FMU on low boost ?

[Belette]

Does FMU is needed when running turbo under 7psi of boost on y7 ?

Does stock injectors will be fine with FPR or I need more supplie of gaz to feed this setup ?

Once again, I don't want to play with wire !

thanx a lot !

:)

[Bizzar]

I would use one. Its a cheap way to get more fuel and yes you need MORE fuel even under "low" boost. Your best bet is to get an adjustable rising rate FMU and fuel pump. I have a cartech fmu and it has been great. JRSC with an 8lb pulley spiking at 10psi boost on stock injectors, cartech fmu and a walbro fuel pump.

[Belette]

Fmu can feed sotck injectors with FPR ?

Does AFC manual controler is good ? easy to install, and make FMU job ?


Where can I find good FMU ? how much it cost ?

thanx

[oscarmayer]

YES you must run at least an FMU.......
even with an fpr you need an fmu. you need to get more fuel tot he engine under boosting at aly level. you won't need the afc for anything under 7psi as long as u haev an fmu.

www.ebay.com get only the vortech fmu. the others are crap. They wear out fast. You will want a 8:1 fmu.

[TurboEF9]

First off, the Jackson Racing FMU works brilliantly, not to mention it's adjustable.

Second, are you crazy?! 8:1 and he'll be shooting flames from his tailpipe!

12:1 on the Vortech.. sheesh.

[Belette]

LOL ! I surelly take vortech one !! 12:1 are good ! I have GREAT article on fuel Ratio !! REad this

http://www.clubcivicquebec.com/ubb/ultimatebb.php?ubb=get_topic;f=21;t=000298


REad this too for NOS sheet

http://www.intox.org/databank/documents/chemical/nitrusox/cie407.htm


Maybe good to put in sticky :)

[oscarmayer]

First off, the Jackson Racing FMU works brilliantly, not to mention it's adjustable.

Second, are you crazy?! 8:1 and he'll be shooting flames from his tailpipe!

12:1 on the Vortech.. sheesh.

the JR fmu sucks. it tears a lot and has stability issues. you might like yours and may not have and an isue with yours, but dealing with many shops and fmu types, the js one is horrible.

What makes you think he needs a 12:1? 8:1 with a properly tunes setup is all he would need. Do you even understand how the fmu operates? or do you think the stock system will take 12:1 and better than 8:1? need to stop for a second and re-evaluate your expirences. Your starting not to make sence and really sound like an inexpirenced tuner giving off horrid advice. If your whole idea abotu cars is soley based off 1 or 2 cars you've had yourself or a buddies car, then you need to sit down and stop talking liek you know things. I had thought I could give you a lot more credit than this but now you jsut plain dissappointed me here.

I'm not going to take a chance I'll educate you on fmu and fuel pressures.


Stock fuel pressure for a honda is (averag) 38psi. Some models are as high as 44psi. But lets use 40 as a good round # because it will maek it easier to break it down for you guys.

Now the sotck fuel pump "CAN" flow a max of 85gph and a total psi of 115-125 (but will not hold that long as the internals will begain to allow pressure to leak by and cause the pressure to drop down to 95-10 max)

Now., Take a 10:1 fmu. It operates off boost pressure. for every 1 lb of boost you get 10 psi of fuel pressure bump. now on a 10:1 and if you run 10psi, you get 100psi fuel bump increase under boosting. Now lets not forget about our starting pressure of 40psi. so that's 140psi. Your going to tell me a stock fuel pump will do 140psi? GET REAL....

Now, lets say your fuel setting was 40psi and you have a 8:1 fmu. that's 80+40=120. That's the limit of a stock fuel pump. Understand why not I stated 8:1? or did that slip by you?

Why is it good to have increased pressures for more fueling? well for cheep tuning and low boosting (anything udner 15psi is considered low boosting) it basically acts like a shaken up soda can. take a can of coke and shake it up and the open it. it exploded a ton of fluid at 1 time, and soemtimes can even empty the can right then. Now take a none shaken can and it poor out slowly. Now is every explosion exactly the same? No, that's the thing about fmu's and why they should never be used past 12 psi of boost. They wer designed as a cheap tunning method to assist cars under very low boosting. runnign them over 12 can not only cause the fmu to repture due to pressure of the fueling greater than the rating of the orphis, but also since the surges in the fuel system anre never exactly the same, then you can't trust it to properly fuel the car over that amount of boosting.

Hope you learned something guys. Especially Turbo EF9.

[oscarmayer]

forgot anoteh reason to mention about the vortec fmu. while it may be adjustable, how do you know EXACTLY wher you are in adjsutments of there is nothing to tell you at what ratio your currently set at after adjustment? Interesting question eh????

[Bizzar]

Good points there Oscar. I agree with you the JR FMU is a pos thats why I went with a Cartech. Its an adjustable rising rate fmu up to I think 15:1 and I know I am nowhere near that. How did I tune it? With a fuel pressure guage taped to my windshield and a volt meter on the 02. My air/fuel guage isnt as accurate as a volt meter for reading proper fuel mix. Also why I suggested a pump upgrade. Believe me I tried on the stock pump and it just cannot keep up. At 6psi it was ok but started to drop off around 75-85 psi. I needed more fuel pumping out those ol stock injectors. Right now my setup is maxed out on boost using an FMU, walbro pump and STOCK injectors. 10psi is really pushing the limits of what those injectors can handle. I have even had a couple hang wide open so I backed off the pressure a tad and retarded my timing to compensate. Kinda crappy way, loss of hp but hey, no knock, no detonation and a good air/fuel mix.

[TurboEF9]

Lets begin to sort out exactly what you're saying here..


the JR fmu sucks. it tears a lot and has stability issues. you might like yours and may not have and an isue with yours, but dealing with many shops and fmu types, the js one is horrible.

Personal opinion, again, confused with fact. But you're allowed you opinion, however wrong it may be.


What makes you think he needs a 12:1? 8:1 with a properly tunes setup is all he would need. Do you even understand how the fmu operates? or do you think the stock system will take 12:1 and better than 8:1? need to stop for a second and re-evaluate your expirences. Your starting not to make sence and really sound like an inexpirenced tuner giving off horrid advice. If your whole idea abotu cars is soley based off 1 or 2 cars you've had yourself or a buddies car, then you need to sit down and stop talking liek you know things. I had thought I could give you a lot more credit than this but now you jsut plain dissappointed me here.


I'll answer the first question in the next paragraph. As for my "expireneces", they far exceed the 12 motors I have personally tuned in MY car, and the 4 - 5 of my "buddies" cars. It extends to the numerous customers who bring me thier cars, and ECUs to tune for thier boosted setups. It extends further into the creation, development, and application of engine management software that is running several 220+whp STOCK internal SOHCs boost motors, and the countless "joe blows" who are running undyno'd force inducted applications daily, and reliably. There isn't a need to question my "expireneces", kiddo.


I'm not going to take a chance I'll educate you on fmu and fuel pressures.


Stock fuel pressure for a honda is (averag) 38psi. Some models are as high as 44psi. But lets use 40 as a good round # because it will maek it easier to break it down for you guys.

Now the sotck fuel pump "CAN" flow a max of 85gph and a total psi of 115-125 (but will not hold that long as the internals will begain to allow pressure to leak by and cause the pressure to drop down to 95-10 max)

Now., Take a 10:1 fmu. It operates off boost pressure. for every 1 lb of boost you get 10 psi of fuel pressure bump. now on a 10:1 and if you run 10psi, you get 100psi fuel bump increase under boosting. Now lets not forget about our starting pressure of 40psi. so that's 140psi. Your going to tell me a stock fuel pump will do 140psi? GET REAL....

Now, lets say your fuel setting was 40psi and you have a 8:1 fmu. that's 80+40=120. That's the limit of a stock fuel pump. Understand why not I stated 8:1? or did that slip by you?


Now lets talk tech... You're pretty accurate in your rewording of SuperchargersOnline's article on FMUs. ( http://www.superchargeronline.com/content.asp?ID=97 )

However, you failed to think about one thing. You were ASSuming a boost pressure of 10psi. Flowing 240cc injectors at 80+40(120)psi of fuel pressure, and 10psi of positive manifold pressure will do two things: Run you lean at anything over ~250cfm, and yes, break something. Fuel pump, as well as injectors.

Now why did I say 12:1? For one reason only, 240cc injectors boosted to 7psi manifold pressure (which I agreed with you in an above post) is 84psi in the fuel rail, plus the 40 psi = 124psi.. Only a 4 psi differential from the example you used to try to make me look like I didn't know what the hell I was talking about. Factor in CFM, and 8:1 is now too lean.

When tuning most any turbo that will work on a SOHC Honda, at 75% efficiency, you're going to only be moving around 230-260cfm.. but our turbos don't run at maximum efficiency. We run at about 60-65% if you're lucky.. which flows more air, but obviously, not as efficient (more heat created), which will be pushing around 370-430cfm with a correctly sized turbo. So we'll say 400cfm at 8:1 will leave you lean at even 7psi on 240cc injectors, no questions asked. Throw a wideband on that setup, and look. While you're at it, have some new pistons and rings laying around, because you'll need them.

But you knew that already.. that's why you told him to use 8:1. :roll:


Hope you learned something guys. Especially Turbo EF9.


...ya, you reinforced the fact that you really have no business on this board. Thank you for the education.

[oscarmayer]

Lets begin to sort out exactly what you're saying here..


the JR fmu sucks. it tears a lot and has stability issues. you might like yours and may not have and an isue with yours, but dealing with many shops and fmu types, the js one is horrible.

Personal opinion, again, confused with fact. But you're allowed you opinion, however wrong it may be.


What makes you think he needs a 12:1? 8:1 with a properly tunes setup is all he would need. Do you even understand how the fmu operates? or do you think the stock system will take 12:1 and better than 8:1? need to stop for a second and re-evaluate your expirences. Your starting not to make sence and really sound like an inexpirenced tuner giving off horrid advice. If your whole idea abotu cars is soley based off 1 or 2 cars you've had yourself or a buddies car, then you need to sit down and stop talking liek you know things. I had thought I could give you a lot more credit than this but now you jsut plain dissappointed me here.


I'll answer the first question in the next paragraph. As for my "expireneces", they far exceed the 12 motors I have personally tuned in MY car, and the 4 - 5 of my "buddies" cars. It extends to the numerous customers who bring me thier cars, and ECUs to tune for thier boosted setups. It extends further into the creation, development, and application of engine management software that is running several 220+whp STOCK internal SOHCs boost motors, and the countless "joe blows" who are running undyno'd force inducted applications daily, and reliably. There isn't a need to question my "expireneces", kiddo.


I'm not going to take a chance I'll educate you on fmu and fuel pressures.


Stock fuel pressure for a honda is (averag) 38psi. Some models are as high as 44psi. But lets use 40 as a good round # because it will maek it easier to break it down for you guys.

Now the sotck fuel pump "CAN" flow a max of 85gph and a total psi of 115-125 (but will not hold that long as the internals will begain to allow pressure to leak by and cause the pressure to drop down to 95-10 max)

Now., Take a 10:1 fmu. It operates off boost pressure. for every 1 lb of boost you get 10 psi of fuel pressure bump. now on a 10:1 and if you run 10psi, you get 100psi fuel bump increase under boosting. Now lets not forget about our starting pressure of 40psi. so that's 140psi. Your going to tell me a stock fuel pump will do 140psi? GET REAL....

Now, lets say your fuel setting was 40psi and you have a 8:1 fmu. that's 80+40=120. That's the limit of a stock fuel pump. Understand why not I stated 8:1? or did that slip by you?


Now lets talk tech... You're pretty accurate in your rewording of SuperchargersOnline's article on FMUs. ( http://www.superchargeronline.com/content.asp?ID=97 )

However, you failed to think about one thing. You were ASSuming a boost pressure of 10psi. Flowing 240cc injectors at 80+40(120)psi of fuel pressure, and 10psi of positive manifold pressure will do two things: Run you lean at anything over ~250cfm, and yes, break something. Fuel pump, as well as injectors.

Now why did I say 12:1? For one reason only, 240cc injectors boosted to 7psi manifold pressure (which I agreed with you in an above post) is 84psi in the fuel rail, plus the 40 psi = 124psi.. Only a 4 psi differential from the example you used to try to make me look like I didn't know what the hell I was talking about. Factor in CFM, and 8:1 is now too lean.

When tuning most any turbo that will work on a SOHC Honda, at 75% efficiency, you're going to only be moving around 230-260cfm.. but our turbos don't run at maximum efficiency. We run at about 60-65% if you're lucky.. which flows more air, but obviously, not as efficient (more heat created), which will be pushing around 370-430cfm with a correctly sized turbo. So we'll say 400cfm at 8:1 will leave you lean at even 7psi on 240cc injectors, no questions asked. Throw a wideband on that setup, and look. While you're at it, have some new pistons and rings laying around, because you'll need them.

But you knew that already.. that's why you told him to use 8:1. :roll:


Hope you learned something guys. Especially Turbo EF9.


...ya, you reinforced the fact that you really have no business on this board. Thank you for the education.

Actually I proved my point exactly EF9. I wrote my article not copying it from someoen else. I wront a simular article about 3 yrs ago. Maybe they got it from me??? who knows, it's not rocket science here. If you have any knownedge on how things work, you should already understand this info.

The pressuers stated were for example only not 100% exact.

man you crack me up.. HaHa :lol:

[TurboEF9]

Uh, I do understand this, and I stand by my statement that a 12:1 ratio disc in the Vortech is the optimum way to go if you want your engine to make it into boost more than once.

Get a wideband, test it.. then come back and tell me your results. I'm 100% sure you'll change your mind from an 8:1 to 12:1.


..oh, and as you ripping that article, it's cool dude. At least you attempted to look something up before you spoke this time. What made me copy and paste parts of your article into Google? The fact that you have not had a post this "informative" since I have been on this board. That is how I knew you ripped it.. but again, good job in at least looking it up. 8)

Maybe there is a chance you can start contributing to this board..

[Belette]

I'll use 12:1 one !!

So, can I use 310 CC injectors with that setup ?
I surelly should need lower fuel pressure on FPR ?

thanx

[TurboEF9]

Maybe.. that is about all you'll be able to do to "tune" your car. And since FPR is a linear adjusment, your best bet is to open loop boost. Otherwise, you're liable to run lean if you tune part throttle.

[Belette]

Well, By you said guys, I can use my stock fuel pump, with stock 240cc injector, with FMU 12:1 & FPR little bit over than stock pressure, @ 6-7 psi without running lean and trouble ?

I'm right ?

thanx :)

[TurboEF9]

Correct.

[Belette]

Good ! I'll go with that setup :)

Last thing to know, how about A/F meter ? easy to install ? how much it cost ?

It'll be surrelly useful !? to know if i'm lean or not ? (or it has another way to know that ?)

thanx

[TurboEF9]

Cake to install.. 3 wires, Postive, Negative, and O2 voltage (normally tapped at your ECU's O2 input pin).

Normally run between $50 and $100.

[Belette]

I got another question:

If i put 325cc injectors with 8:1 FMU, can I get better result ?
I surrely better lasting for injector and fuel pump ? I'm right ?

Thanx

[eg8]

Im sure the lower pressure would make your stock pump last alot longer. Also, with the bigger injectors and lower pressure, I think it would equal out to a higher pressure and smaller injectors. Because common sense would tell you more fuel is going in because the injectors are larger. And you will be happier knowing your parts will last longer too! and if you dont get enough fuel, I would get bigger inejctors rahter than increase the fuel system pressure. so Im thinking an 8:1 with 440's would be good?? ef9, do you think that would work well too? while Im at it, with an 8:1 and 440's how much boost can you handle??

[Belette]

It's what I talked about into earlier post... ! like putting 325cc injector instead of 240cc ones, about 35 % more fuel delivered, If we put 6:1 FMU instead of 10:1 (about 40% lower ratio), we will deliver at 'same amount' of fuel too comparate of 240 high pressure, and 325 with lower pressure...

With a FPR we surelly set static pressure about 25 - 30 % less than stock to reach 'like 240cc ones'... Does it works or - 10 psi at fuel rail will be not enough for static pressure ??


thanx a lot

[TurboEF9]

Running any larger injector without modifying the injector fuel pulse width, or MAP sensor input voltage is a no no!

The ECU thinks you have small injectors, so it has them open for a certain period of time dictated by that injector flow size. So for each pulse, the injector will be flow TOO much fuel during part throttle. The idea may work for WOT under load, but part throttle will run crazy rich, and foul plugs, and have no gas milage.

Very bad idea.. :-/

[Belette]

Yes, I see... If i put resistor box does it works ?


Or can I run Nissan SER 265 CC injector ones (@ -4 or -5 psi than stock or maybe stock pressure) , it's about 10% ... with lower static pressure, and 8:1 fmu , Does it works too or I could be too lean ? not much less pressure but maybe enough to make fuel pump and injector last...



thanx again !!!

(What is the stock pressure on y7 ? 38psi, i'm right ?)

[Belette]

No one ever try it ?

[TurboEF9]

I've not heard of anyone using those injectors before.

Are they top fed? ...side fed? I thought a lot of Nissan stuff was side fed. (At least on the 240SX, and Altimas.. KA24DE).

[civic-vti]

If someone has a fpr on an n/a engine, doesn't the ECU knows that more fuel is added since the fp is higher in order to drop the injector pulse time to set a "normal" a/f ratio?

[TurboEF9]

Nope.

With OBD0, and OBD1, at least, the ECU doesn't monitor fuel pressure. I'm not 100% sure about OBD2+, but I don't think it monitors it either.

[Sonny7730]

what about running the 10:1 fmu with stock injectors? do you think that's cutting it close?