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Discussion Starter #1
I have a boost gauge, but now Ive upgraded to the dual A-piler gauge holder I want more info about the real condition of my engine My question is whats the second most important gauge? Ive been told A/f gauges arent trully functional.(Cant tune by them ect...) EGT? Why???
Thanks
Rob
97 TT BPU+
 
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Discussion Starter #2
Definitally an intersting question... I personally want to get a boost gauge and an EGT, then put the AF guage in the clock area...
 
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I would say that the EGT guage is the second most important guage, followed closely by the oil pressure guage then fuel pressure.
 
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Discussion Starter #4
I have 2 gauges. Boost and EGT. You could possibly argue for Fuel Pressure, but I think a real-time EGT assessment is mor useful. I don't like a-pillars, so I will have to really hack up my dash to put in a 3rd. If and when i eventually do that, the 3rd will be Fuel Pressure.
 
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Discussion Starter #6
Re: why is the EGT gauge important

420tt said:
What does it do?
EGT= Exhaust Gas Temperature

It displays the temperature of the exhaust in the exhaust manifold, right after the turbo or in the elbow of the downpipe. In order to give you a general idea how well your engine is running. Unusually hot exhaust gasses are usually associated with detonation or an unhealthy combustion process, which leads to broken, melted or bent parts. An exhaust temperature that is too low usually implies that a car is running too rich and not living up to its full potential.

AF (Air-Fuel ratio) guages basically do the same thing but they are very slow to respond to quickly changing conditions.
 
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Discussion Starter #7
No, EGT's are slow, and it is best to mount the probe on the number one runner of the exhaust manifold, the A/F guage reacts quick but is not very accurate, and there is no set voltage every car runs, EGTs are accurate but slow.
 
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logb17 said:
No, EGT's are slow, and it is best to mount the probe on the number one runner of the exhaust manifold, the A/F guage reacts quick but is not very accurate, and there is no set voltage every car runs, EGTs are accurate but slow.
This is correct.
 
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Discussion Starter #9
logb17 said:
No, EGT's are slow, and it is best to mount the probe on the number one runner of the exhaust manifold, the A/F guage reacts quick but is not very accurate, and there is no set voltage every car runs, EGTs are accurate but slow.
my bad
 

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1=boost

2 or 3=egt
2 or 3=oil pressure

4=fuel pressure (when going single with fuel)
 

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I need an EGT Guage.. my exhuast gas temperatures are hot, but I have no idea what is considered too hot... the car is boosting around 20lbs on modified twins with just the bleeder T @ BPU right now... after driving the car and parking it, if I put my hand behind the exhuast the air is pretty hot, but thats normal Id say... what are normal EGT temps... I dont have a guage, probe or anything yet.. I hope Im not causing any damage without knowing it..

Plus when Im under WOT and it gets near redline (automatic) or during the shift the exhuast pops REALLY loud once or twice really fast... thats normal right? RMM DP and Racing Medallion... I dont know too much about detonation and how to detect it, im running either 92 or 93 octane usually.. and richer than lean I know that for sure, my car smells like a lawn service :D

When I know im gonna race I usually put a couple gallons of 100 octane torco in the mix though.. any input?

Oh yea... and my friend seems to think when my exhuast does that under Wide open throttle I may be getting a little flame or fireball now and then, I have never let anyone drive my car or been behind it... so I dont know, my friends Corrado shoots flames sometimes and I know that car from getawa in stockholm does as well... is that pretty common for a BPU car under hard acceleration?... my car seems to be running REALLY strong too.... it looses traction 2-3 times now sometimes... and yesterday when turbo 2 came online I spun for almost 2 seconds straight didnt realize it, let off the throttle and the car grabbed and jerked.. its running really mean right now for a little BPU Auto :D
 
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Discussion Starter #12
hmmm.. intersting..

what is the "normal" exhaust temp that a BPU (not +++) should be running... I have hard around 800 .. is that correct (btw, Im not sure of that figure)

And also, according to the above messages, it seems that an autometer AF guage would be a waste of money and I should spend that money on a good oil pressure guage.. hmm?

Note: my car is a stock 94 tt, but Im planning a few bpu's soon..
 
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Discussion Starter #13
i know the max for the DSM's 4g63 is 900c 1600f, dont know how much different Supras are.
 
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uhh hemm... does anyone know what the "normal" exhaust temp needs to be on a basic bpu 94 TT

Thanks!
 

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Kinda hard to say what is normal. My 95TTBPU++ complete with VPC tuned a bit lean, is generally at or around 500C when pulling very hard at ~15psi. I also have, amoungst other goodies, cams with exhaust at -3, DP with Hiflo Cat, HKS EVC EZ. I dunno if this makes a difference or not.

The previous owner told me to worry IF I ever saw it go above 650C. It has only come close once, on a rather severe pull at ~18psi. I think it was around 600C

Eric
 
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Discussion Starter #17
EGT

Your low EGT's are because you have your probe farther from the head. It should be as close as you can get it, 1 inch from the head on the runner. I don't really think that EGT's down that far are reliable because it would depend on other things like vented hood, FMIC, different bumper, etc. They would cause different cooling effects in the hood and under the car.

As far as gauges, I would say that getting both A/F and EGT is the best. You are more sure with the EGT and then you know where your A/F is for that. Afterwards, you can tell if your mixture is a bit rich or lean over a very short period of time by the
A/F. EGT's take a while to register and I wouldn't consider them safe by themselves. Besides, you should get the car tuned by a pro with a wideband. They can adjust the Greddy A/F and EGT gauges to be accurate.
 
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Discussion Starter #18
Probe in the top of the DP is fine, as long as you realize that those temps will be much lower than those immediately placed at the head hot side. I have presonally put the probe in the DP, to prevent probe being melted/broken and damaging the turbo hot side wheel. I know it might not be the quickest reacting placement out there, but with fuel pressure gauge in place I should be able to know whats up at all times. hope this helps.


Also, there is no "normal' EGTs, it varies on each car and heavily depends on mods, boost, probe placement, gas, etc....
 
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Discussion Starter #19
Well its accepted in DSM land to not go over 900c. There should be some sort of universal limit for supras, regardless of mods, unless internal ones are done. The parts in side the engine will not be able to handle over a certain amount. Over 900c in DSM's you could start burning a valve or listen to your rod punch a hole in your piston.

Dang you most have some Doe man!

Ive never heard of a probe breaking off in the runner. And destroying the turbo. I still think they Runner is the best.
 
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