Guest bastaad525 Posted December 12, 2003 Share Posted December 12, 2003 Should be ordering one of these soon... had a few questions. First, mounting it... well, it's a two parter, a) if anyone knows about how large the thing is (it looks pretty big in pictures... why'd they have to make it look like a UFO???) and where is 'the best' place to mount it? Anyone who's using one and have pics? I'm thinking on the wall mounted right next to the fuel filter (slightly in front of and above the front passenger side wheel well). Second, I know it mounts in the return line... now, if I'm not mistaken, this particular unit requires me to keep my stock FPR installed right? So, can I splice it into the return line hose that runs from the fuel rail? I'm talking about the point on the fuel rail where both the inlet and outlet go, on the passenger side of the engine, right above where the mechanical fuel pump attaches to the head (if you were running one). Can I cut the hose coming out of that in the middle and run it thru the FMU? Third, I'm a little concerned about supplying this thing with a vacuum/boost reference. I have the early 280z intake manifold, it only has four vacuum ports on it, and they are all taken (BOV, FPR, boost gauge, and brake vacuum booster). Can I run a tee in the hose that is already going to the stock FPR, and split that one off to go to the FMU, or is that not going to work right? I really really REALLY dont want to have to pull the manifold off to go tapping holes into it. If that is 100% necessary for me to run this unit then I'll pass. If that IS the case, are there any rising rate regulators that DONT need you to leave the stock FPR installed? Fourth, will I only see a benefit from this if I get a better fuel pump? I've been trying to wrap my brain around exactly how this thing works. I guess it basically just restricts the fuel that's returning to the tank right? Like when you put your thumb over the opening of a hose, it goes from a lazy pour to a high pressure spray? Now, I know it's commonly held that the stock pump is only good for so much flow, but if you're increasing pressure at the injectors by blocking off the return line, are you also increasing or decreasing flow? I would think the fuel pump would have an easier time keeping up with the fuel demands in a setup like this... think about it. Using totally wrong numbers, just to make an example. The fuel pump flows 1 gallon every minute, no matter what. Now, at WOT, lets just say that 60% of that gallon is being flowed thru the injectors, and the other 40% is just being allowed to mosey on back to the fuel tank by the regulator. Now, block off an extra 15% of that gallon from going thru the regulator, and it's gotta go somewhere right? so now 75% of it is going thru the injectors, even though the fuel pump is still supplying the same amount of fuel... I wouldnt' think it would have to work any harder... Of course I"m probably wrong hopefully someone can explain it to me. Anyways... I'm just asking because, though a better fuel pump IS definately in the plans, I'm still scrimping and saving here... it's xmas so $$$ is tight of course... and just wondering if I would see any benefit at all from getting the FMU now, by itself, or if I have to wait to use it with a better pump. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 12, 2003 Share Posted December 12, 2003 By the way, just out of curiosity, what is the pressure in psi of the fuel as it exits the fuel pump, but before being regulated by the stock regulator? Quote Link to comment Share on other sites More sharing options...
240zprace Posted December 12, 2003 Share Posted December 12, 2003 bastaad525, i have one on my 240zt using 35lb injectors and a aeromotive fpr, it works wonders. if you are thinking on getting one, get the 2022. how this fmu works is, it kind of shuts off the return line when under boost, and fuel has no where to go but thru the injectors. you can also adjust it so rich that your car will just bogg under boost too (real rich). i also have mines mounted by the right wheel fender wall below the strut tower. you mentioned fuel pump... well, put a fuel gauge meter on the rail and pinch the return line close and see what the pump will push out continuos. if you are 90psi pressure steadily, than your pump is good, if lower than that, you should get a better pump. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 12, 2003 Share Posted December 12, 2003 240zprace - good info, thx. hmmm doesn't the stock pump max out at like 70psi? I thought I remember reading that somewhere... if that's the case then I will have to wait and do both at the same time. Also I'm glad you mentioned the aeromotive FPR... I'm also thinking of ditching my stock FPR for an adjustable, was looking at the aeromotive or at the extremely cheap MSD unit to replace the stocker and run the Cartech unit also... then I'll have even more control for very little cash outlay (like $250). I will be installing a fuel pressure gauge for sure, and I wont install the FMU til I can get down to some dyno (have to find one again) to tune it. Another question I have, now that I figured something out. I thought all of the Cartech units allowed adjustment of the 'onset of gain' but now I know that only the one intended for aftermarket turbo setups has this, whereas, as you pointed out, I want the 2022 which is for motors that have a factory installed turbo. So I can't change the setting for when the FMU starts affecting the fuel pressure, right? If so, I'm curious, at what point does the FMU 'come on'? As soon as boost hits? before then? or at a certain PSI? Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted December 12, 2003 Share Posted December 12, 2003 1. Sounds like a good place to me. 2. Yes, you'll need to use the stock reg and the new one. The stock one is run inline before the aftermarket one. You can cut the hose at whatever location and then plumb the new hose from the outlet into the return line back to the tank. You might need to get about 2' of hose to make it fit and look right after installation of the new reg. 3. Just splice the vacumm line from the stock reg. and run it to the new one. You want them both to have the exact same signal. Or atleast as close as is possible. 4. You'll still get some benifit when using this and the stock pump. The added load on the stock unit will proubably kill it in short order though. Also I wouldn't want to trust my engine to the stock pump in a set-up like this. As a rule the higher the pressure the less actual flow you would have. You could run the stock pump but, I wouldn't run to much boost to keep the pressures down a bit. That is until you get an intercooler and a better F/P. Even with an intercooler and good pump I was only able to run 14 PSI on the good days. 5. Start slow and rich then tune from there. Try to tune in atleast third gear. Get some new plugs handy it's real easy to run it real rich and have then want to foul out. I used to start off gapping them at the stock gap and then as they worn out I would close the gap up to about .032. And I'll proubly take a beatting on this one but, I found that the A/C Delco Rapidfire #4 plugs to work the best and last the longest. These are not the highest quality plugs out there but, they work good for the money. I just installed a set of NGK Irdium plugs and so far I can't tell a difference from the the 6 month old A/C's. The do look like a better plug and will proubly outlast the A/C's and they're so much more P/C for the Z car. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 12, 2003 Share Posted December 12, 2003 thanks for the info Cody. Okay so the tee in the vacuum lines is not a problem... good deal because there was no way I'm pulling that manifold back off to tap a hole in it... noooooo more 'major' work for me for a while... a LONG while. And you did mention something else that had occured to me... that this thing may shorten the life of my stock pump. Are there ANY good, CHEAP upgrade/replacement pumps that I can get? Everything I've seen recommended goes for like $300... is that as low as it gets? Also, I'm not really familiar with how the stock pump is mounted, so this question may be moot: is an upgrade pump going to need anything modified/fabricated to be able to mount it? Or will it just bolt right in? Quote Link to comment Share on other sites More sharing options...
240zprace Posted December 12, 2003 Share Posted December 12, 2003 bastaad525, my fuel set up consist of..... gravity feed under stock fuel tank bosch fuel pump (saab 900 turbo) chevy truck fuel filter 1/2" steel braided fuel line from tank to custom rail all AN fittings.... the pump i got flows 90psi continuosly. good for 20-22lb of boost on my t3t4. i don't want to run hore boost than that on my stock bottom end. alls said, you can pick up a pump from a sabb 900turbo pump at the junk for dirt cheap. any more questions, don't hesitate to ask me..... Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 12, 2003 Share Posted December 12, 2003 You are, of course, free to modify your system anyway you choose. I just posted a response in this thread http://www.hybridz.org/phpBB2/viewtopic.php?t=29016&start=15 regarding the "FMU" as it applies to Nissan ECUs. BTW, It is very cheap to add bigger injectors - I am running Mustang SVO 370cc units I converted to a barb fitting. I spent $7 each for them, and bought enough to flow test and have spares. These Ford 2.3T cars quite literally "litter" the scrap yards. Quote Link to comment Share on other sites More sharing options...
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