Engine/Transmission (1998.5 - 2002) EGTs towing with twins..

[BLively]

ok, i have another twin turbo question... my set of twins seems to run a little hot both when towing and empty. . it is nothing for the temp guage to hit 1500*. and that is with Smarty on SW8 and it doesnt matter if the Drag comp is off or on 5X5. . what do you think the deal is? i just dont want to be dogging on it and the temps go through the roof and boom! there go the turbos. . any ideas??

 

[GDMRTN]

Try SW9 on the smarty and no box. Helped on mine.

 

[JFlagg]

Not a turbo expert by any means, but do your EGT's go down once you get above 2000 RPMs? Also, is it possible your Hx35 is becoming a choke point on your intake side? Not sure how big Dragon Flows are, but might they be too big for towing, even with twins? And maybe I should have asked this question first, is this just a recent development, or has it been like this the whole time you have had twins? And last, have you checked for boost leaks?

 

[KKunz]

I have close to the same set up as you but my injectors are smaller. I tow in the mountains allot 5,000 to 10,000 feet in elevation and rarely get my egt to 1300, I usually tow with smarty on 6 and go now higher than level 3 on the edge. Do you have a 5 or 6 speed?

 

[NoSeeUm]

How much boost are you making?



I had EGT problems for a bit. Eventually I screwed down on the adjustable boost elbow and tightened up the waste gate acuator rod of the DZ just the right amount. Up until then I had been using just a regular brass elbow and had the waste gate acuator rod very loose. I ended up realizing that the top turbo needs to be tuned correctly. As per IdahoCTD the purpose of the bottom turbo is just to magnify the effectiveness of the top turbo.



If I were you I would do a few things to check things out. First try running with a drive pressure gauge and a cold pipe pressure gauge for a bit. The drive pressure of a HX35 can get pretty high on the top end of rpm, but at towing rpm it should be more or less OK. For my experience the drive pressure ratio of a HX35 gets up around 2:1 as low as 20 psi boost (40 psi drive - 20 psi boost). The cold pipe pressure should be around 40-60% of the total boost. At a towing rpm / tune, I am guessing closer to 40%. If possible find a long steep grade to test on and burn a tank of fuel. Mine runs fairly close to 40 - 50% under most boost pressures.



I have no EGT concerns in 4th at all and 5th only when I am lugging the engine at 1670 rpm (60 mph) with my camper loaded and boat in tow pulling a pretty good grade. The EGT will nip at 1200F @ 26 psi boost. At 1800 rpm (65 mph) my 5th gear EGT issues dissapear under almost all grades if I don't have to slow for a curve.



Edit: Generally I tow on injectors only. Currently I am running stock ECM SW.



Jim

 

[BLively]

i have a 5 speed transmission. whether i have smarty and/or the box on or off, they still get hot. . the dragon flow injectors are 10 flow 250 horse rated injectors. i was thinking maybe the hx35 was choking the system, but i talked to someone the other day about this. one thing i didnt mention is the external wastegate. . the guy i bought this from had installed and uninstalled the top turbo a few times and the clamp holding the wastegate to the manifold doesnt really clamp very well. . it does leak soot all over the motor. . could this leak be the cause?

 

[Graphic man]

i would read drive pressures and see what you have and tune it for 1:1



your HX35 may be pushing too much PSI and driving up the temps





Scott