TheTwinTurboRX-7

Can anyone suggest a good exhaust gas temperature guage for this car so I can get to tuning??

Ben

DriveFast7

iTrader: (1)

Sure!

http://personal.riverusers.com/~yawpower/carbtun.html

The process of carburetor tuning is greatly simplified with an EGT guage. (Exhaust gas temperature guage.) You can buy an egt guage from Aircraft Spruce at 1-800-824-1930. They have a dual guage which costs $96.95, and a single guage package which costs 66.40. The part number for the single guage is 282-1 for the guage, and 712-2wk for the probe. The dual guage is sold complete with probes, and the part number is EG005. The probe should be installed about 24" from the exhaust port.


I installed the dual EGT gauge and it is a nice unit. But I got MUCH better results tuning with an air/fuel meter. Air/fuel meter responds MUCH faster and actually tells you if the motor is rich or lean. EGT just tells you how hot the exhaust is.

Just my two pennies.

-bp-

TheTwinTurboRX-7

I have always been told that an EGT is afar more accurate as the A/F runs off a stock sensor, but then that was in a second gen and it could be different in a first gen. What is the other guage in the dual package??

Edit, thanks for the link, its great.

riffraff

a/f guage is only useful if you have a wideband o2 sensor. otherwise, all that you get is a light show.

RotorMotorDriver

iTrader: (1)

But the lights add HP!!

~T.J.

DriveFast7

iTrader: (1)

Took me a FRACTION of the time to tune carb with a/f meter vs. EGT.

Yes, EGT is more accurate, but it just tells temps. Can YOU translate exhaust temps into an accurate air/fuel ratio?

I can't.

A/f meter gives instantaneous feeback of where the air and fuel ratio is. YES, expensive wideband O2 sensors increase tolerances and accuracy. And YES, my $25 O2 sensor is not as accurate. But YES, the air/fuel ratio told me that I was in fact lean here and rich there whereas the EGT just told me how hot the exhaust in the pipe was. I could put richer/leaner jets in the carb and watch the EGT's change, but that didn't help me tune the carb since NO ONE gave me a target temp to shoot for at this rpm and this gear.

Have YOU been able to tune your carb with an EGT only?

Have YOU ever tried an air/fuel meter? I have both installed in the race car and have tuned that carb VERY WELL.

Twin Turbo, you can slice into the stock O2 sensor if needed no prob. or install a 2nd dedicated O2 sensor.

Done here.


:

TheTwinTurboRX-7

The dual guage mentioned above, what is dual about it?? I am slightly confused. Thanks.

Ben

Kill No Cone

iTrader: (6)

Ben, the duel guage allows you to watch the temps of both exaust pipes. So, if you were to get jets that did not match just right, you would see a temp differntce.

I have been planning on tuning my Dellorto this spring. When you are tuning, I have been told to tune to 1550 to 1600 degrees. Anything hotter will reduce the life of your engine, anything lower and you are leaving hoursepower behind.

TheTwinTurboRX-7

got ya
dual sounds like a plan
cheap a/f guage couldn't hurt either

TheTwinTurboRX-7

What stock O2 senor would you be refering too, since there isn't one. Also if an aftermarket one was used where would it be mounted and what not.

gamble302

any stock one should work from what i understand. anyone know where to mount em though? i know with wb o2 the closer to the motor the better due to the need for warmup of the sensor itself. wonderin if he could get one put in just before the muffler where the two pipes in his rb sp exhaust meet or if thats too far away.

DriveFast7

iTrader: (1)

My Halmeter 30 air/fuel meter directions to mount the O2 sensor 24" away from exhaust port and that's what I did.

Twin Turbo you were talking about a 2nd gen and that's what I thought you had. Sorry for the confusion.

-bp-

RotorMotorDriver

iTrader: (1)

From what I have heard, you want to mount the O2 sensor as close to the engine as possible because they need to be a certain temp before they work right, whether wide band or not (unless its a 4 wire self heating sensor, and Ive heard those burn themselves up a lot). Also, youre supposed to mount it in the collected exhaust stream. I assume thats only if your using one sensor though. But if you have street port RB exhaust (I know you do), I dont know where you would put it?

~T.J.

TheTwinTurboRX-7

Never mentioned second gen, thanks for trying though, suppose I would need two a/f meters. Probably not going to do that.

riffraff

you donot need two gauges.. you can just have two sensors, and then wire a switch in before the gauge so that you can switch between the sensors.. that is probably what i am going to do.

TheTwinTurboRX-7

that is one thought, but you never get the same reading at once to see if one barrel is off or not, while you could on repeated test runs it is only 30 additional dollars for the dual guage. might be something for me to think about.

Rx7carl

How reliable is that EGT target? Is that from a good source?

DriveFast7

iTrader: (1)

EGT target I heard was 1750 in top gear at the end of a straightaway. This is on a non-ported or street-ported motor with open exhaust on the racetrack. I tuned fairly close to that but was a little on the rich side for safety.

O2 sensors do need heat to operate, but you simply don't need them right next to the exhaust port. Once the motor is warmed up the O2 is warmed up too. 24" from exhaust port is what the MANUFACTURER of my Halmeter30 air/fuel meter instructed.


-bp-

Kill No Cone

iTrader: (6)

Hey Carl,
I got those numbers from Jesse Prather of Prather Racing. They build rotaries and old Brit engines. They have a dyno in there shop and build, break in and tune engines there using those numbers.

Rx7carl

Wow, thanks man. Better late than never. j/k