gulp... fmu ?

[dosquattro]

I know it's not the greatest form of fuel management but I don't have the money right now to convert to MS or swap over to the L28ET ecu along with everything else that goes along with it. Along with the FMU I was planning on getting a new 255lph fuel pump. This would be to feed dual IHI rhb5 snails running at 6-8psi. Along with 2 step colder plugs. Help me out with my Z turbo noobness. I've used a FMU in other cheap simple turbo setups and it worked fine with moderate boost numbers. The fabrication part isn't a issue and thats cake and dealt with.

[Clifton]

You are going to go through the trouble of TT but use the n/a efi setup? That's alot of work for 6-8 psi....What injectors? What are you doing to pull timing under boost? Get the high pressure 255 pump.

[Pyro]

I run 12 to 14 psi of boost with my NA efi and NA injectors using a FMU. Not the best way to do it but it gets the job done.

 

7 psi will need about 55 or 60 psi of fuel pressure with a decent flow rate when using the stock NA injectors. This is about the max for a stock efi pump. A walbro 255 pump should be able to manage more. Just a guess but maybe 70 psi with enough flow. FYI, 70 psi of fuel pressure is enough for 9 or 10 psi of boost with stock NA injectors.

 

I use two msd 2225's in parallel feed with a Mallory Comp110 low pressure pump, and I have one of the msd's on a pressure switch to come on at 6 psi. Then run 95 psi of fuel pressure at 14 psi of boost. Runs good!

 

I started with the 6 to 7 psi boost with fmu plan but that quickly changed to the 8 to 10 psi plan then to the 12 to 14 psi plan. so, I had to keep turning up the fuel pressure and increase pumping volume with more pumps. I should had just went with bigger injectors and aftermarket efi from the beginning. But I got it to work and I'm happy with the performance.

[big-phil]

I second Clifton, why go through the trouble of TT for only 6-8 psi? Search e-bay you can get all you need cheap if you play the game right.

[nienberg.11]

I'm running an fmu. I worry about my AFRs a lot, smell like gas after each drive, and currently have a partially assembled megasquirt sitting in front of me...

 

Granted, the outlook is a little better if you have a wideband to tune with right from the start, but it's still no substitute for aftermarket efi.

[dosquattro]

It would be cheaper for me to make the manifold and the downpipe and chargepiping then going and buying all the L28ET turbo stuff. I've got both turbos sitting here and I've got all the tools and the weld-els are cheap. After buying the L28et dist, oil pan, wiring harness, ecu, injectors, afm, yada yada... all that compared to a 255lph pump, vortech fmu. Hmmm thats a hard one. Now the guys that run a FMU, what do you do to keep the timing down? Just retard it some or just leave it?

[nienberg.11]

I disabled the vac. advance on my timing, but I'm only running 8psi. Until I get the megasquirt and edis installed I'm not going to run any more than that.

[dosquattro]

So you just unplugged the vacuum lines and left it as that and plugged up the vacuum lines on both ends(manifold and dist)? No ill effects? Your making my future look more brighter with each response.

[nienberg.11]

Might as well have. I actually installed a check valve in the line from the manifold to the distributor to make sure that boost didn't hit the dizzy. I was told that this would result in a drastic increase in timing advance. Anyways, the dizzy barely sees any vacuum now because of the tightness of the check valve. I've disconnected the whole thing before and sometimes I question why I ever reconnected it. It makes no noticeable difference.

[dosquattro]

Thanks for the help. This part of the project looks more manageable. You just used like a fish tank check valve right or something else? I've used the fish tank check valves on honda turbo setups to bleed out boost from getting to the map sensor and worked fine.

[nienberg.11]

Nah, it's a brass npt valve that's more for industrial applications, which is why it opens hard. The fish tank thing would probably be a better option as long as it will stand up to the underhood environment.

[dosquattro]

It's one of those home depot performance mods for DIY turbo honda folks. Besides chipping your ecu and using one of the many ecu tuning programs out on the net. Thanks

[Clifton]

I disabled the vac. advance on my timing, but I'm only running 8psi. Until I get the megasquirt and edis installed I'm not going to run any more than that.

 

 

You still have mechanical unless you have locked it. You need to know your total timing after the mech advance is all in.

[Pyro]

I reduced the lenght of my timing slot in the distributor so the mechanical only advances 8 more degrees. I set the initial timing between 18 and 20 for a total of 26 to 28 degrees.

 

7 or 8 psi can handle 30 degree total timing with 93 octane and 7.4:1 cr.

 

Use the vacuum advance because once the boost comes on it will shut off the advance from the vacuum real quickly. Plus the vacuum advance gives your car much better mpg and off boost throttle responce.

[nienberg.11]

You still have mechanical unless you have locked it. You need to know your total timing after the mech advance is all in.

 

Yeah I know... I have that and some vac advance with my current setup. I would like nothing better than to know my total timing and my AFRs, and just generally have a better picture of what's going on with the car. Hence the fact that I'm building msnse and I already have edis components to use with it. I know my setup sucks, and that's why I don't trust it with any more boost.

[Guest 280ZForce]

u need an fmu? i have a cartech fmu i was using when i had a n/a turbo z.

[Clifton]

I would like nothing better than to know my total timing and my AFRs,

 

Total advance is easy to find with an adjustable timing light, especially with a mech advance dist. AFRs, you'll need a wide band either way.

[nienberg.11]

I'm going to run permanent wb o2 with the megasquirt. And as far as the timing light, I don't have one but I have borrowed one in the past to make sure that my initial timing was right at least. For now it's working, but the stock dizzy will never provide the control over my timing that I want, plus I don't like working with antiquated dizzy systems at all if I don't have to (ie 83 dizzy), so I'm just holding off on messing with my timing until the edis is in.

[Guest ZFury]

Megasquirt is great and all, but I thought I would mention the ol' MSD boxes that will improve your spark plus give you a knob in the cab so you can adjust yur' timing on the fly.

[nienberg.11]

Megasquirt controlling EDIS will be much more flexible even than that, as I understand it. With the obvious exception of when I don't have the laptop with me.