swaping in a diesel engine into a gas VW
 

last weekend I talked to a guy who swaped a Diesel engine in to his gas VW Rabbit, as he explaned it was extreamly simple, as the Diesel engine only uses a fraction of the wires, has a mecanical engine mounted fuel pump, and I belive he said it bolted right in, of course you need a transmition from the diesel as well for the proper gearing (unless you want to use it as a tractor), so I got to wondering, how hard is it to swap in a newer diesel engine in to say a VW gulf? I know that once you get in to things like the new TDI VW's that things get extreamly complecated due to them being a drive by wire system, but how about those older TDI engines? or just the normal turbo diesel vw engines, I think it's worth thinking about, espsialy if you drive distances, and are having truble finding a small diesel car, junk yards seem to want $250-800 for an engine.

Well, since this is a bit of the origin of my handle on here, lemme think. All the golfs are an evolution of the rabbit; all the tdis are an evolution of the original 48 hp diesel beatbox. I imagine they continued to use the same engine mounts and such things for the different engine throughout the years (unless they really suck), and therefore, since I do believe it's possible to put an MKIV engine in a MKI, you could prolly put the MKII TD in there by using some sort of mount kit, same goes for the TDi. Of course, I'm not sure, but this is just how I'm reasoning it out.

I'm pretty sure that (2.5 years ago) when I was into the rabbits I'd seen people with the new tdi in there. It's a good platform, cheap, light (~1800-1900 pounds) and who cares if you beat it up, :p

Generally, there are three types of vw diesel. NA IDIs, Turbo IDIs (TDs), and TDIs, the NAs are all 1.6l and the TDIs are all 1.9L, the turbo diesels come in both sizes.. To avoid lots of crap with the drive by wire system you can pull a mechanical injector pump/cable off of a 1.9l TD which will go straight to the pedal for a mechanically injected TDI. You also need the passenger(?) side engine mount from the factory, but it bolts right up to the other three. I've heard it's nicer to keep the fly by wire and ECU because you can have on the fly fuel map changes. You gain something like 40hp and 15-20mpg, nice swap.

A chipped TDI in a Rabbit modified for around 180 horsepower would be pretty wicked. Prius fuel economy, Corvette performance.

Do extensive aeromods, and fuel economy would rise even higher. I know of an individual with a diesel Rabbit pursuing extensive aeromods. Stock engine, but hopes to exceed 80 mpg. I'd say his goal is pretty realistic. He intends to grow various plants to make his own biodiesel.

Why grow **** for BD when you can get grease for free from restaurants? Why make new when you can recycle old?

While this is off topic, you'd have to know this person to understand why. There is a significant number of people who see peak oil as being so potentially devasting, that fuel for their cars may be unobtainable in the near future. In which case, far more motorists would be using fryer oil than today and obtaining it would be difficult, if not expensive. Fryer oil can't supply everyone.

In preparation for this scenario, being able to make your own fuel makes sense.

Whether peak oil will be that severe I cannot say, but it is a very real possibility and shouldn't be dismissed.

If I had my own land, I'd gladly grow hemp for the purpose of making biofuels. Get me a set of solar panels, a wind generator, and a diesel generator, and I'd be set. The wind and solar could provide electricity, with a set of batteries and the diesel generator acting as intermittent backup. Charge the EV with electricity, and if the sun isn't shining or wind not blowing, the hemp biodiesel can be used to make electricity. 100% renewable, cheaper than grid electricity, running the battery car cheaper than any gas car(including battery replacement). Would pay itself off in savings in only a few years.

I'm more apt to distill ethanol than grow **** for BD, but that's just me, mwahaha.

Anyway, a corvette would smoke a rabbit with 180whp.

I dunno... 180whp@4000rpm and ~270ftlbs@1800-2500rpm? That's a very nice powerband to work with. Considering the Rabbit weighs in at ~2000lbs stock, while the Corvette is someplace above 3000lbs, we're starting to get pretty close in power to weight ratios. If we strip the bunny down to 1500lbs, and toss a hundred pounds of cinder blocks over the really sticky front tires, things would be interesting. But that's not really practical and ultimately, the Rabbit's 1/4 mile weakness comes because of it's fwd layout. What I would bet money on is a diesel Audi 4000 with vw's I5 TDI. It weighs about the same, has better handling/traction because its rwd, and has a lower CdA, along with a close ratio transmission.... Granted it couldn't do much in stock form, but if the I5 TDI drops in there, and if the transmission can take it, it could be one fun car.

I'm just deflating on him, because I think most of the power/fe numbers he cites as easily attainable are way out there.

Anyway, I saw a crx the other day, prolly pushing around 300whp and 250wtq and it only ran high 11s. That thing's light and more aerodynamic than a rabbit , not to mention I give more credit to it's suspension and whatnot.

One for me...one for the tank. :p

I think it sounds like a cool idea. I know nothing about it though.

Give it a search, there's tons of info on it. I actually saw it on the news in MO where someone set up a company building stills (is that how it's spelled) for people to make ethanol for their business.

Those power numbers only require remap on a 2.0PDI four banger. VW builds some durable engines.... When they first released to TDI it only had 90hp, but as injection technology progressed and they found the 1.9L internals to be pretty solid, they increased hp and bore a little bit and ended up with the 2.0PDI pumping out ~170hp stock. Old 1.6NA's can easily be pushed to ~70-100hp with no problems and an increase in fuel economy provided it's done right. From what I've gathered, the limiting factor with diesel power is not the engine bottom end, but EGTs. So if a manufacturer can push fuel in faster, then it should combust as well as it did before and they can get more power out of an engine at the same temperatures. Of course you can always remap and toss more fuel in there regardless, but unless your fuel pressure has increased or you have more air, you'll run hight EGTs and can melt your engine.

The numbers might seem way out there, but such figures have been done before.

Google search "Opel Eco Speedster". 97 mpg, 112 horsepower diesel, 160 mph top speed, .20 drag coefficient, 15.06 square foot frontal area.


The Rabbit is an unaerodynamic brick, .36 Cd and 18 square foot frontal area. Yet it can still get over 40 mpg combined EPA, approaching up to 50 mpg highway attainable at about 65 mph. There's numerous reports of individuals attaining 55-60 mpg at a steady 55 mph, which is about the speed this person drives.

Imagine what happens with extensive aeromods, to get Cd to around .25, along with LRR tires, synthetic transmission oil, drag free brakes, and other simple modifications that this person is planning. Highway fuel economy would no-doubt increase more than 20% from the aeromods alone(evidenced by many examples on this site and elsewhere of extensive aeromods having this impact), 10% or more from the other things.

80 mpg is well within grasp at the speed this guy drives, keeping the original engine unmodified but adopting extensive mods for the car itself.

An updated higher horsepower turbo diesel could actualy increase fuel efficiency even more if this mod along with the ones above were pursued, given that the 80s diesel is nowhere near as efficient as a modern one.

A stock 1980s Rabbit gets slightly over 40 mpg EPA, while a Prius gets around 55 mpg EPA. Take the 80s diesel out of the Rabbit and replace with something modern, even with a performance chip and added turbo boost, mpg in the 50s is probably obtainable. This is before aeromods and such are considered.

Where'd you see .36 for the rabbit? I always saw that mk1 vws range from .42-.46 depending on whether the car's a jetta, rabbit, or rabbit pickup.

I had to borrow my brother's mid '80's diesel Rabbit 4-speed once when my car was being worked on about 10 years ago. My trip to work was 25+ one direction and it was around 75-80% highway. After 2 days of driving to work and driving into the town where my car was being worked on(twice), I refilled it when I gave it back to my brother and the mileage checked out at just over 52 mpg. This was before I was really big into driving techniques.

Before you quote the epa on the rabbit you should note it was evaluated before the epa redid their testing and dropped ~20% off their estimates. The same year that the Diesel L got 48 mpg highway the CRX HF was rated for 67...

Not to mention that it has 48 hp, the cars fall apart like nothing else, and I have been told by more than a few people that cruise control was leaving a brick on the pedal because it couldn't break 75 mph and that in hilly areas it takes everything it has to keep it going.

And then I stopped wanting to buy one and ended up with a crx and couldn't be happier...

Hehe, that's all true in some cases! But it depends on the car/tranny you get... On the postivie side the drivetrain is just about as durable as it gets, and roughly doubling the horsepower while leaving efficiency unchanged can be done for maybe $250-500 depending on how you thrifty you are. The disparity in highway mileage comes from the CRX having a CdA of ~6 square feet, while a Rabbit is ~9 square feet. You have any sources for the EPA estimates?

https://fueleconomy.gov/feg/how_tested.shtml

At the bottom is a little blurb about how they changed them, this is also the reason you can't find EPA estimates older than 85 on the website.

That explains a lot. I figured they would've left the older data there with a big fat disclaimer, but I guess they don't want people getting the wrong idea? Shoot, I dunno...

Crap, you're right.

I had confused the Rabbit Mk I's drag coefficient with that of the Scirrocco.

Although, Uve's EV Calculator does list the Rabbit as .36(a number that's been floating around some groups for the Mk II determined by coast down method).

Even still, cutting from .42 down to the high .2 region would have even a larger impact than doing it from .36 down to the high .2 region.

Mk II VWs had a bit of a drag reduction over their ancestors though. The Mayfield Companion quotes the Mk II Jetta at .32, for instance.

Here is a Rabbit Mk II photo, for those interested in how it looked being run through the wind tunnel:

https://img.villagephotos.com/p/2006-...RabbitMkII.jpg

Not bad at all. Reflects what others have gotten with the cars.

Indeed. The EPA estimates are notorously inaccurate. Little known secret: the EPA doesn't measure fuel consumed, but estimates it from emissions.

But people are achieving and exceeding these estimates with proper driving technique. The figures were convenient and available, so that's what I used as a basis for comparison. Just as there are people getting 50 mpg in Toyota Priuses, there are people doing the same in old Rabbits with inefficient engines.

Replace the old inefficient engine with a more effiicient, high-power diesel engine, and you get the same or better fuel economy, with much more performance.

With all this I can agree.

But many love these cars. The person I am referring to that is aiming to make his own fuel goes by the name "Pilferage" on peakoil.com and on the maxmpg boards. He's keeping the oroginal engine.

If I had a Rabbit, I'd do a swap to something modern. I like to go fast.

Also of note, my Triumph falls apart faster than any Rabbit. But I love the **** out of it.

Converting these Rabbits to a slow EV on flooded batteries and low-power Curtis controller is widely considered a performance upgrade. ;)

Aside from needing gas and not being able to be run on biodiesel, the CRX is a good choice. The HF has a .29 Cd, which is pretty damned good. I considered using a CRX as a base for the electric car I wanted to build, but there were already many of them converted, I don't like the looks much, they are expensive as hell in my area, and I found the Triumph.

The CRX will one day be EV. Mine has .30, the difference between the hf and mine is the rear wiper, there's nothing else worth seeing. Mehbe nixing my antenna will gimme some help.

But anyway, I would still be a rabbit diesel L if one popper up for 100 bucks, but I'm not searching like mad anymore.

O.k. since I f'ed up the calcs, going from Cr=.012, CdA=.485 to Cr=.006, CdA=.276... If I get ~50mpg@55ph I'd get ~90mpg@55mph. Of course, I'm pretty sure I can do even better with synthetic oils, and turbocharging for better engine efficiency (~5% on TDI's). I've seen an intercooled VNT turbo from a newer VW and a turbodiesel fuel pump (has this little gizmo on top that increases fueling as boost pressure rises) dropped on a NA 1.6l, with the result being about the same efficiency, and a doubling of torque through the entire rpm band. There's an old diesel head from Canada who claims that he's getting ~70-80mpg (Imperial) by venting the boost pressure so he gets a *super-lean mixture. The really neat thing about this is that he can push a little knob in to regain boost pressure to the fuel pump for an instant ~30hp. I figure the boost pressure can be bled gradually somehow, so that power/efficiency can be set to whatever level you'd like. All told I think ~50hp/120mpg@55mph or ~80hp/80mpg@55mph is possible, but not unless I get off my ***, get a job, and stop messing with my bikes/internet message boards. ;)

https://www.fuelly.com/attachments/fo...4ecc17445c.jpg
https://www.fuelly.com/attachments/fo...28b99e715a.jpg

*I'm pretty sure this is why those gigantic diesel trucks can pull ~20-25mpg even though they're four times the size/reference area. Because they're in a different EPA class they can run leaner and produce more NOx. This is also why those chips can produce more power, but still get better FE. They lean out the engine even more (actually should create a little bit more torque) for the majority of throttle positions and then richen it on WOT for more power (compared to *factory), which is why you'll see the occasional big diesel with tons of black smoke coming out the exhaust. Of course leaner creates more cancer causing NOx, and richer creates more hybrocarbon pollution, but it's all part of the game I guess...

**Even though these are never tested like gas cars are for smog, they do have to conform to emissions regulations when built.

I think those old British cars were made out of compressed rust (all you had to do was add water). :D

Spitfires make excellent race cars with a few upgrades. About $3,000 of components(mainly GT6 and TR6 stuff, the TR6 engine and tranny/differential are a must as the stock units suck) could make one into a car that does 0-60 mph < 6 seconds, 130+ mph top speed, and ~30 mpg. Compare to the stock Spitfire doing 0-60 around 14 seconds. Rotary engines are also a common modification for these cars. I've read of a 250 HP rotary-powered Spitfire... that would be a sick canyon carver, and still get great gas mileage.

Would I not be concerned about oil use and its political, economic, and environmental implications, I'd be lowering a 350 Chevy into my GT6, instead of an electric motor.

These cars are such an excellent base for a hypercar, but Triumph sadly never had the chance to do much with them. For being made with WWI-era technology, they are quite an accomplishment. 0-60 mph in 9-10 seconds AND 28-30 mpg in the same car is something that didn't start showing up until the late 1990s to early 2000s. The Triumph GT6 achieved that in the 1960s using technology that was very antiquated by the standards of its time.

The stock Spitfire transmissions and axels are horrible. so are the GT6 components. I have a TR6 transmission and differential in mine for that reason; the TR6 units can handle over 300 lb-ft of torque and ~250 horsepower without problems. This is according to the racers I have spoken with. They consider the TR6 units 'bulletproof'. Insofar as Triumph components go, that's as 'bulletproof' as you will get.

The stock Spitfire components are a cheap joke.

Some love that go-kart feel, some hate it.

Mine? Lowering my ride height to 3" with a racing suspension! :D

The GT6 MkII and Spitfire MkIII corrected this by adding rotoflex couplings.

It should have been expected. Given the car's weight distribution and the fact that it had a swing axel system, you'd constantly need to be accelerating through the corner to keep the rear end planted into the ground for traction. One thing a stock Spitfire lacks is acceleration... Get enough power, and oh man, it's heaven. The rotoflex suspension is even better. My GT6 has rotoflex suspension, and this thing handled like it was on rails. I've driven my dad's Audi TT when he had it, and I'm quite certain the GT6 could take corners a fair bit faster. Mind you, mine has modern radial tires, something the cars never originally came with. When the GT6 MkII debuted in the late 60s, I do recall it achieved over .8 Gs on a skidpad, without tires as we know them today.

The boost bleed is used to fool the TDI engine's electronic control unit into thinking there is less intake manifold pressure than there actually is. This delays the electronic command to the solenoid valve which opens the wastegate. The result is a higher boost pressure to the engine is required to equal the trigger point pressure at the ECU. Non-electronic (pneumatic) wastegates can have the same result by increasing the pre-load on the wastegate closing spring or by punching a pin hole in the turbo to wastegate pressure supply hose.

A dyno test with my TDI and boost bleed valve showed a significant increase in torque (and therefore hp) at lower engine speeds. However the increase in boost pressure also caused an increase in exhaust back pressure due to more exhaust through the restrictions in the turbo, rather than freer flowing through the waste gate. The increased back pressure and reduced high rpm 'breathing' capacity cut the peak or maximum hp at the higher rev range. I had more boost pressure, but less power. The trade off of more power down low (with bleed) versus more power up high (without bleed) was a no brainer when I saw how much higher the EGT was with the bleed and the added back pressure. I pulled the bleed valve and never looked back.

70~80 mpg imperial is dead easy, unless that is a daily or a lifetime average. If that is the best or attainable when 'trying' for fuel economy that's only 58~67 mpg US. Been there, Done that, Got the T-shirt, too.

All diesels run "super-lean" because they regulate the fuel only, not a fuel and air mixture. The ratio of fuel injected to the nearly constant air volume per piston stroke may range from 200:1 at idle to about 30:1 at full load.

This is with an IDI engine, just kill the pressure going to the LDA and he gets NA fuel delivery on a TD engine, pretty much an ecodiesel w/o the absurdly high gearing/extra weight. He's claiming he could hit 100+mpIg with his tires at 80psi. The point of this being that the A/F ratio never drops below, say 60-100:1 (or whatever it is), and FE doesn't take a hit with more power, like in a NA.

I miss my Golf Diesel
 

I had a '86 Golf diesel that would get mid-40's every tank without trying. It was the NA 1.6. I sure wish I did not sell it now. :(

I am pretty sure the MkII Golf Cd was 0.34 and the Jetta 0.36. I will have to check my sources.

As did I. My A2 two door also got 45 mpg when I had it between TDI#1 being totaled and my aquisition of TDI#2. Gutless, no power and 5 mpg less than the TDI. I was somewhat sad to sell it. I really liked the car, but the engine performance?...... The TDI engine had spoiled me.
What I should have done is popped in the engine from #1.

That would have been a nice modification. Quick and efficient - the ultimate goal!!!


I still would like to have the old NA 1.6, the only electrical load would be the solenoid on the injector pump and the brakes lights, if you use them. :> The perfect alternatorless car I think. A 5 watt solar panel could keep up with this car!!! :thumbup:

They were pretty slow, but it was fun keeping up with traffic!!

As a 1989 VW 1.6 NA owner, I love mine. I know a couple people that have replaced the Electric fuel choke with a mechanical one and run their car without an alternator and one even has a mechanical starter that I thought was rather interesting looking.

As for the CRX, while reliable. That engine will be long gone while the diesel VW engine being an iron block and not aluminum will far outlast it

I'd like to see some technical documents supporting the idea that iron blocks are better than aluminum, since all I've ever heard about iron is how much is sucks, :p

In any case, welcome to the site! Don't forget to create an introduction.

Can't really find any technical documents, but Aluminum blocks require cylinder sleeves which need to be replaced every couple 100k miles, whereas iron and steel blocks do not require sleeves because they are not soft metals. The problem with iron and steel blocks is when they overheat and warp the damage is far greater than it would be for an aluminum block.

I am not aware of any aluminum block diesel engines, mainly because the sheer pressure of a diesel combustion would punch holes in a thin walled aluminum engine and the sleeves would possibly warp from pressure.

I do like CRX's and Honda has a name in quality and reliability.

I don't really know much about diesels, but I do know the diesel Toureg and the new Mercedes euro-4 diesels both use aluminum blocks.

*shrug*

https://puregreencars.com/news/2007-Touareg-V10-TDI.html

Toureg is cast iron with alloy cylinders

However, the Euro-4 is aluminum, nice catch with that. It is speciality manufactured though, making it more expensive than the standard cast iron or steel

Interesting, must have read that in some bogus source.