Quote:
Originally Posted by 88tlc
Driving test ! - I am still not happy with the power. I can not hold the overdrive when going up a hill, and have to go to third gear, and will go about 55mph. it is at altitude about 6000 ft, perhaps a 6% grade. I had HOPED that the 88tlc would cruise up the hill like my Dodge cummins. but I do not have that kind of power, or torque. I would welcome any thoughts on this.
some data first
stock turbo, no waste gate - the turbo will obtain 10 psi boost, but I gotta have my foot in it! at cruise it is perhaps 4 to 5 psi. egt gage is post turbo.
injection pump, and injectors - stock, rebuilt. fuel turned up approx 6 %. Timing was checked at about 12 deg, but this seems to be a course measure per the manual.
700r4 with overdrive. I also have 33s on the rig now. 4.11 stock gears.
at cruise- 65 mph, egt are at 1000 F, boost about 4psi to 5 psi. there is a bit more power there, but the egt are high!
Up a hill - 4% to 6% grade. i have to shift down to third. it has plenty of power but the EGT can climb quickly . boost is 5-7 psi?
what is the EGT temps that this isuzu handle? the small oil jets that shoot into the cylinders, and cool the pistons, post turbo.
would a wastegate turbo give better power, early in the throttle?
|
You need to shift your EGT probe to before the turbo. Which fuel pump do you have? Some have boost compensators, some do not. If you have a sick boost compensator then you'll be way down on power.
I've run my engine at up to 750 deg C preturbo regularly for a long time with no issues. These engines are built to work hard all day, factory fitted oil spray, oil coolers etc.
What rpm do you think you have at 65mph?
A smaller wastegated turbo will give more boost, but I'm not convinced boost is the only issue you have right now.