Help needed with Eco-mods for VW AAZ Diesel engine!

[320touring]

Originally Posted by UFO

I do not believe this is an IDI, the TD engines like the AAZ are direct injected and would suffer using vegetable oil. A far better fossil-free fuel is biodiesel, I have been burning B100 in my direct injected diesels since 2007. I even get better mileage on it and blends than straight diesel.

I think I am wrong, the AAZ is indiect, which makes it more tolerant of vegetable oil. To me, this would only make sense on long commutes or trips where you can keep the engine hot for long periods of time as vegetable oil needs more heat than diesel or biodiesel to completely combust.

The AAZ appears to be IDI lump according to everything I can find on line- certainly the mechanical fuel pump and lack of sensors etc suggest its not advanced enough to have DI

There also appears to be many folk running the AAZ on various concentrations of veg oil without issues.

It'd be my intention to start off at 10% veg (so 5L veg to 45L diesel) and gradually increase-keeping an eye on filters/engine oil etc

As you rightly point out, the oil does need more heat for combustion, and I'm lucky in so far as I have a 34 mile commute, so plenty time to keep the heat up. Also, my mods (grill block etc) would be geared to retaining heat in the engine compartment

thanks for your concern- plenty to think about

[UFO]

You would be well-served by using a heat exchanger to heat your veg-oil blends. A dual tank is really the only way to make vegetable oil fuel work for the long term as cold starts and incomplete combustion creates accumulations of polymers in your rings and sump oil.

[320touring]

Originally Posted by UFO

You would be well-served by using a heat exchanger to heat your veg-oil blends. A dual tank is really the only way to make vegetable oil fuel work for the long term as cold starts and incomplete combustion creates accumulations of polymers in your rings and sump oil.

I'll look into heating the fuel- Imagine there are a few ways I could do it.

A Dual tank conversion would probably be more than the cost of the vehicle- certainly not for consideration at this point- maybe once hypermiling has repaid the cost of purchase

I dont envisage using either Waste Veg Oil, or 100% oil- my intention is to find a blend that allows normal operation (i.e. no disecernable issues with cold starts/incomplete combustion etc) at the lowest cost.

a 25% veg blend will be ok in the climate here, and will reduce my cost per litre by approx 8p (14 cents)..

I've read about the polymers, and that does indeed seem to be a cause for concern- abatement by using good mineral oil, keeping temps up and watching oil levels seems to be key.

once again, thanks for the informative post- Eyes are wide open on this now

[AndrzejM]

I'm not sure that you should go for EGR removal. I'll tell you the story of Berta and it's EGR. After engine restoration I connected EGR as it was done by the factory but it showed up that valve that was opening EGR was broken. I replaced it two tanks before and I saw much better FE on MPGuino than with no EGR. The difference was easyly noticeable, engine now is working better and it seems that I have more torque in a middle range revs. So you may block EGR tube or just disconnect valve and see the outcome if that will help your FE or not. For Berta constatntly closed EGR valve was messing up with FE. Now I'm thinking if I could increase a bit (10-20%) EGR flow and see if that will help with FE.

Many years ago I was driving VW cars with 1.6 TD engine and after slightly tighteing spring in a wastegate and fuel dose increased by 1/2 turn of the regulation screw on the injection pump engine was running better with better FE as well.

I would recommend finding and installing IC for your engine. Grille block (upper and lower), belly pan, moon discs, spats maybe a discreet air dam at the front.

Good luck anyway and see you on the top of EM Diesel Cars list

[Jyden]

Originally Posted by 320touring

I know what you mean re the torque- about 2000-2500 rpm would be ideal for my commute, as it'd cover 50-60mph

does a longer intake= more torque lower down?

Thanks!

Can't say. Intake is different on every model of car's. Some are spot on from factory, some needs shorting, some needs to be longer. Trial and error!
best done on a dyno.

[tjts1]

AAZ is the dual opening pressure injector engine if I remember correctly.

TOP


All I know is those injectors are a ***** to rebuild and balance because of the dual spring pressures. It needs special equipment compared to other mechanical injectors. A few people have tried them on MBs with limited success although they do tend to be quieter at idle.

[LeanBurn]

I would look into fitting an inter-cooler if you are really looking for cooler intake temps. Cold are intakes are a drop in the bucket in comparison when you look at the post turbo air temps.

Be careful with grill blocks on those cars. Make sure the radiator and cooling system is running absolutely top notch before attempting. The older cars tended to run hot and then at times the cooling system tries to catch up after the fact especially on hot days, driving up hill, I had a dash mount manual fan switch just in case. I got better results by finding an optimum speed, insulating the turbo exhaust side and making sure the muffler is free flowing. My brothers 1.6L TD muffler had all kinds of soot accumulation when he got his looked at.

[320touring]

Originally Posted by AndrzejM

I'm not sure that you should go for EGR removal. I'll tell you the story of Berta and it's EGR. After engine restoration I connected EGR as it was done by the factory but it showed up that valve that was opening EGR was broken. I replaced it two tanks before and I saw much better FE on MPGuino than with no EGR. The difference was easyly noticeable, engine now is working better and it seems that I have more torque in a middle range revs. So you may block EGR tube or just disconnect valve and see the outcome if that will help your FE or not. For Berta constatntly closed EGR valve was messing up with FE. Now I'm thinking if I could increase a bit (10-20%) EGR flow and see if that will help with FE.
Many years ago I was driving VW cars with 1.6 TD engine and after slightly tighteing spring in a wastegate and fuel dose increased by 1/2 turn of the regulation screw on the injection pump engine was running better with better FE as well.
I would recommend finding and installing IC for your engine. Grille block (upper and lower), belly pan, moon discs, spats maybe a discreet air dam at the front.
Good luck anyway and see you on the top of EM Diesel Cars list

Thanks for the suggestion- I’ve yet to see if this car has an EGR at all- GB spec cars were different from most other markets- I don’t know if there was a requirement for EGR in the UK when this car was built.

I’m looking into increasing boost pressure- by modding the waste gate actuator- its adjustable on threaded rod.

Originally Posted by Jyden

Can't say. Intake is different on every model of car's. Some are spot on from factory, some needs shorting, some needs to be longer. Trial and error!
best done on a dyno.

That’ll be something to do once I get her serviced then

Originally Posted by tjts1

AAZ is the dual opening pressure injector engine if I remember correctly.
TOP

All I know is those injectors are a ***** to rebuild and balance because of the dual spring pressures. It needs special equipment compared to other mechanical injectors. A few people have tried them on MBs with limited success although they do tend to be quieter at idle.

I believe the US spec cars are dual pressure ones- European ones are single pressure as far as I can tell- so less rebuild issues thankfully!

Originally Posted by LeanBurn

I would look into fitting an inter-cooler if you are really looking for cooler intake temps. Cold are intakes are a drop in the bucket in comparison when you look at the post turbo air temps.
Be careful with grill blocks on those cars. Make sure the radiator and cooling system is running absolutely top notch before attempting. The older cars tended to run hot and then at times the cooling system tries to catch up after the fact especially on hot days, driving up hill, I had a dash mount manual fan switch just in case. I got better results by finding an optimum speed, insulating the turbo exhaust side and making sure the muffler is free flowing. My brothers 1.6L TD muffler had all kinds of soot accumulation when he got his looked at.

An intercooler and Muffler delete will be on the cards once I have the car tuned and any niggles fixed. An I C seems to work best with turbo and fuelling tweaks
The rad looks ropey, but a new one is under £60- I’d envisage cleaning/rebuilding it sooner rather than later..

[tjts1]

Originally Posted by 320touring

I believe the US spec cars are dual pressure ones- European ones are single pressure as far as I can tell- so less rebuild issues thankfully!

AAZ never made it to the US, they were sold in Canada in the early 90s so getting them here is a pain. I didn't realize the European ones were single pressure, simplifies things. Theres nothing wrong with these injectors, on the contrary, I think they're the pinnacle of IDI diesel tech. The AAZ injector goes together with its own specialized injection pump so theres no real point to mix and match.

[oil pan 4]

Originally Posted by 320touring

I'll investigate reducing restrictions in the intake system- I imagine there's some scope for re-routing the turbo pipework/installing an intercooler etc.

I know what you mean re the torque- about 2000-2500 rpm would be ideal for my commute, as it'd cover 50-60mph

does a longer intake= more torque lower down?

Thanks!

http://ecomodder.com/forum/showthrea...els-23234.html