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Post by enginewhisperer on Dec 1, 2015 20:32:14 GMT -5
yeah anything designed to work in a car will be rated for 14v so I don't think there will be a problem.
Motor power increases with the square of the voltage, so even 1v can make a noticeable difference.
Going from 10.5v to 12.5v would take pump power from 50w to 70w or so.
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Post by smithy1 on Dec 1, 2015 21:46:34 GMT -5
yeah anything designed to work in a car will be rated for 14v so I don't think there will be a problem. Motor power increases with the square of the voltage, so even 1v can make a noticeable difference. Going from 10.5v to 12.5v would take pump power from 50w to 70w or so. Thanks for the confirmation Andrew...muchly appreciated. I'll set about doing some more mods....never ending mods..! Smithy.
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Post by racket on Dec 2, 2015 0:12:10 GMT -5
Hi Smithy The 044 numbers are interesting , if a little disappointing from my perspective as I need 50 psi pressure drop on top of the P2 pressure to get the required flow . With our largish diameter engines when at idle fuel flow rates , unless we use a reasonable pressure drop across the injectors the difference in hydrostatic fuel head means the bottom injectors flow more than those at the top, up to 50% more at the bottom I ran into this problem with the FM-1 engine where I initially used larger gauge syringe needles to keep fuel pressures lowish , but then had to silver solder 23G needles into the injectors to increase the fuel pressures to a point where there wasn't much of an idling fuel flow difference. With my current fuel manifold, the 22G needles are a tad small , but the next size up the 21G needles flow some 70% more , so I'm stuck between having to run highish pressures with the 22G but with no idling fuel flow problems or go the 21 G without pressure problems but with a "hot spot" at idle that could cause thermal warpage problems . LOL , I might have to run the fuel pump on 18 volts like another member here Can we run two 044 pumps in series to increase the pressure ?? Cheers John
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Post by smithy1 on Dec 2, 2015 2:17:31 GMT -5
Hi Smithy The 044 numbers are interesting , if a little disappointing from my perspective as I need 50 psi pressure drop on top of the P2 pressure to get the required flow . With our largish diameter engines when at idle fuel flow rates , unless we use a reasonable pressure drop across the injectors the difference in hydrostatic fuel head means the bottom injectors flow more than those at the top, up to 50% more at the bottom I ran into this problem with the FM-1 engine where I initially used larger gauge syringe needles to keep fuel pressures lowish , but then had to silver solder 23G needles into the injectors to increase the fuel pressures to a point where there wasn't much of an idling fuel flow difference. With my current fuel manifold, the 22G needles are a tad small , but the next size up the 21G needles flow some 70% more , so I'm stuck between having to run highish pressures with the 22G but with no idling fuel flow problems or go the 21 G without pressure problems but with a "hot spot" at idle that could cause thermal warpage problems . LOL , I might have to run the fuel pump on 18 volts like another member here Can we run two 044 pumps in series to increase the pressure ?? Cheers John Hi John, Don't give up on the pumps yet...I've got more testing to do tomorrow....As Andrew said, the "real" 044 pumps should do close to 4L/min @50psi & 13.8v, I'm expecting something similar from the "clone" pump and I suspect with 13.8v at the pump terminals we should have something approaching that. I was indeed able to get 100psi outlet pressure but the flow was minimal... that was with 12.6v at the pump...13.8v should see something considerably better. I'll do a set of numbers for all pressures from 25 to 100psi @13.8v just for reference. Assuming your P2 max of say 40psi we'll need a decent flow @ 90psi to keep your 50psi drop across the injectors. I might even try 14, 15....up to 18v to see what happens....nothing to loose I guess and worth getting some numbers for. I've seen some "specs" for these pumps at the higher voltages and they are indeed impressive if true.....we'll soon find out. They quote numbers like 600lb/hr @ 80psi @13v....and ...780lb/hr @100psi @18.75v...Pppfffttttt I can't see that happening in a hurry..! I wasn't getting anything near 600lb/hr even at 50psi with 12.6v... If it turns out I need higher voltage for the pump to run optimal fuel supply flows and pressures, I will just rig up a 24v relay system and run a higher voltage battery for it. Running the pumps in series should indeed boost flow and pressure and may be an option for us. I believe some of the higher powered cars use this setup. We're getting into some serious hp and fuel flows with these big turbos...so...I guess we need to supply them with the fuel needed to do what we ask of them... Cheers, Smithy.
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Post by racket on Dec 2, 2015 3:55:21 GMT -5
Hi Smithy I'll look forward to your numbers , theres no one better qualified to provide accurate fuel flow data than you , good hard data that we can trust . Yep , serious horse powers and airflow rates need lotsa fuel . I've even been thinking about making my own pump , I've got a 1cc/rev hydraulic gear pump that I originally had as a fuel pump for the TV84 engine to supply its 750 psi fuel pressure , before switching it out for a 2.6cc/rev pump , now one of those 350W 24 volt units from Motion Dynamics www.motiondynamics.com.au/united-my1016-350w-24v-dc-motor-with-11-tooth-chain-sprocket.html direct driving the 1cc pump with a controller for rpm might just be a possibility. There shouldn't be much internal bypassing within the hydraulic pump if only pumping 100psi , and the rated motor rpm is 2750 , whilst no load is 3450 , I might get ~3,000 rpm which would provide sufficient fuel, if not I'll use a bigger pump ..............food for thought :-) Cheers John
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Post by enginewhisperer on Dec 2, 2015 4:35:29 GMT -5
I have a few pumps around too which could be worth checking out.
For car stuff I've found the Walbro "416" pump is one of the best - but it's an in-tank only design.
It flows substantially more than an 044 - but maybe not at super high pressures.
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Post by smithy1 on Dec 2, 2015 14:30:17 GMT -5
Morning Chasps, Well...I've just spent an hour or so testing my "clone" 044 pump using various voltages and outlet pressures etc...results in lb/hr as follows:
13.8v 14v 15v 16v 17v 18v
25psi 362 365 392 410 451 465 30psi 350 352 380 405 430 453 40psi 324 326 355 380 406 430 50psi 298 300 325 358 384 410 60psi 272 274 302 334 358 386 70psi 243 246 274 310 335 365 80psi 218 222 248 280 310 340 90psi 190 194 225 255 284 318 100psi 162 167 204 228 262 300
I'm using calibrating fluid to Military spec Mil-PRF-7024E Type-II, specific gravity is 0.770 @60f....which is close enough to kerosene & diesel as to make very little difference.
To convert to L/hr just multiply by 0.63
Cheers, Smithy.
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Post by racket on Dec 2, 2015 15:11:59 GMT -5
Hi Smithy
Now they're looking good :-)
The 100 psi flow figure has gone up by 3 times with only another 6 volts , a simple solution to my needs .
Thank you again for these numbers , I'll file them away for future reference
Cheers John
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Post by racket on Dec 2, 2015 16:13:58 GMT -5
Hi Smithy
Just did a quick check of my pumps flow at 90 psi and it was 1.7 litres/minute with 12 volts coming out of the battery , battery at 12.5 volts without pump running , battery is a 24 Amp job from a hand held golf cart I purchased secondhand >10 years ago , its been a good battery , heh heh , I only bought the kart for the 12 volt motor , I wasn't interested in the battery , I needed the motor to power the freepowers scavenge pumps on the bike .
It won't take much of a voltage increase to get my 2.6 lpm at 90 psi .
Thanks again for the solution, I won't even have to change my pump :-)
Cheers John
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Post by smithy1 on Dec 2, 2015 17:14:47 GMT -5
Hi Smithy The 100 psi flow figure has gone up by 3 times with only another 6 volts , a simple solution to my needs . Thank you again for these numbers , I'll file them away for future reference Cheers John Yeah the figures are interesting and encouraging indeed....As Andrew mentioned, the pump power roughly increases at the square of the voltage increase....so I guess it makes more sense now. Cheers, Smithy.
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Post by smithy1 on Dec 2, 2015 17:24:54 GMT -5
I'm planning of running the pump with a fully charged 4 cell Li-Ps04 battery, it should have a nominal voltage of 14.4v when fresh off the charger, allowing for a small drop at the pump I'm hoping to see something close to 13.8v at the pump, which should give me ~240ish Lb/hr @70psi....even allowing for losses etc...it should still be plenty for the GT6041 powered "Black Beast". My calcs tell me it should only require ~190-200Lb/hr-ish at full noise...
I'm not sure of the health of the original GP pump on the kart, so I while I have a bit of downtime over the Xmas period I might give it a test and see if it's still up to the task, if not I'll go ahead and fit the "clone" 044 pump and be done with it.
Cheers, Smithy.
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Post by smithy1 on Dec 14, 2015 20:54:46 GMT -5
Hi Gentlemen, I've been able to obtain from my work a scrapped RR250-C20B outer combustion case and inner combustion liner/flame tube. I hope to use the fuel nozzle and igniter mounting boss from the outer case and transfer them to the 6041's outer case. This will hopefully eliminate the need for the propane start. I already have a C20B fuel nozzle, bang box, cable and igniter which will fit straight into the case fittings. I just need to get up the courage to start the modifying process.
John, I've yet to do the math for the hole area but hope to at least have a look tonight. I'll take a couple of photos with them side by side, may help with your opinion. As you may be aware, the C20B flame tube has inner "swirl plates" for the primary holes up near the fuel nozzle, not sure how to take these into account regarding their area etc...? There's also a couple of rows of "vents" down the sides of the flame tube....I might need to do a fair bit of investigation prior to committing to anything. The C20B flame tube also has a purpose built "slip joint" where I can mount it to the lower tapered part of your original flame tube, I just need to do some measurements to get to length/diameter right before I start cutting.
Smithy.
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Post by racket on Dec 14, 2015 23:32:00 GMT -5
Hi Smithy
With the FT cap holes that produce the counter rotational swirl, those holes plus the flow area thru the swirl vanes surrounding the fuel nozzle are part of the total 30% for the primary zone including the sidewall holes.
The louvers in the sidewall that produce a cooling blanket are generally such a small portion of the total area they can probably be discounted or added into the 50% Tertiary hole percentage as they don't contribute to the combustion .
You'll be needing ~4.1 sq ins for Primary , 2.7 sq ins for Secondary and 6.8 sq ins for the Tertiary areas.
How will you reproduce the C20's fuel pressure ??
Cheers John
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Post by enginewhisperer on Dec 15, 2015 0:21:01 GMT -5
If you end up with leftover combustion chamber bits I'd gladly attach them to my 6041 to speed up the process a bit
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Post by smithy1 on Dec 15, 2015 1:43:07 GMT -5
Hi Smithy With the FT cap holes that produce the counter rotational swirl, those holes plus the flow area thru the swirl vanes surrounding the fuel nozzle are part of the total 30% for the primary zone including the sidewall holes. The louvers in the sidewall that produce a cooling blanket are generally such a small portion of the total area they can probably be discounted or added into the 50% Tertiary hole percentage as they don't contribute to the combustion . You'll be needing ~4.1 sq ins for Primary , 2.7 sq ins for Secondary and 6.8 sq ins for the Tertiary areas. How will you reproduce the C20's fuel pressure ?? Cheers John Thanks John....I'll do a bit of maths and see if it's feasible....it should be pretty close actually, well within ~10% or so..! With the fuel pressure...I can shim the fuel nozzle metering tip inner spring to replicate the flows verses the pressures I need, it has primary and secondary flow circuits so all I need to do is adjust as required...the nozzle actually has quite a nice "atomizing" cone to it at just 20psi, even at flight idle the fuel pressure is only ~50psi minimum but rises reasonably fast after that, as long as I keep the P2 in mind and under the pump's potential delta 80psi and obtain the required ~210lb-hr I should be good to go...just a matter of "tuning" the fuel system to suit....if it turns out I need more pressure, I'll just get hold of a suitable pump and make it do what I need. Smithy.
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