first generation gas turbine

[rockstar17]

ok. here I will report on the progress and ask questions on the first engine build.

first step is to buy a turbocharger. I decided that I'll get one with something like a 2 inch inlet.

I'm going to try to get a used one off Ebay. how much should I spend on a used one that still works? (do I need to worry about those weird wastegate things?)

edit: maybe I will just go with a cheap brand new one instead of a used one. alot of the used ones on ebay just look so nasty, have a bunch of junk attached to them, or just have broken wheels/shafts

edit: I think this is a good choice: http://cgi.ebay.com/ebaymotors/SAAB-900 ... 6066QQrdZ1

its a garret turbocharger in good working order for only $99.99 not sure about the size, I will ask. and I think I can take that stupid actuator thing off. what do you guys think about it?

[Johansson]

The Saab turbos are pretty small with tiny exhaust housings, so I would recommend you to get a bigger turbo from a truck or something instead. On larger turbos there are no internal wastegates which is good since you won´t need one.

A Garrett T04B is similar to the turbo used in Don´s GR-1 engine, here is a pic from his homepage where you get an idea of the size. They are quite common so I don´t think that you will have to pay very much for one in good shape.



//Anders

[larry cottrill]

What an absolutely beautiful setup. I'd be smiling proudly, too ...

L Cottrill

[rockstar17]

ok. there are plenty of new T04Es on ebay for about 146. I was thinking of those anyway. looks like that should be the way to go. (this could be an advantage, I think they have a 3 inch inlet which is a good size for building the engine thats going on the motorcycle I will get. if I get a T04 I wont have to buy a larger turbo later)

I heard either propane isn't the best for big turbos or diesel isn't the best for small turbos. Im going to use propane for my first engine. will a big turbo work fine for that?

P.S. what does A/R mean? - nevermind, I got it

[Johansson]

The main reason why propane is no good on larger engines is because they consume lots of it, and diesel is not very practical on a small engine since a combustor for liquid fuel needs to have a larger volume than a propane fueled combustor so the engine will be very bulky for its size.

It is much easier to design a propane combustor since it is in gas form as soon as it leaves the injector, so you are doing the right thing in going for propane as the beginning. Just make sure that the combustor is big enough so you can fit a larger flame tube when you start to experiment with diesel and vapourising tubes later on.

[rockstar17]

The main reason why propane is no good on larger engines is because they consume lots of it, and diesel is not very practical on a small engine since a combustor for liquid fuel needs to have a larger volume than a propane fueled combustor so the engine will be very bulky for its size.

It is much easier to design a propane combustor since it is in gas form as soon as it leaves the injector, so you are doing the right thing in going for propane as the beginning. Just make sure that the combustor is big enough so you can fit a larger flame tube when you start to experiment with diesel and vapourising tubes later on.

I read theres a way to get the diameter and length of the flame tube based on the turbocharger's compressor inducer diameter. is it possible to design the flame tube too large? I may end up rebuilding the combuster/flame tube when I switch to diesel. I don't want to blindly design for the future unless theres some way to know how big I will need it for diesel use.

edit: I've done my homework and according to sal's DIY turbine site, I should have a flame tube with a diameter of 6 inches and length of 12 inches. but something that was written there made me think those are dimensions for a kero fueled engine. how do those measurements sound for propane? if those are fine for both propane and diesel, Im set. unless Im doing a vaporising system later. (new info - actually I will try to be using high pressure pumps and an atomizer injector because on the final build with the bike, I can't afford to lug around propane on the bike as a pilot light, so I probably wont be designing for vapourising tubes)

also, it says:

first measure the area of the compressor wheels inducer (the bent fins at the front), once you have the area, divide it into the various quantities to represent the three zones in the combustion process, namely primary, secondary and tertiary, the primary zone will require 30% of the compressor wheel inlet area for its holes...

I don't quite get what it means. the T04E I plan to use has a compressor inducer area of 3.14 inches. but Im still stuck.

[rockstar17]

I have been reading the project on the site about the low-cost turbine engine and I'm very excited now. in the past I wasn't sure how easy it would be to atomize diesel fuel and igniting it without a gas light thing. but on the project they've used a high pressure fuel pump from an oil burner system (whatever that is??) powered by a DC motor, and a fuel injector from house heating systems and they got perfect atomization to be able to directly ignite the diesel fuel with the spark plug. thats exactly what I hope to accomplish in my later developments. but first I just have to get the propane one working lol! and I still have to buy the turbocharger, hopefully I can do that tomorrow. and since Im buying a brand new one it should work perfectly and for a long time to be able to develop the diesel one.

I also read about the ease of learning MIG welding and that you can get a good piece of equipment for about 600 bucks. hopefully I wont need to weld any thick steel during the building. I just wonder how much the tank of argon costs I've always wanted to weld. can't wait. maybe the same place I should be having access to tools (my brothers garage ) will have one of these. I'm not sure.

I still don't understand the math problem with figuring out the flame tube hole areas. I'll look over it again, sometimes things click later.

[Johansson]

and since Im buying a brand new one it should work perfectly and for a long time to be able to develop the diesel one.

If you are using a new turbo you should spend some time and cash on the oil system and get it sorted out before any start attempts so you don´t ruin your new and shiny bearings, I´ve seen some guys that use a wind screen washer pump with less than good results...

I use a 12V Flojet membrane pump for the gocart with adjustable oil pressure, as long as I keep an eye on the oil temp it works perfectly.

On my bike I use a Bosch fuel pump on a small spray nozzle to keep the engine at idle and heat the vapour tubes, they are fuelled by two syringe nozzles coupled to a throttle valve and another Bosch pump. It is not the simplest system and it takes lots of power from the battery but I won´t have to use propane for preheating and the vapour system needs much less fuel pressure than a spray system at full throttle.

[Ash Powers]

I've used Shurflo pumps in the past with reasonable results, and you'll get a good kick out of this Anders, I even tried using a windshield washer pump for my first gas turbine - they do NOT like driving thick stuff and quickly burn out, especially when you aren't using an oil cooler, LOL. :)

Shurflo pumps are relatively inexpensive and work well. Save yourself a lot of hassle (and expense later when the turbo fails) and spend the time to fabricate a robust lubrication system as Anders stated.

[rockstar17]

Shurflo pumps are relatively inexpensive and work well. Save yourself a lot of hassle (and expense later when the turbo fails) and spend the time to fabricate a robust lubrication system as Anders stated.

ok. good advice. it didn't cross my mind that I would need to make sure my oil system worked well for new bearings. thanks.

if Shurflo are inexpensive and work well, thats definately what Im going for. they have built in electric motors, which is a huge plus! then I wont have to deal with belt drives and other headaches. looks like they provide plenty of GPM flow. what about PSI? can you set the PSI on the pump? I need at least 50 PSI right? Im just thinking outloud. thanks for showing me this, ashpowers, its a great piece of information, just what I needed.

I will probably route it like this:

tank>pump>pressure gauge>filter>cooler>turbo>temperature gauge> then finally drain back to tank.

does that look right?

I figured I will use new or fairly new and reliable components in the oil and fuel lines because I don't want to ruin the turbo, or blow up the fuel from leaks etc. and eventually I plan to be running circuits that cut the engine off if oil temperature rises too high, or if fuel or oil pressure (on the diesel stage) gets too low. that way I don't kill the turbo or waste fuel.

[racketmotorman]

Hi Rockstar
Position your oil pressure pickup in a Tee piece at the the turbo's oil inlet , you need to know the pressure that your turbo bearing are experiencing, not the pressure the pump is delivering . there could be restrictions inbetween pump and turbo that could reduce pressure actually delivered to the bearings .
Cheers
John

[rockstar17]

Hi Rockstar
Position your oil pressure pickup in a Tee piece at the the turbo's oil inlet , you need to know the pressure that your turbo bearing are experiencing, not the pressure the pump is delivering . there could be restrictions inbetween pump and turbo that could reduce pressure actually delivered to the bearings .
Cheers
John

cool thanks!