EGT's for a Rotary

[Boswoj]

I've heard a lot of discussion on teh relative accuracy, or inaccuracy, of commonly available EGT probes and gauges. What kind of gauge and probe do you guys use and who do you get it from?

Thanks - Boswoj

[sburkett]

I bought mine from Mazdatrix. Dual probe/dual needle gauge, reads to 1800 degrees, don't remember the price, but it seemed reasonable at the time. I don't know how accurate it is, but Dave Lemon (owner) races an EP RX-7, and I trust him.

www.mazdatrix.com (http://www.mazdatrix.com)

Steven

[Jim Susko]

I use Westach products. For a readout, I use their dual analog dash gage. Probe accuracy is not the issue with probes, it is response time. To get response time, I am trying their smaller probe (about 3/16 inch diameter) with an unshielded tip. I prefer the type that straps on with a hose clamp. The ferrule clamp style usually corrodes in place and are destroyed when you remove them. Ask for part number 712-2DWKE EGT.

You didn't ask the most important question: You should run about 1650 degrees for best power.

Jim Susko
G-Force Engineering

[Mazdatrix]

(Haven't had time to look at this board is a while -- )
The dual Westech gauges only go to 1700, and I sometimes run my engines at 1725-1750. I had a batch of dual gauges "custom" made for us that go to 1900. (Have never had the time to put them on the website (www.mazdatrix.com/ - shameless plug), nor in the catalog)
If anyone is interested:
GAUGE EGT DUAL 100-1900 DEG DUAL 2DC2-6 $99.75

Probes are: (need 2)
GAUGE EGT 1900 DEGREE PROBE 712-2DWK $38.93

These are the "hose clamp" type, which I prefer. The wires are them are normally just long enough to go through the passenger foot well, and lay nicely to put the gauge in front of the driver.

Dave Lemon --
'90 E/P RX7 Convertible (locked up the Southern Pacific Division Championship a few weeks ago - getting ready to leave for the June Sprints soon)
'85 Pro7 CalClub Champion 2002
"'85" Tube-frame bridgeport supercharged nitrous 20B (3-rotor) drag car (been sitting for 2 years because it's boring compared to road racing)
Sorry for sticking all that in there, but I have not posted here in a long time.

[ddewhurst]

Dave, congrats on step one & good luck with step two.

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Have Fun ;)
David Dewhurst
CenDiv Milwaukee Region
Spec-7 #14

[Mazdatrix]

Thank you -- it's been a very busy year so far.
Are you going to the Sprints ?? Watching? Driving?

Dave Lemon --

[ddewhurst]

Dave, I have a son getting married on Sat. Crewed with Erik Skirmants last year & he sold the car. Hopefully a spectator on Sunday. It's always fun to meet some computer faces. http://Forums.ImprovedTouring.com/it/smile.gif

Have Fun http://Forums.ImprovedTouring.com/it/wink.gif
David

[Festus E. Simkins]

Sorry to disagree with Mazdatrix but Westach sells a 2000 degree dual ETG. I bought one 2 years ago from them. I don't remember the price but Mazdatrix's price seems about right.

Love the Mazdatrix E-prod car. Absolutely beautiful work. Very fast too.

Drive well.

[Jim Susko]

How can you possibly make power at 1750 degrees? We're not talking an IT motor here, are we?

Jim Susko
G-Force Engineering

[Mazdatrix]

Jim - Well, yeah, sorta, sometimes --
I didn't say I LIKED running them that high.
Probe placement also changes the temp range - I put them 12-18" from the motor. Any closer and I burn a lot of probes off, and I don't like running further than that.

When "tuning" the engines I DO like to see about how far, and how fast they might go above 1700.

Looking back through some of my dyno sheets for my Pro7 engines (basically ITA 12A w/o headers), yes, they will make power above 1700. It's always at the top end of the revs (8k+), and I tend to hold them there for a bit to look at all the gauges and write everything down (my dyno is OLD, with manual data writing).

Can't be all bad - out here in CalClub, our Pro7 engines won almost all the races in 2001, ALL of them in 2002, and ALL of them so far in 2003. I think we have the lap record at all the Buttonwillow configurations, + Willow and Fontana.

The E/P 13B (52mm IDA Weber street port) dialed in about 1675 - 1725 at 10,000.

I remember (long time ago) my 13B peripheral port injected Trans-Am RX7 (1750 pounds w/o me) - (probes 6" from engine) coming DOWN off the 1800 degree peg once per lap along Shoreline Drive at Long Beach.

Dave Lemon --

[Mazdatrix]

Btw - if any of you have never seen Rotary headers on a dyno at 1700+ degrees you ought to love one of the movies I have on my website --
http://mazdatrixmovies.com/ep021602.mpg
(9.3 megs, 3.5 minutes, mpeg)

It's my E/P 13B at 7, 8, 9, 9.5, and 10k. The white spot in the middle of the screen IS the headers.

[lateapex911]

Dave, I'm glad you're here! A quick question, a bit off topic, I'm sorry....

What is a realistic number for rear wheel horsepower in an IT 12a??

Assuming new parts, good assembly, but LEGAL!

And also assuming LSD rear, 4.88s and Hoosiers at 42psi?

I'd love to get an expert, unbiased opinion instead of the usual conjecture. Thanks!



------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[Mazdatrix]

Wish I could tell you, but I have never had one on a chassis dyno.

[lateapex911]

hmmmmm...ok, how about a flywheel number?? http://Forums.ImprovedTouring.com/it/wink.gif

Thanks!

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[Mazdatrix]

Never had a customer want an ITA engine built AND dynoed. Extrapolating from Pro7 engines I'd guess about 155-160 (maybe 165?) at the flywheel.

[noresull]

Uhm, David, does that thing blow at around the 2 minute mark or is that just what it sounds like when you close the throttle?

[tdw6974]

[ I had a batch of dual gauges "custom" made for us that go to 1900. (Have never had the time to put them on the website (www.mazdatrix.com/ - shameless plug), nor in the catalog)
If anyone is interested:
GAUGE EGT DUAL 100-1900 DEG DUAL 2DC2-6 $99.75

Probes are: (need 2)
GAUGE EGT 1900 DEGREE PROBE 712-2DWK $38.93

These are the "hose clamp" type, which I prefer. The wires are them are normally just long enough to go through the passenger foot well, and lay nicely to put the gauge in front of the driver.

Dave Lemon --
'90 E/P RX7 Convertible (locked up the Southern Pacific Division Championship a few weeks ago - getting ready to leave for the June Sprints soon)
'85 Pro7 CalClub Champion 2002
"'85" Tube-frame bridgeport supercharged nitrous 20B (3-rotor) drag car (been sitting for 2 years because it's boring compared to road racing)
Sorry for sticking all that in there, but I have not posted here in a long time.[/B][/QUOTE]
Dave are these still avaiable? I searched website with no luck


------------------
Tom Weaver: Logistics & Technical Support Manager IE truck driver for 1980 RX-7 ITA #63
"Hemi Haulin' Rotary" Bill Weaver Driver- 2004 NYSRRC John Chave Award

[ddewhurst]

Tom, if Dave is out of the items he mentioned I bought the same thing (1900* for 1 st gen) from Westach (Westberg Mfg. Inc.) last summer for about the same cost. Type Westach in a search for the site address.

Have Fun http://ITForum.ImprovedTouring.com/wink.gif
David

[Boswoj]

Wow - I see that I started this thread TWO YEARS AGO!!!! I ended up getting Digitrons sweet little digital EGT box and it works great. It has other cool features like some amount of playback, a tach and lap timer as part of the box so it can even be used as limited data acquisition that is downloadable to laptop. The guy that is selling them at Digiton direct is a real nice and helpful guy as well. It was a while ago so I'll dig up their contact info and his name and try to post them.

[paulydee]

I just came across an ad for Stewart Warner Performance. They have an EGT gauge that reads from 600-2200 degrees F. I realize that it is a single gauge vs. the dual setups mentioned above. I just thought I would mention it on this thread.

[cpa7man]

This is a great old thread, thanks for resurecting it.

Does anyone know how often probes should be replaced? I've been getting inconsistent results from my EGT's vs my air fuel reading based on my last dyno tests.

ALso seems to me 1650 is a little high, but who am I to argue with Jim or Dave. I was told by other EP racers that 1550 should give max power...I guess I need to lean out a little more.

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Paul Pineider
ITA 05 (Soudiv)

WTB - Used transponder.

[C. Ludwig]

For a given A/F ratio EGT will vary depending on ignition timing. Just because the EGT is low doesn't mean you're lean. The wideband doesn't lie (unless it's malfunctioning http://ITForum.ImprovedTouring.com/smile.gif ). As has been written EGT can be greatly influenced by probe placement. Not only length from the port but the depth of the probe as well. The best senario is to use a wideband, pyrometer, and dyno in conjuntion to extract the maximum power from the engine and to keep it within a safe operating zone.

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Chris Ludwig
08 ITS RX7 CenDiv