OEM cam differences, modifying fuel pressure.
 

Hi All,

Yes I am new here (been lurking for a while) Its a great site! :thumbsup:

I have searched my ass off and cannot find any concrete data.
My main question is does anybody know the differences in cams from the 2012, 2014, 2015 engine updates and part number changes?? ie lift/duration.

Part numbers

2012 su0030018x
2014 su0030474x
2015 su0030623x

the second part of my question relates to fuel pressure on the direct injection.

Will raising the fuel pressure prior to it entering the direct injection pump raise the output pressure of the direct injectors?

I believe their were some changes to the rocker design and the vavle length and you need to be carefull you match parts. Not aware of any changes to actual cam lobe lift ect, but its possible.

However the vvt cam tables in tunes for all the revisions are almost identical.

If you alter the fuel pressure into the DI injectors then you will alter the fuel delivery. Some E85 tunes do that to increase they fuel delivery by 30% for e85 fuel tunes, the up the DI pressure multiplier in tune tables to up the DI fuel delivery. and the injector scalar for port injection is reduced by 30% to fool the ecu to deliver more fuel?

Thanks for the reply.

Yes i was aware of the valves and rockers and coil packs..
Someone on here was saying the cams had different amounts of lift, was hoping to get clarification on that.

The other question was really just to satisfy curiosity about the di,
If the engine driven di pump is supplied say 40psi as standard, and we upped the supply pressure to say 45psi, would we see a linear increase in the pressure to the di injectors on the other side of the di pump?
I know these things can be controlled via ecu, just wondering about the mechanics of it all. :)

This should help you out in terms of understanding the mechanics I don't know if it's our fuel pump but its probably pretty similar in terms of operation.

[ame="https://www.youtube.com/watch?v=0mjG7-Vc0Co"]Delphi GDi Fuel Pump - YouTube[/ame]

As for increasing the inlet pressure, to increase the output. Nope. Due to the design the output is independent of inlet, you might get a little more but no linear trend upwards.

In theory yes, the HPFP is a mechanical booster pump and acts like a hydraulic fulcrum. This is how the BMW N54/N55 crowd band-aids the fueling system. But we have DI+PI so I our fuel system has a much higher ceiling above stock power than theirs. As far as I understand, our fuel system can handle more power than our rods?


-Josh

If you mechanically change the pressure you might find the ecu works against you as it measures DI pressure.

The OFT guys adjust the fueling for E85 in the manner above
ie drop the port injector scale by 30%
Increase the DI pressure multiplier tables by 30%

no mechanical or hardware changes needed, i believe they have run a turbo car on about 10-12psi producing about 340hp on E85 with completely stock fuel system components doing that and i suspect altering the DI/PI ratio tables.

http://www.ft86club.com/forums/showthread.php?t=100699

i run 50psi of base pressure, rising to 80-85psi at full boost. di pressure table wasn't touched in motec to compensate for the rising rate going into it. i also ran a rising rate setup on ecutek and we didn't have to alter the di pressure control valve either. after 8k rpm the high pressure did start to oscillate though.

I'm not sure I understand. Are you saying the increased pressure did increase the di, or not? Sorry I am new to the 86 and tuning.. Assume the ecu is locked, running di only, no pi.. and I'm running lean. Can I add more fuel with adjustable fpr?

The ecu requires a seed\key handshake to access read\flash mode.



Some tune systems like brzedit or ecutek change this protocol so it effectivly locks the ecu to that system. Other systems like OFT or Tactrix ecuflash do not lock ecu or tunes so you still have open access

The cheapest way to gain access and be able to tune car is with a Tactrix cable and ecuflah software all up about $170 usa, see coloured links below.

for tune systems see here
http://www.ft86club.com/forums/showthread.php?t=106068


what mods are you tuning for ?

What are you trying to achieve? Have you maxed out the available IPW? Why is the ECU "locked"?

I don't think the higher inlet pressure changes the di output pressure. Factory runs a mix of DI and port, or just di depending on conditions met. You are trying to add fuel without any tuning software?

You might need to supply more info like

why is ecu locked
if its running full di, why
and if its running full di only its obviously been tuned by someone
what mods ie turbo sc
usually tuners increase pi injector size to increase fuel delivery and lean on the port injectors more.
what fuel
etc

else were just having a stab in the dark :-)

yes my motec is locked. only headers, no cat, big pipes.
No i can't unlock it.
did a dyno run and it appears to run lean.
I am trying to ascertain why and if there is anything i can do about it.
I see people run anywhere from 11.5-12.5:1.
Mine is 13.5ish!
http://i962.photobucket.com/albums/a...psbxhohzrz.jpg

Their is no reason an NA car should run lean due to maxing out fueling even on E85 their is plenty of headroom.you jist nned to get the tune fixed, i assume the motec should be able to run both pi\di fueling systems.

why do you need a motec for an NA car seems way overkill ?