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12-18-2012, 11:46 AM | #26 | |
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Re: Overdrive Swap Economics
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You've got some real advantages on the highway too. Your 3"/5" drop means that you're pushing much less air. If you lifted it back up to factory height, I bet you'd see about a 2mpg drop right off the bat. You're also running low-profile street tires. If you were running anything close to the factory tire diameter and weight, and you'd lose more mpg. The low profile tires and lightweight truck allows you to run 3.42 gears. He'll never get away with that in a 1 ton with full size tires. More mpg lost. Your 10 bolt rear is also less of a power drain than the gargantuan 14 bolt that he likely has under his truck. Overdrives make much more sense in small, light cars (which your K5 is bordering on). This is where you see the claims of a 25 or 30% mpg increase. They're not pushing much air, they've got small engines, and their light. The same recipe does not work in a heavy truck. You drop engine RPMs, but the engine has to work much harder to produce enough torque to keep that weight rolling at the lower RPMs. That's why you don't see much mileage on the highway. You'll never see good mileage with a big inch motor in a heavy truck around town. The overdrive has no impact on mileage at all below 45-50 mph.
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86 Chevrolet K20/30 Suburban - 8.1/NV4500/NP205/Dana 60/14 bolt FF, build in progress 73 Formula - 400/Doug Nash 4+1, resto on hold 86 Chevrolet K30 3+3 - 350/TH400/NP241, Air Force/Forest Service Rescue Truck, for sale 01 Ram 2500 - 5.9L Magnum, daily driver 91 BMW 325i - Chumpcar series racecar |
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12-18-2012, 12:05 PM | #27 |
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Re: Overdrive Swap Economics
Another aspect of the TH700 to keep in mind is its extremely deep first gear, and corresponding really long 1-2 shift. Everybody talks about it like its some sort of performance plus to have that really low gear. Other than rock crawling or towing an extremely heavy trailer (which you really won't be doing with a TH700 anyway), it's more of a nuisance than anything. The 1-2 drop really lugs the motor, it was much smoother driving the TH400 around town than the TH700. The 4L80e doesn't have that problem, but it also costs much more, has no provision for a mechanical speedometer, and requires a very expensive dedicated electronic controller unless you're running an LS motor PCM. I'm sure the controllers are reliable, but someday one is bound to give out. If you happen to be that unlucky person, you won't be able to diagnose the problem, nor will you be able to walk into an O'Reilly's wherever you're stranded and order a replacement. Your vehicle will be down for quite a while, not good if you use it as a DD or for a lot of road trips.
For the money spent, you'd be much better building a bulletproof TH700 (~2k) or putting a gear vendors on your TH400 (<1.5k if you watch for a while and find a good deal used). Why spend 2-4k on a good 4L80 setup when a comparable transmission can be had for less money without all the electronic controllers? If you want the best of both worlds, build a TH200. You'll have the lockup converter and overdrive of the TH700, with the gear spacing of a TH400.
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86 Chevrolet K20/30 Suburban - 8.1/NV4500/NP205/Dana 60/14 bolt FF, build in progress 73 Formula - 400/Doug Nash 4+1, resto on hold 86 Chevrolet K30 3+3 - 350/TH400/NP241, Air Force/Forest Service Rescue Truck, for sale 01 Ram 2500 - 5.9L Magnum, daily driver 91 BMW 325i - Chumpcar series racecar |
12-18-2012, 12:06 PM | #28 | |
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Re: Overdrive Swap Economics
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My tire diameter (275/40/20 or 28.8") is actually about an inch taller than factory tires (225/75/15). Also my 20x8.5" & 20x10" wheels weigh alot more than factory 15x7" steelies. I didn't choose the 3.42 gears, in fact I am going with either 3.90 or 4.11 gears (along with a custom 9.5" 14 bolt) in the next few weeks. Mine isn't a daily driver anymore, I just like the OD so I am not spinning the engine to the moon when cruising down the highway.
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Cable -K5 Blazer 2wd: 6.0 LQ4, 7875 Turbo, Tick Stage II Turbo Cam, Built 4L80e, RevMax Billet 3600, 9.5" 14 Bolt -Chevy 3+3 Crew Cab Dually: Cummins 12v P-Pump Swap, Compound Turbos, A2W Intercooler, NV4500HD, 4wd conversion, Radius Arms, Coilovers, Crossover Steering, etc Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=803608 Last edited by Ford Assassin; 12-18-2012 at 12:16 PM. |
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12-18-2012, 12:26 PM | #29 |
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Re: Overdrive Swap Economics
I gotcha. That's still really sweet mileage out of your setup, I'm just warning that it's in no way applicable to what kind of mileage increase he would get out of a 1 ton big block with an overdrive swap.
I didn't realize that the K5s came with that small of a tire from the factory. That's only a shade bigger than the 275/40/18s that I'm running on my GTA. The 3/4 ton and 1 tons came factory with a 235/85/16 tire (which works out about 32-33" IIRC). They also sit about 2" higher than the factory 1/2 tons, so probably about 5-7" taller than your K5 is now. Cool setup, but like I said, it has a lot more in common with a car than a big truck when it comes to merits of an overdrive swap.
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86 Chevrolet K20/30 Suburban - 8.1/NV4500/NP205/Dana 60/14 bolt FF, build in progress 73 Formula - 400/Doug Nash 4+1, resto on hold 86 Chevrolet K30 3+3 - 350/TH400/NP241, Air Force/Forest Service Rescue Truck, for sale 01 Ram 2500 - 5.9L Magnum, daily driver 91 BMW 325i - Chumpcar series racecar |
12-18-2012, 12:33 PM | #30 | |
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Re: Overdrive Swap Economics
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However I recently built a 4L60E to put behind a 6.0 in my blazer, to hold 600HP and quickly spent $1500 on the trans alone. So they aren't exactly an economical swap either. Works fine in my blazer, but I still wouldn't use it in my 1 ton truck. The 502 in my 1 ton dyno'd at 540 ft lbs. with a very flat 500 ft lbs. curve from about 2600 to 4700 rpms. So it yanks the trailer around even at low rpms very easily, even with the overdrive engaged isn't a problem, which is why I went with Gear Vendor, can't tow in overdrive with a dedicated 4 speed auto overdrive. I also specifically did the Gear Vendor on the back of the original 400 turbo because I didn't want a lockup converter with this setup. I hate towing with a lockup converter, they constantly kick in and out and drive me nuts even when pulling in 3rd gear. I pull too much weight to deal with that. With the gear splitting ability it's also now a close ratio, it acts like the allison trans in my neighbors duramax. The 400 is still one of the toughest trouble free transmissions that GM built, and the Gear vendor is good for 1500 HP, it's a tough combo that won't break. Just alot of reasons for me that make this combo perfect for the intended use of my truck. Reliability isn't a really big issue with the electronic stuff. The electric motors on the fans can be bought most anywhere (that's why I use GM stuff ) The electronic transmissions have been around long enough that most all the bugs are worked out. There really isn't anything on my vehicles that I can't repair with relative ease on the side of the road. I agree, I love simplicity, some of my cars still run points and I'm fine with that. But when you want gas mileage and efficiency, sometimes that simplicity will have to be put asside for some modern tricks. Just how far you want to take it is the question. Lots of mileage can be found other ways before that overdrive goes in. Last edited by Firebirdjones; 12-18-2012 at 12:39 PM. |
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12-18-2012, 12:53 PM | #31 |
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Re: Overdrive Swap Economics
Well put, and great points. The TH400 and Gear Vendors is by far the best choice for someone who tows heavy stuff. That's why I said that a TH700 or Gear Vendors TH400 would probably be his best choice. Depends on the application to choose between the two. Ditto on the 502, you've got quite a bit more low RPM grunt to pull that overdrive. A 489 (or bored out 496) with the extra stroke would probably be even better for towing and pulling a low overdrive gear. If you run a lot more time unloaded, a 454 (or even a 383, 6.0, etc) will do just fine.
In defense of the overdrive trans though, you can actually tow in overdrive as long as it's built to handle it. Raptor transmissions and PerformaBuilt both offer TH700s that will tow in overdrive all day long for around $2k. I'm sure there are comparable 4L80s that can be bought as well. I see absolutely no reason to go with a 4L60 swap into an old truck. You get virtually no benefit over a TH700, with all of the same hassles involved in the 4L80 swap. I'm not certain what you're using to control your lock-up converter, but I've never had a problem towing with mine. Hauling 6-8k pounds, I just leave it in direct drive and set the controller to engage the lock-up converter at 60mph. I just leave it on after that, and it will disengage if I drop below 55mph. I've never had to manually disengage it while driving down the highway because I needed more power. I get about 10mpg driving 65-70 with that weight, and trans temp never gets over 180, even in Texas summers. It's actually really nice, because with a lock-up converter, you can run a higher stall to get things moving from a stop, and still get great mileage and low temperatures at highway speeds (no slipping). That higher stall converter makes the 1-2 drop a lot nicer, especially when you're towing. Granted, hauling 16k pounds is probably a whole different story, but most of us really aren't going to be doing that. If that's the case, you're almost certainly better off with a TH400/GV. Whichever you go with, I think the 4L80e isn't a good choice unless you're also swapping over a LS-style motor and PCM. It's too expensive, and brings nothing to the table that a well built TH700 or TH400/GV setup doesn't do simpler and cheaper.
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86 Chevrolet K20/30 Suburban - 8.1/NV4500/NP205/Dana 60/14 bolt FF, build in progress 73 Formula - 400/Doug Nash 4+1, resto on hold 86 Chevrolet K30 3+3 - 350/TH400/NP241, Air Force/Forest Service Rescue Truck, for sale 01 Ram 2500 - 5.9L Magnum, daily driver 91 BMW 325i - Chumpcar series racecar |
12-18-2012, 01:31 PM | #32 | |
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Re: Overdrive Swap Economics
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12-18-2012, 01:32 PM | #33 | |
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Re: Overdrive Swap Economics
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I did the 4L60E in my 4x4 blazer because I like the tunability with a laptop. I already have the software to tune our LS based camaros so that helped with the decision too. Playing with shift points, pressures, lockup, downshifts, is as easy as a few key strokes. Since the original 350 turbo was slipping, and I knew I wanted an overdrive at that point (it's my daily driver) I had to make a decision. Much like you are saying,,,,I couldn't see spending $600 or more for a stand alone trans controller when I could run a GM computer that would control an engine AND a transmission. See where this is going? I didn't want a cable operated 700 with a governor. Tuning the governors on the 400turbo cars for precise shift points around here was already time consuming and messy. So I decided to just do a 6.0 LS swap, 4L60E, and use a GM computer to run the whole mess. In the end it's the best thing I've done to the blazer, knocks down 17 mpg city and 22 mpg highway with 33" tires and 3.73 gears. It works great in this combo, it's just a driver though. |
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12-18-2012, 01:34 PM | #34 |
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Re: Overdrive Swap Economics
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12-18-2012, 01:58 PM | #35 | |
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Re: Overdrive Swap Economics
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I receive the e-mail updates from RideTech & recall they had a failure that Bret contributed to 'owner error'. That might be acceptable for a guy that owns his own company, but not so much for a poor-boy like me.
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. Last edited by SCOTI; 12-18-2012 at 02:07 PM. |
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12-18-2012, 02:35 PM | #36 | |
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Re: Overdrive Swap Economics
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12-18-2012, 02:36 PM | #37 |
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Re: Overdrive Swap Economics
Cost to swap an 80 in to a square is all about how much shoping you want to do, and how crazy you want to go on beefing it up beyond stock (an 80 is stout already) and I am sure some will queston this statement, for most an 80 will not need to be "built" but the rarely found art of transmission tuning will be needed to get the best performance.
I picked up an optishift controller and harness on group buy for 600.00 ish (controller 500 normally 600) I also picked up an 2003 80 for $250.00 from craigslist. So I have 850 in my swap But I am going cummins so I have other costs that I am not showing. A lower cost controller might be a megasquirt (mega trans) controller. |
12-18-2012, 02:40 PM | #38 | |
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Re: Overdrive Swap Economics
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Posted via Mobile Device
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Cable -K5 Blazer 2wd: 6.0 LQ4, 7875 Turbo, Tick Stage II Turbo Cam, Built 4L80e, RevMax Billet 3600, 9.5" 14 Bolt -Chevy 3+3 Crew Cab Dually: Cummins 12v P-Pump Swap, Compound Turbos, A2W Intercooler, NV4500HD, 4wd conversion, Radius Arms, Coilovers, Crossover Steering, etc Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=803608 Last edited by Ford Assassin; 12-18-2012 at 02:55 PM. |
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12-18-2012, 02:44 PM | #39 | |
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Re: Overdrive Swap Economics
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So the cost of the rebuild for the trans on top of the purchase price starts to look ugly. Plus I wanted to modify it to tow in overdrive, but had shops telling me they could but don't recommend it, warranties came into play etc.... So I decided to sell it to someone else that didn't mind dropping a used transmission in his vehicle. |
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12-18-2012, 02:44 PM | #40 |
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Re: Overdrive Swap Economics
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12-18-2012, 02:52 PM | #41 | |
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Re: Overdrive Swap Economics
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Not sure who builds your trans, but my guy told me to tow whatever I wanted (as long as I had an external trans cooler). Still has a 2 year unlimited mileage warranty too. Posted via Mobile Device
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Cable -K5 Blazer 2wd: 6.0 LQ4, 7875 Turbo, Tick Stage II Turbo Cam, Built 4L80e, RevMax Billet 3600, 9.5" 14 Bolt -Chevy 3+3 Crew Cab Dually: Cummins 12v P-Pump Swap, Compound Turbos, A2W Intercooler, NV4500HD, 4wd conversion, Radius Arms, Coilovers, Crossover Steering, etc Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=803608 |
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12-18-2012, 03:20 PM | #42 |
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Re: Overdrive Swap Economics
It was in the e-mails updates I was getting once the car was done. It ended their trip on the Power Tour & required replacement (from what I remember). I delete the e-mails on my work account after a certain amount of time when they're from outside sources.
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
12-18-2012, 03:21 PM | #43 | |
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Re: Overdrive Swap Economics
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turned out I couldn't use the 4L80 in my blazer swap so I went 4L60 instead, and wanted to use the 80 in my 1 ton for towing. But I'm just not going to drop a used trans in my 1 ton (or any of my vehicles for that matter) so a rebuild is a must for my intended purposes. I don't really care if some shop says stick it in and go with it,,,,they aren't the ones doing the back breaking labor,,,,or coming to get me when I'm stuck 1500 miles away on the side of the road |
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12-18-2012, 09:51 PM | #44 | |
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Re: Overdrive Swap Economics
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I think you might of misunderstood earlier about my 4L80e, I bought a '02 core from a trans shop AND had them rebuild it with all the good stuff. Because they rebuilt it and stand behind their work, it has a 2-year unlimited mileage warranty, including towing. I doubt the same warranty would apply with a 4L60e since they aren't known to handle towing duties, regardless of mods. I have been doing business with this shop for 10+ years, they even warrantied a 4L60e with a sheared off input shaft, including the R&R, even though they didn't do the installation. Lastly, I think you might want to pick another hobby since ALL toy cars/truck breakdown from time to time, regardless of the quality of parts.
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12-18-2012, 09:57 PM | #45 |
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Re: Overdrive Swap Economics
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12-18-2012, 10:01 PM | #46 | |
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Re: Overdrive Swap Economics
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There is alot of nay sayers on the strength of the 80 I am going to find out for myself, and i can think of no greater test than a cummins. Sorry wrong quote (oops) Last edited by Chevyman350; 12-18-2012 at 10:02 PM. Reason: miss read |
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12-18-2012, 10:04 PM | #47 | |
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Re: Overdrive Swap Economics
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As far as strength / duriability / all I have to say is they came stock behind d-max in the Chevy and GMC fullsize vans (de-rated of course). And not wanting to put a uesd trans in is a prefrence I can respect. But at 80 k I wouldnt worry much but that is me. I can agree that there arn't alot of trans shops selling "hot" 80's mostly due to the massive backing of the 700 / 60's and peoples ability to destroy that trans. (heavy truck, high torque, big tires) = alot of repeat buisness. Last edited by Chevyman350; 12-18-2012 at 10:12 PM. Reason: expounding |
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12-18-2012, 11:39 PM | #48 | |
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Re: Overdrive Swap Economics
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I do this for a living so it's too late for me to pick another hobby, I'm in too deep |
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12-18-2012, 11:45 PM | #49 | |
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Re: Overdrive Swap Economics
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I didn't want to go through the trouble (and money) for this swap to toss in used equipment with nearly 100,000 miles on it, that's about 8 years of driving knocked off the end result for me. Now if I were installing this stuff just to flip it, or per customer request, that's a different story. |
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12-19-2012, 04:58 AM | #50 | |
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Re: Overdrive Swap Economics
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I've spent so much more on trashing 700's that were advertized to be able to handle 1000HP etc. I've not been able to buy a 700 that handles my modest 400HP engine in the mountains with 6 guys and a loaded truck. After multiple broken 'custom' 700's I gave up. This 4L80E has not let me down thus far and has improved my economy to about 14mpg coming from 11. |
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