Turbo Boost Adjust?

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I've just had my pump timing set and the pump brought up to the good end of the specs. Prior to the "tune up" my EGT rarely reached 900 (before the turbo). My max boost pressure is 19. Since the tune up the EGT when towing easily reaches 1100. I'm thinking (uh-oh) that I may need a little more boost (say 22-24) to help keep things cool. My concern is because I haven't made any long trips since the pump was tuned up and that I may end up having to let off the throttle or downshift to keep things cool where in the poor performance days I could have just strained the guts out of the truck and never overheated anything. Is there a simple solution to increasing boost and is that the right approach? Thanks.

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98 12V, 2500QC, Auto, Chrome Package, Towing Package, EGT,
Boost/EGT, 4. 10, LSD, Rancho 9000s, K&N

 

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Alan,

Could you elaborate a little about what "... timing set and the pump brought up to good end of the specs. " means. You did not mention what your boost was before the tune-up, do you know? Also, your EGT went from 900 to 1100 after your tune-up. I would suspect that some performance upgrades were done during this tune-up. Let us know everything you know about this tune-up.

I have upgraded my 94' truck with the TST 230/605 power upgrade kit and love it. It contains a fitting used to increase boost. You could contact TST about buying something from him, but I would recommend that you get his 230/605 kit. Any tampering with these devises may void your warranty, therefore you just as well get the power upgrade if you do anything.

Later,
Tim

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94' 2500 4x4, std cab, 12v, 5spd, gauges, TST 230/605, 110k mi.
96' 2500 4x4, ext cab, 12v, 5spd, Cummins Exhaust brake, 50k mi, 8-10K horse trailer (wifes).
Phx, AZ

 

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There were no upgrades done to the engine. The engine was down on power towing or empty. RPMs would fall back very quickly on any grade and by the time the engine reached it's peak torque range of about 1800 RPMs it was losing momentum so fast that speed would continue to drop.

I took it to a local diesel injection shop and after some preliminary diagnostics they felt as though the internal pump timing was off in addition to the timing of the pump to the engine. The suspected internal timing was based on a TSB indicating the pump internal timing should be advanced (if I remember correctly) by 2 degrees. Well to do all of this, the pump has to come off the truck and go on the machine. So with the timing set and flow set to the upper end of the specs (the pump was at the very low end of the specs) the pump was reinstalled and timing set to the engine itself. You would not believe the performance difference it made. However, the boost pressure both before and after is still 19 psi. There has been an increase in fuel flow with the pump adjustment. With the 200 degree increase in temp when pulling off with a 7000 lb load, thought more air might be in order. I installed a K&N as recommended by the shop but all I do is get to 19 PSI faster than before. I'm not in the danger zone with the temp, just want to make sure I don't go there The shop is willing to do some things but don't want to void any warranty. So I'm curious about my options from anyone who may have faced a similar problem. By the way, all the clamps are tight so I don't think I'm losing anything anywhere. Alan

 

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Typically, the pump shop just moves the stock torque plate forward, and may advance the pump timing when putting it back on the engine. This reset does the same thing to your warranty as a genuine TST Power Kit would do, but without giving you anywhere near the power gain. I don't know where you are measuring the egt nor how accurate your gauge is. Up to 1300 in the manifold (or about 1100 in the elbow @20 psi) is OK for short duration. I like about 100 deg. lower for a long pull just to be safe. Fuel=heat=power. No way around it cheaply. Some of us have chased this issue with bigger turbine housing, low restriction exhaust, head porting, completely bigger turbo, etc. Then we add more fuel and get back into trouble!

I have heard of so-called pump shops and self-proclaimed experts charging $300-500 just to move the torque plate, unfortunately. You should get a TST Kit for that price range.

If you do get a TST Kit, you can move your torque plate back some so the gain is about what it should be. use vernier calipers to check the distance between munch marks on the top of the plate from the washers under the hold down screws to see how much the pump shop moved it, or just put the new plate about in the center of its slots. That is about where most of them came from the Bosch factory (215 hp pumps often about 1/32" forward of center, or 3/16" back from fully forward).

 

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Joe, Thanks for the reply. Like your articles in the TDR.

The timing issue was a warranty issue that the dealer was very good about helping me get taken care of. A new cam plate is probably in my future along with injectors.

The EGT is measured in the manifold. If it stays at 1100 on long pulls, I'll be a happy boy. The shop did a good job, but like me, were happy that there was a warranty still covering this and they had an opportunity to show me how professional they are and what they could do by correctly setting timing, flow, etc and hopefully utilize them for any future service/upgrades I may want to have done. One thing about having this done as they put it, it that now the pump is at a good baseline so that when any upgrades are done, I should get the maximum return (enjoyment) on my investment.