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Old 04-08-2005, 07:54 PM   #1
happasaiyan
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Default 1640F EGT @ top of 5th (120+?)

i denied a flyby today from an e500 and went from 3-7k in 5th gear...when i looked at the peak value, i saw it hit 1640F. the most ive ever seen in 4th is 1600F. i did lean out my map a tad yesterday, and stupid me, i didnt log today because i was sure i wasnt going to be able to do anything because of all the traffic. my luck, there was a HUGE opening, and the e500 playing with me. i cant remember the last time ive done a 5th gear run, so its not too bad since its not a common occurance.

how bad is 1640F?
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Old 04-08-2005, 07:57 PM   #2
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I don't know how bad it is, but I have hit it myself a few times in 5th. So hopefully you'll get your answer so I can get the same answer.
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Old 04-08-2005, 08:46 PM   #3
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Slow down there bud on the public roads. Anyways, anything over 1600 for sustained periods of time is not good on the engine and could cause seisure. If you hit it for a short period of time no worries. I would richen your fuel curve a bit though, or get a professional to look at your tune.

Remember, the temperature probe heats up much faster then the engine components...
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Old 04-08-2005, 09:37 PM   #4
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Quote:
Originally Posted by timman_24
Slow down there bud on the public roads. Anyways, anything over 1600 for sustained periods of time is not good on the engine and could cause seisure. If you hit it for a short period of time no worries. I would richen your fuel curve a bit though, or get a professional to look at your tune.

Remember, the temperature probe heats up much faster then the engine components...
1) i dont need a lecture on speeding. thats not the point of the post.
2) i know over 1600F for extended periods of time is not good.

maybe you didnt read this:
Quote:
Originally Posted by me
i cant remember the last time ive done a 5th gear run, so its not too bad since its not a common occurance.
3) my fuel curve is still fairly rich at 10.9 at redline...and i dont need a pro to look at my tune...ive tuned my car from day one in its current form, and have ran 12k miles like this without issue. it makes good power, and thus far has shown to be reliable.

maybe i shouldve clarified my post and just asked what other people are seeing for EGTs at the top of 5th...as i wasnt posting to be taught anything...
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Old 04-08-2005, 09:58 PM   #5
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....it might be a good idea to look at your timing at the top.....it may need a nudge...
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Old 04-08-2005, 10:20 PM   #6
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Quote:
Originally Posted by Uncle Scotty
....it might be a good idea to look at your timing at the top.....it may need a nudge...
heh...yeah...DOWN.

i dont know if it was just me being in 5th and it being a little bit colder today or what, but my CEL light was a little more active today. never more than 1 knock event (otherwise i would feel the timing being retarded)...

...time to throw some more torco in next tank. this gas has teh suck.
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Old 04-09-2005, 12:19 AM   #7
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Well,

With a 3 and 4th gear pull to redline I will hit 1625. I have not run 5th to redline and dont want to be thrown in jail.

04STI tuned Accessport+tuner. Greddy EGT mounted in the driver side exhaust manifold. LM-1 11.1/1 a/f that tapers to 10.9/1. We have crap gas here in Oregon and could use some additional timing in my maps. We will see.

Hope this helps.
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Old 04-09-2005, 08:32 AM   #8
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Wow. Awful defensive-agressive for someone just trying to help up there.

Anyway, you didn't say where your EGT probe is tapped.
Quote:
heh...yeah...DOWN
You sure about that?
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Old 04-09-2005, 08:54 AM   #9
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We've all heard people gripe about going fast on public roads already. If we didn't, the rest of the forums outside of the "general" and "members gallery" catagory would never get posted in. And we all know fast driving accusations are a 'throw the first stone' deal.

And posting "You sure about that?" isn't "someone just trying to help up there" either. (I'd insert a goofy wink or something here, you know, to avoid the sting, but we are all adults here.)

So...

Throw us some theory Guru. I'm still learning about tuning. Getting a lot better, but when it comes to all the dynamics like super high RPM egts and the effects of more fuel or less timing NOT being the safer route, then I'd like to know why. I'm guessing by your response that he should add timing. But without reason and discussion, that is a leap of faith. And as helpful as I've found nasioc, I by no means have faith in any, single post I've read.

If you'd been responding to a noob, I'd also take it with fewer grains of salt, but Happas(can never spell it without scrolling down so...) has worked with the stuff a lot longer than I, and has a good rep as far as I know.

So why add timing to cool EGTs at high RPM? Discuss.
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Old 04-09-2005, 08:58 AM   #10
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I'm no tuning expert here, but adding timing lowers EGTs. If he isn't knocking up high and he has enough fuel, then adding timing could be the answer to lower the EGT.
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Old 04-09-2005, 09:05 AM   #11
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Quote:
But without reason and discussion, that is a leap of faith. And as helpful as I've found nasioc, I by no means have faith in any, single post I've read.
As well you shouldn't, which is why you and the original poster should consider "You sure about that?" and make sure you understand what your reasoning is for the idea. I consider that a very helpful comment.

And just as "we all know" driving fast accusations are a throw the first stone deal, "we all know" that if you want a productive thread, nobody needs to hear about the circumstances of your highway pulls and doing 120+ on public roads, etc... unless it is directly relevant to the problem being reported.

"I hit 1640F at redline, is that too high? Thanks." works pretty well.

My "guru" title means jack-all.
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Old 04-09-2005, 10:05 AM   #12
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Fifth gear in an sti is kinda like fourth in a wrx right? Either way, I never see higher then 1560F(even in 5th gear at over blah-mph in my wrx), and at that point I start getting scared. I think jblaine is trying to tell happ to turn his boost down, and maybe also richen up the a/f ratio a bit. He's running an fp green at 22+psi with timing that would make most tuners laugh. Something like 14 degrees at 5000rpm and 16 and 6000. I know this thread isn't titled "what should I do to lower my egt's", but maybe it should be?

On an 8.25 compression engine, the ideal boost(according to some people, not me in particular) for 93 octane(if there is such thing) is something like 17psi........blah. Imo makin threads like "more octane = knock" or askin questions like "how bad is 1640F" is askin people around here to tell you to turn the boost down and use more advanced timing. Kinda like sayin you're goin 120mhp is askin people to tell you to slow your ass down or you're gonna kill someone when your engine seizes or a tire blows. Course some people might just say, "are you sure about that?". Sorry for the gripe.... What I ment was 1640F sounds really high to me.

peace
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Old 04-09-2005, 12:41 PM   #13
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Depending on which engine management setup and boost controller you're running there are different ways to attack this problem. Retarding the timing a degree may keep you from knocking while your EGTs are high, but richening the mix slightly to cool things down would probably be a better way to handle this issue. Some engine management systems have comprehensive options for temperature correction of fueling. A temperature probe placed post IC could be used to add fuel when the intake charge gets too hot.

Alternatively, with some EBCs such as the AVC-R you can adjust gear dependent boost to lower boost in your final gear a touch. By running your turbo and intercooler under conditions which they are more efficient, EGTs can be held in check during a top end run without fuel/timing adjustment.

What form of management and boost control are you using?

-Mike

Last edited by Innovative Tuning; 04-09-2005 at 12:48 PM.
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Old 04-09-2005, 01:00 PM   #14
happasaiyan
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Quote:
Originally Posted by hippy
Fifth gear in an sti is kinda like fourth in a wrx right? Either way, I never see higher then 1560F(even in 5th gear at over blah-mph in my wrx), and at that point I start getting scared. I think jblaine is trying to tell happ to turn his boost down, and maybe also richen up the a/f ratio a bit. He's running an fp green at 22+psi with timing that would make most tuners laugh. Something like 14 degrees at 5000rpm and 16 and 6000. I know this thread isn't titled "what should I do to lower my egt's", but maybe it should be?
i think what would make most tuners laugh is how much our 93 octane gas completely sucks. have you seen the timing curve that jorge has to run? pretty similar to mine. we are both running chicagoland gas. we both have the same engine, with similar turbos (his is actually more efficient with a higher flowing turbine housing)...so i have to run even less timing than him. i never get severe knock (txs tuner with bosch sensor lights up often, but never more than 1 count)...so technically, i should even retard timing more. and btw, i get these knock counts anywhere from 5750-redline. so saying that my 16* of ignition advance at 6000 would make a tuner laugh is arguable if they were actually driving my car. EGTs are not ridiculous in 4th gear (90% of the time, i see 1560F at redline in 4th), so the fuel curve and ignition curve i am running are not completely off base. and just an FYI since you think you know my setup, i am NOT running an FP green. i am running a PnP'd SR50 with ~22psi in the midrange and 19psi at redline. i AM running less boost at redline, so dont make it sound like i am doing something ridiculous like running 22psi at redline on 93 octane. i agree, i should richen it up a bit at redline. it has been really warm the past few days, so i started making a summer map. that map ran a bit rich at 10.8:1 at redline, so i removed a tad of fuel to bring it to 10.9:1 at redline. then today it got 30* colder than the day before. so chances are i was running 11.0:1 or so...possibly 10.9 still, i dont know for sure, since i wasnt logging at that time.
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Old 04-09-2005, 01:03 PM   #15
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Quote:
Originally Posted by Innovative Tuning
Depending on which engine management setup and boost controller you're running there are different ways to attack this problem. Retarding the timing a degree may keep you from knocking while your EGTs are high, but richening the mix slightly to cool things down would probably be a better way to handle this issue. Some engine management systems have comprehensive options for temperature correction of fueling. A temperature probe placed post IC could be used to add fuel when the intake charge gets too hot.

Alternatively, with some EBCs such as the AVC-R you can adjust gear dependent boost to lower boost in your final gear a touch. By running your turbo and intercooler under conditions which they are more efficient, EGTs can be held in check during a top end run without fuel/timing adjustment.

What form of management and boost control are you using?

-Mike
UTEC + UTEC boost control (controlling a perrin ebcs). please note, my boost curve is ~22-23 midrange tapering to 19psi at redline...not 22psi flat out like hippy believes.
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Old 04-09-2005, 03:10 PM   #16
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Quote:
Originally Posted by Innovative Tuning
Retarding the timing a degree may keep you from knocking while your EGTs are high, but richening the mix slightly to cool things down would probably be a better way to handle this issue.
Retarding the timing will just raise the EGT a little more. Over-fuelling can sometimes do the same thing depending on how slow his burn angles are. As long as you're not richer than about 10.3:1 or so, fuelling is probably the best of these two options. Though lowering boost at top end would be better still.

Adrian~
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Old 04-09-2005, 04:08 PM   #17
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Quote:
Originally Posted by happasaiyan
UTEC + UTEC boost control (controlling a perrin ebcs). please note, my boost curve is ~22-23 midrange tapering to 19psi at redline...not 22psi flat out like hippy believes.
In that case you don't have gear/speed specific boost and the IAT for mapping is taken at the MAF so it won't show the increase in intake (at manifold) charge temp as the sensor is pre-turbo and at high speeds there is plenty of air cooling the air intake. That temperature correction feature can be very usefull in other conditions, but it probably won't help here. You're left with fuel and timing adjustments for all gears/speeds on your existing hardware.

As a disclaimer, without being able to make tuning adjustments for high end runs, you will continue to see higher EGTs than you do in lower gears. In your case you have to sacrifice some power across the board to provide a greater margin of safety on the top end runs.

In this case, as I said before, I'd fatten up your fueling enough to keep EGTs below your target ceiling. In some cases adding fuel in the midrange can correct a high rpm high cylinder temp issue as less heat is carried through the pull. Keep that in mind while making your adjustments. I've seen people richen up the top end excessively instead of making much smaller adjustments throughout the power band to achieve the same amount of cooling.

-Mike
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Old 04-09-2005, 10:48 PM   #18
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1640 is high, but not holy isht high. if it's short term, no worries. if you want to keep pulling like that, richen it up three tenths.

jm2c
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Old 04-09-2005, 11:31 PM   #19
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i just started with my UTEC stage 2 base map in the sti and i am planted at 800c while cruising, when i wind out 4th completely i hit 875c in the higher rpms. seems kinda high to me, but if i'm crusing around at 800c then it doesn't seem all that far-fetched...

i'm just getting started with these maps though but my timing from the logs looks spot on (within 1-2 ticks).

never topped out 5th, gotta get 4th finished first
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Old 04-10-2005, 10:58 AM   #20
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Do a compression test/leakdown test if you're concerned,but in all likelyhood your car is fine. I'm sure happasaiyan knows how to tune this out! He just needs more 5th gear pulls to 120. This PC Posting "unwritten rules" is completely BS. Some of the people on these forums need to be bitch slapped.
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Old 04-10-2005, 11:36 PM   #21
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What was the temp outside? I know I will be 1600+ if it's below 40 outside. Above 70 I won't go past 1550.
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