Supra Forums banner
1 - 10 of 10 Posts

· Registered
Joined
·
3,131 Posts
EGTs cool by ~200 F per 12" of un-wrapped header runner at lower RPM (at higher RPM the exhaust gas velocity increases greatly, so the cooling rate becomes less and less as RPM/velocity increases). So depending upon where your probe is located and what RPM you're cruising, your 1200 F reading is probably a good bit lower than the actual temp coming out of the exhaust port. When I had my open element probes in my header runners 8" from the exhaust port, cruise EGTs showed to be about 1400+ F or so at 70 MPH. (I can't recall exactly the temps -- I have them written in my tuning notebook at home -- but they were in that general range).
 

· TRNSFST
Joined
·
1,043 Posts
The probe for my EGT is located 4" from exhaust port on runner nearest firewall on my SR20DET equipped 240SX. Crusing temps always read about 1200 IIRC.

This is on a Full-race manifold.

No EGT on the supra yet, sorry.
 

· Will work for Supra parts
Joined
·
709 Posts
Speaking on the subject, when mounting an EGT probe inside the runner of an exhaust manifold, or header, which cylinder is the best to monitor? Obviously you want to watch the temps on the cylinder known to run the warmest. Is there one on the Supra known to run a bit warmer due to the cooling system design? I'd rather monitor that cylinder then have an average reading of all cylinders, from the down pipe, with temps that have already cooled off.
 

· Will work for Supra parts
Joined
·
709 Posts
BPU+ Justin said:
i have mine in the last cyl to get fuel since it should be the first to lean out and the first to have higher egts
Interesting theory, but there shouldn't be more then one fuel injector open at any given time, right? So even if there was a pressure drop when one injector opened, the pressure would go right back up as soon as that injector closed, a split second before the next opened. I'm not so sure the injector at the end of the rail would have any less pressure available for it's use. The regulator and pump(s) shouldn't have a problem keeping up anyway in a healthy fuel system. Or am I wrong?
 

· Banned
Joined
·
2,275 Posts
Espeefan said:
Interesting theory, but there shouldn't be more then one fuel injector open at any given time, right? So even if there was a pressure drop when one injector opened, the pressure would go right back up as soon as that injector closed, a split second before the next opened. I'm not so sure the injector at the end of the rail would have any less pressure available for it's use. The regulator and pump(s) shouldn't have a problem keeping up anyway in a healthy fuel system. Or am I wrong?

when you start pushing the injectors upto higher duty cycle levels, more then one injector tends to be open at a time

i mean, when you push them all the way, they are static and constantly open!

but, the fact is, the rail feeds from the 6th cylinder to the 1st...
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top