EGT help please

[benracin]

I was having some carb issues at the track and the first line out of anyone that was trying to help me was "what does your EGT read"? And yes, I'm a very very bad boy and I don't have one. So I've been doing some internet searching for one and it's kind of hard. I don't have a ton of cash because, like usual, there's lots of other things to buy. Anyone have any recommendations? Sounds like I need the probes for these things as well? I'm pretty lost. The cheapest thing I've found is at: http://www.aircraftspruce.com/catalog/inpa...west3gauges.php (http://www.aircraftspruce.com/catalog/inpages/west3gauges.php)

Thanks for the help. I'm really not sure what I'm shopping for.

Ben
#33, LOL, ITA

[ddewhurst]

Ben, your on the correct track. IMHJ & not from experience you will need gauges capable of reading 1750* which means the ones you posted that read 1700* will not proivide the info you require.

EDIT: Along with the gauge you will need two thermocouples with wire of some length & hose clamps. Ya drill two holes in the header at your motor builders recomendated location. Ya then use the hose clamps to secure the thermocouple probe to the header. Ya need to drill a hole in the hose clamp so that ya can slip the thermocouple thru the hole before inserting the thermocouple in the header.

Someplace some time back I viewed some that were capable of reading something over 1700*. I think it was 1900*.

I don't have them at this point but they are on my list of things to do.

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

ps: Dump the fuel HOG so that you can afford to race.......... My friken Ranger at 18 mpg towing gets the jobe done real nice. & when not towing the thing is so happy it gives me gas back. Now that my man is trash talk. But factual milage while towing. See ya where ever whenever.

[This message has been edited by ddewhurst (edited July 01, 2004).]

[lateapex911]

I got mine from them as well.

An important consideration is that the absolute number is a relative item. In other words, what number do you want, and why?

The best use for them is as a reference. IMHO. I'm no rotary guru, nor an engine builder, but......do some dyno tuning, and record what the readings are when the engine is most productive.* Now, at the track, you can rejet to reacheive those numbers, and of course, the horsepower.

I got mine from aircraft spruce as well. It is a small 2.25 inch size, and came with the probes and wiring. I use the smaller probe size. The guage I have doesn't go up as far as I'd like either, but it doesn't appear that it has a pin to limit it, so....

The setup I got from them included the probes, the wiring and the hoseclmps with the probes already installed.

The header I have came with the bungs welded on, about 10 inches or so from the port. I assume that going a bit further would result in slightly cooler gasses....

I would call them and discuss the situation. They have probes on the site as well...here:
http://www.aircraftspruce.com/catalog/inpa...ges/westegt.php (http://www.aircraftspruce.com/catalog/inpages/westegt.php)

I have a dyno session planned for the 4th, I will report temps at that time. Curent temps are meaningless, but are in the 1500 plus range at 7000 rpm. (kinda busy driving to take notes!)

* OK, the dyno isn't going to happen for you???? That's cool, another method is to tune on the track. Test days are good for this. Begin by finding a straight, then selecting a gear that you can stay in up through the range. Lets say 4th, Now, as you are on the straight, start at 3500 RPM For example, and go full throttle. At 4K, start a stopwatch, then stop it at 7K. (You can use different numbers) , but the idea is time the engine, over a given range. On the same peice of track, on the same day, you should be able to repeat those results to a decent degree of repeatability and accuracy. Note the EGTs. Now change the jetting. Repeat...note EGTs. Slower? Go the other way on the jets, note the EGTs....continue, until you get the best performance....run a video if it helps just on the guages...poor mans data aq!

Finally, go to Yawpower.com, and read up on the carbs as a primer. Some think he's the holy grail, others think he's a quack, but there is a lot of good info there about the carbs regardless, worth the time.

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

[This message has been edited by lateapex911 (edited July 01, 2004).]

[Eagle7]

Dual 100-1900
2DA2-6
http://www.frostalarm.com/cat/p10.html
Don't know if that's the place to buy it.

------------------
Marty Doane
ITS RX-7 #13
CenDiv WMR

[This message has been edited by Eagle7 (edited July 01, 2004).]

[This message has been edited by Eagle7 (edited July 01, 2004).]

[benracin]

Engine builder eh... well... I guess that's me! Unless I should call the junk yard I got the thing at. I'm using the RB header and I don't think it has threaded holes on it. Might be some drilling and welding involved huh. So I've heard distances from the exhaust ports as small as 1" to Jake's 10". I'm sure the distance makes difference in temps read and probably the main thing is to keep the two probes an equal distance. Any clarification on what a good distance should be? Does it matter a ton?

Thanks!!!

[ddewhurst]

Ben, ask some question where ever you procure your EGT gauge. The simple deal is to use the type that ya drill a hole in a hose clamp & drill a hole in the header. Used that type Karting & it worked well. Keep in mind that the high rollers use the weld in bung type. Save some money for your gas hog so ya can make more races. http://Forum.ImprovedTouring.com/it/smile.gif


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

ps: Started the racer up today with all the new goodys & so far only one oil leak which is taken care of. I'm going out to the fire pit & pretend it's next weekend. Except that tomorow there is no racing therefore I'm gona down a couple tall cool ones from Miller.

[lateapex911]

Originally posted by ddewhurst:
.....
Have Fun http://Forum.ImprovedTouring.com/it/wink.gif
David

ps: Started the racer up today with all the new goodys & so far only one oil leak which is taken care of. I'm going out to the fire pit & pretend it's next weekend. Except that tomorow there is no racing therefore I'm gona down a couple tall cool ones from Miller.

You got Bill Miller to send you some beers????? Wow! I'm impressed!



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

[Eagle7]

Mine're at 8" from the flange. Don't know if there's a right or wrong. No bungs - hose clamps.

------------------
Marty Doane
ITS RX-7 #13
CenDiv WMR

[lateapex911]

Here's a link that has a picture of SDJs dyno with the header and EGT hoseclamps visible:
http://www.sdjmotorsports.com/Engine.htm

I'll leave it to you, but it looks like lot more than 1 inch to me! http://Forum.ImprovedTouring.com/it/wink.gif

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

[benracin]

Thanks Jake! 1" does seem pretty close. It just seems that with the high temps that these headers reach, making a hole so close the the flange might do something bad.

So does the probe come with a gasket or something? What seals up the hole you put the probe in? Just the hose clamp?

[lateapex911]

My probe looked like a 2 stage rocket, so to speak. The tip is a constant diameter for an inch or so, then it flares out a bit, then narrows again with a step.

The area where it flares is an angle, lets say 30 degrees or so. On my set up, the bung has a chamfered hole that mates with the angle of the flare onthe probe. The hose clamp hole slides over the narrow section, and mates with the stepped area to pull the whole thing tight with the seat. I would think that if the bung idea is not to your liking, that the hole drilled in the header could be chamfered with a countersink bit or a "unibit" of the correct angle.

If this site had the ability to host pics I'b be happy to snap and post one...

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

[This message has been edited by lateapex911 (edited July 03, 2004).]

[David Ferguson]

A great source of EGT parts and knowledge is

http://www.exhaustgas.com

Here are some articles on tuning with EGT's:

http://www.sdsefi.com/techegt.htm

The Airplane guys have been using EGT for a long time to maximize the performance (power, effeciency). Dig into this article far enough to learn about how EGTs vary as the mixture is both too rich and too lean.

http://www.avweb.com/news/columns/182084-1.html

[Eagle7]

Wow. Great stuff. Thanks.

------------------
Marty Doane
ITS RX-7 #13
CenDiv WMR

[ishod]

Here's my $.o2 worth. Spend a little extra (ok maybe a lot extra?) and buy digital readout EGT gauges. You need to read them when you're coming off a long straight and the small gauges are difficult at best to get an accurate reading when you are trying to set-up for a corner. You need two gauges, one for each header tube (secondary reading) Both probes should be 18" from the header flange. You can purchase from 7's Only in California. Ask for Tom. He is a fountain of knowledge anything 1st Gen. You can also purchase spare jets from them.

[Boswoj]

Digitron makes a really nice dual egt gauge that also has some data logging features that are basically tacked on for free! Check digitrondirect.com for info or e-mail Mark Kowalski at [email protected] for more info. I'm not connected with these guys at all, but Mark sure was helpful when I needed EGT's in a hurry and gave me a great price.

Boswoj

[This message has been edited by Boswoj (edited July 12, 2004).]