1.6TD IDI vs AHU 1.9 mTDI - cold weather starts, mpg, weight - Suzuki Samurai - Diesel Swaps - VWDiesel.net The IDI, TDI, and mTDI source.

• 1.6TD IDI vs AHU 1.9 mTDI - cold weather starts, mpg, weight - Suzuki Samurai by Chuck1978 on 05 Feb, 2019 22:27
• After 9 years of owning a 1.6TD IDI CY powered Rabbit pickup which I absolutely love driving, I decided my 4x4 choice would be a Suzuki Samurai due to my loyalty to VW diesel engines & their fuel mileage a common, widely suported engine swap choice), love for old Suzuki motorcycles, and the cool factor and aftermarket support for the Samurai platform. 
  My wife traded her 81 Mercedes-Benz 300SD turbodiesel for an 82 Rabbit pickup when we first met, and now has an AAB 5 cylinder diesel powered VW Eurovan Camper as well... 
  
  I was contemplating converting the lightweight 175lb aluminum Suzuki 1.6L to a 16v head + 4 motorcycle carbs, as those engines are pretty great, but fuel mileage is a big goal for this, and pushing even "smaller" 45lb 265/70R16 aggressive extreme terrain tires will require a good bit of torque to not be pedal to the floor at highway speeds.
  Some Samurai owners with diesel swaps are reporting mid 30's or even 38mpg with a VW diesel.  Mine is lifted a pretty fair amount (more aerodynamic drag) and is running about the maximum tire size one can expect to knock down any respectable mpg, so an engine with lesser output will be pedal to the metal trying to maintain highway speeds and not get run over. This may kill the fuel efficiency, so more torque and at the right cruising rpm with gearing selection is crucial. Cruise rpm at peak torque, 2800-3200rpm.
  
  What I really started realizing is that with further enhancing the gasoline engine's power output, the mpg was not likely to improve any...yet with a good performance diesel build that was well tuned, I could both increase my power substantially, and retain respectable fuel economy. The gas engine made the same peak torque, 98 ft-lbs, as the stock CY 1.6TD, but at 4,000rpm instead of the diesel's 2500-3000rpm range, which is broader and more preferred especially in a 4x4 application.
  
  
  
  
  
  
  I am considering buying:
  91 Jetta 1.6TD Eco engine with 220,000 miles and K14 stock turbo, and a regular full turbo 1.6TD pump with LDA (needing rebuilt), $800 semi-locally. 
  -vs-
  shopping for an AHU to build as a 1.9 mTDI.  I realize this will cost a bit more, and is definitely heavier by at least 60lbs. Searching AHU weight gives me numbers all over the place, so I am uncertain. 
  
  
  Factors I need help deciding on:
  
  1.) COLD WEATHER STARTING
  I have read mostly people stating that the TDI's are much better at cold starting.  It's no fun to rely on a vehicle, and then not be prepared for leaving your vehicle unplugged overnight in sub-zero (Fahrenheit) overnight temps, and not have it start in the AM. Or even leaving it outside at work all day. I read one argument that the IDI glow plugs have a significantly smaller area to preheat, and therefore will start better than the TDI.
  I have experienced a lot of difficulties in the past decade with the 1.6's not starting or not starting well in frigid temps.  The Samurai does have dual battery trays which I could utilize in the winters if the IDI really needed more than 2 or 3 glow cycles.
  I have not used 5W30 or even 0W30 (Just a Canadian winter weather thing?) in the winter, I always use Shell Rotella 15W##. I now realize 5W is the way to go for winter starts. Perhaps this and a stronger battery will make an IDI start well enough? And 2 batteries will give me confidence down to -10F temps even?
  
  I have a feeling most will say the AHU TDI will start far easier. Does stock e-TDI vs m-TDI have any effect on cold starting difficulties?
  I also predict some will say they can get their IDI's started in frigid temps well enough with special cares taken (winter fuel or additives, strong battery, garaging it - not always possible, oil viscosity, pump timing, etc) & others especially TDI lovers will say the IDI is very troublesome in the cold.  Please share!
  
  
  2.) FUEL ECONOMY vs POWER OUTPUT
  I understand that by design of the IDI prechamber vs the direct/swirl injection head/piston, the TDI is at least 10% more efficient than the IDI, if not 15%.
  Weight is a big factor, as adding a 1.6TD is already 100lbs heavier than the all-aluminuim Suzuki 1.6L engines, and one of the biggest attributes to the Samurai off-road are it's size and very light weight. The AHU has a cast iron head as well, vs the 1.6's aluminum head, as well as being bigger displacement and hence slightly bigger bottom end components. 
  If I drop a well-spent hefty sum on a Giles 1.6TD Super Pump build, I was told that I could make up to 150hp and 225ft-lbs if boosting up to 20psi... HOLY SMOKERS, This really renewed my interest in the 1.6TD!!!!!!  Granted I would want more durability, so I would probably keep it at 12-14psi boost and hope for 110hp & 160ft-lbs.
  
  If I were to shoot for the same target power out of a TDI build with an mTDI (TDI-M?) pump, what kind of fuel economy numbers could I expect out of these two? Or rather, what differences in fuel economy could I expect comparing them as theoretically installed in the same vehicle? Is the 1.6TD going to be real close to the mTDI if both set up well and same power output? Or is the mTDI able to knock down significantly better mpg at the same power output?
  
  
  3.) DURABILITY - high output 1.6TD IDI vs closer to stock 1.9 m-TDI AHU with similar power
  Is the 1.6TD IDI MF code engine block, head, rods, crank etc up to the task of making 110-130hp and 150-180 ft-lbs RELIABLY?  Is there a lot more concern on the IDI of head cracking or warpage since they run an aluminum head? The IDI runs a lot hotter and therefore requires a larger radiator to keep it cool. Therefore is more sensitive to cooling system issues without a doubt, and may result in a warped head if a fan motor failure occurs, or a coolant leak. I remember some cracking in between the valves that was common on the 1.6 mechanical n/a heads at least, from when the wife's n/a rabbit pickup engine went through a couple head gaskets over the years. I was told this was common and the cracks do not go all the way through, and it was commonplace to put them right back in service. I think the block deck was .002" distorted at the head bolt thread areas from past overtorquing. Within VW spec, but I suspect it was a cause of 2 head gasket failures since she owned it. the 11mm block is not as tough in this regard. It has head studs and a Gaskets-To-Go MLS gasket in it now.
  
  Again, the 1.6TD IDI "MF" is far lighter than the 1.9TDI "AHU" by 60lbs or even 100+lbs according to some accounts.  I am pulling for the 1.6TD IDI to be able to last 200,000 or MANY MORE miles with nothing more than regular service and timing belts, but am not sure in boosted fueled modified form, if it will be up to this task.  The AHU, I will assume can handle this durability concern with no sweat at all.
  
  
  
  
  Eagerly awaiting your commentary.  Thank you,
  
  Chuck Lambert
  Columbus, Ohio, USA
• #1 by Chuck1978 on 05 Feb, 2019 23:20
• Two other things I was weighing in with this... The Samurai stock is barely heavier than my Rabbit pickup, around 2100lbs. Aside from the extra unspring weight of wider heavier duty Toyota axles and bigger tires, it has a winch and winch bumper out front, adding a lot of weight far ahead of the front axle.  If I go TDI-M and add even more weight than a 1.6TD IDI, that is even more weight on the front end, and lesser percentage of the vehicle weight on the rear tires.  Less balanced. I am not sure if I should be too concerned with an approximate 60lb or 70lb additional gain up front?
  
  
  One thing to combat that, is that I eventually plan on saving up thousands of dollars more to buy an aftermarket Aqualu reproduction corrosion-resistant marine grade 5/32" thick plate aluminum Samurai body made in the LWB (Long Wheelbase) version, with  a 55" cargo bed instead of 32", so this will add even more weight stretching the frame, fiberglass hardtop, and driveshaft, but will also help to ballast out the weight better with a longer back end, as well as help with trailer tongue weight capacity and braking capability with a trailer pushing from behind. I am hoping to pull a 4x8 utility trailer or at least a motorcycle tray trailer to pull several dirt bikes or perhaps 1 dirt and 1 street bike. 
  The extra power will really help out in the mountains and towing, and both if I go on really good trips!
  
  
  As it is, although I sold off these 33x12.5" tires (pictured) for 31x10.5's (265/70R16) for better use of the engine's power and better mpg:
  
  
  
  What I need to save up for after all the $$$$$ diesel swap investments:
  
  
  
  
  
  
  
  
• #2 by libbydiesel on 06 Feb, 2019 19:39
• First, I'll mention that the following is not conjecture on my part.  I don't tend to discuss my extensive experience but in this case I will briefly, as it is pertinent to actually knowing the differences.  I have owned and operated the 1.6TD and the 1.9 mTDI AHU in the same vehicle.  Both were tuned exceptionally well.  I have also done quite a few other 1.6TD, 1.9TD (AAZ), 1.9 mTDI (both Mk3 and Mk4) engine conversions.  I done a whole lot of work on VW diesels for the last 25 years.  I currently own and operate vehicles with the 1.6TD, 1.9 mTDI AHU, 1.9 mTDI ALH, and stock 1.9 eTDI ALH.  I have operated all of them in temperatures ranging from lower than -5°F to higher than 100°F, and ranging in elevation from close to sea level to 7,000+ feet of elevation.
  
  In the following comments I am discussing engines in good tune for an apples to apples comparison.   
  
  

  Quote from: Chuck1978 on 05 Feb, 2019 22:27

  1.) COLD WEATHER STARTING

  
  The TDI will start easier.  mTDI or eTDI doesn't really matter, either one will start easier than any of the IDI engines.  Like seriously, no contest.  The comment that the IDI glow plugs heat a smaller area and therefore start easier is nonsense.  The TDI combustion chamber heat loss is much less than the IDI, which is the main reason for the better fuel economy and higher torque on the TDI.  The TDI engine will benefit more from 'afterglow' than the IDI engines in very cold weather.   
  
  

  Quote

  2.) FUEL ECONOMY vs POWER OUTPUT[/b][/i][/u]

  
  Given the same power output, the mTDI fuel economy will ALWAYS beat any of the IDI engines by at least 10%.  Always. 
  
  

  Quote

  3.) DURABILITY - high output 1.6TD IDI vs closer to stock 1.9 m-TDI AHU with similar power

  
  The mTDI wins on durability/reliability as well for a variety of reasons.  Assuming similar power levels, the higher displacement means lower peak cylinder pressures which is easier on everything, especially crank and rod bearings.  Because of the TDI's higher efficiency it dumps a LOT less waste heat into the cooling system (~1/2).  That reduced waste heat in the cooling system means that temperatures are more easily controlled, better oil temps, better oil viscosity, fewer cracks in the heads, etc...  The IDI pre-chambers are known to crack with age and especially when the IDI engines are pushed harder than stock.  Once the pre-chambers crack in half, they will start moving, wallow out the head, damage the piston top and sometimes will even fall into the cylinder.  The TDI's do not suffer from that ailment. 
  
  

  Quote

  Again, the 1.6TD IDI "MF" is far lighter than the 1.9TDI "AHU" by 60lbs or even 100+lbs according to some accounts.

  
  The 1.9 blocks are a little bit heavier.  The block is 1/2" taller.  The crank has longer throws.  That said, I seriously doubt that they are 60 lbs more (no way).  I can't imagine the long blocks are even 10 lbs different in weight.  The AHU heads are aluminum, not cast iron, and weigh much the same as the 1.6TD head.  Any other additional weight is just which accessories you bolt on.  I'd assume you would use the same accessories with either engine.  If you actually doubt this, I'll consider going through the pain in the ass of actually weighing both engines.  I have both in my parts storage but would prefer to avoid the heavy lifting. 
  
  Hope that helps.
• #3 by libbydiesel on 06 Feb, 2019 20:08
• I would also mention that you might not want to discount the possibility of using an ALH (Mk4) mTDI.  They give similar output to the AHU (mk3) but have some distinct improvements and seem to last forever.  They are also currently more readily available for cheap than the Mk3 TDI's. 
• #4 by ORCoaster on 06 Feb, 2019 22:40
• AS Always Libby, Great Response!  The voice of experience and reason is always welcome to be heard. 
  
• #5 by Chuck1978 on 09 Feb, 2019 11:10
• Libby, EXCELLENT info there, thank you for the incredibly helpful reply! I had started off a reply several days ago, but this week has been very hectic!
  
  I was amazed this morning that I was able to start up by 1.6 mechanical had IDI turbo engine after 11 degrees Fahrenheit overnight low, at 10:30AM in 17 degree weather. It was just 11 degrees at 7AM . It started pretty well. Compared to my wife's at least!
  My first thought this morning was, oh darnit, I forgot to plug in the Rabbit pickup!!!
  I am now thinking that I should not have too much trouble with and IDI with dual batteries and the good glow plugs on an engine in good condition.
  I guess it has been many winters since I have actually driven the old rabbit pickup trucks. I try to keep them out of the road salt. All of the 60° rains have washed away. Going junkyard hunting for an AHU/1Z this morning!
  
  
  your comments about the block and crank only weighing a marginal amount more have swayed me a little bit, as well as the 10% efficiency which I already knew was an issue. The cost of building a mechanical TDI is much higher than I'm building up a 1.6 IDI turbo. Also, the longevity of the engine worth in the pre-chamber cups having a very slight chance of having problems after a higher boost for a high amount of miles, and the TDI running much cooler, are all major factors. I still could go with an old IDI, but I am trying to make this vehicle last me beyond the next 40 years which I can see myself being alive and driving... I honestly I'm trying to set this thing out to be the ultimate four by four and daily driver. The road manners might not be that great no matter what I do with the off-road capability still remaining intact, but I think I can manage it. Aftermarket Aqualu 5/32" thick corrosion resistant marine-grade Aluminum body in the 55" cargo bed LWB (Long WheelBase version) full Toyota 4x4 drivetrain (full floater '85 axles, land cruiser '84-'90 transfer case, R150F rugged transmission). And an AHU or possibly ALH...
  
  I had veered away from the ALH option after two things, one is that none of this Suzuki Samurai VW diesel swap kits work with that engine architecture aside from the engine to Suzui or Toyota transmission adapters, so all mounts, brackets, oil filter angled adapters or remote relocating adapters, Etc will not work with the ALH into a Samurai (I can fabricate all of this, but it is just more work for me - & time is always running short for me), & also I was concerned about the cost of parts, as I had read that in ALH timing belt job costs around $400 in parts, versus an AHU, which is $99... I also wondered that since they are the same basic block architecture, if many parts for the AHU engine were interchangeable with parts all the way back into the early 80s? VS the ALH which was only 1999 - 2004, correct? If we were talking about just primarily only Parts availability 1996 - 1999, vs 1999 - 2004, I suppose that would not be much of an issue. But I assumed that perhaps more parts from the older models would fit the ahu as well. I'm trying to think long long-term, what am I going to be able to get when I am 65 in 24 years?
• #6 by libbydiesel on 10 Feb, 2019 11:43
• The ALH block style has continued up to the current engines with minor changes similar to how the earlier block style was used from the mid-70's through the mid 90's.  The block itself is stronger and the metallurgy is better so they just don't seem to wear provided you do proper maintenance.  I have one ALH that is a daily driver that has over 260,000 miles and has never used a drop of oil, ever.  I have never seen the level on the dipstick change at all between oil changes.  I like that the ALH drives the oil pump off the crank and the vac pump off the cam, so the intermediate shaft is eliminated.  Also, the 'bypass hose' is cast into the block and the water pump is driven by the timing belt.  The result is that all engine critical components are driven by the crank and timing belt eliminating potential dead-in-the-water situations that can be caused by the failure of non-essential accessories in the earlier engines.  The ALH parts are also at a peak right now, whereas the mk3 TDI stuff is getting somewhat rare.  Just things to keep in mind.  Either engine can can produce similar power and fuel economy, and either can be run with a mechanical pump.  The commonly used Land Rover 300TDI pump is more easily used on the ALH than the AHU.  Just things to consider. 
  
  If there is not support for the engine mounts on the later block style but there is on the earlier block style that could be a deciding factor.
  
  I want to mention that you should take care on where you get an mTDI pump.  Do not get one from Hans auto parts or from Prothe (same person).  I have heard multiple disaster stories and not a single success story with their pumps. 
  
  If you're actually completely rebuilding a 1.6TD or an AHU/1Z, the total cost is much the same.  If you are purchasing a 1.6TD vs. an AHU/1Z the difference in cost really depends on where you find the engines.  Bear in mind that selling off the electronic injection pump and other electronic engine management can offset the cost of getting the mechanical injection pump.
  
  The Land Rover injection pump is an excellent option and IMO the best 'bang for buck' that is currently available for mTDI injection pumps.  They are available new/rebuilt/used and priced accordingly.
  
  As far as planning for 24 years in the future, it's hard to know what the future holds.  I seriously wonder if internal combustion engines or operator driven vehicles will be outlawed by then...  :-P     
• #7 by Chuck1978 on 10 Feb, 2019 17:04
• Well, libby....
  
  Congratulations, as you are doing a very excellent job of convincing me of the ALH engine...
  I had figured the metallurgy may possibly be significantly better in the newer generation of blocks. Chevrolet started introducing higher nickel content in some of their engine blocks in the late 1970s, such as the ####509 "010 020" (casting marks indicating 1% more nickel and 2% more tin or vice versa) casting of the 400 small block which I have for a 1971 Chevrolet Camaro project that my father and I were working on a decade ago. Those blocks barely would wear any, whereas the same engine in a slightly older casting would get big ridges at the tops of the cylinders. Likewise with the 5.0 Ford Mustang blocks.
  
  I suppose eliminating the intermediate shaft and the possibility of associated parts going bad, and additional wear needing addressed on a rebuild, is another substantial benefit in choosing an ALH.
  
  I have read two or three threads where people put ALH engines into their Suzuki Samurai, but they did not go into much great detail of engine mount process, although they did weld additional steel to the frame and fabricate their own mounting surface using some universal motor mounts.
  
  Having to purchase primarily only the VW to Toyota V6 transmission adapter as part of the aftermarket supported swap kit would definitely be beneficial from a cost standpoint. I think I will search for more info on ALH swaps into Samurai's.
  
  The other excellent thing about the ALH, is that the Rover 2.5L TDI injection pumps are already the same size snout as the ALH pump bracket accepts, whereas if you put the Rover pump on an AHU or certain model AAZ mounting brackets, that fit this mTDI application, the opening has to be enlarged on the mounting bracket to fit the ALH-sized Rover pump.
  
  ALSO...on an mTDI (or TDI-M as Giles refers to it as) pump build, it is approximately $300 cheaper @ Performance Diesel Injection to supply a Rover pump, OEM TDI pump, and 1.6 IDI pump cores, vs supplying an AAZ pump (which Giles converts to a 20mm shaft from 17mm)  using parts of the TDI pump and 1.6 IDI pump.
   Plus obtaining an AAZ pump core. Although he seemed to indicate that himself being in Canada, finding an AAZ used pump core is much easier than tracking down a Rover pump core.
  
  the other important thing is, even if the timing belt parts cost significantly more to do a proper job on an ALH, the engines are currently very very plentiful used, and I would not likely have to do any teardown. Perhaps replace the rear main seal and other external oil seals while it is out. And a timing belt job. If they do run forever as stated, this is a huge bonus has the engine should still be in better condition, and is newer than the ahu so therefore it will have less miles. Also, I don't have to worry about trying to figure out if it has the older 1Z pistons or not, as the AHU/ALH style pistons are significantly upgraded over the first generation TDI (1Z) pistons.
• #8 by Chuck1978 on 10 Feb, 2019 17:13
• What turbo does the ALH use? I assume it is a VNT.
  I was hoping to use a wastegated K14 (2100 or 2300rpm spooling) or K03 (1800rpm spooling?) for simplicity and very little turbolag.
  
  How would one go about fittimg a wastegated small turbo to the ALH?
  Is there another applicable turbo that has the same mounting configuration? Or would I be able to use an AHU exhaust manifold? Or is the block/head architecture completely different on the manifolds?
  
  
  
  I also had been considering an imported European AFN engine, which I understand is just a more high output heavier-duty version of the AHU, although some AFN engines do not have the proper engine mounting boss threads on the sides of the block as the AHU & older have.
  
  having sputter bearings and stronger rods, different camshaft, and different injectors I believe were the primary differences.
  
  
  Non-VNT turbo choices or lack thereof could sway me back to AHU/1Z/AFN.
  
  THANKS!
  
• #9 by libbydiesel on 10 Feb, 2019 18:52
• If you get a Land Rover 300TDI or 200TDI pump there isn't any reason to have anyone do anything to it other than perhaps the governor mod.  Even unmodified it will perform great and even outperform a stock eTDI.  There is definitely no reason to provide any core injection pumps with it for making into an mTDI pump for a VW.  It already IS. 
  
  Yes, the snout fits the ALH better.  You still need to do a couple trivial external pump modifications but it is 98% bolt-on. 
  
  Stock turbo on the ALH is the VNT15.  Any of the earlier wastegated turbos will bolt up to the ALH without issue.  By earlier I mean ALL of them back to the mk1 1.6TD.  Just get the manifold and turbo and Bob's your uncle.