Questions about new guages & new power

[TN farmer]

I have my guages in, it wasn't as hard as I thought it was going to be, but it has led to a few questions.

1. What temp. can I safely shut the motor down? I have noticed EGT being around 350 when I first park and then shortly it will settle at 300.

2. With hot juice in L4 I am seeing 25 pounds of boost. I have heard of hitting 28, will it not reach that point with stock intake & exhaust?

3. Why does the truck in the article about testing the 90hp juice smoke so much(it is under topics)? I barley get a puff of black with 120hp setting. What is everyone else seeing as far as smoke?

[SoCalDieselNewbie]

TN Farmer,

Generally, I shut down at 300 degrees farenheit. Personally, I am not really worried about EGT temp but rather Turbo housing temp.

The bright side is that the Duramax has a liquid cooled Turbo but it only operates, with water circulation, when the motor is running.

So if I was running hard... I'll let it idle longer, despite the EGTs being at 300, just to make sure the Turbo has had a chance to cool down.

When I get some time, which is real tight in the winter between fishing and hunting, I'll install a turbo housing temp monitor w/ shutdown.

As far as the boost some of these guys are seeing.... I am interested at how they are getting that high of numbers. The wastegate on the Duramax is a mechanical device that is NOT electronically controlled unlike the Ford PSD.

It will start opening at the same PSI regardless of the addition of an aftermarket power box or programming for the PCM.

There are 3 methods of increasing the boost level, that I am aware of, at which the Duramax will operate...

1) Change the waste gate spring or wastegate itself so that the waste gate opens at a higher PSI.

2) relocate the bleed off hose from directly behind the Turbo housing to directly before the intake. While the wastegate will open at the same PSI as before, it will now be measuring boost after 'air system' loses, rather than before, thus effectively increasing the boost that the motor will experience.

3) Plugging the hose that leads to the waste gate. Using this method, I have heard of motors experiencing up to 32 PSI. According to the turbo guys that I have talked to, you are now in jeopardy of experiencing a turbo spool back. Simple put... Not Good!

[SoCalDMAX]

TN farmer,

I personally shut down anywhere below 350*. The turbo is water cooled in addition to the oil flow. The EGTs we are seeing don't correspond exactly with turbo housing temp. I consider 180* to be the low end of oil operating temp range here in warm CA. When I glance over and see 179* oil temp, 145* tranny temp and 140* diff temps with an EGT of low 300s, I feel pretty confident that nothing's too hot to shut down. I realize the turbo vanes may be considerably hotter than the bearing surfaces, but I'm pretty sure Delo 400 isn't coking at 179*. ;)

IRT why is the truck in the pic smoking so much, it's because the Juice is on level 4, the Power Plug (which increases fuel rail pressure a set amount regardless of RPM)is on 50% and the propane is on. I've since experimented and decided the Power Plug was adding WAY too much fuel at lower RPM and it's now disconnected. Most of that smoke was from the PP.

Now if you want a real kick in the pants and get rid of that last little bit of tell-tale smoke, add a PS2000 propane kit to complement that 120hp Juice. It will warp time and tear the fabric of space, or something like that. At the very least, it will shorten your tire change interval and make you act like a 16 yr old kid again. Don't say I didn't warn ya... ;)

Regards, Steve

on edit: The wastegate opens at 20psi and dumps excess boost. Apparently the outlet is not large enough to dump the boost as fast as a modded Dmax can produce it, thus the increased boost to 24-26psi. I've moved my boost sensor from the wastegate hose to the intake, just prior to the huge intake heater. (Why Isuzu put something that big and restrictive in the bend of the intake is beyond me.) I saw no difference in pre or post intercooler peak boost readings. This indicates to me that the intercooler does not currently pose much of an obstruction and the engine or turbo exhaust section itself might be the choke point. I think JK knows a great deal more on this than I do.

[ 12-04-2002: Message edited by: SoCalDMAX ]</p>

[Kennedy]

Steve,

I'm just sitting back and absorbing all this :D

My observations have been that: Stock 20-22psi peak. Mild box 24 psi. Juice box and above, 25-26psi WITHOUT rigging the gate. I believe that I've seen 28psi peak on an un rigged gate. It is all based on how fast you can get the little gerbils turning the wheels :eek: If you can drop back psi post turbo, it will affect psi pre turbo, and the internal pressure exerted on the wastegate which is also a factor. The amount of heat energy in the exhaust can also be a factor...

[hoot]

I see 25 psi reading post intercooler, propane.

[Maverick]

On WOT runs pulling my trailer on level ground always seems to set the SES light. It is always "Excessive Turbo Boost" code. Happens after I get done passing all the Fords and Dodges and let off the gas fast to slow down. If I ease off the gas it is less likely to happen. Anbody else have this happen???????

[SoCalDieselNewbie]

Steve,

Your "on edit" portion is exactly right but I don't count bleed off boost, where the needle bounces between 22 & 25 Psi, despite no change in load or throttle position... it is unreliable boost.

Anyway, at this point, with these programs, it doesn't really matter how much boost you are putting in up top. They are already pulling fuel out to keep the Ally from going into limp.

It is why the guys that blocked of the bleed off hose to the wastegate see little or NO INCREASE in power over an unmodified wastegate.

Once the Ally can be beefed up to handle additional power, more fuel can be added and additional boost will make more power.

IMHO, a modified wastegate is the only way to fly at that point.

[ 12-04-2002: Message edited by: SoCalDieselNewbie ]

[ 12-04-2002: Message edited by: SoCalDieselNewbie ]</p>

[hoot]

Yea mine does that and MAF code when hammering on the highway with lp on.

Only difference is I can't pass anybody cause she backs off on me.

[imported_]

mav.. i have the same code now too... i feel for ya!