Actual Temperature Difference of EGT in Manifold VS Downpipe
 

Does anyone actually have a real life experience or solid answer as to how much of a temperature difference there is from putting the probe in the downpipe? I ahve my probe RIGHT after the turbo in the downpipe due to lack of space on my manifold. and the highest I've seen it is about 10000F but that was at about 5000RPM and 3/4 throttle in boost in 3rd. I'm sure it would go up alot more in boost WOT. That's what worries me. I read somewhere taht it can be as off as 600F. if that's tue. I would be around 16000F if i had it in the manifold. that's way hot... and thats not even at full WOT yet since I only hit 10000F 3/4 at 5000RPM in 3rd. My wideband arrives in a few days but I just wnt to see where I am sitting at right now. base timnig is at 16 degrees so I dun really want to advance it much more.


Modified by Tchleung at 7:27 PM 10/10/2004

TTT

I would like to know this also.

Re: (BB6-213)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BB6-213 &raquo;</TD></TR><TR><TD CLASS="quote">I would like to know this also.</TD></TR></TABLE>

Re: (BB6-213)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BB6-213 &raquo;</TD></TR><TR><TD CLASS="quote">I would like to know this also.</TD></TR></TABLE>

Me three.

Re: (tegunderpressure)
 

I think it is more like 200-300 degrees... although have no data to back that up sorry.

Re: (twkdCD595)
 

Here is a link for you about placement of the egt. They state that many times over they have found about a 100degree difference.
http://www.evans-tuning.com/vi...#6110

Re: (johnmay19)
 

Where's the link?

Re: (NightRider-gsR)
 

Sorry forgot to put it in, edited post.

they only stated that once. Everyone on every message board generlaly says, "Yeah it reads lower" I just was hopngi tog et some ahrd facts from multiple people hehe.

Re: (Tchleung)
 

Well dc2r714 has been around many cars that jeff has tuned. So I know he has seen them in both places. So that would be why he comments they have found a 100degree difference several times.

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (Tchleung)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tchleung &raquo;</TD></TR><TR><TD CLASS="quote">I ahve my probe RIGHT after the turbo in the downpipe due to lack of space on my manifold. and the highest I've seen it is about 10000F but that was at about 5000RPM and 3/4 throttle in boost in 3rd. I'm sure it would go up alot more in boost WOT. That's what worries me. I read somewhere taht it can be as off as 600F. if that's tue. I would be around 16000F if i had it in the manifold. that's way hot... and thats not even at full WOT yet since I only hit 10000F 3/4 at 5000RPM in 3rd. My wideband arrives in a few days but I just wnt to see where I am sitting at right now. base timnig is at 16 degrees so I dun really want to advance it much more.

</TD></TR></TABLE>

What fuel management do you have? AFC hack/Hondata/AEM?

Also, depending on your setup, I don't think you're able to lose 600F between the manifold, turbo, and DP. The "ONLY" way to know for sure is to tap a secondary EGT into the manifold somewhere. But seeing as you don't have any room, just check your ignition timing and fuel maps. Keep the A/F on the rich side and a conservative timing and you should be okay.

Re: (johnmay19)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by johnmay19 &raquo;</TD></TR><TR><TD CLASS="quote">Well dc2r714 has been around many cars that jeff has tuned. So I know he has seen them in both places. So that would be why he comments they have found a 100degree difference several times.
</TD></TR></TABLE>

Ohh okay that's cool then thanks! :D

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (Finest)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Finest &raquo;</TD></TR><TR><TD CLASS="quote">

What fuel management do you have? AFC hack/Hondata/AEM?</TD></TR></TABLE>

For this temporary motor it is just a b16 with afc hack and custom ecu chip to counter the igntion timngi to return it back to stock timing(well, very clseo to it atleast) I ahve hondata, but that is for my real project. :D

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (Tchleung)
 

what should optimal EGT be around ?

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (project dc2)
 

There is no set temp because every car is different. Best way to find yours is when being tuned. Check the temp under WOT, with the Afr at your desired point. Then you will have a base temp to work off of. But 1200-1300 is a rough idea.

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (johnmay19)
 

reviving-- see i do search!!! lol

my current setup has the EGT probe in the manifold, but i just ordered a new manifold and DP for my new turbo setup-

the DP is used and already is tapped for the EGT- but my inline pro mani will be NEW
should i tap my manifold for that 100-300 degree difference??

I am using hondata and will be tuning it using a wideband O2 by a professional on the dyno, as well there is also an O2 bung lower down on the DP

My inclination is to leave the inline pro alone and keep the EGT in the DP as long as im tuned and only use it for backup. its not the most accurate way of A/F but closer than a 600 wideband. correct me please

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (95gsrturbo)
 

if you think about it, putting the EGT in the downpipe is pointless, if your interessed in the actual EGT. 'cause you don't know how much energy\temp is lost in the turbo. and if temperatures are starting to go up it could just be the turbo that's getting old. (not as efficient, therefor not able to absorb as much energy\heat) just changing the boost pressure should change the amount of energy\heat that is absorbed in the turbo, so you'll never know the actual temp.

make sense?

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (mh)
 

NO- it doesnt - EGT are based on several factors
mainly the fact that as the fuel mixture gets more lean the temps get hotter while when the mixture is rich - egt is cooler

increaseing boost pressure will increase temps at the same fuel mixture because you are leaning the mixture

so in the DP or in the manifold will still be able to tell temp its just that one is farther from the actual cylinder head than the other--

as well many people have stated that the probe in the DP will be 1-300 degrees cooler-- how so?? YEs the probe is farther down and gasses have had an instant to cool as well they have passed thru the turbo - but keep in mind they have passed the HOT side of the turbo, which is typically hotter than the exhaust manifold,

therefore temps should be equal due to the nature of the exhaust housing on the turbine.

.

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (95gsrturbo)
 

heat is energy, energy (both, heat and air pressure\flow) drives the turbine of the turbo. there is a temperature loss bacause the heat, transforms to rotating energy.
I'm not saing it's as much as 300degF, but it is lower than the temp in the manifold.

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (mh)
 

in your last post you said its pointless in the dp now you say its only a 300 deg diff?
if im tuning with a wideband o2, whats the diff

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (95gsrturbo)
 

I'm don't know how big de diff is, that's the point, there is no sett diff, it all depends on how much heat is lost in the turbo therfor EGT in the DP is not an option if your looking for actual EGT numbers.

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (mh)
 

I beg to differ, EGT is exhaust gas temperature, where you measure from can tell you how much your system is cooling as gases move thru.

however, i would be hard pressed to say there is a big diff in before and after the turbo, now if you are talking in the DP near the cat that would be a BIG diff in heat loss, but not right at the exhaust hougin of the turbo???

and how much of a drop will we see is the main Q, 100, 200, 300 deg and is this 300 deg in F or C???

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (95gsrturbo)
 

up

Re: Actual Temperature Difference of EGT in Manifold VS Downpipe (95gsrturbo)
 

Actually an overly rich mixture will cause high EGT's because the extra fuel can ignite in the exhaust manifold.