LMM: LMM 68stg2R high EGTs, possibly converter?

[lmmcbrown0917]

About the Lmm in my sig,

Egts will get around or over 1100 degrees when driving normal around 1/4 to 1/2 throttle just getting the truck up to speed. it almost feels like the converter is to tight causing the truck to lug, It has a DPC triple disk, stock stall.

i don't believe its the tuning since i haven't heard of anyone else having this issue with marks tuning, (which is great btw).

it only gets worse when towing.

thanks in advance for anyone who has any ideas..

 

[N2BRK]

I had a converter so tight that if I floored it the truck wouldn't even move for a solid second... my EGT's weren't abnormal at all (same turbo as you). I'd look for a problem and not just a side effect of something in good working order. :thumb: Maybe it'll be as simple as your EGT probe?

 

[clrussell]

Id look into probe also.. 68r likes a tight converter in my experience

 

[lmmcbrown0917]

Id look into probe also.. 68r likes a tight converter in my experience

Could the prob only be wrong at a certain point? Around idle and WOT it's accurate.

 

[Rancelot211]

Yes sir. I had one go bad and thought I was chasing a boost leak. I can get to 1200 normal driving depending on outside temp grade throttle position ect.

 

[NC-smokinlmm]

Whats it at wot?

 

[lmmcbrown0917]

Whats it at wot?

1400-1500 at WOT

 

[kiwilml]

Sounds normal to me. I've got a fixed vane single and I'll get up to 1100 no problem at under half throttle. More like 12 probably, but it would seem like you'd have more boost then me on easy take out and therefore be cooler idk.

 

[NC-smokinlmm]

Dont worry about it, those turbos have the veins clamped down to assist spoolup. You can call mark, but I'd say its pretty normal as long as it dosent go crazy at wot and mine used to go wayyyy past 1600. Haha...

 

[lmmcbrown0917]

Dont worry about it, those turbos have the veins clamped down to assist spoolup. You can call mark, but I'd say its pretty normal as long as it dosent go crazy at wot and mine used to go wayyyy past 1600. Haha...

Mine has been past 1600 in the past on some wot passes, that doesn't really bother me i just didn't think it was normal for this turbo to feel so "laggy" especially in the higher gears at cruising speeds and light acceleration?

 

[Rancelot211]

It's biggie then the factory turbo. Gonna get some lag from it compared to a stock charger.

 

[malibu795]

Also acceleration takes more fuel than cruising.. be it part throttle or WOT.

 

[Dozerboy]

Egts don't sound abnormal to me. The 68Rs are definitely laggier then a stock turbo until you get on top of it some. Then it pulls a lot harder.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[N2BRK]

I hate to hijack, but you guys must have converters too tight and or not running larger injectors. Mine lights faster than stock. I ride back and forth between my buddy's lmm with a stock charger and mine.

 

[Headless_Horseman]

You might look into improving your airways a bit. I might bump 1000 during acceleration at 1/4 - 1/2 throttle. When towing I can keep it 1200 or below going up long grades. I am running the same turbo, but I have upgraded the entire airway so I have a ton or airflow coming in to the turbo and going out. Stupid question but, are you still running stock DP or exhaust?

 

[Dozerboy]

I hate to hijack, but you guys must have converters too tight and or not running larger injectors. Mine lights faster than stock. I ride back and forth between my buddy's lmm with a stock charger and mine.

The lag test thread would disagree with you.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[N2BRK]

I remember that thread. I thought mark outspooled stock with it. Something a half second quicker. I'll have to re-read it tonight when I get home.

 

[lmmcbrown0917]

You might look into improving your airways a bit. I might bump 1000 during acceleration at 1/4 - 1/2 throttle. When towing I can keep it 1200 or below going up long grades. I am running the same turbo, but I have upgraded the entire airway so I have a ton or airflow coming in to the turbo and going out. Stupid question but, are you still running stock DP or exhaust?

No sir, downpipe and 5inch. Intake, full EGR delete with lb7 up pipe and a lml driver side manifold.

 

[Dozerboy]

Well after I opened my big mouth I went back and looked and couldn't find the 68. The 3794stg2 was faster then the stocker to 20psi.

I should clarify my opinion they are slower to start building boost, but once they start it comes on faster. Thats lag to me. All my logs show it took longer for the maf to alow full fueling over the stocker and that on the 3794stg2 not the 68.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[Headless_Horseman]

No sir, downpipe and 5inch. Intake, full EGR delete with lb7 up pipe and a lml driver side manifold.

Hmmm that is odd, for the most part we have a lot of the same/similar mods. I know David has changed the converters and clutches he uses since building my trans. Mine is rocking on 5 yrs I think since it was built. To me the EGTs seem a bit high, others say otherwise, but with similar setups you and I see a bit more variation than just general fluctuation.