Re-routing wastegate hose for more boost

[DragRacer68]

I was told that on my 2000 model 3126 CAT that I can reroute the boost reference hose on the waste gate to the intake manifold instead of the compressor housing. Its a short little orange hose. This will make more boost in the engine since it makes up for the loss in the intercooler and tubing. Makes sense to me. I was told that CAT did this themselves in around 2002 anyway. Anyone do this? Would be a heck of a lot cheaper than buying a $500 power programmer and give me the extra boost I need pulling my trailer on long hills. I assume the factory tuning could account for the increased boost, surely there's enough margin in the programming for a few extra psi. Also, anyone know where I can find pics of a 2002-up 3126 engine where I might be able to see the how the waste gate is referenced? Thoughts?

[wb7auk]

I changed the waste gate boost line to the intake manifold and while at it put a
adjustable waste gate controller in line as on my engine the waste gate is not
under the control of the ECM.
A Perrin waste gate adjustable ($80.00 item) allows you to increase the boost
pressure to increase the amount of boost before the waste gate opens.
One needs to know what the boost pressure is to adjust it correctly.
The increase of changing the location depending on pressure loss of your system can
be a couple of pounds without the Perrin.
Hose and connections were just under $7.00 at my local house of hose store.

[Cat]

Be careful about over boosting. Turbochargers are turning running very high rpms 90,000-120000. Going above their design specs can and does cylic over loading of the compressor wheel. This causes the wheel to split in half= new turbo.

[Mr_D]

Originally Posted by Cat

Be careful about over boosting. Turbochargers are turning running very high rpms 90,000-120000. Going above their design specs can and does cylic over loading of the compressor wheel. This causes the wheel to split in half= new turbo.

And therein lies the problem with do it yourself "hop up" tricks. Sure they might work but at what cost and for how long? If the wheel breaks the pieces are going to go into the CAC and probably destroy it.

Too bad they don't make a Banks kit for the CAT's like they do for some Cummins, it really made a difference on ours.

[wb7auk]

Both Mr D and Cat are correct in their statements when it comes to operating
pass spec's.
The mod I posted is well within the spec's of the turbo and engine if the boost
level is 35 or less psi, that is 10 psi below turbo max per spec's.

[DragRacer68]

Originally Posted by wb7auk

Both Mr D and Cat are correct in their statements when it comes to operating
pass spec's.
The mod I posted is well within the spec's of the turbo and engine if the boost
level is 35 or less psi, that is 10 psi below turbo max per spec's.

Thanks. I agree with what you guys are saying CAT and Mr D. I don't think it will add that much 'extra' boost to the engine. Probably not anymore than you might gain in really good atmospheric conditions....really cool dense air makes more boost also. I just wanted to hear from someone else who's done this to make sure there's not any pitfalls. I plan to also add a boost gauge first so I can see what boost its at now and after the hose mod. Is there any open ports on the intake to add a new fitting? I looked around a bit and didn't see anything. Thought I may have to remove the upper intercooler tube and weld in a bung.

[wb7auk]

The manifold should have 2 or 3 plugged port just in front of the factory boost sensor.
Which are located on top of the manifold toward the rear of the engine.
Make sure you clean the area of any dust or other junk before you remove a plug.
The plugs require a hex drive of the proper size to remove.
When you install the connector use straight connectors as 90 degree type will not
work because of the angle of the intake and the head.
Relocating the boost line to the more accurate engine boost at the manifold rather
than a source that the air is hot and takes no account for the losses in pressure
due to piping, CAC looses or the pressure drop once the air is cooled.
This change in location should net something along the lines of 2 psi or more and
that is about 20 hp give or take.
If you want to raise the boost up it is far cheaper to install a adjustable waste gate
control in line than to replace the stock control that cost upwards of 160.00 dollars.
There is a limit in the amount of boost one can increase without increasing fuel where one of the power chips comes into play that tricks the ECM into doing that.

[DragRacer68]

Thanks Art for the help!

[wb7auk]

The best investment you can make is a scan D or similar unit, scan D's are about
139.00 for the real one and stay away from copies.
It will provide you with all kinds of information that will alert you to a problem
and also provide information for best engine operation.
The items I keep an eye on are intake air temp, coolant temp, transmission temp,
and boost.
I also have a stand alone boost and EGT gauge because I run a chip and the ECM
does not report EGT and the boost will be wrong with the chip turned on.
Feel free to PM me if you have questions.

[Skip426]

Art, thanks for the detailed information, I wish I had seen it 2 years ago.
When I got my coach , it would de-rate on long pulls , unless it was running on cruise control. Took a while to track down the cause. During engine install into the frame the 90 degree fitting on the turbo housing had been snaped off and the hose punchured in 2 places. 3 owners 52,000 miles , the waste gate never operated, I had the turbo off to extract the broken fitting, no carbon in the chamber past the wastegate plate, waste gate " pot " dented but still operational.
Had been looking at Scan gauge D , and now will pull the trigger.
What brand of , EGT/Boost gauges are you running ?

[wb7auk]

Skip426,
I purchased the GlowShift 3 in 1 gauge for oil, EGT, and Boost (main dial).
That gave me oil and EGT in LED read out and a regular gauge for boost but
you can order them anyway you want.
NOW their EGT probe is a joke.(probe way to short for diesel)
Order a 4 inch probe with exhause band and install it at the turbo output with
the probe at least half way inserted so the tip of the probe is in the middle exhaust
stream.
I ordered the correct probe from Auberins.com.(best price)
I ordered the Perrin waste gate control from StreetRays.com. (best price)
You can purchase extra EGT cable(comes in 45 to 50 ft rolls) OR you can use shielded data/communications wire.( some phone wire is the same thing)
Temp error is less than 1 degree and a lot cheaper.
Before someone pops a fuse in EGT probe location that is the only place where
you get all of the cylinders average temp but that temp is approx 300 degrees
below true temp taken at the exhaust port of the head.(as measured by a lazer
temp gun)

[emdub27]

I can concur with everything art says. I have been running my engine at 33-34 psi for a couple years now. I also use glowshift 3 in 1 gauges. I have two of them. One measuring egt in the exhaust manifold, pre CAC boost, and turbo drive pressure aka exhaust back pressure before the turbo. The other measures egt post turbo at the pacbrake test port, manifold boost pressure and oil temp. I just hooked up the turbo drive pressure sensor today, so no data on that yet. The stainless tube coming out of the exhaust manifold goes to a filter and then to the drive pressure sensor, so the sensor doesn't melt. The most important part though, I can give solid data on pre vs post turbo egt. On my engine at full load I see about 1300 in the manifold and about 1000 at the pacbrake. A word of caution, pacbrake told me on some of their brakes the blade will swing back all the way to the test port potentially hitting the egt probe and damaging it and or the brake itself. I tested mine with my air compressor and it has a solid 1/2" clearance from my probe.

[Mr_D]

The new ISL 450's seem to run 35 psi. Our ISC with Banks (new turbo housing and waste gate control) brought the boost up from 25 psi to 35. That, and the injector control in the Banks kit, made a huge difference in power.

[jauguston]

My C-7 ECM will derate fuel if the boost gets much over factory spec (27.5psi). I can watch it happen on my pyrometer. I have a MP-8 that gives me a lot more power but the boost never goes over 28psi.

Jim