Dual EGTs
 

I'm looking at getting a dual EGT gauge setup. I wouldn't mind datalogging either, but for now I'll be happy with just gauges. I've seen the setup by Pineapple Racing...

http://www.pineappleracing.com/index.asp?PageAction=VIEWPROD&ProdID=24

...but is there any reason not to go with this setup instead?

http://www.pegasusautoracing.com/productdetails.asp?RecID=4861

I don't know what all the Pineapple Racing setup comes with, but it looks like the one from Pegasus comes with everything I need, but I don't know cause I've never installed this before. Maybe I'll want probes that react faster or something, but I don't know for sure. I don't even know what exactly each of these comes with as far as quality of probe. I also know of the SPAL gauges...

http://www.pegasusautoracing.com/productdetails.asp?RecID=2942

But $500 is a little out of my price range right now, and I don't need it to be digital anyway. I saw something at the last SEMA that would work too I think, but I don't remember the name of the company now. From what I remember the gauge itself is a datalogger.

Any ideas?

Honestly... didn't I just go through this? There's a few ways you can go. The pineapple racing one does come with everything you need and is very high quality. Also pay particular attention to the scale of your EGT. The pegasus auto racing one you listed is pretty good but is maxed out at 1800F which is kind of low for my tastes. The pineapple racing one maxes out a little after 2000F which is perfect for a rotary. (Remember under WOT 2000F is not unheard of) This leaves you with some options, so long as you don't have the EGT's that will surpass 1800 you should be fine with either or (thought pineapple is cheaper).

Now if you have the realestate you can get two gauges to actually do this. This is the route I did because I wanted peak/warn functions as well. This way I wouldn't have to look at them 24/7 when driving to see if I'm close to the limit. I could just set the alarm and look at it when something's not running right. For that, I went with two prosport gauges. I found after discount that going that route cost LESS than going with Pineapple. But that's up to you.

my opinion is a gauge is too slow and inaccurate and should only be used as a reference once tunned.

now you said you want dual and datalogging.... HC(howard colman) on the 7club has a great thread on exactly this. dual digital datalogging egt setup for something like 120$ish im planning on going that route just not till i put the single on.... hmmmm better go order the parts as im almost ready to do that.

z


i really need to start doiong theseand bringing a thread over here so we have more tech info>>>>>>

Look again, the cheaper one goes up to 2000* too, that's why I was wondering what the difference was. It even says right there on the page it goes to 2000* haha. And the Pineapple one goes up to 2000* and stops as well. And I don't really have the real estate, that's why I want to fit it into 1 gauge. I have 5 STRI gauges and 1 wideband already, I'm already going to have to add a spot to put this one haha.

Yeah I've been reading the hell out of MANY of Howard's threads, he's very knowledgeable. My only problem is from what I've gathered on his datalog setup so far, it's kinda out of my league. I fear I'd mess something up trying to do it like him. And I'd like to at least go the gauge route first and add the datalog later, and take the datalog part slowly so I do it right the first time. Know what I mean?

ya i get it at least you know where your limit is unlike most people. seems your on the right track for whats gonna work for you.

z

For logging and speed, Ludwig has recommended these probes to me:

http://tscsensors.com/egtep0720001ssnexhau.html

They also list another interesting one:

http://tscsensors.com/egtip0720000ssnindividu.html


You'll need a convertor of some type though to allow the millivolts of the TC to be translated into a 0-5v signal for an ECU or logger to read. You basically have to choose between a guage, or logging though since there's no way to split the signal off of one probe to do both jobs.

The pineapple unit is good, I never had any real problems with it. I'm running two prosport EGT's at the moment though which are working well. Can't comment on their speed vs. a "true exposed" tip TC (Prosport TC's **appear** to be exposed, or what some companies sell as exposed) but they are faster then the pineapple unit, that is for sure.

Could probably do an Op-Amp circuit (which I plan on doing with my wideband), or running a conversion box to 0-5v then to an op-amp to split the signal.

The PLX units are $120 each with the signal conditioning box, but if you need the gauge it is another $250. The gauge supports up to four boxes.
The EGTs can be just datalogged without a gauge and shown as a MAP WATCH on your computer screen.
Barry

http://i287.photobucket.com/albums/l...5-2586_IMG.jpg

http://i287.photobucket.com/albums/l...6-2664_IMG.jpg

Alright cool, I'll check those out. Thanks!

Yeah, PLX was the other place I was thinking of, I couldn't think of the name. Hmmm.

preturbo EGTs are extremely helpful for setting your timing curve. post turbo EGTs are a waste of time and effort.

EGTs need to be digital and logged. as an example i had been doing a number of dyno runs and focusing on 1550-1600 at one bar on up.

i looked at my 0 to one bar EGTs and found them to be in the 1200s.... even though my AFRs were fine.

we added timing in that area and brought the EGTs up to the high 1400s and picked up a bunch of midrange... all the while the AFRs did not change.

your really would never been able to do that watching a gauge... BTW, i have had some experience w Greddy EGT gauges (2) and found them to be slow acting and not accurate. i literally gave them away for shipping.

fixturing a proper EGT setup is neither difficult nor expensive but you do need a Power FC/Datalogit or something similar.

howard coleman

I was looking at pineapple too but like Howard Coleman says for proper tuning you need to be able to log the pre-turbo temps. Also, Mazda claims that engine damage is likely with EGTs over 1500 degrees, can anyone confirm that?

I have never ever even heard that before. Got a link or a paper about it?

yeah, it WAS part of the Mazdaspeed knowledge base:
http://www.mazdaspeedkb.com/activekb/index.php

But they removed their articles.....so no, that's why I was looking for confirmation.

Yeah Sean at A-Spec is putting a couple bungs in for me just after the exhaust flange, and your threads on the other forum is actually why I'm doing it haha. I never really thought about monitoring EGTs before, much less datalogging them. I have a PFC and datalogit at the moment, but I'm not real clear on everything needed to datalog. Is there some way I can hook that up through the datalogit? I'll read up on your thread again before I do the job. Thanks HC!

Uh oh, I hope that's not true.

EGT thermocouple wire hooks to converter module. module generates 0-5 V readings which you wire to the Auxiliary side of your datalogit just like your wideband and other inputs. you then get the conversion table and input two voltages and their respective F temperatures and go logging. very basic and extremely helpful. i log fuel pressure, exhaust back pressure, two EGTs and AFR. since you have the Datalogit, your cost is around $50 for a Teamrip thermocouple and less than $50 for the converter and some wire.

preturbo EGT should be 1550 to 1625

hc

Awesome, thanks Howard!

I have gauges for fuel press and some others, but it never crossed my mind to datalog them.

My EGTs go very hot at the top of a run.... 1825ºF OR 1000ºC. It scares me to death!

I have tried mediating the temps with 50/50 Meth and 100% water, have also tried advancing and retarding the ignition with very little improvement if any.

This is what a logged run looks like on datalogit. It is hard to make out the pink and yellow traces of the EGT. Sorry.

This time extra knowledge is frightening! Any ideas?

Barry

http://i287.photobucket.com/albums/l...bordes/egt.jpg

Only thing I can offer for your question barry is support that I also have very high EGT's in the upper RPM ranges :)

I can crest around 975C by redline (8000rpm on my FC block) at 20psi (T04-R, 67mm compressor.....1.00a/r divided rear)

I've also tried a number of different things to reduce the temps, but I'm starting to think that perhaps back pressure is the real culprit for the high temps...unfortunately I do not yet have this parameter monitored in my car :(

The largest difference between my car, yours, and howards, is the fact that he has nearly DOUBLE the turbine area, and exhaust area and volume we do. And his EGT's are reportedly solid and *much* lower then what you and I have found.

Classicauto, which manifold are you using. Didn't you switch from a cast to a tube type? If so, did the temps drop lower assuming slightly lower backpressure?

Maybe a 4" downpipe would also help drop backpressure.

I am using a RB 3" single tip catback. People speculate on these having high backpressure.

Barry

Barry, yes I moved from an FC greddy cast (collected, an majorly unequal runner length) to a-spec's FC manifold. It would be considered medium length IMO. Runners fully divided, length about 9".

The EGT's have gotten slightly lower on the setup. A decent back to back test was on the very same engine (basically stock port S5 TII) done minus the turbo change....

Using the cast with the aspec GT3574 .84 T4 housing, and same WI nozzle, EGT's could touch just over 1000C by redline. (@20psi)

Aspec manifold, T04-R 1.00 T4 housing and same WI nozzle, EGT's stay under 1000C (usually 975C highest) by redline.(@20psi) (also note, that this setup with larger turbine housing and turbo was as responsive as the old on the log type mani!!)

They have also stayed more equal during boost between front and rear with the new mani.

Exhaust on both setups was custom 3" piping from turbo splitting to dual 3" infront of the axle.

I've also thought of moving to 4" from the turbo down to the 3" split. Turblown has told me the extra volume is really helpful on a p-trim turbine (what my t04-R has)

I doubt I'll make that change this year though, because I'd like to be able to log EBP, and make the change on the dyno for a direct comparison.

Classic,
It would be interesting to see your temps with larger AR turbine housings, say .96, 1.0, and 1.15.

I really think that our high EGT are a port overlap problem. The exhaust gases are contaminating the incoming charge causing a slower burn rate.

The solution then might be to redesign the exhaust port to slow gas reversion.

Barry

Interesting thought!

Whats your port configuration barry? The engine I ran on the two setups outlined above is a stock port...for the most part. I cleaned up some casting and added a little shape to the bowl, and brought the intakes UP ~2mm on primary and secondary.
Exhaust was slightly widened, and brought DOWN ~2mm.

Stock overlap (S5 TII block)

Also, on your point of running different size turbine housings, note that I did step up from .84 on the old turbo to 1.00 on the T04-R :)

EDIT: That stock port engine is currrently being "refreshed" and I'm thinking of going a little larger all around on the exhaust to promote better evacuation of those hot gases, thoughts on that?

Oops, I missed the change to 1.0 from .86 on the turbine housing. I would have thought that going larger on the AR and dropping the cast manifold would have dropped the EGTs more.

My ports are from a Judge ITO template.

My thought on the exhaust port is to smooth the bottom and sides for more flow but on the upper/closing side to duplicate the stock Mazda sharp step and possibly adding a second step at the beginning of the sleeve to help discourage reversion.

If you notice F1 headers (and others) use reversion cones every few inches on the exhaust headers. An idea we need to incorporate.

Barry

Hmm, you're good at turning the hamster wheel in my head barry.

Most of what I know about anti reversion sleeves or chambers is in regards to non turbo exhausts and design. Do you have any information about how it relates (or if it even differs) to a turbo application?

The simplest design which I would think fairly easy to include in a mani. would be these:

http://www.patentgenius.com/image/6336471-3.html

I'd imagine them directly placed on manifold flange?

Also, on the A/R change I made, the only other variable that I can think which would have made the change have less impact on EGT's would be because the .84 was on the aspec tubo which uses a - according to aspec - more rotary suited (larger I guess) wheel from the GT line, where as the t04-R has the trusty, but very old design, p-trim.

But I'd hope for a greater decrease as well :(

From the TCS sensors website mentioned on page 1:

"Analog Retransmission Output: User Selectable; 4 to 20 mA, 0 to 20 mA (1 to 5 VDC or 0 to 5 VDC using included 250 ohm resistor)"