How to Increase Turbo boost on a 97 6.5

[freddys]

I have a 1997 6.5 turbo L56 with the EGR. How can I increase the boost and what about getting rid of the EGR valve.

thank you

[rjschoolcraft]

Electronic boost controls from Kennedy will let you set boost to about whatever you want.

Charliepeterson can tell you how to disable the EGR.

[david]

Forget about doing the electronic way ,get heath's controler.
That's the best way, then throw all that junk away
David :eek:

[whatnot]

If you get the turbomaster you still need the electronic one to keep it from setting a code. You can make one for a couple dollars using the schematic in the 2000(I think) reprints.

So, I would say that you are better off trying the electronic one first and get the turbomaster later if you don't like the way it works.

[rjschoolcraft]

When people don't understand something, they get scared. Then they either run from it or try to kill it. Alas, electronic controls are evil and must be destroyed.

If folks want to listen to bad advice, that's their prerogative.

[matt-max]

you can read my post on the mods to my tahoe and then ask knowledgeable generous folks like those above for more info

you may not be able to do the programming change on the ecm like i did because of the year of your vehicle and gm's pass theft deterrent system. not sure.....

matt

[jjgmc96]

with the electronic boost control I was able to set the boost to 10 lbs., any more than that set a code. I don't have an intercooler yet to run more than that anyways.

[freddys]

With the electronic boost control how do they work and how much boost can you get without setting codes?

Quote from Whatnot

[rjschoolcraft]

There is a boost sensor mounted on the plenum cover of the intake manifold. If you place a boost control on this device, you can bias the signal that it sends to the PCM, causing the PCM to command more boost. However, there is another device called a BARO sensor that looks just like the boost sensor but is calibrated differently. This sensor is mounted on the firewall and is used to sense atmospheric pressure on the L65's and EGR vacuum on the L56's. If you set the boost control that I previously talked about too high, the PCM will set a code 78 Waste Gate Solenoid Fault. To prevent this, another boost control can be installed at the BARO sensor to trick it and allow more boost without codes. This causes the PCM to set the Waste Gate Solenoid in 100% duty cycle, so that more vacuum is applied to the actuator to hold the waste gate closed longer.

This sensor and boost control is what was referred to earlier concerning the TurboMaster. If you set the TurboMaster to 14 psi boost, you will likely set a code without faking out the BARO sensor.

Go to Kennedy Diesel's (http://www.kennedydiesel.com/) web page to learn about the electronic boost controls.

If you do a search on this forum, CharliePeterson has explained several times how to disable the EGR system on L56's. I don't have one, so I don't want to comment on that.

[freddys]

So all you have to do to stop the EGR from working is

Disconnect vacuum line to egr valve, insert #6 panhead screw into egr valve vacuum port, reconnect vacuum line. simple way to disable egr system.

will this make any codes come up?

thanks guys

[triggerman]

Yes, it will set a P0401 (insuficient Exhaust gas flow). I have modifyed my EGR system to function at a zero egr flow rate at 64 mph or higher. this mod also increases boost up to 10 lbs.from the stock 6 or 7 max. I have occationaly set the P0401 with this mod but have gone over 1000 miles between setting that code. It is a simple (in theory) and cheap mod (10 bucks). Remove the black box on top of the intake man. This is your boost sensor. I installed a 1/4" brass barb into the side of the sensor port just above the manifold orifice that alows the boost pressure up to the sensor. trim the sensor nose back some to allow pressure to escape into the brass barb. Now install another 1/4" barb in the rubber intake hose between the turbo and the MAF sensor. put a piece of 1/4" tubing from barb to barb and your done. the ECU will automaticaly give you more boost because you robbed a portion of the manifold pressure and put it back into the turbo.So the wast gate is told to close untill the (leak) under the boost sensor is satisfyed. This then tricks the MAF into thinking there is not enough air comeing into the engine for a proper EGR mix ,so the ECU keeps the EGR closed at hiway speed. The only thing I would do differently is instead of drilling and taping the manifold for the 5/16th barb thread, I would make a 1/2" aluminum plate to be fit under the boost sensor and port the plate with the barb so it would be a drop in install. Good Luck

[freddys]

How does it know that there is (insuficient Exhaust gas flow).

freddy

[Bobbie Martin]

I'm not guaranteeing this will work, but you guys with computers & turbo masters may want to try this. According to my reference book, the PCM is looking for .8 to 3.9 volts from the boost sensor (it sends +5 volts out). All the boost sensor does is change resistance according to manifold pressure. So, if you cut the gray & light green wire off the boost sensor and soldered a suitable resistor across them, say maybe something around 2000 - 3000 ohms, the computer should be happy. You might have to experiment with the proper resistance to get it right. The trick would be getting a setting within the tolerance of the PCM.

If you are trying to decide between the computer turbo control & the turbo master, keep this in mind. The PCM method uses the vacuum pump, related hoses, several sensors, wiring harness, a electrically operated vacuum solenoid and a vacuum operated waste gate controller. That is an awful lot of stuff just to operate the wastegate. The Turbo master uses a rod and a spring. Can the PCM control the wastegate more accurately? Sure. But you have to ask yourself, does the simplicity (and inherent reliability factor) of the TM outweigh the advantages of the PCM control?

[rjschoolcraft]

NO!

[triggerman]

freddy;
I'v asked that same question here before and no one has been able to offer a definative answer. since there is no one sensor that measures egr flow, I would guess there is a ECU formula that takes throttle position,rpm,temps,MAF and engine load all in to consideration. This is a tuff nut to crack ! 95 and older can be simply pluged and blocked off. Hopefully, someday a real techy will share the particulars of this system here.

[turbovair]

Ronniejoe,
I sense that you believe strongly in the electronic approach to turbo control. Its nice to hear someone with such conviction.To me, the turbo master seems kinda chinsey. Is your boost system stock, or do you use resistors to up the boost?

[rjschoolcraft]

For the record...

I have no axe to grind against the Turbo Master. If I had a mechanically injected truck, I'd probably buy one or fab something similar to use. I don't think it is a smart move for the electronic trucks, but more power to those who do it...it's your choice.

I do think that the electronic appraoch is a good approach. There is flexibility available with it that is not available otherwise. Yes, the TM is simpler, but complexity isn't always a bad thing. I have had to replace all the components in the waste gate control system (184,000 miles is a lot of miles) and now it works better than it has since I've owned it. Presently, the only boost control that I have is built into the Kennedy chip. With everything working correctly, I now can sustain 13 psi in OD when towing for a considerable period of time. There is a hill near my home on a 4-lane state highway that is my bench mark. In stock trim with my loaded utility trailer, the truck would lose speed badly in OD and EGT would climb to over 1300F. If I down shifted to 3rd (direct) I could barely gain speed, but the EGT would try to climb more, sometimes over 1450F and I would have to back out. Now, I can accelerate up the same hill (better than in 3rd before) with the same load in OD running 13 psi boost at about 1050F EGT. It's amazing.

I will probably eventually add a boost control to the BARO sensor. The only thing that I don't like about the function of the system now is that at high rpm, the boost will taper back to 8 or 9 psi...still much higher than before. My EGT starts to climb then. Some have said that GM did this to protect the engine, but I'm not sure. I've noticed that at high elevation, the boost will not taper off as far. It will hold at about 10 psi right up to redline. This is because the PCM is compensating for altitude effects. The boost control on the BARO sensor will make the PCM think that it is at altitude when it is not and should limit the taper even at sea level.

Everything I've experienced with this engine says it really likes boost even if you don't add fuel in proportion. It seems to over come the losses in the intake and exhaust ports... which says that the turbo compressor is a more efficient air pump than the engine is. More boost pressure increases the intake air charge velocity which increases turbulence in the combustion chamber. This promotes better atomization of the fuel and better combustion. I've heard horror stories of blown head gaskets and warped heads, but I've never talked to anyone who actually experienced it. While I would like to build an 18:1 engine, that's a ways away financially, so I want to get as much boost and performance as possible with the stock compression for now. I've done some serious towing at the higher boost pressures now and all seems well. At some point, I will probably be looking for a turbo upgrade. ;)

[ 11-25-2003, 06:39 AM: Message edited by: ronniejoe ]

[autocrosser]

I have installed a Turbo Master mechanical boost controller on my 96 6.5 and am quite happy with it. I don't have any trouble codes setting and will soon remove the vac pump and go to the earlier earlier engine belt to bypass it.

I was starting to have trouble with the vac. solenoid. I installed the Heath controller and everything works great now. The next thing is to find a PCM from a non EGR engine to get more fuel.