Daydream - building a 1.5L CR engine.

TDIMeister said:

Incorrect. It will be much rougher than an as-designed 3-pot.

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Have you ever felt a Suzuki 1.0L idle? A 4 cylinder with a thrown rod idles smoother (no I am not kidding). Now that same 3 cylinder with a thrown rod runs pretty smooth, too (seen that more than once, LOL).

But is there any inline 3 cylinders that are NOT essentially a 4 cylinder with one bore missing? The Justy engine comes to mind.

I'd imagine the crank throw weights would be different though. Our Yanmar diesel is pretty rough at low RPMs, too.

oilhammer said:

Have you ever felt a Suzuki 1.0L idle? A 4 cylinder with a thrown rod idles smoother (no I am not kidding). Now that same 3 cylinder with a thrown rod runs pretty smooth, too (seen that more than once, LOL).

But is there any inline 3 cylinders that are NOT essentially a 4 cylinder with one bore missing? The Justy engine comes to mind.

I'd imagine the crank throw weights would be different though. Our Yanmar diesel is pretty rough at low RPMs, too.

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oilhammer said:

Have you ever felt a Suzuki 1.0L idle? A 4 cylinder with a thrown rod idles smoother (no I am not kidding). Now that same 3 cylinder with a thrown rod runs pretty smooth, too (seen that more than once, LOL).

But is there any inline 3 cylinders that are NOT essentially a 4 cylinder with one bore missing? The Justy engine comes to mind.

I'd imagine the crank throw weights would be different though. Our Yanmar diesel is pretty rough at low RPMs, too.

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Agree my Yanmar is also rough at low idle-but built tough as well. What do you happen to have yours in. Mine is a 332 L&G tractor.

Funnly story about taking cylinders out. Guy I worked with in WY said an he was with an unstable person that worked on and flew his own plane. Don't remember the full story but he got mad, pulled his 44 mag pistol and shot a hole point blank and bolted things back up. Needless to say it didn't run although he didn't get hurt from the debre either.

Ours is in a JD compact garden tractor. Big tractor has an actual JD 4cyl though.

Tractors...one of the pleasures of living in more rural areas with land. Sucks to have only 1/3 of an acre

I believe the Top Gear guys talked about the Smart car having a 3 cylinder engine (funny episode when Richard and James spend 24 hours in one). Its not a VW but its German. I don't know much about Smart cars but I think the engine they sell here is a 3 cylinder though I doubt it is diesel. Those cars arent cheap to buy though and for racing purposes I don't think the engine would perform like you want it to.

The Smart's abysmal gas engine is a Mitsubishi or something.

yup... I should have checked wiki.

"with a 70 HP naturally aspirated Mitsubishi-sourced gasoline engine of 999 cc for North America"

TDIMeister said:

Where would you plan to obtain 76.5mm TDI pistons?

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Diamond I'm sure could make a set. If this is not intended to last more then say 10k or 20k billet pistons are fine.

really monotherms would be awesome, but a single one off run would be some serious coin. I know I looked into it. I have a 2.5L that needs to go 82mm.

Jetmugg said:

It would be great to hear from anyone with experience, knowledge, or crazy ideas about how to build the most possible power from 1.5L or less, using a VW-based diesel engine.

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Going to a 3 cylinder is a step backward IMHO.

Assuming use of ALH block @ 236mm deck height.
Compression height of stock piston = 236 - (95.5/2 + 144) = 44.25mm

Stock bore x stock stroke = 79.5mm x 95.5mm = 1896cc.

Currently available crankshaft strokes include:
77.4mm - 1.6 AKL crankshaft - cast
86.4mm - 1.8T 20V - forged & cast
92.8mm - 2.0 FSI / 2.0 8V AZG - forged and cast
95.5mm - all common TDI motors.

In order to obtain 1500cc your best bet would be to use the AKL crank.
77.4mm x 79.5mm = 1536.80cc
77.4mm x 78.5mm = 1498.8cc

With a 77.4mm stroke crank you would need a 153.05mm connecting rod with a 26mm wrist pin.

So to answer your questions:

1. Take OEM ALH pistons and have them turned on a lathe to reduce diameter by 1mm. The steel bands should still be adequate but this is more of an experiment than anything. Otherwise custom piston with capircorn ($1200USD+).
2. Sleeve the block from 79.5mm to 78.5mm bore
3. obtain piston rings from total seal or mahle motorsport - $130
4. Pauter forged connecting rods using a 154mm blank to obtain a 153.05mm rod / 25mm thick @ big end / 25mm thick @ small end with a 26mm wrist pin and a taper for the OEM ALH piston - $300 USD / each

HTH

Model year 2006 Smart Cars in Canada were 3cyl CDI Diesels with 799cc displacement. The 6 speed transmission only topped out at 89mph and zero to 60 took almost 20 seconds.

K.I.T.T. said:

How much distance is this top speed going to be measured over? 1.4 TDI + R783 + 1756VK = 160+ WHP. In theory anyway. I've been meaning to do such a build, but don't see it happening till next year.

Ash

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I would also like to see it happen, just take a EU5 1.4tdi (has the ARL styls rods and crank), bore it to 81mm so you can use crafter (16.x:1 CR) or BHW (18.x:1 CR) pistons and use ARL or maybe slightly bigger injectors.. use a decent vnt turbo (in the magnitude of a BV38), for gearbox I would choose a 02S, then it fits all ncie and pnp in a polo while still keeping weight to a minimum

this setup would make easily 140-145hp all day long and low end driveabilty would be a million times better than the sucky stock 75hp 1.4tdis with the WG turbo

INA said:

Going to a 3 cylinder is a step backward IMHO.

Assuming use of ALH block @ 236mm deck height.
Compression height of stock piston = 236 - (95.5/2 + 144) = 44.25mm

Stock bore x stock stroke = 79.5mm x 95.5mm = 1896cc.

Currently available crankshaft strokes include:
77.4mm - 1.6 AKL crankshaft - cast
86.4mm - 1.8T 20V - forged & cast
92.8mm - 2.0 FSI / 2.0 8V AZG - forged and cast
95.5mm - all common TDI motors.

In order to obtain 1500cc your best bet would be to use the AKL crank.
77.4mm x 79.5mm = 1536.80cc
77.4mm x 78.5mm = 1498.8cc

With a 77.4mm stroke crank you would need a 153.05mm connecting rod with a 26mm wrist pin.



So to answer your questions:

1. Take OEM ALH pistons and have them turned on a lathe to reduce diameter by 1mm. The steel bands should still be adequate but this is more of an experiment than anything. Otherwise custom piston with capircorn ($1200USD+).
2. Sleeve the block from 79.5mm to 78.5mm bore
3. obtain piston rings from total seal or mahle motorsport - $130
4. Pauter forged connecting rods using a 154mm blank to obtain a 153.05mm rod / 25mm thick @ big end / 25mm thick @ small end with a 26mm wrist pin and a taper for the OEM ALH piston - $300 USD / each

HTH

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I see 2 major hurdles with this

1.Turning down a piston would be extremely difficult since the piston body is not round
2.Piston rings are not that easy to find since they are tall and the inner ring groove can not be machined down much in diameter before weaking the piston seriously,so basically you would need a piston ring with identical ID as the ALH and 78,50mm OD

Then there is the cost of this
Custom pistons (which i think is needed)
Sleeves
Custom rods
77.4mm crank

Furthermore,a 78,50mm bore will reduce the efficency due to valve shrouding
79,50mm is bad enough
There will also be an air gap between block/head edges due to small cylinder/big diameter head gasket

The AKL crank has only 4 counterweights and MIGHT have harmonics issues when used in a Diesel

The 10mm pump from the ALH is also not capable of alot of power,so even more money has to be spent there

This is why i suggest finding a complete 3 cyl with engine loom and everything.

Then basically all you need is:
81.50mm pistons
Head gasket from 2 liter PD (just cut of the 4 cyl)
Stronger rods
Nozzles
Bigger Turbo/custom manifold
And a Tune

All the parts above is easy available except from maybe the exhaust manifold,but it is not rocket science to make an exhaust manifold for a 3 banger to fit in a race car.....

I also believe this engine could make decent power for maybe less money than an ALH build and also be a lighter engine package

Rub87 said:

I would also like to see it happen, just take a EU5 1.4tdi (has the ARL styls rods and crank), bore it to 81mm so you can use crafter (16.x:1 CR) or BHW (18.x:1 CR) pistons and use ARL or maybe slightly bigger injectors.. use a decent vnt turbo (in the magnitude of a BV38), for gearbox I would choose a 02S, then it fits all ncie and pnp in a polo while still keeping weight to a minimum

this setup would make easily 140-145hp all day long and low end driveabilty would be a million times better than the sucky stock 75hp 1.4tdis with the WG turbo

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What engine codes are for the EU5 1.4 PD? Whilst I don't know about those engines, I have a sneaky suspicion that the internals between the 75ps AMF and 90ps ATL found in Audi A2 (18.5 CR) are the same. I looked into this once, and the pistons and rods were the same for sure. My ETKA is broken here, won't show Audi parts any more. I'll try and compare the EU4 and EU5 engines once I find out the engine code.

What headgasket would you recommend to use with BHW pistons? I have a feeling that GTB1749VK found on 4.2 TDI twin turbo would be an excellent match for this engine...

mk3pd said:

All the parts above is easy available except from maybe the exhaust manifold,but it is not rocket science to make an exhaust manifold for a 3 banger to fit in a race car.....

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3 pot exhaust manifold actually exists. Most of the time the turbo is integral to the manifold like on transverse 4 pots, but sometimes they are separate. I have no idea why. I have one in front of me:



K03 fitment, but nothing that can't be fixed with a welder...

Geir, do you think the crank itself would pose problems when running high torque levels on the 3 pot? Balance issues come to mind. Also, the engine uses a chain driven balancing shaft. With better rods, what do you think a safe torque limit would be?

Ash

I don't think there will be any problems with the 3 pot crank even at high torque numbers
The weight would be almost unchanged if using 81.50mm pistons and H-beam rods,so no issues with balance either.

Not that it really matters for an powertrain with a required lifetime of 3 miles at Bonneville, but what nobody has considered is that when you reduce the cylinder count, the torque fluctuations within a crank revolution decreases in engine order and increases in peak-to-valley magnitude. Here is a good reading about it: http://www.epi-eng.com/piston_engine_technology/torsional_excitation_from_piston_engines.htm

These torque peaks and fluctuations are what eat clutches and destroys gearboxes, especially on very high-output engines. This is since the measured torque is only the mean, but the peaks will deviate significantly from this value, all the more with fewer cylinders. Though on a different case, on torsional harmonics,

EPI said:

High-output odd-fire V-6’s have been known to shatter the strongest of dynamometer driveshafts in a rather short time.

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A 3-cylinder 4-stroke engine has its first major critical harmonic at the 1.5th order; a 4-cylinder at the 2nd order. torque fluctuations can/will have to be dealt with through ever heavier flywheels. Again, that's not really necessary for a 3-mile engine, but that's what engineers have to think about.

While there's more than one way to skin the proverbial cat, the complexity of some of the suggestions above (including, admittedly, my first post in this thread) are solutions in the search of a problem. The two most feasible and promising are the simplest:
1) A 3-cylinder (whole, not a 4-pot with one cylinder missing... ) using stock- or modestly larger piston diameters to get as close as possible to the 1500 cc limit, or
2) A straight de-stroking of a 4-cylinder, period.

None of this nonsense of sleeving, turning-down pistons, unobtainium fuel injection systems, 9000 RPM speeds or making a Frankenstein out of a 30+ year old bottom-end to a contemporary head. All efforts should go into figuring out a feasible fuelling system and air-flow management to support the targeted power around one of the above two solutions. Thankfully, it's not all that hard if expectations are realistic and brain-power is invested in the right place.

BTW, for land-speed runs, aerodynamics are far more important than the difference of 10, even 100 pounds shaved off the engine or anywhere else.

TDIMeister said:

None of this nonsense of sleeving, turning-down pistons, unobtainium fuel injection systems, 9000 RPM speeds or making a Frankenstein out of a 30+ year old bottom-end to a contemporary head. All efforts should go into figuring out a feasible fuelling system and air-flow management to support the targeted power around one of the above two solutions. Thankfully, it's not all that hard if expectations are realistic and brain-power is invested in the right place.

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Actually, I think I may have a novel way to achieve a relatively efficient 9000rpm with a diesel motor. I hope that in 4 years or so I'll be able to share this idea with everyone.

mk3pd said:

I see 2 major hurdles with this

1.Turning down a piston would be extremely difficult since the piston body is not round
2.Piston rings are not that easy to find since they are tall and the inner ring groove can not be machined down much in diameter before weaking the piston seriously,so basically you would need a piston ring with identical ID as the ALH and 78,50mm OD

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Geir,
I would assume if he is building a race car engine then he should know about piston taper...
pro seal can make a ring in whatever bore you need but this is all speculation really.

manual_tranny said:

Actually, I think I may have a novel way to achieve a relatively efficient 9000rpm with a diesel motor. I hope that in 4 years or so I'll be able to share this idea with everyone.

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Conceptually, it's called homogeneous-charge compression ignition or premixed-charge compression ignition. There's no scope to inject, evaporate, mix and burn fuel inside a window of about 45-degrees crank angle at 9000 RPM. That's 833 microseconds. Injecting and premixing the fuel well in advance is how it would have to be done.

INA said:

Geir,
I would assume if he is building a race car engine then he should know about piston taper...
pro seal can make a ring in whatever bore you need but this is all speculation really.

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Hi Issam

A taper is pretty easy to do,but the piston is also oval which is quite difficult to do in a lathe (you are a CNC guy so you know this for sure)
Don't know if Pro seal can custom make rings
Total seal can possibly do it but the width of the ring has to be reduced by 0,5mm

So like you said,this is just speculations

TDIMeister said:

BTW, for land-speed runs, aerodynamics are far more important than the difference of 10, even 100 pounds shaved off the engine or anywhere else.

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True
However it seems that he must use a truck chassis
Not sure how aerodynamic those can be

Weight is often added intentionally to LSR attempts in order to aid traction and improve stability. Since the courses are fairly long (3 miles or 5 miles), raw accelleration is less important than raw power and aerodynamics.

This is an excellent discussion. My most likely path will probably be to go with the old school approach (1.6L TD block and head, 1.5L rotating assembly, pump work, a bigger turbo, and a water-to-air intercooler. Thousands of dollars worth of custom made TDI pistons and rods would be grounds for divorce in my wife's eyes. Unless I hit the lottery, this will have to be a simple approach.

Jetmugg said:

My most likely path will probably be to go with the old school approach (1.6L TD block and head, 1.5L rotating assembly, pump work, a bigger turbo, and a water-to-air intercooler. Thousands of dollars worth of custom made TDI pistons and rods would be grounds for divorce in my wife's eyes. Unless I hit the lottery, this will have to be a simple approach.

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I figured as much.

The value of a good technical discussion cannot be overlooked, though. If someone really wants to raise the bar significantly with a 1.5L or under diesel engine (like from 105 mph to 120 mph), I think the techniques discussed here will be necessary.

what aero mods are permissible?

Lowering, mirror removal, and adding a tonneau cover are ok. No airdams, headlight covers, or aftermarket spoilers of any type. All "sheetmetal" must be 100% stock in appearance. This is a "production" category, but engine swaps are permitted. Aero mods are restricted to the "modified diesel truck" class, where all engine categories run against one another.

Here's an article about the former recordholder (100 mph at Bonneville, 105 at El Mirage). Since that time, this truck has been transformed to a full-on race vehicle in the modified class, running as fast as 195 mph with a 2.0L Turbo gasoline engine.

http://www.whitegoosebar.com/European Car Nov04.pdf

Check it out if you get a moment.

Maybe start off with a Subaru Brat. Australia has some modern El Camino/Ranchero types that's not so different from a Holden/Opel Astra. Very aerodynamic compared to any 80's car and you could massage the excellent GM/Fiat 1.3L common rail Diesel...

I'm sure that vehicles of that nature will start showing up for LSR attempts in the future. Small pickup trucks will continue to become more aerodynamic. However, my pockets are not deep enough to make it happen. I'm going to have to "run what I brung".

TDIMeister said:

Maybe start off with a Subaru Brat. Australia has some modern El Camino/Ranchero types that's not so different from a Holden/Opel Astra. Very aerodynamic compared to any 80's car and you could massage the excellent GM/Fiat 1.3L common rail Diesel...

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What makes you think that engine is excellent for performance oriented destinations?