Hi there from the currently world-cup obsessed UK

I'm going to take delivery of a UTEC for my 350Z this month, as I've (and any competent UK tuning shop) has given up trying to get a decent tune out of the SS box.

The only problem is, people are suggesting that unless I uprate the fuel system (bigger pump, injectors, return system) that it will be pointless. Will it?

I currently have the Vortech stock in-line aux pump, and my other question is; does the Utec allow you to trigger the aux pump in the same way the SS box does?

I'm really not interested in adding all the fuelling stuff because I'm not looking to take my car much further, just to tune it better with the spec it currently has.

Thanks in advance!

 

Can anyone help ... ?

 

Believe the FMU/Aux fuel pump are driven by S.S. Box. The FMU is boost pressure sensed aand actuated by the S.S. and the Aux fuel pump receives it's signal (Voltage) from the S.S. box .. How the UTEC would perform these functions is what you need to resolve..If you have not upgraded the pulley from stock (3.33) upgrading the fuel system seems pointless...UTEC by itself will not increase power ?

 

you can use the utec with your current setup, no problems. But you'd get more out of your setup if you upgraded your injectors to 380's or 440's. Safer & more power. Also, with the UTEC you can bump your rev limiter.

 

I dont think that is what he is getting at, he wants to know if the UTEC can drive the stock fuel system that is provided with the Vortech kit, i.e. the inline auxillary pump. He isnt looking to upgrade the fuel system or the pulley, just change from the SS box.

 

bump! Where the pro's? I wanna know if the Vortech fuel pump and ss box will power bigger injectors. Or do I have to get some other management for my Vortech if I get bigger injectors. Thanks

 

The Utec has a 'spare' solenoid that can be programmed to do a variety of things, and come on in a variety of different ways. You can boost reference the solenoid to control the aux pump.

However, if I were you, I would just upgrade the fuel system. Ditch the AUX pump, add a return line, and maybe some bigger injectors. I would be very weary about having an aux fuel pump in my car, because you won't know if it fails until its too late.

 

OK, thank you for that

 

First...Why cant you get a good tune out of the SS box ?

Second...The Utec should have some aux. inputs to control the aux. fuel pump . The SS box turns on the aux. pump at a user set rpm and psi level . You can set it up to come on at a set rpm level.....or a set psi level ....or both

 

The FMU/Aux fuel pump come on with boost + rpm..Don't believe it one or the other but both..

 

Yes you can set it up that way . You can set it so both have to be met before it turns on . Or which ever one [ psi or rpm ] is met [ reaches ] first . You can also set the levels of boost or RPM's it needs to meet

I am talking about the SS box here.

 

RPM alone does not make any sense..You would always hit it (RPM) under non boost driving..Believe boost is a pre-requisite and RPM is secondary but necessary..?

 

There is a pull down to set it for...rpm and boost . And another option to set it up as.....rpm or boost .
So you could set it on...rpm or boost . And have the rpm set at [say ] 6500 and the boost set at 1.5 psi . The aux fuel pump will always come on at 1.5 psi . Or you could set the rpms at 3000 and the boost at 5 psi , and the pump will always come at 3000rpm because you will always be more than 3000rpm when at 5psi . See what Im saying ?

WHen you get the kit from Vortech , it comes preset at really low rpm and boost levels and basicly is running most of the time. I think it is set at boost and rpm ....and the settings are -boost [ vacuum ] and 2500rpm . Some thing real close to that . Most reset them so it doesnt run all the time

 

All though the aux. fuel pump maybe running most of the time [ stock settings ] The FMU does not increase the fuel preasure untill boost rises . And the FMU is set to raise at a 8 to 1 rate on older kits and 6 to 1 on newer cars

 

How does the SS box raise the fuel pressure?

 

It doesnt.....The FMU raises the fuel preasure . You have a vacuum line running from the plenum to the FMU . When boost rises the FMU will raise the fuel preasure

 

The FMU allows fuel flow to the Aux fuel pump that raises the fuel pressure to the fuel rails..

 

I believe it is the other way around . Fuel pump goes to the FMU and from there it the fuel preasure is regulated .

 

oh, ok, I gotcha. I was thinking the SS was also called the FMU as it technically is a fuel management unit. So the FMU is basically a rising rate regulator t hat rises at a rate much higher then the typical rising rate regulator (1:1).

I'm surprised there havn't been more blown motors with that setup. Seems like you are a lot of 'ifs' in the system, between the aux fuel pump (and loose fititngs) and a mechanical regulator.

Regardless, its still hands down better then the solution provided with the Procharger.

 

Looking at the flow diagram provided with the install instructions, If you follow the arrows it seems that the FMU (activated by boost pressure) allows fuel into the Aux fuel pump which is controlled by an electrical signal from the S.S. box. The variable fuel flow rate (pressure) I believe is controlled by the boost pressure sensed at the FMU. The rising rate fuel pressure is a function of sensed boost pressure in the FMU. I suspect the FMU has a diaghram/spring that allows fuel flow as a function op sensed boost..What do you think?