vw diesel engines

[the4ork]

here is the pd100 engine before and after a chip upgrade (this is the electronic/mechanical pump)



here is the 2.0L TDI with the common rail injection



1.9 engine with just a chip



1.9 engine with a bigger turbo upgrade, vnt-20 @ 25psi



another vnt-20 upgrade on a 1.9


anywho, i have seen PLENTY of 200+ whp dyno's for the 1.9 engines with vnt-20 or vnt-22 turbo upgrades and bigger injectors ect...

question is making the power/weight ratio

[Andy_RR]

you say you've seen plenty of 200+whp, yet you show us three graphs which alledge around 160-170 flywheel hp (using some usually dodgy correction factor fiddling)

VW put out an engine at 150ps or so that they know will last under normal driving conditions - getting this to 200+ps is going to take the materials to their very limits (and probably over). How is this going to allow for TBO's anywhere close to the 2000hr of a Lyclone?

The short answer is, it's not!

A

[the4ork]

the 150ps engines have pretty much the same sized turbo's as the 90ps engines and with just a simple turbo upgrade and a tad more fueling, 200hp is easy to achieve without stressing the engine

anything over 250hp you have to start worrying about the headgasket and egt's

the twin cam 4v per cyl engines would be ideal for 200hp use, but are hard to come by in the states because they were only available in europe... but the 1.9 tdi's can get 140 hp @ 3k rpm pretty easily and are available in the states. however i woulnt mind spending the extra $ to have a euro motor imported if i had some extra cash.

im going to look into using a 1.9 TDI-M engine, which is basically a tdi long block but with the older style mechanical injector pump... so no electronics to mess with. the only upgrades i would do would be a "giles pump" which is the best upgrade for the buck you can get on these little motors (im putting one on my 1.6TD) and a VNT-20 turbo. this is because it has variable vanes in the turbine housing instead of a wastegate, and can be controlled via mechanical linkage. this way you can really dial in the hp when you need it, and at cruise you could pull the rpm's back a tad and pull the boost back easily..

still though, weigh is an issue, im going to weigh my 1.6 engine complete and that should give me a ball-park figure of what the 1.9 will weigh

[pierre smith]

Another point that has not been addressed is whether or not the thrust bearing can even stand being continually loaded by prop pull, assuming you intend doing direct drive.

In cars, the thrust bearing only takes periodic pressure from your leg when you push in the clutch to shift, if it's a manual transmission.

Really, what's wrong with a good used Lyc anyway? I suppose if you want to "experiment" then do so....or would you rather fly?

Regards,

[rtry9a]

My first inclination is that the motor does not have sufficient torque to go direct drive, and not enough hp (high rpm) to use existing redirive setups. You cannot ignore the weight of auxiliary parts if you want to compare with similiar, i.e. O-320/360 powerplant. You will need to get delivered power up to 160+ and weight including cooling, manifolds, redrive, pumps, motor mount, etc under ~350lbs. Unless the installed motor is significantly more reliable, cheaper, or has some other advantage over existing motors; it is probably not worth the effort. With diesel selling for more than mogas these days, Id be surprised if the cost savings would be a factor over other automotive offerings.

fwiw, there are some folks experimenting with diesel powered rotary engines that might eventually work..l.

[1:1 Scale]

Originally Posted by Andy_RR

you say you've seen plenty of 200+whp, yet you show us three graphs which alledge around 160-170 flywheel hp (using some usually dodgy correction factor fiddling)

VW put out an engine at 150ps or so that they know will last under normal driving conditions - getting this to 200+ps is going to take the materials to their very limits (and probably over). How is this going to allow for TBO's anywhere close to the 2000hr of a Lyclone?

The short answer is, it's not!

A

The first two dynos were done on chassis dyno's, so those numbers are less than you would see at the crank, add 12-15% for a crank # estimation. I'm not sure what the third dyno is from, but the fourth dyno that claims "flywheel HP" is another brand of chassis dyno called a dynapack that actually bolts to the wheel hubs, so those numbers aren't crank HP/TQ numbers either. The correction factor would be slightly less since you don't have the rolling resistance of the tires.

I'd love to have an engine that produces peak tq down around 2000rpm and just cruise there all day long, but as Pierre mentioned, the thrust bearing could be an issue.

[John Clark]

Originally Posted by 1:1 Scale

I'd love to have an engine that produces peak tq down around 2000rpm and just cruise there all day long, but as Pierre mentioned, the thrust bearing could be an issue.

Another issue that needs some thought is the thrust line, the centerline of the propshaft/crankshaft. With an inline engine like the TDI the thrust line would be way too low for an RV. The two common fixes are a belt/gear drive, which could cure the thrust bearing problem but add weight or, like many inline aircraft engines, turn it upside down. Major issues with that, lubrication being one.

John Clark
RV8 N18U "Sunshine"
KSBA

[rv6ejguy]

I'd also mention that the typical SAE correction factors used on DynoJets are invalid for turbocharged engines. Best to use uncorrected or observed hp. The difference is substantial if the facility is well above sea level.

[gtmule]

the 2L engine appears to be making 160whp at 2700 rpm, which seems to be about the limit of what a 2 blade prop that's big enough to absorb ~200hp can spin up to efficiently. If you used a 3 blade (or 4?!?) you could get a little more (engine) speed (and power) at the cost of some efficiency; that'd make a nice simple optimization problem.

Add 10% for losses and that works out to something like 176hp net at the flywheel (conservatively). Run an electric water pump(s!) and toss the p/s pump in the trash and you're probably looking at 185hp avaliable to the prop, call it 180. You'd want to do some thrust load analysis, but it wouldn't be difficult to add a thrust bearing. The issue becomes installed weight, and sorting out the electronics. I'm willing to bet the (inevitably) Bosh system on the stock 5 spd euro TDI's could be tricked into thinking it was in a car, or better yet, re-flashed to ignore things like neutral safety switches, wheels speed sensors, etc. All you really need for a diesel is injector pulse and timing as a function of rpm and load (boost).

The crank centerline issue would be tough, I'd be interested to see a drawing or really good straight on picture of the rear end of one of these engines with a ruler in the pic (and something similar for a lyc). More than likely this would be unacceltable for a (stock) RV airframe, but I can imagine alot of different configurations where it would be fine (or even desirable!). If they're shorter than I think they are, you might be able to lean the cam cover over to the passenger (co-pilot ) at a 40ish degree angle to gain some height, of course that would involve fabbing a funky oil pan and pickup (no biggie).

[the4ork]

yes but ur talking about using an electronic TDI pump...

if you search for TDI-m they are taking newer TDI engines and installing the older style bosh pumps that are completely mechanical. they need 1 positive wire to operate the fuel shutoff valve and thats it, talk about simplicity!

there are also companies that can seriously trick out these pumps with little to no affect in fuel efficiency but are the BEST bang for buck in hp/tq... a stock 1.6 turbo diesel (mine) had 40% more power just by changing the pump and adding 5psi more boost, the 1.9 i would imagine would be the same or higher jump in power

also, the mounting in an RV-x woulnt be a problem for me, as im thinking about using this engine in a dragonfly... although i'll probably stick with an aircooled vw engine for simplicity/cost/faster to get flying

but i would like to experiment later down the road maybe on a 2nd project... i dont think a repositioned prop with a belt would be too hard for anyone with fabrication skills... and good idea on the 3/4 blade props...