Bigger turbo options (Britannic)

[Turbine Doc]

Britannic,
In my ongoing quest for more power what is your opinion of the stock GM-8 in my 6.5 vs. the MHI you are running now,or even the Peninsular 300 hp turbo. I talked with Kennedy a bit about experimenting with a bigger turbo he has, but it may take some creative engineering on my part to make it work.

I fit the large Sperco IC kit which was not supposed to go into a K1500-L/56, and am fairly adept at coming up with creative solutions, I guess what I'm after is an answer is there a power gain from turbo swap over stock set up out there worth the effort.

I'm still running stock pistons not ready to go to 18:1 yet, so even with the IC I think I'm best to limit to less than the 15 psi boost I can get get with the GM-8. I run at 3-7 psi boost with boost control unless heavily loaded where I can peak boost up to 15 hard on the throttle, I could tweak up the boost setting some more but haven't done so yet as I'm hesitant to run that high a boost sustained with stock compression.

With press vs temp vs cfm relationship in air compression; I'm wondering if what I'm after is more volume not so much as a pressure increase, or a reduction to turbine back pressure. What is best way to go from your experiments, bigger turbo less back pressure/ smaller turbo more pressure, or bigger compressor on GM-8?

[DogDiesel]

I have run the GM4, the GM8 and now the Peninsular Performance Turbo.
With your trucks set-up, and what I'd suspect your use, the GM-8 (or GM-4) is best.

The wastegated turbos run clean, and give the best spool up and pep. They do have draw-backs.

My PPT makes those little cars that crawl under your rear bumper (yeah-those with the fart-tubes) back off, on each gear (5 sp) if I don't feather the throttle. My goodness, I love this new tool! smile.gif

Until someone makes a better wastegated turbo, for empty running and light towing, the GM-* series with boosts set at 10-12 are good.

Wayne

[Turbine Doc]

Wayne ,
Thanks for the input, should have mentioned what my goals are. I'm not after more power for racing but for pulling some serious weight estimated 15K of trailer & backhoe, that needs moved to high ground during hurricane season, so it doesn't get underwater at my camp on the river again, as happened 3 years ago.

Way over GVR but am only moving 20 miles on farm roads maybe 2x a year, bought a real trailer new 9T cap gooseneck tandem dual axles all bells & whistles, I've upgraded my truck brakes, suspension, tires & wheels, equivalent to 3/4 T running gear, will eventually change suspension to 3/4 or 1T single axle if I can come across a can't pass on it deal. If I have to move any real distance I think I'll rent a Medium or Heavy duty truck designed for that kind of weight.

Should have bought a dually from get-go but never figured I neeeded a truck that big, too much into this one now to start all over again on another, plus this has turned into a labor of love project, never figured myself as a Diesel nut, as my heritage has been gas & jet engines, but here I am out of the closet Diesel-head.

[DogDiesel]

My truck is a 5 sp 4x4 single rear axle, and I have 4 trailers. My largest hauler is an equipment GN hauler.
Recently, I did similar what you are considering. I put a 16.5K HD-5G crawler loader(which I thought only weighed about 12K) and tractor front loader attachment (750lbs), and moved it, however to my favor, I could lock all four brakes on my GN and slide tires, plus perfect brakes on truck. I thought I was about 3K over GVWR, but to my dismay, when I ran it over the scales, I grossed 28,400lbs. I knew trailer weighted 4400lbs, and figured truck and extra fuel at 7400. Ouch, what a load. But I whipped right thru the gears, and it handled well. I really felt bad about the weight, but had already traveled well over 700 miles with it. Good thing I was almost home at the scales, cause I had treadmarks in my BVDs.

I can remember my truck when it would run out of power (stock) with a load. Pulling my RV at 60 MPH was simply not on the do-able. But as I added modifications, more power came. Suspension and brakes have always been super. But with low compression and now this turbo, I may just have more engine than I need. The power it delivers now is totally OK. I have to be cognizant of not pulling it as hard as it can, because I lost a 5 speed NV4500 transmission, in similar fashion to the cummins trucks. Fluid there, just cleaned off the gears. So I don't hammer it loaded.

When I bought my Peninsular Performance Turbo,to replace a normally functioning GM8/heath Cont, Matt at Peninsular fully explained the 300 HP would smoke WAY WAY too much for a standard, that the PPT would be better, but that neither would be as smoke clear as the wastegated turbos.

Never more right. While it makes gobbs of power, down low, and all the way to 4K RPM, pulling in a caliber not of 6.5 similarity, it smokes. If you want power, the PPT will make it. If you want to drive a nice clean pretty truck, that makes people wish they had it, don't move, cause the dark gray smoke cloud it makes on takeoff will give you up as a non-environmental lover. Power equal on low end to the GM8 and better on the top end. But not without tale-tell exhaust.

The PPT is not for light duty drive around trucks, but if you're pouring the fuel to it, then I have to say the spool up is not as quick as the GM8 up to 2500, specifically from 1500-1800 it is stagnant, but then wakes up.

I wish someone made a controllable wastegated turbo just a vein heigher than the GM8, but their is not.

Before the FORUM crash, I reported on my PPT. I rated it A minus, due to smoke up 1500-1800, and forget using below 1500 like I did with the GM8.

Just as my load was too much, probably too much for the trailer, as if it had the third axle, one more set of brakes, OK, I would not urge you to knowingly overload a 3/4T.

I'll pull my load again, when I put the 3d axle under the GN. Plenty power. Used with common sense, it will perform for me for years to come.

I don't pull punches nor try to fool you my setup is perfect, right now on the market, there is no perfect turbo for the 6.5 modified with low compression pistons, and mods. I do believe the GM4 and GM8 are good for most 6.5s.

Wayne

[britannic]

The MHI TE06H was used by Bank's on the Ford 6.9 and 7.3L engines. It has excellent spool up, good CFM and produces 15psi on my engine above 2800rpm WOT under high load. I'm injecting over 70cc3/min/2000rpm/@ WOT and EGTs can eventually reach 1100F on a hot day during a serious hill climb. An intercooler is definitely in my future :D !!

I don't have any way of comparing the GM8 to the MHI and originally I was planning to fit one, until research showed the MHI downpipe connection needed less modification of my Bank's Sidewinder set up and was a direct bolt in to the manifold (the GM8 would have fitted as well).

Since Bank's designed it for the larger displacement engines, I knew it would work well in mine, because the original Bank's T04B was boosting off the scale of my 15psi pressure gauge above 2800RPM.

Bank's never intended their Sidewinder for the 6.2L to be fueled by a DB2-4911 and 6.2L injectors and had anticipated max boost of 9psi. They deliberately set the A/R of the turbine to flow more exhaust than the 6.2L can produce with a stock fuel system and a compressor trim that would supply lower boost levels at high rpms.

I needed a way of controlling the intake air heat by capping peak boost pressure and also to reduce the turbo lag and black smoke at lower engine speeds.

The MHI performs really well, plenty of boost when you need it and it cut my EGTs around 200F overall in comparison with the Garrett T04B, so I was able to turn the pump up another 1/8 of a turn.

[DogDiesel]

I think this wastegated setup has merit.

If it will hold boost, it will pull.

Wayne