swaping in a diesel engine into a gas VW

[SVOboy]

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.

[omgwtfbyobbq]

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.




*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.

[Silveredwings]

Originally Posted by The Toecutter

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

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

[The Toecutter]

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 Toecutter]

I dropped a Toyota Corona engine and tranny into mine- turns out there wasn't much point to that since the toothpick stub axles in the diff weren't up to the job.

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.

Even if they were, that car gave a better illusion of speed than actual speed. With your butt 4" off the pavement and a windshild so low that I could look over it when the top was off, it was little more than a go-cart with nice sheet metal draped over it.

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

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

I dunno, "hypercar" might be a bit enthusiastic. That swing-axle rear end was terrible for handling, prone to "jacking" and unfavorable camber changes.

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

I remember one time taking a cloverleaf ramp about as fast as I dared- I was being followed by a friend of mine who was in his mom's full-size Chevy station wagon- he was right on my bumper- what a let-down!

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.

[Lug_Nut]

Originally Posted by omgwtfbyobbq

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.

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.

[omgwtfbyobbq]

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.

[BeeUU]

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.

[Lug_Nut]

Originally Posted by BeeUU

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.

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.

[BeeUU]

Originally Posted by Lug_Nut

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!!!

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