Twin mixers off one converter?

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jono
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Twin mixers off one converter?

Post by jono » Thu Nov 09, 2017 2:18 am

I have seen twin mixer set ups on big vee 8 s but never looked and remembered the detail so question is ...can I run a pair of 100 impco mixers off one L converter. Intended to be feeding same plenum not one per bank.

Any comments welcome


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storm
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Re: Twin mixers off one converter?

Post by storm » Thu Nov 09, 2017 5:24 am

I'd be wondering if 2 100s would be able to provide enough signal for an L to work efficiently. An L certainly has enough capacity (over 300HP), but is it to big? I'd be very interested in what C3H8 and Franz think.
Fuel flow requirements calculations viewtopic.php?f=5&t=1638

jono
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Re: Twin mixers off one converter?

Post by jono » Thu Nov 09, 2017 6:07 am

Well, I ran a 125 off the L converter on similar engine- flat four, 1791cc but it was a single port head and intake. This is twin port head and intake and did not like it so swapped the 200 in and (swear word) does it go now! Bogs down a little if I don't drive it to suit. Now have great induction roar on standard pea shooter exhaust, not convinced big or loud exhaust is needed.

I am hoping two 100s or 125s each getting vapour from one L mixer will actually work and not be competing with each other to the detriment of performance or just correct behaving system. I have all the bits to do whatever combo just want to keep it simple and would like to sort principles on the NA before the turbo version goes in. I always felt the turbo. 200 and L could have run a little leaner and not have some flutter between cogs

jono
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Re: Twin mixers off one converter?

Post by jono » Fri Nov 10, 2017 11:52 pm

Franz is likely to be nodding his head thinking I am silly as a J and 125 is at the sweet spot of an 1800cc four...but am in learn prep mode for turbo and prefer learn on something free of a propane fed turbine !!

This little beast of 1791cc will see 12 or 13 psi boost up to about 6500 - 7000 rpm

jono
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Re: Twin mixers off one converter?

Post by jono » Sat Nov 11, 2017 9:29 pm

Hmmm....looks like Franz and C3 have become casual visitors here,or got nothing to say :x

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storm
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Re: Twin mixers off one converter?

Post by storm » Sat Nov 11, 2017 10:16 pm

jono wrote:Hmmm....looks like Franz and C3 have become casual visitors here,or got nothing to say :x
I just had a look at their member profile pages and it looks as though Franz hasn't been here for nearly 2 months, C3H8 hasn't been here for a few weeks. Both are very busy men so I appreciate anything they post.
Fuel flow requirements calculations viewtopic.php?f=5&t=1638

jono
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Re: Twin mixers off one converter?

Post by jono » Tue Nov 14, 2017 6:12 am

Gosh, they have looked in here almost daily in years gone.

Took me months to pull a finger out and go for a diagnostic rune with tailpipe analyzer .....now I am running an L converter I rebuilt years ago and it sat idle for a long time before working nicely with a 125 on different engine in same ute. Now got the 200 on it without touching a thing from when it was on my turbo flat four in another heavier sedan. You could not have got such a stoic reading if you tried! The power valve was at half and never gave richer than 14.6 so I made it a little richer to see mid thirteens under flat stick. When it bogs down because the L , 200 combo is over recommended size for 1781cc saw 22:1 and got no power.

This experimental stage shows how sweet such old design impco stuff can be. I went from turbo 7.7:1 compression running up to 13 psi over to NA of about 9.0:1 comp ratio and this mixer delivered fine.

Gees I love propane and impco

C3H8
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Re: Twin mixers off one converter?

Post by C3H8 » Wed Nov 15, 2017 11:20 pm

Hi guys. I'm still around. Just noticed that the new posts tend to stall for a while sometimes now. I don't check in every single day unless I see something happening, like now. All of a sudden several new posts added the last few days.

Dual mixers can be run off of a single convertor. You have to keep in mind several items though. The engine has to be in pretty good shape with even compression in all cylinders. The second thing is to ensure the vapour hose at the Y to the mixers should be the same length and the fitting used to split the single hose to a double should be a "Y", not a couple of 90's. I've used the model E, L and J on 100 mixers and found they all work. Sometimes the starting on the smaller engines with the E and L will take a few more cranks but once running they should work fine.

jono
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Re: Twin mixers off one converter?

Post by jono » Thu Nov 16, 2017 2:07 am

Thanks for explaining stuff C3

I have also run 100 and 125 off an L converter but this time whatever was up don't know. The 200 resolved everything at that point.

I am mucking about in prep for turbo application.

With turbo in mind, 1800 cc boosted to 12 psi and rev to 6500 its cfm comes almost exact to the 200s maximum cfm rating

One 125 obviously comes in too small as far as cfm is concerned.

The turbo engine is only rated at about 115 HP but add six pounds boost no idea what it ramps up to in HP or torque

I have found a silicone Y shaped pipe set up in 2 1/8 into 3" so should do nice for intake.

It should all work out OK if I keep all piping equal.

Thanks again

jono
Posts: 333
Joined: Wed May 16, 2007 11:46 pm
Location: New South Wales, Oz

Re: Twin mixers off one converter?

Post by jono » Fri Nov 17, 2017 10:24 pm

Hmmm.....maybe two 100 HP rated J or Cobra converters to feed the perfectly sized in air CFM 200 mixer? Thinking my lean bogs could be dealt with by the Peel Instruments CP401 nicely.

I must apologise if my tinkering confuses people as I am playing with a non turbo version of engine partly in prep for turbo engine conversion and current guinea pig
gegets installed in similar vehicle

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