Engine Specific Info and Questions > Diesel Swaps
1.6TD IDI vs AHU 1.9 mTDI - cold weather starts, mpg, weight - Suzuki Samurai
Chuck1978:
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
Chuck1978:
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:
libbydiesel:
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 February 05, 2019, 10:27:57 pm ---1.) COLD WEATHER STARTING
--- End quote ---
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]
--- End quote ---
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
--- End quote ---
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.
--- End quote ---
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.
libbydiesel:
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.
ORCoaster:
AS Always Libby, Great Response! The voice of experience and reason is always welcome to be heard.
Navigation
[0] Message Index
[#] Next page
Go to full version