turbo propane set up

Propane, Butane, LPG, GPL, C3H8, C4H10
storm
Posts: 796
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: turbo propane set up

Post by storm »

C3H8 wrote:Thanks for the plug storm,
Anytime, your technical knowledge is invaluable and has taught me more than I learned at TAFE. You're also in Canada and know what is supplied there.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

The engine is called the Essex engine, but it's different than the British one your talking about. The Canadian ones are built in Ontario Canada and have a 90 degree V block. They are quite tough, but most people overlook anything in American cars that isn't a v8.

My father in law has a wrecking yard and today I spend a few hours looking for propane parts, lots of tanks, model E evaporators, but mostly there is impco 425 mixers, most vehicles that have been converted to propane here are pickup trucks and vans with v8s and the odd inline 6 motor.
Found a van with the electric fuel cut switch, new model E and a vacuum start assist. I'm all set! Just gotta buy a mixer.

storm
Posts: 796
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: turbo propane set up

Post by storm »

gearhead wrote:The engine is called the Essex engine, but it's different than the British one your talking about. The Canadian ones are built in Ontario Canada and have a 90 degree V block.
Interesting, learn something new everyday and today I learn Ford built 2 different engines in 2 different locations and gave them the exact same name. I'll do some research on them.
Fuel flow requirements calculations
Engine air flow requirement calculation: CFM = Cubic Inches x RPM x Volumetric Efficiency (VE) ÷ 3456

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

i have run 20 psi with just the stud mod ( though i have an extra modle L convertor to be sure that i have a reliable 300 + worth of flow )
how is the model L plumed in your system?

bumpstart
Posts: 133
Joined: Wed Jan 20, 2010 9:09 pm

Re: turbo propane set up

Post by bumpstart »

model E sits flat and model L sits vertical ( outlet down ) with its back to firewall .
both tee together on the main delivery line to the mixer
this way i have both setup so they cannot collect the various condensate mustards that can come in the LPG blends
and that at any moment i have at least one convertor not affected by G force
be it braking , acceleration or cornering ( its an rx7 ! )

a model E is designed to fit flat and the L vertical , and the E just outflows the L ( 330 bhp V 300 BHP )

if your manifold takes the 2 barrel holley carbs then the 200 mixer will fit right on ( on top of the optional impco 2 barrel throttlebody )
if the motor uses a TB then a 225 will fit onto the end of the EFI hose ducting
( though being boosted you would make yourself an alum adapter and not use the rubber components )

no mods required for a 200 as they are inherently stronger than a 225
but a 225 would prefer at 1 bar boost to fit a permanent stud in the alum mixer body to hold on to the hat a bit firmer than the original bolt
and would require a rubber seal around the edge of the hat for moderate boost
( i use an off the shelf split rubber seal )

erring to the smaller mixers ( over the 425 ) will give better throttle responses and mixture control and they are more compact to install
when the going is hard, don't retard, remember your lubrication

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

ok, that sounds like what I was thinking. I just wasn't sure that a 'tee' fitting would be good for flow. some kind of 'y' fitting might be better?
I know people complain of freezing regulators at full throttle for too long, this helps doesn't it? It pretty much halfs the job of each regulator, less chance of freeing up.
my father in law has a wrecking yard and lots of model E regs so i'll probably use 2 model e's. Unfortunately he's got no 200 mixers, only 425 impco's.
Do you run two separate fuel lines from the tank to the regulators? and two vacuum lockouts?

I'm gonna run a 200 directly into my throttle body(3.8v6 ford is fuel injected and carb'd manifold is 450 usd!!) and use the factory buttery fly valve. that will work right? I'll do what ever mods needed for the mixer and regulator to take boost.
sounds like a gas 3.8 v6 with a turbo needs around 10 psi of boost to make 300 whp, give or take, depending on other mods. I'm guessing i'll need 12 or 13 psi to achieve the same results, being as propane has less btu's and that propane needs more air for the max power ratio

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

And Merry Christmas everyone!

bumpstart
Posts: 133
Joined: Wed Jan 20, 2010 9:09 pm

Re: turbo propane set up

Post by bumpstart »

under boost you will be surprised ..as the motor will like significantly leaner mixtures than its petrol equiv
and as such the BTU thing becomes irrelevant in the context where at 1 bar boost with petrol it must run at around 11:1 mixtures to keep flame speed within a margin and to maximise boundary layer cooling
where as the LPG engine has no or minimal extra benefit for either of these at such rich mixtures ( often the reverse ) and thus runs at least one full point leaner ( and sometimes two )
and a mixture anywhere 12:1 to 14:1 doesn't drastically alter the power number like it would with petrol

so pound for pound ( of fuel used under boost ) you find extra work in the LPG pound you wasnt expecting

mostly you control the power AFR with regards to exhaust temp/ cylinder head temp
( where as i dont suffer with a valve in a rotary engine and i can see 1000C exhaust temp )

and once you push further than 1 bar you will need a big coil ( or aftermarket ecu with adjustable dwell ) and a water injection system to keep exhaust temps within reason
( for which the petrol engine runs as rich as 11:1 to keep exhaust and head temps within check )
and the water becomes your boundary layer buffer and keeps the engine very clean

you must realise that the impco mixers work like SU carbs with "constant depression" and so inherently have a pressure drop through the mixer
in any turbo boosted setup. the total restriction on the inlet will reflect as 1.5 to 2.0 times that as backpressure in the exhaust system from the typical turbine wheel
so it is important that you thus build the rest of the inlet system for minimum pressure drop
that means not running a tube fin intercooler. but making provision instead for a larger bar / plate "indy " cooler instead so that you can win back the potential losses that will be seen in the mixer
( your typical bar plate runs less than half the restriction of a tube fin though is larger to have the same cooling potential )
when the going is hard, don't retard, remember your lubrication

TurboDario
Posts: 10
Joined: Sun Mar 03, 2013 1:38 am

Re: turbo propane set up

Post by TurboDario »

I would run one 425 in blow thru and one model e, run a 5/8" balance line from the hat to the model E, should make 300rwhp easy, I did 700rwhp with 2 model e's and 2 425's on a 6.0l LS. https://www.youtube.com/watch?v=EDXoLRQROrQ

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

I would run one 425 in blow thru and one model e, run a 5/8" balance line from the hat to the model E, should make 300rwhp easy, I did 700rwhp with 2 model e's and 2 425's on a 6.0l LS. https://www.youtube.com/watch?v=EDXoLRQROrQ
how much boost were you running? A lot of people have said the 425 doesn't like any more than a few psi of boost. fuel flow makes sense, but will the mixer last?

TurboDario
Posts: 10
Joined: Sun Mar 03, 2013 1:38 am

Re: turbo propane set up

Post by TurboDario »

18lbs on the 700hp runs, I'm building a Colorado right now with dual 425's that I plan to make 800rwhp with, I'd have no issue running 30lbs.

C3H8
Posts: 1129
Joined: Fri Sep 09, 2005 11:23 pm
Location: Winnipeg, Canada

Re: turbo propane set up

Post by C3H8 »

A 425 should not really be affected by boost pressure within reason. The top of the mixer is encapsulated by a hood which means the operating portion is totally inside the boost area. There are a couple of weak points to consider. The gasket on the hood to mixer gasket surface will have to be of excellent quality. Secondly the single center stud is not really strong enough for high boost pressures. The single stud will pull up on the center of the mixer distorting the cap and changing the spring pressure that controls the diaphragm. This will change the mixtures once boost pressure exceeds moderate pressures.

There is an easy solution to this. Schwans', a US fleet with about 6000 vehicles, designed a single plate to utilize the outside lid screws as an anchor instead of the existing center stud hole.
- They installed a triangular steel plate utilizing three of the screws to hold the plate onto the mixer body. It could have been done with 4 also. I'm not sure why they elected to use 3.
- The existing stud was changed for a bolt and remounted with the bolt head at the mixer end in this reinforced plate and this kept any pressure from pulling in the center portion of the mixer. On two bolt air cleaners they installed two studs. They were maintaining the existing GM aircleaners on their installations.
- Longer screws were required for the lid mixer screws to properly reach through the plate along with some small spacers to clear the domed portion of the mixer lid and apply pressure on the outside of the mixer to seal the gasket. It worked very well. It was never available commercially but it would be easy to replicate.

The boost pressures you guys are discussing would be best if two studs or a larger diameter stud were added to hold the hood secure.
Parts required include:
- one steel plate custom cut to fit inside the hood and still allow adequate airflow. Four holes drilled to match the lid screws. One hole for a large stud or two for smaller diameter studs.
- 4 spacers to allow the installation of a center stud to clear the center portion of the mixer lid. The plate could be lower if the stud(s) were welded.
- 4 new screws with the correct thread pitch and length to install the plate. Make sure adequate thread depth is achieved.
- One or two studs. Modification of the standard 425 hood might be required.

TurboDario
Posts: 10
Joined: Sun Mar 03, 2013 1:38 am

Re: turbo propane set up

Post by TurboDario »

On my very first blow thru propane car I did something like that, I had a 1"x1/4" bar that went between 2 (really long) of the carb base studs to help hold it on. On the dual 425 setup I just drilled and tapped the 425's to 5/16" studs, used a rubber impregnated air cleaner gasket glued to the 425 and I never had any issues, I plan on doing the same on my Colorado.

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

good to know!
for fitment the impco 200 is much better for the engine I plan on using. The 425 needs a 4 barrel or 2 barrel manifold and the ford 3.8 v6 has only one aftermarket manifold available which is 450 usd and then I need the snorkel with is another 100 bucks. The 200 is just simpler and easier to fun in a previous fuel injection engine. I just put it in the inlet before the butterfly valve and that's it!
Any thoughts?

gearhead
Posts: 28
Joined: Wed Dec 16, 2015 1:58 am

Re: turbo propane set up

Post by gearhead »

having said that, i'm gonna built it right the first time. If it costs more, so be it.

between a impco 200 and 425, i'm guessing the 425 will be much more in the power goals of 300 whp? where as the 200 it's borderline?

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