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Thread: Lb7 intercoolers and wastegate adjustment

  1. #1

    Question Lb7 intercoolers and wastegate adjustment

    My 03 LB7 with a magnaflow 4", edge Attitude, and AFE stage 2 with a Banks Big head, pulls 25 psi of boost in 4th towing a steep hill at 2500 rpm. It tows great at 70 mph and gets 15+ us MPG towing. between 1500 rpm and 1800 rpm the torgue seems real weak pulling any kind of a grade. I emailed banks but got no response. Should I crank up the Big head to improve torque in that range.

    My second question is I am starting to hear that aftermarket intercoolers make a big difference, in both power and mileage. can someone tell me thier experiences with the larger intercoolers. 1700 bucks is a large amount and I am hoping to find out how much difference it makes. Second question do they just benefit during towing or all the time given the cooler air going in.

    Thanks

    TG

  2. #2
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,382

    Arrow

    The larger aftermarket intercoolers provide more of a benefit for competitive diesel owners who are running quite a bit more than stock boost pressures.

    I'd like to see more dyno, track and road testing that compares the stock to aftermarket IC's. Not enough data out there to really know.

    The '03 LB7 makes its best torque at 1800, according to GM. From an engine efficiency standpoint, 1800 up to 2700 or so would provide the best towing performance while pulling big trailers up steep grades. Let the powertrain programming pick the gear and RPM. It does a pretty good job.

    Jim

  3. #3

    Default

    1) Are you running stock diameter wheels and tires?

    2) Do you always run in Tow/Haul when towing?

    3) What Edge setting are you towing with? EGTs while on the grade, experiencing the sluggish performance?
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  4. #4
    Join Date
    Aug 2004
    Location
    Boise, Idaho
    Posts
    20

    Talking

    Quote Originally Posted by homerent@telus.net View Post
    My 03 LB7 with a magnaflow 4", edge Attitude, and AFE stage 2 with a Banks Big head, pulls 25 psi of boost in 4th towing a steep hill at 2500 rpm. It tows great at 70 mph and gets 15+ us MPG towing. between 1500 rpm and 1800 rpm the torgue seems real weak pulling any kind of a grade. I emailed banks but got no response. Should I crank up the Big head to improve torque in that range.

    My second question is I am starting to hear that aftermarket intercoolers make a big difference, in both power and mileage. can someone tell me thier experiences with the larger intercoolers. 1700 bucks is a large amount and I am hoping to find out how much difference it makes. Second question do they just benefit during towing or all the time given the cooler air going in.

    Thanks

    TG
    I installed my new BD "Cool It" Intercooler yesterday. Did a long test drive today and noted that @ 70 mph on the Interstate that my egt's were down 50 to 75 degrees and that under full throttle accelleration 0 to 110+ mph the egt's were down by about 125 degrees with my Kennedy ECM on the 100HP setting. The install was pretty easy even for an old Guy!
    '03 Chev Duramax ext. cab, Kennedy ECM,After Market turbo,tranny, triple disk convertor, Exhaust Brake, electric tran. cooler, dual exhaust, Supertank 57 gallon.

  5. #5

    Default reply to quote 243475

    Quote Originally Posted by Mark Rinker View Post
    1) Are you running stock diameter wheels and tires?

    Yes I am currently running stock rims and tires. When I change tires this fall I am considering upping to a 265-75R16 from the 245 stock tires which after 116000 km are down on the wear bars.

    2) Do you always run in Tow/Haul when towing? YES

    3) What Edge setting are you towing with? EGTs while on the grade, experiencing the sluggish performance?
    Edge power level 2, currently pulling a 9000 lb trailer with a stock tranny. I sometime have tried 3 with better overall towing performance but EGT levels increase more quickly. I try to keep EGT's below 1300 by backing off the throttle. If it gets higher than about 1250-1300 degrees for any length of time I generally lock out the overdrive to get the rpm up which increases fuel consumption, but cools off the EGT

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