EGT... when do you get nervous? - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• EGT... when do you get nervous? by addautomotive on 22 Nov, 2006 07:00
• I was tweaking my jetta last night and got it running really sweet. Very responsive and spools up very quickly. This is as nice as the car has run in months & months.
  
  Only downside is the EGTs are up. Steady 950* pre-turbo @ 120 km/hr, and 1150-1200 uphill. Going uphill, I can accelerate to 140 but the EGT climbs to 1400*.
  
  My boost is showing 9 PSI. I can up that to 12 and that should bring my EGTs down.
  
  However, I am wondering at what stage you guys get nervous. I am wondering what "real world" EGTs you would feel comfortable with on a daily-driver.
  
  Let's put it this way... you're headed out on a 9 hour drive, and you set the cruise control for 130. Knowing you're going to be driving for 9 hours, answer the following 2 questions:
  -What is a reasonable "steady" EGT at that speed
  -What is a reasonable "spike" in temperature when passing or climbing a hill
• #1 by QuickTD on 22 Nov, 2006 07:26
• Mine is a true daily driver. My business often takes me on 9 hour drives. I wouldn't want to cruise at anything over 1000 steady state. At 130km/h mine only runs 600-800 pre turbo with a K03. A reasonable spike for hill climbing/passing would be about 1400, any more than that for any sustained period of time could be trouble. I start to worry when my guage passes 1600, which it will do if I hold it to the floor for 30 seconds or more. At that point I'm not doing a legal speed anymore so it doesn't happen all that often.  
  
   Your steady-state temps seem awful high, timing a bit retarded? If you still have the cat in there it might be clogged. It could be just a characteristic of the larger turbo. My K03 is making 8-9lbs of boost at 120km/h, so it may be cooling the EGT's.
• #2 by addautomotive on 22 Nov, 2006 08:30
• Well, I'm going to wheel back the fueling a bit then. Seems like I'm running a bit hot; at a steady 130 I'm holding 950*-1100*.
  
  Catalytic converter WAS plugged, now it's not. That's all I'm gonna say about that. :wink:
• #3 by saurkraut on 22 Nov, 2006 09:23
• You might want to diddle with your waste gate.  I've got the kkk turbo that has the somewhat adjustable waste gate.  I think its only opening partially, but also at higher booste.  If I leave it to the mat, I get 20+ psi booste, with a little smoke, but my egt is not going sky high.  Its rarely over 1200 on full throttle acceleration.  Probe lag time my be a factor, i have the VDO set up, preturbo.  I also have a full 2.5" exhauste, so your results may vary...
  
  I believe my cruise egts are lower now as a result.  Your waste gate may be partially open at cruise, and that might drive up the egt.
  
  Try disconcting it for test purposes, and see if your cruise egts go down.  If so, do the pressure regulator thing in you waste gate line and adjust its opening to your likeing
• #4 by QuickTD on 22 Nov, 2006 19:25
• Quote

  Well, I'm going to wheel back the fueling a bit then. Seems like I'm running a bit hot; at a steady 130 I'm holding 950*-1100*.
  

  
  
  Dialing back the fueling won't do a thing for cruising EGT's, or EGT's at anything other than near full throttle. At steady state, a diesel engine will simply accelerate if more fuel is provided, if you're not accelerating or drag/power limited then something else is driving up the EGT. Check the exhaust and intake for restriction. How's it start? I'm thinking the timing could be a bit late.
   
   I was playing tonight (on a closed course  :wink: ) and I can cruise at 160km/h with 850º EGT's. Something's odd about your setup.
• #5 by addautomotive on 22 Nov, 2006 19:38
• Well, a couple days ago I could drive 130 with my EGT steady at ~800.
  
  Since playing with the fuel screw, I get 950-1100. Haven't touched anything else, other than resetting the idle.
  
  Starts easy, and timing is dead-on.
• #6 by QuickTD on 22 Nov, 2006 20:16
• I'm still of the opinion that it isn't related to fuel. Adjusting the quantity adjuster does exactly the same thing as just pressing the pedal harder. It delivers more fuel at a given pedal position, at any position less than full throttle the fueling is still directly controlled by your foot. Everything else being equal, if it went 130 with 800º EGT's on yesterday's fueling it will do the same today regardless of the quantity adjustment, thats a fact. Something else has changed... Maybe its just a headwind, hill, dragging brakes, I dunno?
• #7 by 935racer on 22 Nov, 2006 20:17
• Turn up your boost, no reason why you can't run 20+psi, if you have modified fueling, and compared a ko3 to a t3's EGT's and kept everything else constant during the swap the bigger turbo will net lower EGT's.
• #8 by addautomotive on 22 Nov, 2006 20:37
• Quote from: QuickTD

  Something else has changed... Maybe its just a headwind, hill, dragging brakes, I dunno?

  
  
  Well, now that you mention it, it was very windy on the way home. Enough, in fact, that it was making me nervous enough to slow down. I guess I didn't think headwind would be enough to raise EGTs that much, but now that you mention it, it may heve been a factor. I'll see in the morning.
• #9 by QuickTD on 22 Nov, 2006 20:47
• Everything has an effect on EGT. My EGT will jump 50-100 degrees at idle by turning on the AC! The difference between level ground cruising and a slight incline can be 100-200º. It's important to find a good repeatable "test facility"... The location of mine shall remain a secret, in case the local constabulary reads this board...
• #10 by 745 turbogreasel on 22 Nov, 2006 21:03
• I'll have to make a note of how much EGT my fan clutch is good for....
• #11 by addautomotive on 23 Nov, 2006 05:00
• Quote from: QuickTD

  Everything has an effect on EGT. My EGT will jump 50-100 degrees at idle by turning on the AC! The difference between level ground cruising and a slight incline can be 100-200º. It's important to find a good repeatable "test facility"... The location of mine shall remain a secret, in case the local constabulary reads this board...

  
  
  Too funny, I do have a repeatable "test facility" and I'll get out there this weekend.
  
  FWIW, I was ~700-850 this morning. I think part of it was wind, the other part placebo. Previously, I wasn't able to accelerate uphill from 120-140. Now I can, and low and behold, I get higher EGTs.
  
  QuickTD, thanks for your help thinking this through!
  
  Either way, I'm still interested to read what other folks are getting, both in normal driving and in their pursuit of diesel madness.
• #12 by burn_your_money on 23 Nov, 2006 06:09
• EGTs don't effect me since I don't have a gauge
  
  One day I'll get one. My car is all stock so I'm not overly worried
• #13 by addautomotive on 23 Nov, 2006 06:20
• Quote from: burn_your_money

  EGTs don't effect me since I don't have a gauge
  One day I'll get one. My car is all stock so I'm not overly worried

  
  
  Here's what happened when I started goofing around with bost & fueling without an EGT gauge;
  
  
• #14 by burn_your_money on 23 Nov, 2006 06:23
• Which is exactly why I'm not touching anything until I get my gauge.
  
  What did that sound like? It all went out your exhaust right? and not into your engine?