Boost referenced FPR for M90?

[spf_lexus]

so we need static fuel referencing? Well just some more into the mix.... my Synapse non-diaphram FMU IS static adjustable. I can tailor my fuel pressure curve however I want (given I have a wideband + gauge). It also goes for a little over $200. i never have any issues with mine... I leave my static fuel pressure "loose" since I keep my stock reg. I let stock one handle idle and the rising rate to handle high RPM boost. Works flawlessly... for me anyway.

 

[stevechumo]

Thanks for another believer. :tongue: It's a true and try system. If a high boost system is required, a combination of the FMU and bigger fuel injectors can be used. The FMU ratio needs to be lower to decrease the pressure under higher boost. However, the fuel injectors still need to be trimmed down by the piggy back ECU accordingly.

 

[striker]

BS crowd here!

get the engine some brains, and run fullstatic or stock, rrfpr is a no go in the racing world, must have a reason don't you think?
as for the brains very decent systems can be had for good money these days, and which ever your upgrade plans in the future are you can always retune for what you think up next.

grtz Thomas

 

[ozvenom]

it work and works well.

Hi Steve it seems that a few are getting puffed up over FMU
I fitted a m112 eaton to a 1uz with a standard ecu with a custom built manifold . I used the vortec super fmu to tune it on a dyno it had different size diaphram plates to change the rate at which it rises i tried a 8:1 non adjustable but it ran too rich under power so on went the super fmu and i changed it twice after doing data loged dyno pulls to find the best ratio. which once set gave consistant results on the afr's . now the ratio used my not suit everyone as boost intial fuel pressure and pump capacity will vary the final flow rate i have flow tested 1uz injectors and found that for every 10 psi you increase the fuel pressure you get 10% more flow it worked up to 20 psi over standard . thats why it works.

As far as a restriction goes its on the return line to the tank and does not effect the fuel flow from the pump.
FYI it ran 7 psi and made 287 rwhp.
any more than 7 and you real should be thinking about ecu tuning either a piggy back/ inteceptor or standalone.
like a motec or adptronic.

 

[stevechumo]

Thanks for clarifying this. :biggrin: I'm always interested on how the M112 runs on the 1UZ. Are you running 7 psi? 287 rwhp for 7 psi is very....impressive. Do you have this setup on the Soarer or another car?

I'd say this setup is only for street daily driving, but not for track.

 

[ozvenom]

converted

ITs has been fitted to a vs commodore wagon also has a shift kit fitted to the trans.
Its a daily driver since the conversion and dyno it now has extractors and cam shafts fitted so it would easily be making over 300 rwhp.
oz

 

[1uzvl]

So less return flow to the tank is good?I would of thought alarm bells would be ringing meaning your reserve feul for any giving situation is running low.

 

[ozvenom]

unclear

if you understand how a fuel system works you would understand . so the return line is has 2 purposes it allows the fuel to flow thru and prime the injectors so there is no air locks and it maintains pressure by bypassing fuel to the tank . the pump is flowing any where near its full flow rate so as fuel demand increases the pump increases its flow untill its at maximim and then the amount of fuel going back to the tank starts decrease at which point the system is at max flow and you will suffer a lean out situation that is if the injectors are maxed out first which is what nrmally happens.
Thus ends todays lesson lol.
oz

 

[1uzvl]

you must of miss understood,my comment was sarcastic.

Its my understanding(which is quite reasonable but not extensive)if your are running more pressure to overcome the short falls in your injectors you will have less flow back to the tank.

Whouln't that give you less margin for error?I mean they recommond not
to max out your injector for the same reason.Now i dont know wether this would ever happen but im sure its a possibilty.

 

[ozvenom]

ok

I am not having a go at you personally it seems to a completely misunderstood subject .
What flows back to the tank is irrelavent its how much more flow the pump has to feed the injectors .
maxing out either is not good.
If you watch the return line with a flow meter and do a power pull on a dyno and the flow stops then you real need a bigger pump. most Efi pumps can handle the extra pressure its only going to be the boost pressure x the ratio of the fmu plus the base pressure.
oz.

 

[Sabre_Logos]

I'm running a BEGI FMU on my Turbo Q45. It worked out great with the blow-thru MAF setup. It's adjustable so you can play around with it and get a nice a/f ratio under boost.

My stock injectors are 370cc so all I needed was just a bit of extra fuel under full throttle which the FMU helped out with. When I'm cruising, it's out of the picture and driveability is spot on. For the money, a boost referenced FMU can't be beat for a low boost setup.

 

[Mattmannz]

Thanks for all the info guys.

How are the adjustable units adjusted? Threaded rod?

What ratio's are people running?

Matt.

 

[Peewee]

Yeah, threaded rod, usually adjusted by an allen key.

 

[spf_lexus]

the synapse units have a threaded thumb adjusted-knob on top thats hard to turn... god thing cuz it wont ever move out of place. The static fuel is a threaded shaft w/ an allen port on top that locks w/ a locking nut at the base. Once you find the sweet spot just lock in place.

 

[Mattmannz]

spf_lexus - the thumb adjuster, is that for the rising rate component? Have you got any pics of yours installed?

Cheers
Matt.

 

[spf_lexus]

synapseengineering.com click on their FMU they have pics. Yes the "rising rate" component is thumb adjusted

 

[-Nemesis-]

So is there an agreed ratio for a 7psi system on a stock 1uz? 12:1?

I'm going to run mine on LPG injection 90% of the time so a bandaid fix on the petrol system is plenty. I'd rather buy a set rate rising rate, but am unsure what ratio?

 

[stevechumo]

So is there an agreed ratio for a 7psi system on a stock 1uz? 12:1?

I'm going to run mine on LPG injection 90% of the time so a bandaid fix on the petrol system is plenty. I'd rather buy a set rate rising rate, but am unsure what ratio?

I always use 12:1 to make sure it can provide enough fuel under boost. The lower ratio is usually for combination when the system already has some sorts of higher fuel capacity than regular stock system.

 

[Mattmannz]

Steve when you say 12:1, does that add 12 psi of fuel pressure for 1 psi of boost?

If stock pressure is 40psi and boost is 6 psi then is total pressure 72psi or 112psi?

Surely not 112!

Cheers
Matt.

 

[stevechumo]

Steve when you say 12:1, does that add 12 psi of fuel pressure for 1 psi of boost?

If stock pressure is 40psi and boost is 6 psi then is total pressure 72psi or 112psi?

Surely not 112!

Cheers
Matt.

Yes, it is. I'm currently running 9 psi with 12:1 ratio FMU. 9 x 12 + 40 = 148 psi. It's running really great so far, but I know I'm reaching its limit. I'm very tempted to run 8:1 ratio FMU at 12 psi of boost and use (8) 297 cc/min injectors in place of (8) stock injectors. This is a blind walk but who knows it'll turn out great. :icon16: