Performance, Boost, and EGT readings

[Mikie12]

I recently installed an Autometer boost, and pyrometer gauge in a really cool steering column mount.

As per the instructions, I attempted to drill the manifold at the rearward port but was unable to because the A/C dryer canister was in the way and I could not get a straight shot at it. I had to place the probe in the front port instead.

Question; will this not work as well? What is the preference for placing the probe in the rearward exhaust manifold port? It seems to work fine.

As I pulled some steep grades going up I-5 with a 10k trailer, still on legal fuel, I was pulling a grade in 6th. When the rpms dropped to 1800, I down shifted to 5th and mashed it. Boost bounced to 35 for a second, then settled at 30 and held steady. RPMs dropping slowly in 5th, EGT stays at about 1350 from 2500 rpm down to 1800. I down shift to 4th, rpm goes to the governor, and stays there, EGT rises to 1450. Water temp increased from 195 to about 205, but settled back after I crested each hill. I only kept it at 1450 for 30 to 45 seconds on 3 occasions. Letting up slightly sent the temps down to between 1300 to 1350 fast.

Only having experience with an old 335 Cummins in a '64 Kenworth, I thought that as you relieved the strain on the motor by shifting down-the motor running freer at a higher RPM, the EGT was supposed to drop??? I just thought the rise in EGT after I down shifted was counter to what I expected.

Don't get me wrong, this truck is a pullin SOB, and I have no complaints about its performance. It would climb a tree if you asked it to.

I think the pyrometer is reading hotter than it actually is because when it's cold out, and the motor is stone cold the gauge will read about 95 on it's scale after I have switched the power on but not yet started. Also, after idling for 3 to 5 min the EGT won't drop below 350, you could idle it until Christmas and it'll be at 350. This has to be balanced against the probe located in the forward most port on my truck where the temps in the exhaust stream may not be as hot.

Are the temps OK for the conditions I stated above?

Thanks, M.

 

[Devan Manis]

Yeah, the temps are fine for an 05 truck, the 1450 would get me nervous, but for that ammount of time would be fine. The reason for putting it in the rear port is because cyl 6 runs hotter than the rest, and you want to get the hotter of the two readings.

 

[Mikie12]

Devan; You don't think I started to melt the pistons do you with the high exhuast temps?

 

[Devan Manis]

no, not only that hot for only that long, i can, and have pegged my 1600* pyro for probably 20 seconds top, so it was alot hotter, but for less time, however your engine can handle more heat than mine, due to the gallery cooled pistons. I would say your probably fine. you might try a cold air intake, or a bhaf, to help with the cooling.

 

[JVolpe]

I have pegged my Autometer at 1600* and seen 1710* on the TST readout on the track a lot of times. Only for a few seconds, but 325/600+ seem to run hotter than what previous Cummins did. Probably because of the cat and additional injection event. I have two pyros on top of manifold between 3 and 4 cylinders about an inch apart. You will see temps close enough to what is going on to take action as long as it is pre-turbo. I have my TST set to defuel at 1500* for daily driving and I never really worry much about EGTs except on the track, and then only as an afterthought. The first time I saw 1710* on the TST readout I was thinking "dam your going to nuke this engine if you don't let off". But I was just a little ahead of the Mustang and not far till the end of the quarter and it was only for a little while. Now I try not to look at the EGTs at the track.

 

[Devan Manis]

yeah, i only glance at it as soon as i cross the finish line, and have the same after thought.

 

[GSchroder]

With the same rpms, throttle, etc. as you state, I get the same thing. I'm stock and get those temps with the probe in the front turbo port. This is where a mechanic that does this kind of stuff told me to install it anyway. He says this is the hot port between the two. 1450 makes me nervous also but with a stock engine I guess it shouldn't be a major problem. The water temp does the same too.

 

[Mikie12]

Thanks guys; I don't have a racer, I just want that slight effiencey edge-I want this car to last (especially after what they are doing to our diesels with all this smog crap). I would settle for an extra 60 USABLE HP with out the heightened EGTs. The HP is not usable if you have to keep backing off the throttle.

I've ordered the "blue" hose for the tween turbo and air box, and the cool air hose from the bottom of the air box to behind the bumper setup.

I'm thinking that I should ditch the EZ box and go with the TST that advances the timing with out forcing more fuel in from increased rail pressure. But I don't need the extra probe, and boost stuff for the TST to monitor.

Oh, and the cat, and stock muffler were the first things I got rid of. Banks muffler on now.