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Post by smithy1 on Nov 22, 2015 14:06:01 GMT -5
Hi Chasps,
Just a minor update on the "Beast"...
Over the last dozen or so engine runs at the car shows I attend, I've noticed my max rpm/P2 has slowly been dropping off....this would normally not be an issue if I had been adjusting the max flow stop to achieve this, however, I had previously set the max P2 to ~39.5-40psi. As mentioned, over the last several engine runs my max P2 has slowly dropped down to ~29-30psi with the throttle on the stop...needless to say I have either a restriction in the fuel system or the main fuel pump has started to deteriorate, the maximum fuel pressure has also dropped in sympathy which leads me to believe the pump itself has started to fail or it has a restriction. Starting and running up to idle along with EGT's and oil pressure etc have been normal and I have not detected any engine vibrations etc...
I believe the core of the engine is fine, there's no evidence of heat stress on the turbine and it's coloring looks good, so I'll be removing and inspecting all the ancillary items.
Over the Xmas break I'll pull the whole fuel system down and give it a good looking at, change all the filters, flexible lines and make sure all the associated gubbins are working as John designed them to work. Cheers, Smithy.
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Post by enginewhisperer on Nov 22, 2015 16:40:14 GMT -5
assuming the battery is ok?
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Post by racket on Nov 22, 2015 18:42:48 GMT -5
Hi Smithy
Could it be the throttle "needle/oriface" is wearing a tad and allowing more bypass back to tank ??
If I remember correctly , the fuel pressure is taken off at the throttle , so not much chance of "problems " there .
If there was an injector blocked the fuel pressure would be higher .
I'd look at the needle/oriface as the culprit first , LOL, you're wearing it out with all these runs you do ;-)
Cheers John
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Post by smithy1 on Nov 22, 2015 21:48:37 GMT -5
assuming the battery is ok? Hi Andrew...yeah..batteries are good, measured @ 12.45v after yesterday's 3 runs, I normally charge them on the way to the car shows using the van's battery pickups, which has ~14.45v when engine is running. I might experiment with connecting a 3 cell lipo and see if that helps next time. Cheers, Smithy.
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Post by smithy1 on Nov 23, 2015 2:32:29 GMT -5
Hi Smithy Could it be the throttle "needle/oriface" is wearing a tad and allowing more bypass back to tank ?? If I remember correctly , the fuel pressure is taken off at the throttle , so not much chance of "problems " there . If there was an injector blocked the fuel pressure would be higher . I'd look at the needle/oriface as the culprit first , LOL, you're wearing it out with all these runs you do ;-) Cheers John You could well be correct John, and yes...I don't think it is a blocked injector, fuel pressure is not higher, in fact it's probably lower than optimal which makes sense. I may just have a dying pump...I've got a spare 044 pump so I might plumb it in and see what happens....I'll fit a manual regulator between the pump and fuel control with the relief going back to the tank or inlet side of the pump..... so I don't "over-fuel" things. Cheers, Smithy.
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Post by smithy1 on Nov 26, 2015 17:26:11 GMT -5
Hi Gents, Turns out Andrew was correct, I have two new motorcycle batteries in place of the original old car battery, they charge and hold charge ok, even after the engine runs I still had a goodly amount of voltage remaining...but I never tested the voltage under load and/or with the turbine running...
I did some simple testing last night and I ran the igniter, oil and fuel pumps together, the voltage drops off to just under 10v while these two pumps and the igniter are running..!! I suspect it will be significantly less when the A/B & hot-streak pumps, solenoid & A/B igniters are running.!!
Seems these new motorcycle batteries can't handle the load which is rather strange. I then reconnected the old car battery and the voltage has returned, even under load the battery delivers a good 12.5v...Lesson learned.
I have a car show this coming weekend so I'll charge & re-fit the old car battery back in and report back with results. The reason for going with the motorcycle batteries is to allow the front fairing to be fitted....seems I may have to do a little "re-think".
Cheers, Smithy
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Post by racket on Nov 26, 2015 18:22:15 GMT -5
Hi Smithy
A nice simple fix , excellent news :-)
Cheers John
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Post by enginewhisperer on Nov 26, 2015 18:37:33 GMT -5
I'll bring you some LiFePO4 cells next time
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Post by smithy1 on Nov 26, 2015 19:41:52 GMT -5
I'll bring you some LiFePO4 cells next time I've got a few of those Andrew....but they're only 3 cell 9.9v jobs for my smaller turbines...I might invest in some nice big capacity 4 cell 13.2v items and see what happens... Cheers, Smithy.
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Post by enginewhisperer on Nov 26, 2015 21:05:29 GMT -5
I have a bunch of Headway 40160 cells (15Ah, 3.3v)
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Post by smithy1 on Nov 26, 2015 21:32:29 GMT -5
I have a bunch of Headway 40160 cells (15Ah, 3.3v) Hmmm....you've got me thinking now....do you have a link to these cells please Andrew?? Smithy.
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Post by enginewhisperer on Nov 26, 2015 21:44:30 GMT -5
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Post by smithy1 on Dec 1, 2015 18:46:34 GMT -5
Hi All, John & Andrew, I brought my spare "clone" Bosch 044 pump into work this morning and plumbed it into my FCU test rig...I ran the pump connected to a 12v car battery to simulate the conditions found on the kart....with a normal -4 outlet (which is also what I use on the kart), @50psi outlet pressure I'm seeing ~215lb/hr....135L/hr, ~3.6lb/min or 2.25L/min @4.8amps. I then slowly closed off the outlet until there was no flow and the pressure indicated just shy of 91psig @12.35amps...this is obviously the internal relief setting.
So I assume with a P2 of 40psi this pump should be fine. I'm not totally sure of the GP fuel flow requirements, at idle or a P2 of ~3.5psi it should need in the vicinity of 40-45lbs/hr-ish. At a P2 of 40psi the fuel flow requirement should be ~190-200lb/hr-ish. So the 044 pump should be fine for the purpose with a bit to spare.
One thing I did notice just this morning is that I'm seeing quite a large voltage drop when I put a multimeter across the pump terminals..Ideally I should be seeing ~12v at the pump, but when the pump is running I'm only seeing ~10.4-10.6v across the terminals...as soon as I stop the pump, the battery voltage returns to the nominal 12.4v-ish.
I suspect this may get even worse when all the kart's electrics are running, such as oil pump, engine GP fuel pump, A/B pump x 2, igniters & hot streak pump & solenoid...All these items running at the same time using the same power supply my be pulling the voltage down to silly levels....you guys have any thoughts??
I've just received a new 4cell 13.2v 8400mah 30C Lithium-Phosphate battery to do some experiments with...so it will be interesting to see how it performs. If it performs as I hope, I'll get a second one and connect them in parallel to double the capacity.
Cheers, Smithy.
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Post by enginewhisperer on Dec 1, 2015 19:12:23 GMT -5
A genuine Bosch 044 is supposed to do ~4L/min at 50psi, but at 13.8v.
I have a genuine one if you want to do a comparison test.
You'll definitely get a fair bit of voltage drop over the cables unless they're pretty massive - and car batteries usually sag a bit under load, especially if they're not in perfect condition. Dropping to 10.4v with that sort of load seems a bit much though. What sort of cable are you using?
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Post by smithy1 on Dec 1, 2015 19:50:32 GMT -5
A genuine Bosch 044 is supposed to do ~4L/min at 50psi, but at 13.8v. I have a genuine one if you want to do a comparison test. You'll definitely get a fair bit of voltage drop over the cables unless they're pretty massive - and car batteries usually sag a bit under load, especially if they're not in perfect condition. Dropping to 10.4v with that sort of load seems a bit much though. What sort of cable are you using? Hi Andrew, I'm using 8agw wiring so it should be plenty. I just did another test with the Li-PS04 battery, it has a nominal 13.2v.... and I'm getting a lot better results, when pump is connected to the battery I'm seeing ~12.6v at the pump when it's running and the resultant flows are 246lb/hr (2.6 L/min) @ 50psig and I even had 104lb/hr (1.1L/min) @ 100psig. I might bring my 1000watt variable power supply in tomorrow and test the pump at the 13.8v. We might see something a bit closer to the 4L/min you suggest. Testing the pump at 100psig is a bit pointless really, it will never see this sort of pressure, even 50psig is a bit over the top... as long as it can see it's way past the 40psig P2...we should be good to go. There's very little flow change between 40-65psig outlet pressure on the pump so I'm reasonably confident with it. It seems just an increase/decrease of just a single volt has a dramatic effect on the pump's performance... I think you may well be right Andrew, a fully charged matched pair of the Li-Pso4 batteries should see a marked improvement over the lead acid batteries I've been using. One thing I must be wary of is the other components which are 12v rated such as the hot streak solenoid and switching relays etc... Although, a lot of normal cars will see in excess of 14v when the battery is charging so I suspect I may be worrying needlessly. Smithy.
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