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I went with a custom tune from a local shop. Cost me $100 less than a hand-held, and I got so much more. Additionally, any changes I want they make for free. This works for them, because anytime I go into the shop, I get the bug to do something to the truck. At this point I know a cam replacement is in the future, and it'll pay off for them. I paid $75 for a dyno run (and final tune) that enabled us to squeeze a bit more out of the system while dropping back the fuel requirements. The original tune was a 91 octane (which is what 6.0L LQ9 is supposed to run), but now I get to run 89 octane no problems. It's been excellent to watch the mileage go up, and the octane requirements go down. And for what I paid, 1.5MPG (12 to 13.5 in city and almost 2.5 on the highway going from roughly 16 to 18.4) it's definitely helping pay for the tune.

Was very very fun to see the HP and torque curves, too. Knowing that I get 80% of my power at 2000 RPM and it peaks at 4400 RPM helps me really "Get" the fact my engine has a nice powerband that isn't only producing at insane RPMs.

Love my truck... I imagine you feel even more so about yours, with all the work you've put into it.

Skippy
 

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Riley
Thanks for asking
No we rode it out-and it was MUCH WORSE than I expected.
The winds were higher than I expected-it was just a Cat 1 so I expected maybe 60 mph winds-but we had steady 80 mph-and gust to maybe 100 mph or so
AND the WIND- lasted FOREVER- about 24 hrs of very high wind.
Most hurricanes give you about 8-10 hours of hell-this one lasted forever because it was so slow-5-6 mph-and so large-400 miles across.
It rained for 50-60 hrs straight-steady not torrents-so pumps kept up,

Oh-I had to tow our Prius off the lawn with the Suburban-used 2 sets of MC tiedown straps-the Prius has nice rear tow "hooks" built into the rear frame-surprised to find them
3 days of rain meant lawn was really soft- but stupidly I put it in reverse- backed maybe 2 feet-and then just dug in.Got the Suburban backed into driveway-rear tires on concrete-pulled it right out-3000 lbs in sucking mud 6-7 inches up tires.

Hey-glad you beat the Navigator($40,000 probably)-and 17 mpg-with that monster motor-stunningly good mpg!!
Charlie
PS Sorry for hijack
PPPS Coleman -Tecumseh 3000-3750 WATT gen-worked great- 2 small window units+ fridge+TV+DVD player-very noisy but worked great!Very very hot humid here in River Ridge-70123
 

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Discussion Starter · #23 ·
*UPDATE* - Magnaflow exhaust
I'm posting an update because I've had a small issue with the Magnaflow exhaust system. First of all, let me be clear, I LOVE this exhaust system. It lets the engine breathe so much better, sounds great, and is high quality.
However, there is one problem. Magnaflow has a design criteria for these systems in that they use all the stock factory hangers and locations only and require no welding. This makes installation simple enough that you can do it yourself. On these trucks though (and I'm guess this applies to a lot of the GM/Chev pickups as well), the stock hangers are arranged such that they put a torquing force on one of the exhaust joints. The one right behind the muffler as pictured in IMG_20120818_122021.jpg. This twisting load eventually, and inevitably leads to the joint coming loose. Usually it starts flopping around before it would ever drop right off, but if you weren't attentive to your vehicle it could conceivably fall right off.
This is one reason I always do a walk around before I get in my vehicle.
Anyway, this is not Magnaflow's fault per se as they use the factory mounting points and it stays in place fine for months so they probably never noticed it in testing. The quick fix is to wrestle the tail-pipe back in place and crawl under the truck with a wrench and a spark plug socket (fits perfect) and tighten it up again until the veins in your head start to pop. But that's not permanent and no compression joint could possible survive a torsional load forever.
The way I see it, the fix is to either weld that joint or do what I did.
I drilled a hole through the joint, including the clamp, and installed a 5/32" stainless steel blind rivet ("pop rivet"). I used this because it's the heaviest rivet size that my rivet gun will handle and I used stainless because I didn't want dissimilar metals in contact for several reasons.
I just did that a few weeks ago and so far so good, but we'll see how it holds up in the long term. I have a buddy that had the same kind of problem on his 78 Trans Am with an aftermarket exhaust and this was his solution so hopefully it works for me too.

Meanwhile, this in no way reduces my recommendation of the Magnaflow exhaust for these trucks. I only add that I would have the muffler shop weld that joint instead of using the clamp.
 

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I've been thrilled with my MagnaFlow's performance... not so thrilled with a few other things. The Magnaflow exaust muffler is stainless steel. Right now it looks like Rusted Steel. In less than a year, it was all patchy, and now 5 years later, it's nothing but rust, with a few patches of stainless steel shiny things (smaller than a penny). Unimpressed. I was told it would look good for the life of the product.

Second thing that bugs me is that the exhaust pipe seems to emit far more heat, than the stock did. How do I know? It's warped my shock boot. Not a big deal, but I have to spray WD-40 or Silicone on the thing all the time to keep it from rubbing and squeaking on the shock. Basically, by heat damaging the inside of the boot, the boot is now pulled toward the muffler.

NONE of these problems have anything to do with my MagnaFlow's Performance (Love it). Just wish it still looked good, and didn't warp my boot!

-Skippy
 

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Any updates? Gonna be doing this swap on my 99 in the near future.
Yes, as good as this thread is, I'd sure like to hear about any updates too.

I upgraded the wife's '99 Tahoe with an HT383E. However, I haven't done the cold air intake (yet) nor the headers. After about 10,000 miles I'm still working the bugs out. Got the pesky P0305 (cylinder 5 misfire) fault code from time to time and more rarely, the P0430 (catalyst system efficiency below threshold, bank 2).

I'm not to worried about the cat fault code. I'm thinking of removing them soon anyway and reprogramming the ECM. But the cylinder 5 misfire has me (and many others) stumped. Believe me everything has been tried and every diagnosis attempted.
 

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bamcis,

How do you like the swap? Is it worth the extra $?


Just do the Spark plug anti foul trick with Ox sensor to get right of cat code
It was a very straight forward swap. Pretty easy in fact. Like Tachyon said in one of his posts, FOLLOW THE INTRUCTIONS to the letter and you'll be fine.

As for it being worth the extra money.....well, the jury is still out. The old 5.7 motor that had 250,000 miles on it towed my boat nice and this one tows it better. I'm just not sure it's north of 3 grand better. I don't abuse it by any stretch of the imagination, but you can sure feel the extra torque. It really sets you back in your seat. The wife sure likes it. The mileage is about the same as the old one, maybe a smidgen worse. :eek:

I aware of the anti-foul trick you mentioned, like I said, I'm not to worried about it. However, I think I may have a handle on the P0305 code. When I swapped the motor, I also installed a new spider, for north of $400.00. Damn, those things are not cheap. Anyway, I've been dumping in Techron fuel additive for the last two tanks and so far (fingers crossed) the code hasn't reared its ugly head. :cool:

Along with the swap I also ****-canned the stock transmission and oil cooler lines. After I learned the cost :eek: of new ones, I built some using #6 AN steel braided hose and fittings. I could have bought brand new replacements from NAPA or Autozone, but I just have OCD about replacing parts made by the Chicoms. :mad:

Tachyon recommended swapping the transmission. I agree. As of right now I haven't touched mine and I don't know if this is the right thing to do or not but I'm going to wait until it breaks hard and then upgrade it too. I figure if I can get another 25 or 50,000 out of it I'm money ahead. :D
 

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Discussion Starter · #29 ·
Just thought I'd pop in and mention the old girl is still running great. I've never regretted the HT-383E swap for a minute.
Though we did have one mishap recently.
One of the few original parts from the factory engine I kept instead of replacing was the water pump. Well that finally failed in a big way. Right where one of the bolts passes through the backplate of the pump. Anyway, I had it replaced with a Napa HD pump and my mechanic recommended a new, synthetic coolant instead of Dex Cool. Apparently one of it's major benefits is it prevents the dielectric effect that happens with the dissimilar metals in the cooling system, causing corrosion, pitting etc. The other thing I've noticed is that it runs noticeably cooler. It's like even better than regular coolant with Water Wetter added. Apparently it has good thermal transfer characteristics and similar surfactant properties to Water Wetter. Either way I'm very happy with it and it feels good to have a fresh water pump and freshly flushed and filled cooling system.

The other uh-oh that happened at the same time the water pump failed was the driver's side rear lower shock mount broke right off the axle. I was freaked thinking the axle tube was damaged. But it's all good. Once again my awesome mechanic did a nice job repairing and building up the broken mount bracket and welding it back onto the axle tube. He even gave it a fresh coat of paint.

Unfortunately my todo list still has items. I have already purchased a new pair of high-end Bosch O2 sensors and I plan to replace those when I get the time. The old ones have been flaky and throwing codes for a while.
I also need to replace the front driver's side wheel speed sensor and install some s-clip bolts and new gaskets on the headers. <sigh>
But hey, every time I want to complain, I think of the thousands of trouble free kilometers the truck has given us in some of the harshest conditions known to man and I can't complain. I've still spent way less than a new truck costs and you can't put my truck in the ditch remotely by hacking the radio! ;')
 

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Discussion Starter · #30 ·
UPDATE - Sep. 2015
OK gang, it's time for another update. I'll be my usual wordy self so that I cover everything. ;')

One thing you learn as you get older is that you can't think of everything any more than you can afford everything anyway. When I did the HT-383E swap in the first place, I tried to think of as much as I could, but things were missed, like replace the original water pump. But then considering it lasted another 4 years, maybe it was the right call...anyway, another thing I missed was upgrading the exhaust gaskets and bolts.
I'm old enough that I accepted the idea that I'd just have to re-torque the header bolts every year unless I wanted to cough up for drilled and wired header bolts because those were the only options we used to have. That's worked OK until recently when I just plain blew out the header gasket and now the truck sounds like it's part of the ******* jamboree orchestra. Today I'm fixing this issue once and for all.
I've bragged on my mechanic here before, and I'll do it again because truly good mechanics are becoming more and more difficult to find. When I had the water pump done, I asked him to go ahead do my yearly header bolt re-torque for me. He did, but he also recommended an upgrade to fix the issue once and for all. That's what we're doing today.
The upgrade is to replace the header gaskets with Remflex crushable graphite gaskets and replace the bolts with Stage 8 locking bolts.
The Remflex gaskets are several times thicker than standard gaskets but they crush up to 50% so once you torque the headers, the gaskets crush to form fit and make a nice, tight, perfect seal. Because they're graphite, they can also handle high temperatures without breaking a sweat and they don't need any other sealant.
The Stage 8 bolts have a locking mechanism that means you torque them once and forget about them forever.
So that's today's upgrade and frankly it's one I recommend for anyone doing the swap or putting headers on their vehicle.
One other thing. I had mentioned previously that I have been having issues with popping O2 sensor codes. I had planned to replace the sensors, but when I got the header bolts re-torqued last time, the codes stopped for a while. This leads me to believe that the real problem was the exhaust leak causing the emissions system to misread the O2 sensor data. Because of that I'm going to wait a week or two after the header gasket/bolt upgrade and see if the problem recurrs or goes away. If it comes back, fine, I'll replace the O2 sensors. If not, hooray.
Here's some resources and pictures of the parts I mentioned here.

Remflex crushable graphite gaskets - http://goo.gl/3xedfo
Stage 8 locking fasteners - http://goo.gl/3sqxvy
Note that these are links directly to the correct parts for this (my) application in case anyone is duplicating this thread. You can browse your way to the main page of those sites from there.
Here are the photos of those parts. These are the actual parts for this HT-383E + Headers application.





 

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Discussion Starter · #31 ·
bamcis,

How do you like the swap? Is it worth the extra $?


Just do the Spark plug anti foul trick with Ox sensor to get right of cat code
Personally I think the "right" way to handle this is to buy a performance CAT instead of cutting out the CAT and tricking the sensor.
Not only do you not have to deal with computer/sensor issues, but you're still legal. Given how they're cracking down on emissions stuff in most places these days, it's just less hassle IMO.
That said, the anti-fouler trick is pretty slick.
 

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Great stuff-someday I plan to put a 383E in my 1998 Suburban.
It won't make $$ and cents sense of course
because my 229,000 mile motor still runs great-,
but not everything is about $$ and cents sense.

Huge aside
A long while back-on a GM truck forum-maybe this one
a member posted a long thread -might have had to do with HORRENDOUS mpg and knocking
Anyway he was from the NE somewhere-Mass NY Maine NH Vermont-Somewhere up there
Well Long story-somewhat shorter-
he finally traced his problem to some sort of exhaust leak.
Apparently the leak made his O2 sensor think he was running too lean-lotta O2 detected
so it kept pumping in more fuel-
but the OVER rich mixture GUNKED and Carboned up the heads(maybe he was knocking also??)
made it get horrible MPG- the ignition was retarded because of the KNOCK detectors-making the FE even worse
maybe it did in the cat con also.

Anyway a big cascade of crap from an exhaust leak
Yeah hard to believe it was just an exhaust leak-maybe I got it wrong,but…

It always seemed odd that there wasn't a "built in map in the computer" that would prevent extremely rich mixtures-??
There must be some base settings for running with the MAP and the O2 sensors both DEAD??-running with just RPMs and throttle position telling it how much fuel to squirt in??

Thanks
Charlie
PS Crude question-roughly how much out of pocket would you guess the switch has cost to date??
The engine is about $5000 delivered-real bargain-for genuine drop in GM
Guessing you must be around $8500-$10,000 depending on labor-bargain for almost 35% more HP and -70-80 more Lb-Ft
 

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Discussion Starter · #33 ·
UPDATE: Sep. 03 2015 - Part II

Sooooo....<sigh> I'm getting new headers too. Aside from the factory gasket failure, the cone dropped out of one of the headers. This is a "unique" feature of the JBA headers, a cone in the collector that smooths the airflow yada yada. Anyway, I thought by the sound that I had a collector leak too but I thought it was the usual need to have the collector donut re-tightened nonsense.
I'm going to go with the JBA's again, in part because they're still the only emissions legal (they have the AIR injector bung) shorty headers for that vehicle that drop right in place of the factory manifolds. I'm disappointed, but I'm not blaming JBA just yet. I think it was a combination of thermal cycling, the local temperature extremes, and some local bad road pounding. In fact this started when I hit a bad pothole section down the street the other day...
Anyway, in looking at the JBA's, the failure seemed to happen at a weld seam. Otherwise the headers are in pretty good shape for being over 4 years old in a winter used, daily driver.
Here are pics of both the failed header and the good one with the cone still in place. You can also see how the O2 leak has caused the vehicle to run rich and carbon up the exhaust.








One amusing part of this story is that since we got this engine replaced, it's been a point of pride for my wife to tell people that she wrapped those headers. (great wife eh?!)
So it brought a little humour to the situation when her biggest/first complaint at the news was that her wrap job won't be in there for her to brag about any more.
;')
 

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Discussion Starter · #34 ·
Great stuff-someday I plan to put a 383E in my 1998 Suburban.
It won't make $$ and cents sense of course
because my 229,000 mile motor still runs great-,
but not everything is about $$ and cents sense.

Huge aside
A long while back-on a GM truck forum-maybe this one
a member posted a long thread -might have had to do with HORRENDOUS mpg and knocking
Anyway he was from the NE somewhere-Mass NY Maine NH Vermont-Somewhere up there
Well Long story-somewhat shorter-
he finally traced his problem to some sort of exhaust leak.
Apparently the leak made his O2 sensor think he was running too lean-lotta O2 detected
so it kept pumping in more fuel-
but the OVER rich mixture GUNKED and Carboned up the heads(maybe he was knocking also??)
made it get horrible MPG- the ignition was retarded because of the KNOCK detectors-making the FE even worse
maybe it did in the cat con also.

Anyway a big cascade of crap from an exhaust leak
Yeah hard to believe it was just an exhaust leak-maybe I got it wrong,but…

It always seemed odd that there wasn't a "built in map in the computer" that would prevent extremely rich mixtures-??
There must be some base settings for running with the MAP and the O2 sensors both DEAD??-running with just RPMs and throttle position telling it how much fuel to squirt in??
No that sounds believable. I've seen a bunch of ramifications from exhaust leaks myself. From rich operation, carbon build up, poor performance etc. I can't imagine how bad it is on a newer, even more computer dependant vehicle. The computer does have a "limp home" mode, but apparently this failure isn't bad enough to trigger it, and actually I'm glad it doesn't. The reason being that this means the default MAP and fuel system have enough headroom to provide fuel for some reasonably substantial power upgrades. By my best estimates I'm already pulling at least 125 HP worth of fuel flow over stock, minimum, through the factory fuel system and throttle body.

phoebeisis said:
Thanks
Charlie
PS Crude question-roughly how much out of pocket would you guess the switch has cost to date??
The engine is about $5000 delivered-real bargain-for genuine drop in GM
Guessing you must be around $8500-$10,000 depending on labor-bargain for almost 35% more HP and -70-80 more Lb-Ft
As for dollars invested....tough to answer specifically. I've guessed it's around $22-25k at this point, including what I paid for the truck.
The engine swap was roughly $11k, BUT, that includes, among other things, labour, a new 4L80E transmission, front drive shaft, front brakes, oil cooler lines, fan clutch and having the radiator removed, pressure tested, and the cooling system flushed and filled with Dex, etc.
This also includes some new front end components (thanks pot holes), rims and tires, rear axle and pinion seals, new grill and lights, grill guard, new water pump, the magnaflow exhaust system and cats, Hypertech programmer, HD class IV hitch receiver, lights, K&N Cold air system, Power Stop brake kit with slotted/drilled rotors, and pretty much everything else I've posted about here.
Overall, even with today's repairs, I'm very happy with the truck. I had a plan from the beginning to find a 99 K2500 HD with a good body at a cheap price and build it up from there rather than investing in a new truck. I have the truck the way I want it. It runs well, has lots of power in the right ranges. It gets decent economy and can tow or haul a house with a household full of gear and people loaded inside. Best of all, unlike a new vehicle, it doesn't have any of the government nanny systems in it so I'm in control of what it does.

I can't say if this project is worth it for everyone, but it's been well worth it to me. I plan to keep this truck for years and only add other vehicles to my stable, not replace it.

Note: These numbers are all in Canadian dollars, but when most of this was done the Canadian and US dollars were near parity so the difference should be minimal.
 

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Tachyon
I wanted to say Thank You for your posts detailing your journey with you drive-train replacement. I found your thread doing a search for information concerning the GMPP HT383E. After reading through your post I see we have similar products on our trucks. I replaced my CAT back system about 6+ years ago with a Magnaflow system and could not be happier. I decided to go with the Brute Force air induction system from AEM as it allows for the use of the stock plenum on the truck. At the time I was making my purchase K&N was having issues with their cold air intake coming loose at the throttle body.
If by chance you happen to have time could you let us know what coolant you went with, the reason I ask is after going through two radiators I finally bit the bullet and bought an all aluminum 3 core radiator as a replacement, wanted a 4 core but they were still developing it at the time and couldn't wait. Anyway would like to use something better than the Dexcol product.
I was on the fence about getting the GMPP HT383E or going with the 6.0 LS engine swap, staring to lean towards the HT383E so as to keep it original and I already know the system. This is my second Tahoe, my first was a 1995 2 wheel drive, have had this one since new in May of 1999 with only 0.7 miles on it. Was thinking of moving to another truck but just can't let this one go, so my plans are to put new life into her like you did.

Again Thank You and keep updating.
 

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Discussion Starter · #36 ·
Just an update. So far the replacement JBA headers have been fine. I think my guess of a one off fluke manufacturing defect combined with extreme temperature cycling was probably right.
Next up is a fuel spider replacement and upgrade (sigh). I'm having the rich/lean issues indicative of clogged injection tubes. because heavy duty injector cleaner in the tank does provide some temporary improvement, I'm doubly sure. I also think the lower manifold gasket has been leaking on and off as a result of the occasional gas soaking. But that's going to be a while.
My more immediate project is new brake pads and upgraded, new calipers. I'll post on that elsewhere.
I'm so pleased with the Powerstop brake upgrade kit that I'm using their pads again and adding their calipers.
 

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Discussion Starter · #37 ·
On another note, of all the upgrades on this truck that I've done since I've been posting here, the only one I really am unhappy with and regret is the damned low quality Anzio headlights. Avoid like the plague.
 

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Discussion Starter · #39 · (Edited)
I want to add one more thing to this post.
Anyone doing this swap should be sure to also replace/upgrade the fuel injection spider. The original system is flawed and WILL eventually fail. The replacement is better in multiple ways. More reliable for one. But it also converts your vehicle from CSFI to MPFI which gives better fuel economy, throttle response, and emissions. It's all win and it's WAY cheaper to do at the time of the swap than later.
Below is a linked photo of the upgraded unit. This is what you want to buy.

BTW, anyone with a 96-99 Vortec truck should consider this upgrade whether you're doing an engine swap or not. It's a worthwhile upgrade for all Vortecs

See more at: http://www.fuelinjector.citymaker.com/Vortec_spider_fuel_injection_conversion.html
or http://www.fourwheeler.com/how-to/1012or-csfi-to-mpfi-vortec-engine-fueling-fix/

 
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Thanks for a great, long-term thread. Great read!
 
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