or the Heraeus system to see what the peak EGT was, but I don't really take any action based upon that info. AFR is king with me.

Regarding a Group Buy, I already did two and can now offer group buy pricing on an ongoing basis. Check out www.fjoinc.com for product details and then E-mail me for pricing if you want a kit at the group buy price.

Steve
[email protected]
 
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Discussion Starter #18 (Edited)
EGT is important because there are other things to consider besides A/F. Stuff like too much timing or a hot intake charge could cause failures as well.
 

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Re: Re: Re: 2 most important gauges for BPU Supra?

Normally I would agree with you, but the original post did say BPU. It's is extremely unlikely for a/f ratios to fall that far off the mark at BPU.


-Mike



burnmacs said:


How about a WB O2 sensor instead? :) I've personally seen A/F shoot to 14:1 and the EGT budge less than 10 degrees C. If we didn't have a WB we wouldn't have known to stop immediately. Makes me wonder if the EGT would save you in time. Good thing our engine can take some abuse.
 

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EGT as useful as a narrowband O2? I would have to say whoever gave you this information are one ones in question.

Instant 16:1 lean condition? Sounds good on paper, but in practice, how many folks have their engines blow at BPU because this type of failure. Can I see I show of hands? anyone?....anyone?

-Mike

White_lightning said:
after speaking to some of the big supra poeple.. it seems that an EGT is really about as usefull as a narrow band o2(well. maybe a bit more usefull.. but not much)

lets say you are running 640c egts.. which is well below "a problem".
you hit and instant lean condition. spike to 16:1 AF.. and then drop back to regualr fuel.. your EGT wont even move.. but you could have just melted a piston.
Personaly.. IMO the 2 most importnat guages are Fuel pressure and wide band O2.
D.
 
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