L18 8.1L swap resource thread

[Kay86K5]

I second the additional costs people don't take into account. Depending on how pretty of an install you want (I think Larry's installs are on the top as far as clean installs goes ) but then there are some of us that care a little more about function then clean which can save a little coin. Either way, especially with a later model motor swap, I think the $2000 above the cost of motor to budget in to get it running is a good estimate.

But just as Larry said, the factory clam shell motor mounts for either a BBC or SBC will bolt on to it just fine.

 

[wetoolowdingbangow]

Hmm I just got poly mounts so I would want to adapt to those. This is for the 73 trail dedicated truck so it doesnt need to be to crazy nice install. The guy doesnt have the computer or wiring harness so id have to source that. I wouldnt be running any smog stuff either so im not sure of the effect on a stock computer...

Im a little worried I wouldnt be able to keep this big boy cool when im rock crawling.

 

[Kay86K5]

Hmmmm, finally found an 8.1.....









2002 8.1L with 91k miles on it. Already has the workhorse brackets on it with the correct water pump, just need to get the correct harmonic balancer for the workhorse and the tensioner puller as that is missing. Also came with an L29 throttle body (no spacer yet so need to get that too) with the correct oil filler neck as Larry mentioned before (missing the stupid cap so need to get that and also Larry will probably notice that the plastic cover is the 2002 model, so if I want to run that and make it look clean I will need to get a 2004+ one to match the oil filler tube). So some odds and ends to still pick up on it but those are not bad. I will end up doing a Howell full stand alone now that I have this setup.

I'm pretty freaking excited!!!

 

[Team208Motorsports]

Last 2 Howell 8.1 dbc tunes I have seen were 5.3 tunes with nothing properly corrected. Just a word of warning.

 

[Larry]

Hmmmm, finally found an 8.1.....

2002 8.1L with 91k miles on it. Already has the workhorse brackets on it with the correct water pump, just need to get the correct harmonic balancer for the workhorse and the tensioner puller as that is missing. Also came with an L29 throttle body (no spacer yet so need to get that too) with the correct oil filler neck as Larry mentioned before (missing the stupid cap so need to get that and also Larry will probably notice that the plastic cover is the 2002 model, so if I want to run that and make it look clean I will need to get a 2004+ one to match the oil filler tube). So some odds and ends to still pick up on it but those are not bad. I will end up doing a Howell full stand alone now that I have this setup.

I'm pretty freaking excited!!!

Awesome! That thing looks clean! Congrats! The crank pulley/balancer that you need is part number 12555140

Last 2 Howell 8.1 dbc tunes I have seen were 5.3 tunes with nothing properly corrected. Just a word of warning.

My two L18’s run Howell tunes with 5.3L VIN numbers as well. Howell told me the reason was the fact I prefer to run mechanical throttles where the L18 never used mechanical throttle (outside of Marine L18’s running on MEFI-4 ECMs) so they use an early (99-02) 5.3L calibration that has the firmware to support mechanical throttle. Then they sprinkle L18 fuel and spark maps over that. I wouldn’t doubt the 5.3L VINs in most of their tunes also have something to do with the tuning software sham that where royalties are due for each individual VIN. I bet a dime to a doughnut the VINs in my Howell ECMs are the same VIN on the L18’s you “fixed”.

Like I say, I am no tuner but I’ve dealt with enough of them to notice each tuner is better than the last, or at least they think they are. I can tell you this based on experience, the Howell tune for mechanical throttle body runs great. I’ve been running that tune in my K10 since 2009 (and about 35,000 miles) and it runs circles around my stock 2001 Silverado HD’s L18. Unlike the live tune I paid $600 for in Colorado Springs (that has now been replaced along with big cam) the Howell tune is a very smooth drivable tune with zero BS hiccups, mystery check engine lights, etc. It starts, runs and runs better much stronger than stock GM calibration. Can’t beat that for an out of the box tune even if it is based on a 5.3L plateform.

 

[Team208Motorsports]

Like I say, I am no tuner but I’ve dealt with enough of them to notice each tuner is better than the last, or at least they think they are.

Sorry you have been burned by other guys and I see you have no faith in small companies because of it. I am speaking from experience as well and when all the airflow is calculated based on a 5.3, its wrong. The maf will save it but the base calculation is WRONG. Its fine to base the tune on a different platform but when you miss all the small things in a tune, it may seem to run fine but thats the ECM correcting when it shouldn't have to.

Doing this on the net is pointless, take all the jabs you like. You want to measure, I want engines to run correctly. So I'm out.

 

[Larry]

Sorry you have been burned by other guys and I see you have no faith in small companies because of it. I am speaking from experience as well and when all the airflow is calculated based on a 5.3, its wrong. The maf will save it but the base calculation is WRONG. Its fine to base the tune on a different platform but when you miss all the small things in a tune, it may seem to run fine but thats the ECM correcting when it shouldn't have to.

Doing this on the net is pointless, take all the jabs you like. You want to measure, I want engines to run correctly. So I'm out.

I gotcha and see what you mean but dude, don’t lose sleep over my personal opinion. I wouldn’t go so far to say I’ve been burned by any tuner, over the years I've just noticed each is better than the last every time. Really it boils down to everybody has a different method to skin a deer and there is a lot of pride in tuning work, rightfully so. We see on the OEM side as well. I work for a truck manufacturer where we are the largest consumer of GM Powertain engines and transmissions outside of GM themselves. Back in 2009 when we were launching the L20 4.8 and L96 6.0L GMPT had the calibrations out of whack where the 6L90 transmission would never upshift if the throttle angle was 68% or higher (Being GM is the supplier of the powertrains they are responsible for the emissions certifications so they handle all the calibrations just like Cummins would be on the big diesel side of the business).

Well, after the first several hundred 2009’s were built with the L20 the trans issue upshift issue came up and GM told us their calibration team (GM calls their tuners calibrators) were too busy working on the Chevy Cruze launch and would not be able to revise the W-chassis calibrations for 120 days but we could use one of their approved outside engineering firms to work on the calibration then they would review and approve it providing the new calibrations still met Federal and CARB emissions regulations. Since we were sitting on a huge 2,500 unit order of UPS trucks we couldn’t wait 3 months for GMPT to get off their duff. First our engineers reached out to Tech Services in Indiana where they worked on the calibrations. After about of week of calibration and validation work we all felt they did a great job of clearing up the upshift issue and still met all emissions requirements. Along the way Tech Service mentioned how goofed up the GMPT calibrations were. Once GMPT reviewed the calibrations they said it wasn’t right and had too many issues so they recommended we use Roush Enterprises in Detroit because Roush had just done a lot of calibration work for GM on Natural Gas L96 6.0Ls and did a great job. So then we were off to Roush where tweaked it further while commenting how goofed up the GMPT calibrations were and the Tech Service calibrations but theirs would clean everything up and still maintain emissions certifications/powertrain protection. So after they worked on the calibrations (which felt good and corrected the upshift issue just as the Tech Service calibrations did) GMPT reviewed it and still said it was all wrong. In the end GMPT reworked the calibrations that Tech Services did as well as Roush claiming both of their calibrations were too far out of whack while also admitting their own first calibrations were out of whack (different GM calibrator than the original person). That said, I’ve seen this on an OEM manufacturing side of the auto world as well as the hobbyist side and it is the same story. Hell, we even saw two different GM calibrators have different ideas what was “correct”. I've done some DIY tuning on a MEFI-4 ECM and it is obvious I should keep my day job. My several attempts at tuning sucked! LOL

That said, don’t be butt hurt about my comment. You will fix a lot of other guy’s tunes and there will be other guy’s fixing your tunes…..Like each politician is better than the rest. Just the way it goes. Like I said in the beginning, it seems there is a lot of pride that comes along with the calibration/tuning experts and each individual has a different method or idea of a correct tune. The reality is, all of them are smart guys and the differences between each ones tunes probably wouldn’t be noticed by the average person driving a vehicle normally. Once you get down to trying to squeeze every last piece of HP (or try to maximize HP met emissions and still maintain powertrain protection) that is where the experts get separated from the rookies. I don’t know you from Adam, but I assume you know what you’re doing. It would be nice to have a knowledgeable tuner in the CK5 community. Relax! I would certainly be interested in having you do the tuning on a L96 6.0L I have in the garage once I find a project vehicle to put it in.

 

[Team208Motorsports]

Not butt hurt at all. I'm a big boy and know how to choose battles. Just no point in arguing over it. Total waste of both our time.

 

[Larry]

Not butt hurt at all. I'm a big boy and know how to choose battles. Just no point in arguing over it. Total waste of both our time.

Well, that is good you’re a big boy and we are now on the same page now because there for a second your last two posts on this L18 topic was looking like you were living the stereotype of the typical immature tuner talking smack about the last tuner and how much better your tunes are. That may very well be the case (I am sincere about that), but your first contribution to the L18 world starting off with a tone of “Last 2 Howell 8.1 dbc tunes I have seen were 5.3 tunes with nothing properly corrected. Just a word of warning.” just gives the vibe of the typical arrogant tuner stereotype.

….maybe something more like an introduction as “Well, I’ve worked with other 8.1L aftermarket tunes. Specifically the Howell hot tune, and their spark was off by X degrees at 29,569 RPM and the fuel maps where off by .345 grams of neutinflanges and - .083 of defamation angle where that could cause premature detonation, exhaust inflammation, steering wheel incompetency and slight lack of throttle response at 2,342 RPM and blah, blah, blah” would command more respect than the typical….BEWARNED! The other guys apples are rotten!

Don’t be pissed at me, because I am really a nice guy. We would probably be buddies if we met somewhere on the street. I just tell it as I see it and have a low tolerance of immaturity, forum BS and lack of professionalism even on a hobbyist forum.

 

[Team208Motorsports]

Two way street. Give to get. I also get the net is full of easily Google searchable material. Whether it be tuning related or engine or what ever your flavor is for the day.

Lack of knowledge on their part is the problem. It's called "installed options matrix". 8.1 dbw can be converted to cable with an 8.1 base tune. Same exact way guys do it with dbw 1 meg ecms. When the correct base tune is not used there are about 65-70 tables that have to be changed aside from what they change. It's all air flow related. Gen 3 airflow calculations lead too most problems. This is what separates weekend warriors from guys that feed their family. With stock engines the ecm is forgiving. With cams you better be a good tuner....... Or you will be putting a stock cam back in. Right.

That's as in depth as I'm going for now. I have too much to catch up on from the KOH crunch. I only tuned one or 2 nobodies down there....... After a "professional" ex gm guy tried. Cars wouldn't fire, idle or rev clean. Can't tune a race car like a stock rig or an 8.1 like a 5.3.

 

[blazinzuk]

I wish you guys could see how much stuff Josh changes.

I have seen enough to know if he says its not right, well its not right.

Yah tuning the little guys lol like a king

 

[sweetk30]

so larry if you have a choice of doner vehicle pull what would be your pic ?

year and vehicle style .

I might be looking to do the 8.1 swap for the raw power for work and trailer pull ability .

 

[Larry]

Two way street. Give to get. I also get the net is full of easily Google searchable material. Whether it be tuning related or engine or what ever your flavor is for the day.

Lack of knowledge on their part is the problem. It's called "installed options matrix". 8.1 dbw can be converted to cable with an 8.1 base tune. Same exact way guys do it with dbw 1 meg ecms. When the correct base tune is not used there are about 65-70 tables that have to be changed aside from what they change. It's all air flow related. Gen 3 airflow calculations lead too most problems. This is what separates weekend warriors from guys that feed their family. With stock engines the ecm is forgiving. With cams you better be a good tuner....... Or you will be putting a stock cam back in. Right.

That's as in depth as I'm going for now. I have too much to catch up on from the KOH crunch. I only tuned one or 2 nobodies down there....... After a "professional" ex gm guy tried. Cars wouldn't fire, idle or rev clean. Can't tune a race car like a stock rig or an 8.1 like a 5.3.

so larry if you have a choice of doner vehicle pull what would be your pic ?

year and vehicle style .

I might be looking to do the 8.1 swap for the raw power for work and trailer pull ability .

It doesn’t really matter what vehicle to pick as a donor. The big difference is return type or returnless fuel rails and the accessory brackets. It’s no biggie to change rails but the brackets can get expensive and hard to find. If you plan to install one in a 67-72, square body or something with a narrow frame and run A/C then a Medium Duty, 01/02 3500-HD, Workhorse or G-van is the best donor to grab but if you want a complete powertrain (engine, trans and 10.5" 14 bolt FF rear axle) to pirate from a donor then a Suburban or Avalanche with a 4x4 4L80E would be a good donor (I'm not that big of fan of swapping in Allisons into older trucks because there so damn big where a body lift or floor work is needed) The only problem with a Sub or Ave is the accessory brackets won’t be right for running A/C in an older truck. Then again, you could be like one of those hacks that just cuts the frame to make room for the low mount A/C compressor

 

[zombiyjay76]

Larry would you happen to know the part numbers for the workhorse serpintine bracket bolts? Just got the brackets in but none of the bolts from the original suburban brackets are long enough.

 

[Larry]

Larry would you happen to know the part numbers for the workhorse serpintine bracket bolts? Just got the brackets in but none of the bolts from the original suburban brackets are long enough.

Unfortunately not. The way the Workhorse parts catalog is written it lists all the bolt part numbers but doesn’t call out which bolt goes where. Your best bet is to contact a GM dealer using this GMT400 L18 VIN and have them look them up by application. 3GBKC34G61M101958 This GMT400 3500-HD chassis cab Vin uses the same brackets as the G-Van, light medium duty and Workhorse. Some positions take bolts and others take studs and nuts.

 

[zombiyjay76]

Unfortunately not. The way the Workhorse parts catalog is written it lists all the bolt part numbers but doesn’t call out which bolt goes where. Your best bet is to contact a GM dealer using this GMT400 L18 VIN and have them look them up by application. 3GBKC34G61M101958 This GMT400 3500-HD chassis cab Vin uses the same brackets as the G-Van, light medium duty and Workhorse. Some positions take bolts and others take studs and nuts.

Thank you sir

 

[Kay86K5]

Has anyone run e-fans on their 8.1? My motor didn't come with the mech fan or clutch, so trying to determine if I just decide to go e-fans (can Howell include e-fans into the wiring harness and tune on the ecm to control them?) or just pick up the correct mech fan and clutch setup (does anyone know a part number for that?). What say you guys?

 

[Larry]

Has anyone run e-fans on their 8.1? My motor didn't come with the mech fan or clutch, so trying to determine if I just decide to go e-fans (can Howell include e-fans into the wiring harness and tune on the ecm to control them?) or just pick up the correct mech fan and clutch setup (does anyone know a part number for that?). What say you guys?

Yeah, Howell can set up a harness for e-fans or you could just get a fan clutch/blade from just about any GM engine with the spin on type fan clutch. I believe I am running an 1998ish L29 7.4L clutch fan on the K10 and a 2009 Workhorse 8.1L fan clutch with a mid-90’s 7.4L fan blade on the Burb. You just need to make sure the fan blade is off of a serpentine belt driven engine as it spins backwards


***Actually, I had that backwards…the K10 has the Workhorse fan clutch and the Burb has the 1998 spec K2500 fan clutch. Most people probably wouldn’t like the Workhorse fan clutch as it is pretty aggressive and does eat power when it engages but it sure moves some air! The truck never gets anywhere close to overheating idling around in the desert on a 100 degree day while blasting the A/C. The same could probably be achieved with efans without the expense of the loss of HP but that is one less electrical gismo to go wrong in the middle of nowhere. ***

 

[Larry]

Had to tear my 2001 Silverado down to replace a rear main seal. If anybody ever wondered what a Silverado HD ZF S6-650 looks like here you go….

GM flywheel part number 12582964. Now here is something odd, the 12582964 I used on the 8.1L in the K10 and Suburban look different. This is the first 8.1L flywheel I’ve ever seen with the big “METRIC” on it but this truck is a very early GMT880 and L18. Build Date of 12/2000 which would have made the engine production around Sept/Oct 2000

For comparison sake here is the service replacement 12582964 that are in the K10 and Burb

Another interesting thing found is this truck did not come with downstream O2 sensors. I don't think I ever remember anything about the L18's no having having them. I've own this truck since new

Pesky oil leak

 

[Kay86K5]

Is there a special too to remove the crank pulley/balancer to swap over to the workhorse style crank pulley/balancer, or will any standard puller work?