Boost Level

[6.5 MONEY PIT]

HEY GUYS i JUST INSTALLED my new gages and put my 80 hp chip back in my question is when crusing on the high way I have only about 2 psi of boost is this normal. when pulling out or excellerating I have about 8 psi I have a turbo master boost control that I can turn up if I have to .. any info is appreciated thanks :)

[JohnnyRebel]

that is normal stock boost, so dont worry :P
if you want more oomph, you can turn it up to AT MAX 14-15 psi @wot. any higher and youre walkin on thin ice :)

[gmcsmokesblack]

how do you turn up ur boost?

[JohnnyRebel]

you can buy a mechanical wastegate controller that replaces your sh*tty stock vacuum one. it has a spring and adjuster-bolt thingy. you can turn it up or down there.

the mechanical ones are bloody expensive for some metal and a calibrated spring... someone on this site made one themselves, i dont remember who tho.

[Donkey]

Where can I buy a mechanical wastegate controller at?

[nedaclu]

I have a 93 chevy3500 dually 6.5 turbo with a mechanical wastegate controller. I have looked and felt all over it, I can not find a place to adjust it any ideas? thanks

[sshewins]

Hey guys, you can get a mechanical boost controller I know Walt swears by the stock vacuum controller and with good reason, but I'm still using the mechanical one - far less to go wrong. BUT, install a guage at the same time. Other wise you're asking for trouble.

On a 93, you have a mechanical injection pump, but unless you have some sort of threaded rod going from the waste gate lever (on the pass side of the turbo - just above and slightly foreward of the exhaust tube) foreward to some sort of fixed bracket with a spring (about 1" X 4" or so) keeping a set amount of tension in order to keep W G open to acheive desired boost, you don't have a mechanical boost controller. It boils down to this, if you have a vacuum pump, chances are you have the stock vacuum controller, as the pump has no other purpose in life but to run the W G.

[6.5X2]

I have 2 6.5 trucks and they both run adjustable waste gate controllers. I bought both of mine at Heath Diesel.

[Chevylover]

I have 2 6.5 trucks and they both run adjustable waste gate controllers. I bought both of mine at Heath Diesel. Go to www.heathdiesel.com


Anyone there, who will bet with me, how THIS long this posting exists, until Garth_J will erase it ???

Cu,
Sven

[santafe]

I took my mechanical waste gate controller off of my truck and simply bent the actualting rod in a "z" to make it shorter which will keep the waste gate closed longer. With the air snorkle on or off, didn't matter, I can only build a maximum of 8 LBS boost. Other than my 4" exhaust (from Walt) and full gauges, there are no other performance mods on my truck.

SantaFe

[Husker 6.5]

I took my mechanical waste gate controller off of my truck and simply bent the actualting rod in a "z" to make it shorter which will keep the waste gate closed longer. With the air snorkle on or off, didn't matter, I can only build a maximum of 8 LBS boost. Other than my 4" exhaust (from Walt) and full gauges, there are no other performance mods on my truck.

SantaFe
Use your search function on the tool bar to go back to my post on diesel combustion, boost, power for the details. In a nut shell:

You can keep the wastegate closed forever, and without additional fuel injected beyond your current level, you will not see boost higher than what you are currently reading.

The wastegate is a safety valve to dump excess exhaust around the impeller. This keeps keeps the common shaft that spins the compressor from over revving and producing too much boost, or in worst case destroying the turbo. (Some vehicle MFR's also use a pop-off valve in the intake set at a certain psi to open and bleed off excess pressure (boost) in the intake tract along with the wastegate for the exhaust, GM doesn't, Audi did on their 5000 TD). Spent exhaust gasses flow through the impeller which is a restriction in the exhaust. This causes back pressure, which actually helps to spin the impeller faster, thus spinning the compressor faster and causing higher intake pressure (boost). When the exhaust back pressure reaches a certain level, the wastegate opens and diverts the excess pressure and gasses around the impeller to the exhaust outlet, thus limiting the speed of the impeller, and hence your intake boost pressure.

To increase the volume of exhaust gasses produced to thus raise the back pressure, you need to introduce more fuel for combustion, that spins the impeller and compressor faster and hence produces more boost (which is cramming more air into the same volume of the cylinder).

It is NOT the fact that your wastegate is opening that is limiting the boost you're getting, but rather that for the amount of fuel you are providing, the impeller won't spin any faster! More fuel = more boost, until the point that you acheive enough back pressure to open the wastegate.

This said, since your engine is essentially stock, you need to introduce more fuel by adding a #9 resistor, marine injectors, and a 40 or 80 HP chip/ECM, or if you have a DB-2 pump, adjusting the pump screw and/or having it rebuilt with the piston bores honed oversize and larger pump pistons installed to increase the fuel shot. You will then see the 15 psi max. boost that you want at wide open throttle (WOT) under load.

DIESEL ENGINES DO NOT WORK LIKE GAS ENGINES, FORGET WHAT YOU KNOW ABOUT THEM WHEN IT COMES TO DIESELS!!

Husker 6.5

[keplinger78]

Husker,

What are you talking about by putting larger pistons in a Injection pump? I have a 93 with the black tag of death on it,but seems to not show the hot start problem anymore....It smokes at start up when cold.I'm going to get a new pump or mine rebuilt,can you tell me more about the "Big Bore"pump.

About the boost controllers,If some one would take a fishing scale and check the lbs of the spring I'll build my own. I need gauges first before I play with FIRE!!!

Thanks Tom K.

[Husker 6.5]

:D Husker,

What are you talking about by putting larger pistons in a Injection pump? I have a 93 with the black tag of death on it,but seems to not show the hot start problem anymore....It smokes at start up when cold.I'm going to get a new pump or mine rebuilt,can you tell me more about the "Big Bore"pump.

About the boost controllers,If some one would take a fishing scale and check the lbs of the spring I'll build my own. I need gauges first before I play with FIRE!!!

Thanks Tom K.

It's the same difference as boring or stroking an engine to gain displacement. Ex: The old 12 valve Cummins M.I. 5.9L used the P7100 mechanical injection pump. The real serious power freaks after going with larger injectors, would rebuild the P7100 and bore out the pumps and put larger diameter pistons in the pump bores. The end result was about 30% more fuel per injection cycle at a higher pressure.

The same thing is done on common rail systems, both the first gen Cummins VP44, and the D-Max/2nd-gen Cummins use the Bosch CP3. Both pumps can be "hotrodded" by boring out the cylinders to provide more flow and pressure.

I don't know if the Electronic pump (DS-4) can be done, but a competent shop that specializes in diesel injection pump rebuilds and modifications can certainly perk up the 93-earlier mechanical Stanidyne injection pump (DB-2). Unless you have a highly modified motor, it is a waste as there are physical limits as to how much fuel you add until you toast your engine. Turning up the screw on a sound mech IP with marine injectors will give you all the HP the motor can physically handle. A chip/ECM and marine injectors with #9 resistor will do it for 94+.

Incidently, the mechanical Stanidyne was also used on the pre-'Stroke 7.3 and 6.9 Ford/Navistar diesels. These pumps could, and were, routinely reworked to increase their displacement, as the engines could certainly handle the stress being de-tuned medium-duty commercial truck engines.

Hope this satisfies your curiousity on "bigger pistons".

Husker 6.5