The episodes where they don’t finish a truck and leave a year long cliffhanger? How many trucks is he gonna start and not continue showing any long term updates?
I highly recommend the new direct fit transmission cooler from Mishimoto. It makes a huge difference in transmission temps. I installed one on my Silverado.
I have a TransCool on my Tahoe and the difference is night and day. Just the increased cooling surface alone is impressive, but keeping my trans temps down when towing a boat thru the Adirondacks is even more so.
The 8.1 was largely a boat anchor... and partly magic. The magic came is the form of making oil disappear. No smoke... no obvious leaks... still loses two quarts between changes (minimum). The best thing about the 8.1, was their duty cycle. They didn't make enough power to tear themselves up... so you could run one at nearly full throttle, all day, without worry.
I almost bought a 2500 quadrasteer suburban with an 8.1 and opted for another quadrasteer Suburban with a 6.0 instead. I just couldn’t fathom paying the fuel costs the feed that thing for not that much power difference.
Saw the title and I said YES FINALLY. In my mind I’d like to see someone turbocharge a big block aimed at towing. Turbocharged big blocks can put out diesel like power and torque. Personally I’d like to build a 632, de tune it somewhat and then add a turbo for around 1000lb ft torque. I think that would compete to any modern gas or modern diesel
This is my ultimate truck. The setup with it being 3/4T, crew cab and a 8' bed with the big block is what I want. If it had a diesel it might be better, but the big block is sweet. I have an 03' Z71 Tahoe I would like to to do 3/4T running gear and the 8.1.
I'm n9t trying to pick a fight here, but, why? I get the whole, more is always better thing... but from a tow right perspective....it's gonna be good...
@@mattyancey28 well, if you look at his channel he's had an 8.1 NA, turbocharged, and now NA with a top end kit. I didn't mean this truck, just a modern 8.1 with a blower in something. Also, RAM TRX tows just fine.
I prefer big block over diesel now. I have a newer 7.3 ford and it was at the shop the other day getting new tires so the boss made me drive his personal truck for the day. His truck is a brand new ram 3500 HO mega cab Cummins. I don’t like how you have to throttle for boost to get the truck pulling. The big block goes from a dig much better without having to pay much attention to the throttle. Of coarse his truck gets better gas mileage but the big block feels better. The kicker of it all is I payed 56 for my f350 and he payed 109 for his ram and the max tow numbers are between 2 and 4k lbs apart. I wouldn’t go for one of these new diesels anyway just build an old square body from the nineties and do a compound setup with anti lag and no def.
Im following closely. I love my 06 ccsb 2500hd, only year that got 6 speed Allison. I pull a 30' camper all summer and a 4 enclosed sled trailer all winter. Even in stock form i love it. Ive had a few 6.0 ls trucks and they dont come close to how good this 8.1 tows. Also doesnt hurt the gmt800 is the best truck GM has ever produced.
Why not show off the cam specs? Any builder with a cam doctor can get them for under 100$ . Silly to be so secretive about something that customers need to know
If the factory rating of 440ft-lb is to be trusted, (and I believe it should be SAE NET and therefore correct), that's a 35% drop in torque from the flexplate to the rear wheels. So either that engine had some problems already or the dyno pulls weren't done right. Anyone pull the transmission dipstick lately? 😅 The biggest power issue with the 8.1 is the PCM tune. There was another video on RU-vid that had a guy tuning one of these and he found the total timing was abysmal, something like 16 degrees all-in. He put 8 or 10 degrees to it and totally woke the motor up - immediate HP and torque gains. It's like they designed these to run on 70 octane fuel. A local tuner told me the fuel maps are just terrible, he called them lazy - like the engineers had homework due the next day and just copied a small block map. Doubling the fuel economy isn't unheard of by re-mapping the fueling on these - which isn't saying much since they get 7mpg. Anyway, I'm staying tuned for this, looks very interesting.
it's not a lazy tune from factory, it's a lot of work to get it to not raise fleet emissions too much. you might ask what's the point in then fitting such a big engine if you need to damp it with the tune to get it out the door? many people might ask lol same as harley. but once it's out the door epa is your problem not theirs.
Why not start the dyno run from a lower rpm? The torque peak on the initial graph is when full throttle is applied at 3300rpm. Start it at 2000rpm so we can see changes in that range as well...
@@jessesyfie7244 , a chassis dyno will load at any engine rpm if the vehicle is a manual. An engine dyno has trouble loading at low rpm and still read accurately at high rpm. So you kind of have to pick where you want to take your sample. Have you seen diesel dynos? They load as low as 1500 rpm on chassis applications. But an automatic equipped vehicle will downshift at those rpms. So you have to do a midrange pull to make everything happy.
And if you have a stall converter you have to reach the flash rpm before the pull. Unless you lock it. But the converter has be rated for a full throttle pull.
I bought an '04 8.1/Allison brand new. It scooted around town, but was pretty doggy as a tow vehicle, got 8 mpg, and had a ridiculously small gas tank yielding very poor range. Within less than 2K miles the Allison started acting up, and the truck spent the better part of the year I owned it at the dealer, until I finally Lemon Lawed it. Good luck.
I just want to say that all these 8.1 videos have got me making plans that my wife doesn't like. I currently have a clean California 2005 GMC Sierra 1500 crew cab short bed 2wd. Plan is to get a 4x4 2500HD extended cab short bed for the frame, with a 6.0, swap it for an 8.1 and then solid axle swap with Super Duty Dana 60. Don't really want a truck that came with an 8.1 because i don't want an Allison, plus I could use the 6.0 for my Yukon project.
I basically have the same exact truck, 02 gmc crew cab, 8.1 liter with Allison! Mostly used to tow the camper. Can't wait to see the power you get out of it.. please let us know how much it costs.. Wish i had money to send it to you!
Run it on E85/Flex Fuel and you will pay 1/2 the cost of gallon as diesel. $2.40/gallon in my area. I tow with supercharged gas V8 on E85 when possible, so much better than towing on gasoline. MPG is practically the same.
Holdner has a video on turbocharging the gen 7 BBC & he had a reader write in that put a small turbo in a pure stock gen 7, it made (memory here) approximately 6 psi of boost, he said he had been running that way for a long while in that configuration & was extrememly happy with it.
Going to have a bear of a time to get thoes stock L92 injectors to work in hptuners on that early 411 pcm.the offset vs vac data isn’t really stable down there due to the e38 translation . Add to the fact the spray angle starting in the head and you might want to fire it on the stock 42s or go with a deatchwerks or fuel injector clinic units with really stable data . Just my .02 cents
I love that you baselined it on the dyno. Can't wait to see what it makes after the upgrades. Are you going to be setting it up for flex fuel at all? Or just regular old pump fuel? What long tube headers are you going to be using?
Hey LT! If you get a chance, it would be awesome to get a parts list for this build. Depending on how this one turns out on the dyno, I might have to do all this to mine! I can’t wait to see how it all comes together!
LOVE the content! The camera moving around so wildly makes it difficult to watch, though. Move it more slowly and it'd be less likely to cause headaches. I recall the little hole for PCV in the valley. Will that cause any issues with this being an NA engine?
I'd say between 400-500 at the wheels ought to be a reasonable target. I was able to get dang near 400 out of my 6.0 in a 03 2500hd. I use my truck for the same purpose as him. Doing truck stuff
Some people need to learn what tow rig means. Ya you could build a 6.0 to 500hp, but if it makes peak torque at 4000rpm, it’s useless for towing. You need power down low. And nothing builds torque down low like an 8.1. And yes for long highway pulls, turbo diesel is king. But for in town pulling, displacement is what you want.
People get way too caught up in numbers. It’s more important HOW it puts the power down. I guarantee that’s what your stock 8.1 puts down. But it’s the way it puts down that power. It’s super low rpm. So you get all of it at once off idle. Makes it feel like a lot more.
One of my favorite body styles GM made but the truck itself in the frame itself should have been boxed in and it should have had a diesel engine in it which the truck deserved 6.6
What a difference in the baseline from Ugly Truck. 216/287 here and 306/428 on Ugly. Do you think the transfer case and 14 bolt rear end made that difference?
LT, please try reduce the amount of phone swings, (your face to main), and slow down the movements in general. It's as if you're on too much caffeine LOL. Maybe it's because I have a headache, but I found this one hard to watch. Love the content.
There is more to towing than just pulling. There is stopping. No gas engine will have the engine braking of a diesel. Yes, having proper brakes on your trailer is required but nothing like setting the cruise control and being able to descend long grades with the engine brake on maintaining a steady speed without touching the brake pedal. You'll never do that with a gasser.
10:54 ya that's so we have to buy his. Still looking for a max piston valve clearance on these to guage duration/lsa with. Sucks when required info is withheld.
You should keep those stock heads for uglytruck. It would get you a portable set. I'd be willing to share my observations from during my dig into my "holy sacrificial chamber" lol
You keep saying "Towing Application" but keep mentioning parts and modifications that take away from low end power... Wouldn't changing the rod length and going to a higher compression piston be simpler? The purpose of the 8.1 was to compete with the Duramax. So Wouldn't keeping the operating range between 1400-3400 be more beneficial for towing? A forged set of 6.385 rods and 1.645 pistons on the stock heads and intake with tuning should put torque up to at least 600ft#'s @ 1700. I'm just wondering why you'd want to increase the effective RPM range by pushing power further out for something you claim is for a towing application? Would be the equivalent of going from oval port heads to AFR heads on a 454 when it only needed a rod and piston change.
8.8 heads will slightly bump the compression. The runners are not big they are just a better port which flows good at low lift numbers as well. 8.1 are way under cammed stock so going up in cam as long as not too big increases low end torque along with power output The 8.8 intake has long runners which also is alow rpm torque design but not restricted inside or by the small 8.1 throttle body
@@randysullivan5723 with the 8.8 top end kit and a rod and piston change would increase low end torque even more? I'm genuinely curious to see if a big block could see 600-700 NA ft#'s between 1500-1700 rpms reliably.
@bladenrexroth2555 I'd just start with the 8.8 to try for them goals. The propane fueled 8.8 liter as psi uses in generators is 565 ft lbs at 1500 rpm and designed to run at full load 24hrs a day. They rate the engine reliable to 1000 ft lbs but keep in mind its rated for continuous duty. I have no fears with my mild cammed ported head 8.8 t6 s475 turbo combo I'm doing for my 2500 suburban backed with allison 6 speed
@@randysullivan5723 do you think the 8.8 is capable of being bored out to a 572? I've seen a couple of psi cores listed on Ebay and have wondered if if a 572 towing motor was worth it. Cores seem reasonably priced when they pop up. Getting the block bored out wouldn't be difficult if it can be bored to 4.5 reliably and I'd only have to worry about rods, pistons and fueling.
Well now, IF he really wanted to build the ULTIMATE BBC tow rig ever, he should got the extra wheels. They make a real difference when towing, especially towng heavy.
Why mess around with the 8.1...grab a PSI 8.8L core for $2000, port the heads like Josh, possibibly bore it to 4.4" if it needs it, 547ci, 325-350cfm, port match the intake, 92mm tb, cam, springs, headers. 500-600hp 550-650tq...
Before ANYBODY dogs on the low horsepower and torque, figures... Everybody has to remember that this is being done at 6000 FT ABOVE sea level. There is no air to start with!
