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Stupid Doubt about FMUs
All the FMUs Im looking at say either 8:1 or 10:1 i.e. for every 1 PSI of boost fuel flow goes up 8 or 10 right?.
Then other regulators say Adjustable from 30psi to 120 psi. But my requirement is I need the Fuel to flow at 4 PSI when not under boost. And then when boost starts it needs to go up like 1:1 How do I make sure the FMU I get will work for my application |
Re: Stupid Doubt about FMUs
You get a standard pressure referenced regulator with 1:1 ratios and the right spring for 4psi.
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Re: Stupid Doubt about FMUs
Originally Posted by chinoy
All the FMUs Im looking at say either 8:1 or 10:1 i.e. for every 1 PSI of boost fuel flow goes up 8 or 10 right?.
Then other regulators say Adjustable from 30psi to 120 psi. But my requirement is I need the Fuel to flow at 4 PSI when not under boost. And then when boost starts it needs to go up like 1:1 How do I make sure the FMU I get will work for my application |
Re: Stupid Doubt about FMUs
It is carbed
till 16 PSI then Extra Injectors and a speprate system take over. But lets not confuse the issue for now lets just say yes its carbed. Its working fine till arround 10-14 PSI then my home made hand built FMU takes a Dump. I can not build another one or just put some money down for something that just works. Probalem most all the FMUs I see start at 30 PSI and are adjustable from there out. Where as I need it to be 4-6 PSI and then 1:1 I got a brother offering me a unit for 85$ in the HMT classfied section will it work for my app. |
Re: Stupid Doubt about FMUs
FMU's suck herpes infested dick for fuel injected apps
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Re: Stupid Doubt about FMUs
Ron Chinoooooooyyyyy!!!! :)
If you go to Jegs or Summit (dunno if they ship to your part of the world) then you can find 1:1 ratio "FMU" under their carb section. I imagine a stock fuel pressure regulator off of any fuel injected vehicle can be made to wok for you, as they are 1:1 "FMU" |
Re: Stupid Doubt about FMUs
Thanks Bro thats just what I did got an FMU off a regular fuel injected car. Opened it up played with the spring to get my base 4 PSI and then let the boost handle the rest.
Its working quite ok actually. Maybe Im just thinking if I pay for a fancy looking setup it will work a little better. Will chk the sumit catalogue. |
Re: Stupid Doubt about FMUs
yeah you don't need an fmu per say, most aftermarket, vacuum refrenced, fuel pressure reglators will raise fuek pressure 1:1 which is what you want for a carbed setup
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Re: Stupid Doubt about FMUs
the aeromotive fpr is like 2:1 i think ???
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Re: Stupid Doubt about FMUs
Ok here is the problem may need to put the brain in gear to follow.
A stock FMU yes will be 1:1 but Ive gone and moded the spring to give 4 PSI when not boosted. THis has kinda rocked the boat I suspect. The fuel pump puts out 40 PSI whcih should be good enoughf for a carbed setup. Non boosted is fine steady 4 PSI. Then we go to boost. The fuel pressure scales right up to 25 PSI thats fine. Because the FMU has a return line. But so does the carb so when the bowl is full the excess fuel flow returns via the carbs return line. But whats hapening at very high boost levels i.e. we have gone upto 22 PSI with WG disconected. the car just seems to run out of gass. Give it a second to fill up the bowl and she is ready to go. So Im thinking new FMU or maybe increase the dia of the outlet pipe from the FMU the pressure will drop but the flow should go up right. Logic is even at 24 PSI the pump only needs to be making 28 PSI to flow right. Considering all the facors such as how pressure in the carb also effects flow thru the jets. The carb is doing a pretty decent job of keeping the a/f ratio ok. Im using a narrow band with the LM9044V to track a/f and its showing a healthy range bwteen 12:1 to 14:1 Guess all ya young pupps are not old enoughf to have done too many Carbed setups eh! ;D |
Re: Stupid Doubt about FMUs
it will still be 1:1, even with a mod'd spring.
-Dustin |
Re: Stupid Doubt about FMUs
what kind of fuel pump
Originally Posted by chinoy
But whats hapening at very high boost levels i.e. we have gone upto 22 PSI with WG disconected. the car just seems to run out of gass. |
Re: Stupid Doubt about FMUs
Ron, remind me when I am sober to forward to you all of Bruce "Grumpy" Plecan's 6 coil CDI DIS information, when he upgraded from a wasted spark DIS. I think it's in line with what you were experiencing when you had all the power gains from your DIY ignition modifications. VERY interesting stuffs!
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Re: Stupid Doubt about FMUs
http://store.summitracing.com/defaul...=egnsearch.asp
this has been run one some boosted carbed crx's.dont know if it will fix your problem because the ew motors blow before 20 psi |
Re: Stupid Doubt about FMUs
You ever sober Bro ?
Thanks for the inputs guys. The sumit link takes me to the NOS page will try spending some more time going thru their catalogue to figure it out. |
Re: Stupid Doubt about FMUs
Originally Posted by chinoy
Considering all the facors such as how pressure in the carb also effects flow thru the jets. The carb is doing a pretty decent job of keeping the a/f ratio ok.
Im using a narrow band with the LM9044V to track a/f and its showing a healthy range bwteen 12:1 to 14:1 |
Re: Stupid Doubt about FMUs
Right thats why Im buying a WB
But my little DIY O2 setup has saved me an a few budies from blowing up our engines. Till the WB arrives its better than nothing. And it does work. I also built a WB setup but turned out I had the wrong sensor for the circuit. Thats what you get for rushing into projects. Now Ill just buy one as work with the Ignition development means no time to spare. I asume you where refering to this unit NOS-15851NOS http://store.summitracing.com/defaul...=egnsearch.asp |
Re: Stupid Doubt about FMUs
Alcoholism is not failure.
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Re: Stupid Doubt about FMUs
Originally Posted by Joseph Davis
Ron, remind me when I am sober to forward to you all of Bruce "Grumpy" Plecan's 6 coil CDI DIS information, when he upgraded from a wasted spark DIS. I think it's in line with what you were experiencing when you had all the power gains from your DIY ignition modifications. VERY interesting stuffs!
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Re: Stupid Doubt about FMUs
okay okay.
Originally Posted by Bruce
To: <fangle@yahoogroups.com>
Subject: [fangle] 6 coil DIS From: "Bruce Plecan" <bplecan@woh.rr.com> Date: Thu, 23 Feb 2006 22:23:36 -0500 From: http://www.t6p.com/forums/showthread.php?t=11341 Well, I've finally got things bolted down, and wired up well enough to do some intial testing. The 6 coil part is that I used the DIS module, and instead of just firing 3 coils, I now fire 6. The module probably wouldn't handle firing 2x the current from 6 coils, so I used an ACCEL 300 CD ignition module with each coil. Those modules only reguire a 250ma, *sink* to fire. This also means multispark firings, up to redline. The intial findings are: Low load EGTs, are down 100dF. High load EGTs, are down 200dF. The idle speed is higher by 100 RPM, and smoother. There is a slight decrease in %TPS to maintain, freeway speeds. There was no signifigant change in AFRs. This comparison, is against a DIS system that had 3 ACCEL 300 CD ignition modules, each module firing one of the *normal* DIS coils. In adding the CD modules to the original set-up, I had to add some fuel to maintain the pre change, AFRs. Next up, is opening up the plug gaps, and seeing if the engine is less prone to high boost misses. Bruce |
Re: Stupid Doubt about FMUs
Originally Posted by Bruce
To: <fangle@yahoogroups.com>
Subject: [fangle] More 6 coil DIS From: "Bruce Plecan" <bplecan@woh.rr.com> Date: Sun, 5 Mar 2006 13:42:21 -0500 From: http://www.t6p.com/forums/showthread.php?t=11341 The latest posting: Well..... Here are the first datalogging results from the 6 coil DIS. These are the corrections that some analysis software I have, has generated. Across the top are the MAP values, and along the L/H edge, RPM. A *0* entry means that not enough data was found to average out a final correction. The corrections are based on a max value of 255, a min of 0, and a *no correction needed value of 128*. The *target* AFR is 14.7:1. So a correction of 125 means fuel was removed, to maintain a 14.7:1, and a 130 would mean fuel had to be added. This data was collected at 55-75 MPH, basically just in cruise/ light load conditions. There was some low speed *running* before getting to freeway speed, as evidenced by the 1,000 RPM entries. So what does it mean?, It means that at the lower load areas, the engine could be leaned down, to maintain the 14.7:1 AFR, ie the *burn* is more complete. In the higher load areas, there is a demand for more fuel... Meaning that while under load, the better *burn*, can use more fuel in order to maintain the same AFR. **** Now for some really interesting stuff. What few people look at is that while a Turbo can make boost, it can also assist the engine in breathing while still in less then boost conditions. Pre 6 coil, I generally cruised with a max MAP of 65 K/Pa. In this log you can see that I was *cruising* with K/Pas ranging up to 95!. What this means is the turbo had enough exhaust flow, to start to spool it up at a MUCH lower load condition. ie better spooling..... And, this is with a TA-62 on a 85 long block, stock heads, 87 intake, Poston Headers, Cotton's F/M, 206/206 cammed *mule engine*. This is a really mild of engine combo.. --- Corrections --- 0,20,25,30,35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 400,0,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 600,0,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 800,0,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1000,0,0,0,0,123, 124, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1200,0,0,0,0,125, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1400,0,0,0,0, 0, 0, 125, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1600,0,0,0,0,128, 130, 130, 129, 129, 0, 0, 0, 0, 0, 0, 128, 0, 1800,0,0,0,0, 0, 125, 127, 126, 126, 128, 125, 123, 124, 0, 0, 0, 0, 2000,0,0,0,0, 0, 130, 127, 126, 127, 130, 126, 126, 129, 128, 131, 131, 0, 2200,0,0,0,0,128, 127, 123, 125, 125, 126, 125, 125, 124, 126, 129, 130, 0, 2400,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2800,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3200,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3600,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4000,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4400,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4800,0,0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, Oh, and stay tuned, I did some WOT logging. The results there are also interesting, I just have to figure out how to post the results in an easy to understand way..... Bruce |
Re: Stupid Doubt about FMUs
This is something along the lines of what we achived.
http://www.rddreams.com/rddreams/htm...wtopic&t=10165 But basiclly he should just hook up a gas analyser and post the results it will be a lot easier to understand. The funny thing we noticed is the more gas you keep feeding the engine the more the power keeps going up. Which is kinda hard to explain. The Smuit unit @ close to 120$ is outside my budget. It sure looks like the right pice of kit. Guess Ill keep alook out on ebay. Or try making another unit. Or just try with a better fuel pump. |
Re: Stupid Doubt about FMUs
Have played around with modifying any of your spark plugs?
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Re: Stupid Doubt about FMUs
;D So you read my post on plug mods ?
Dam I hate this country spent 20 minutes typing up reponce and the power went. On the Plugs. Hate them fancy stuff. Hate the 4 wire gimick plugs. Hate em gold and platinum plugs only cause Im allways broke lol Good ole NGK or regular plugs in the right heat range. Bend the earth strap back. Sharpen the earth strap to a point. Sharpen the electrode to a point. Then dull the point a Bit. We dont want it becoming red hot glowing seting off deto. Re-gap the plug works well. WOnt last 100,000 Kms but will last at least 20,000 Kms. The guy above may not get the same results we are geting. We get the results cause we take out the regular 250 Volt .5MFD cap. We then put in a 400 or 600 volt Cap with a 2 MFD cap. Each cap is charged twice but discharged only once. Cars is a diffirent ball game. The only way out here is to get a Ferite core going. THen get the IGBTs and SCRs as used by the TIG welding guys. Pump out 600 - 800 volts from the ferite control the spark with a pic and your ready to rock and roll. |
Re: Stupid Doubt about FMUs
Originally Posted by chinoy
;D So you read my post on plug mods ?
I cut back the ground strap on NGK BRK7E-11 and the NGK R5671-A8/-A9's sometimes to help quench, that's about it.
Originally Posted by chinoy
On the Plugs. Hate them fancy stuff. Hate the 4 wire gimick plugs. Hate em gold and platinum plugs only cause Im allways broke lol
I generally don't like creating a sharp-ish point on anything in a combustion chamber, and with a conventional coil system you don't want a point that aids arc-over. The power you are pushing... do you have problems with un-pointed plugs misfiring? I can envision arc-over wandering all over the place, like with lightning, and am unsure if you'd run wierd because of it. |
Re: Stupid Doubt about FMUs
Yeah, all the idiots buy overpriced iridium spark plugs, that look more like glow plugs to me with the needle thin electrode.
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Re: Stupid Doubt about FMUs
Originally Posted by baldur
Yeah, all the idiots buy overpriced iridium spark plugs, that look more like glow plugs to me with the needle thin electrode.
Endless iscusions phew. No man no point more like a rounded edge. If you must do something do that. WIll probally land up looking like your mod. No I dont have any misfire issues. With or without the plug mod. Ok geting back on topic. Drag Nationals are 4 weeks away. 99% of the competition in my class is runing nos so beating them shouldnt be hard if I can sort out my FMU. Im running in the Forced Induction class upto 1400cc. My cars weight is 865 Kgs or lets say 965 Kgs with me in it lol. The fastest time with NOS is like 15+ seconds. Now dont laughf you arent runing our piss poor gas. Or piss poor engines. Fact is in a country of 1 Billion People thats the fastest. Runing anything under 14 should garuntee a national record. Took the car out to a decent road today to figure out whats going on. Im runing rich as per the O2 readings that for sure. Not a problem will lean out when the WB comes in. But the problem is with when you floor the accelrator. THe bowl in the carb goes empty in 2 seconds. Then boost falls and it goes into a viscious circle till it stalls. Where as if I accelrate slowlly. Basiclly give the boost enoughf time to hit the FMU. It increases flow and the flow keeps up with the boost. And she accelrates cleanlly not runing out of gas. all the way to the redline hits the PSI seting set WG opens and she keeps runing fine. There is a term for this i.e. geting the FMU to start working before the onset of boost. Hits the FMU. How does this work. any idea. Maybe I can build a new FMU that does it. |
Re: Stupid Doubt about FMUs
where is your FMU vacuum line hooked?
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Re: Stupid Doubt about FMUs
MAn I have nowhere near the knowlage or understanding of these things as you guys do.
But I was wondering if going with a larger fueline would help?It could be just draining all the fuel volume for the line before the fmu and pump can catch up? |
Re: Stupid Doubt about FMUs
Is your fuel pump boost referrenced?
I dunno your setup, but with a mechanical fuel pump, driven off the engine, that supplied most carbeureted cars in America, you can drill a hole in the top of the pump and epoxy in a vacuum barb. Run a hose from manifold to fuel pump, and as boost increases, the pressure on the far side of the pump increases so that the fuel pressure doesn't fall off. |
Re: Stupid Doubt about FMUs
woo we are actually having a serious discusion on HMT open forum. Some pretty smart guys here.
Thats a good idea with the fuel line will try it. Ok this is the setup. Orignally the fuel pump that came with the car was 4 PSI. Its an in tank electrical pump. Since this is a total Getho setup we hit the junk yard and looked for Used Electric Fuel Pumps from another car which was EFI. We found two one that made 45 PSI and one that made 35 PSI. I got to keep the 35 PSI pump. The logic was carbed setup. We only need boost + 4PSI. So even at 16 PSI we only need the pump to do like 16+4 PSI. The pump was installed in the tank. And the FMU spring was set so that output without boost is 4 PSI. Now to answer your very inteligent question about where the FMU signal is refrenced. Last night as I sat looking at the setup I was thinking the same. Basiclly you have 4 locations to pick for your FMU and BOV refrence. You can use a point in the pipeing just before it hits the carb. Thats where my Boost gauge is hooked up. You can use the point which controls the vacum advance. Or you can use a point just above the buterfly or just bellow the buterfly. Or off the manifold. Im pretty sure we tested each and every point and finally picked a point just above the buterfly on the carb to refrence the FMU and the BOV the same line is split to the FMU and the BOV. My Boost gauge is hooked up the the tubing after the intercooler as is my BOV (The Physical BOV not its refrence line). My Plan of action for today. 1. Experiment with more tubing from the FMU to carb 2. Measure the Vacum and boost at all the posible refrence points. And note them down Im pretty sure we allready did this during the install. 3. Consider geting a better Fuel Pump. That puts out at least 50 PSI. 4. Chk the FMU to make sure its really working 5. Consider buying one of those fuel pump with FMU and gauge for like 25$ on ebay. 6. Dig out Corky Bell and all the other Turbo Books and see what they recomend for carbed setups. One issue that worries me is that the hole dia on the FMU fuel out is smaller than the combined dia of my Jets. So maybe I need to drill that hole out a bit but that would upset the pressure setings right. |
Re: Stupid Doubt about FMUs
Hey guys problem fixed. Thanks for all the ideas and thoughts.
Give me a day to test my theory if it works Ill post up. Now can pretty much launch at any Boost. |
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