EGT question
12-08-06, 10:43 PM
#1
EGT question
it doesnt seem like alot of people here like to/believe in EGT gauges
why is that? it seems to be one of the most useful tools...
on diesel performance, the EGT is mandatory - i have one on my truck, and i would not say it is slow reacting at all.
could it be that people mount it incorrectly? (after downpipe)?
why is that? it seems to be one of the most useful tools...
on diesel performance, the EGT is mandatory - i have one on my truck, and i would not say it is slow reacting at all.
could it be that people mount it incorrectly? (after downpipe)?
12-08-06, 10:53 PM
#3
Passing life by
It should be mounted in the mani or runner port. They are extremely useful. I think its just laziness and lack of knowledge. I know some tuners here say they are awesome and some just say hell with it and use a wide band. I am not a tuner as of now but I think only using one is only leaving yourself with half of the results obtainable.
12-08-06, 11:01 PM
#4
Haven't we ALL heard this
I wonder...if you are on the dyno...running it so you can put a load on the dyno...I guess dyno brake?
So you can hold say 5000 rpm and 12psi...could you then mess with advance and retard and watch the egt so you can tune that way?
James
So you can hold say 5000 rpm and 12psi...could you then mess with advance and retard and watch the egt so you can tune that way?
James
12-08-06, 11:20 PM
#5
yes you can ^^^
i think the reason that some motors pop, even though their AFR is 'safe' is their EGT climbs, esp under a long load...
we all heard of these guys here who thinks they are all bad *** with their tuned car and when they decided to stretch its legs and do a 5th gear pull on a hot day and it pop... i think its more than just afr
i think the reason that some motors pop, even though their AFR is 'safe' is their EGT climbs, esp under a long load...
we all heard of these guys here who thinks they are all bad *** with their tuned car and when they decided to stretch its legs and do a 5th gear pull on a hot day and it pop... i think its more than just afr
12-09-06, 08:21 PM
#7
I don't know what rx7 people you are talking to but most of them that go full turbo upgrade make it almost manditory to have at least one pre turbo and if you really want to monitor stuff right then you will put two pre turbo, one in both runners. I've only got one in for now and it's on the rear runner on the turbo manifold because lets face it, Rear rotor temps are always higher.
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12-09-06, 10:21 PM
#8
Originally Posted by slpin
yes you can ^^^
i think the reason that some motors pop, even though their AFR is 'safe' is their EGT climbs, esp under a long load...
we all heard of these guys here who thinks they are all bad *** with their tuned car and when they decided to stretch its legs and do a 5th gear pull on a hot day and it pop... i think its more than just afr
i think the reason that some motors pop, even though their AFR is 'safe' is their EGT climbs, esp under a long load...
we all heard of these guys here who thinks they are all bad *** with their tuned car and when they decided to stretch its legs and do a 5th gear pull on a hot day and it pop... i think its more than just afr
EGT per port is the way to go.
12-09-06, 10:32 PM
#9
you can decrease timing and increase fuel with air temps, i already have that mapped out for just such an occasion. as for laziness, not for me, i just found the AI kit was more beneficial at the moment than an EGT but the EGT is the next step as i want to get a little more out of the timing curve.
12-09-06, 11:12 PM
#12
read this thread, it talks about EGT's : http://forum.teamfc3s.org/showthread.php?t=50764
Here is my understanding of that thread: his point is that EGT's are really important on a rotary especially because, no matter how well you have your timing and AFR's, gasoline will spontaneously combust no matter what if it gets to a certain temperature--this is pre-ignition before the spark plug is fired, rather than the detonation that occurs after it has fired and the flame front is already in the process of propogating. Higher octane and methanol combust at higher temperatures, so they can save you from this pre-ignition that is assocatied with high EGT's etc.
Now, I have an EGT gauge on my Turbo II. I find that the EGT gauge in my experience isn't straightforward to use for tuning because you can't be sure what a "good temperature" should be. Cruising in closed loop in the highway, it's at about 1400 degrees. Then if I drop it into 4th and start boosting it it will actually drop a little to 1300 or so... I mean it really just depends. It does different stuff depending on driving conditions etc.
I actually just took it to Virginia International Raceway two days ago. I was driving behind a CTS-V pace car, mostly hanging with him, and the gauge was pegged beyond 1600 degrees and I was boosting the **** out of it. What does this tell me, someone with let's say average or perhaps slightly above average tuning knowledge? Nothing. It just says that rotaries run really hot when you tach them, and that I might have a higher chance of pre ignition. But how much? Who knows. It never detonated and didn't miss a beat the whole 25 minutes I had it running hard.
There is a group by for a dual EGT gauge, one for each rotor, that I think reads up to 2000+ degrees. If you're going to use an EGT gauge, just get that. I know that the rear rotor usually runs hotter and leaner, and that's why it seems to always blow. My EGT gauge is practically useless because it just pegs out.
Btw, my friend with the 600awhp VR-4 told me that if their EGT's get up to 1300 degrees they are supposed to shut the car off b/c they're about to melt something...
Here is my understanding of that thread: his point is that EGT's are really important on a rotary especially because, no matter how well you have your timing and AFR's, gasoline will spontaneously combust no matter what if it gets to a certain temperature--this is pre-ignition before the spark plug is fired, rather than the detonation that occurs after it has fired and the flame front is already in the process of propogating. Higher octane and methanol combust at higher temperatures, so they can save you from this pre-ignition that is assocatied with high EGT's etc.
Now, I have an EGT gauge on my Turbo II. I find that the EGT gauge in my experience isn't straightforward to use for tuning because you can't be sure what a "good temperature" should be. Cruising in closed loop in the highway, it's at about 1400 degrees. Then if I drop it into 4th and start boosting it it will actually drop a little to 1300 or so... I mean it really just depends. It does different stuff depending on driving conditions etc.
I actually just took it to Virginia International Raceway two days ago. I was driving behind a CTS-V pace car, mostly hanging with him, and the gauge was pegged beyond 1600 degrees and I was boosting the **** out of it. What does this tell me, someone with let's say average or perhaps slightly above average tuning knowledge? Nothing. It just says that rotaries run really hot when you tach them, and that I might have a higher chance of pre ignition. But how much? Who knows. It never detonated and didn't miss a beat the whole 25 minutes I had it running hard.
There is a group by for a dual EGT gauge, one for each rotor, that I think reads up to 2000+ degrees. If you're going to use an EGT gauge, just get that. I know that the rear rotor usually runs hotter and leaner, and that's why it seems to always blow. My EGT gauge is practically useless because it just pegs out.
Btw, my friend with the 600awhp VR-4 told me that if their EGT's get up to 1300 degrees they are supposed to shut the car off b/c they're about to melt something...
12-09-06, 11:19 PM
#13
Wow, I thought 1500-1600 was the max for pump gas (or were you on race gas?) Anyway, I wouldn't use the EGT gauge as much for tuning as I would for safety. For example, I would know what they should be, and if they start getting hotter then something could be wrong and back off.
Also, the temps and combustion of fuel is the reason alchy injection works so well. It considerably lowers the temps seen. For example, BDC was running meth injection and 25 pounds of boost on the stock TMIC. He was seeing 1300-1400 degree EGT's, while he saw 1500-1600 at lower boost without the meth injection.
Also, the temps and combustion of fuel is the reason alchy injection works so well. It considerably lowers the temps seen. For example, BDC was running meth injection and 25 pounds of boost on the stock TMIC. He was seeing 1300-1400 degree EGT's, while he saw 1500-1600 at lower boost without the meth injection.
12-09-06, 11:27 PM
#14
^ I did have 5 gallons of 100 octane unleaded mixed with maybe 3 or 4 gallons of 93 left in the tank... so maybe 96, 97 octane? I just put it in there for safety.
You gotta remember that the EGT's in a short drag race or in some hard straightline driving is nowhere near what I was seeing from taching it 6 grand for 25 minutes. That's why I'm just not sure how to really use an EGT gauge properly... especially one that just pegs out when you run the car hard.
You gotta remember that the EGT's in a short drag race or in some hard straightline driving is nowhere near what I was seeing from taching it 6 grand for 25 minutes. That's why I'm just not sure how to really use an EGT gauge properly... especially one that just pegs out when you run the car hard.
12-09-06, 11:49 PM
#15
my point exactly and why the auxiliary injection is more important to me, i have already found that 18psi is the threshold for me on premium pump fuel and skyrocketting internal combustion temps, i got tired of replacing irons and AI goes farther than the still limiting of the EGT gauge, an AI increases performance while increasing the safety margin, the EGT just increases the safety margin of keeping your tune under control as well as your foot. i would much rather keep my foot into it than have to watch the EGTs float in the red, AI brings the EGT down to a more reasonable level, allows more boost and more timing.
not saying EGT is useless but it is a step down from an auxiliary injectant in my list of upgrades to do.
pre-ignition is the killer of MANY engines, you can only control EGT so well with tuning but at higher performance levels you will always be near that borderline.
prior to the methanol injection install i could see the intercooler heat soak and temps climb with boost, now the temps actually drop at least 10*C when i begin boosting and hang at about ambient when i am pushing the car. my car loves the ****...
not saying EGT is useless but it is a step down from an auxiliary injectant in my list of upgrades to do.
pre-ignition is the killer of MANY engines, you can only control EGT so well with tuning but at higher performance levels you will always be near that borderline.
prior to the methanol injection install i could see the intercooler heat soak and temps climb with boost, now the temps actually drop at least 10*C when i begin boosting and hang at about ambient when i am pushing the car. my car loves the ****...
Last edited by RotaryEvolution; 12-09-06 at 11:55 PM.
12-09-06, 11:51 PM
#16
I just have trouble trusting methanol injection... I've had my electronically controlled auxilary ports flake out on my nonturbo before, and that is a competely uncritical thing. With my luck the methanol will crap out on me and blow my motor. I'd rather just stick to straight race gas, even though it doesn't cool the intake temps.
12-10-06, 12:13 AM
#18
I'm not too familiar with most AI systems, but what BDC uses is basically a complete fuel injection system in itself, and just as reliable. I looked it over when I was at his house, and it was very impressive. I wouldn't hesitate to trust my motor to it, assuming I had a turbo car.
12-10-06, 12:21 AM
#23
I dunno, I haven't seen anything about it in a while. I knew he was hacing some issues, but it was more related to tuning, I think.
Edit: It looks like something happened to the pump. Here is what he had to say over at TeamFC3S when asked if anyone else had seen the pump problem:
So it looks like it was outside factors that messed it up.
Edit: It looks like something happened to the pump. Here is what he had to say over at TeamFC3S when asked if anyone else had seen the pump problem:
Originally Posted by BDC
Nope. It seems to be the most bulletproof system around. That's why we bought it. I don't mean to give off the impression that this system is unreliable. It's far from that. Honestly, I am the first person in three years to botch one of these Alkycontrol pumps and I believe it happened due to the combination of alcohol fuel lube and a bit of leaded race fuel that made its way into the first jug.
Last edited by Sideways7; 12-10-06 at 12:29 AM.
12-10-06, 12:34 AM
#24
yea, i'm not worried about pump failure. i keep my wideband in my car so if the AFRs start to lean out i know i am missing fuel or AI so i hope i can back off before it's too late but really i don't expect a high HP motor to last forever and running race fuel on the street is just impractical.
12-10-06, 12:36 AM
#25
Getting power with race gas is about as pointless as running nitrous, at least to me. If I can't routinely use it on the street, its of no use to me. I don't want a dyno queen that belts out high power on race gas, I want something that runs reliably 24/7 on the street.