I have been searching for the last half hour but have not run into the info I`m looking for.

My 88T2 is in the process of some upgrades while I`m not driving it during the "salt season"

I am upgrading fuel injectors to the following. ( rebuilt by witchhunter )
Primaries are both 696cc at 43psi
Secondaries 724cc and 728cc at 43psi
I have an S5 turbo and manifold, turbo going to BNR for stage 2 upgrade.
FD fuel pump
Racing beat turbo back exhaust.
K&N cone.
Removed Emissions.
I also will be installing a Megasquirt for fuel and spark. (already run one on my NA)

I would really like to upgrade to an adjustable fuel pressure regulator, problem is I can`t seem to find info that explains what parts besides the FPR I will need.
Also, what do I do with the stock FPR? Do I have to come up with a new secondary fuel rail or is there just a mod that is done to the stock rail/FPR.

I also want to dump the rats nest and go to a simple vaccum layout but can`t seem to find any posted diagram or verbal instruction.

 

i just got gone looking my self. www.fc3spro.com has a fpr mod and www.kgparts.com has full setups prebuilt. happy shopping let me know how it goes

 

You don't need to upgrade your FPR for your mods.
Just run the vacuum line from the FPR to any fitting AFTER the throttle body plates - this cleans up a lot of the vacuum hoses and wiring for the stock FPR.


-Ted

 

Thanks for the reply Ted. I guess I get overcautious due to all the "opinions" on the forum about engine damage due to a lean condition. Also part of my reason for upgrading the FPR is getting the benefit of a pulsation dampener combined with it.
I have the extra banjo bolt and washers (hope I`m not opening a torrid of **** with that comment) so I suppose I could dump the dampener OR go to one like the Marrin PD. I also thought that since the stock regulator runs at like 38psi will I not be getting less than the tested flow rate from my upgrade injectors?

One last thing, is there a writeup for the simple vacuum layout?

 

Um, I dunno how the FPR could cause a lean condition?
Not enough fuel is usually due to a too-small fuel pump or fuel injectors are not big enough.

Run a fuel pressure gauge to see if the pressure is dropping under boost?


-Ted

 

I asked a couple of questions in my last post but only get a response to the first sentence....go figure. There were also questions about the upgrade FPR having the ability of a pulsation dampener combined within the one unit. The elimination of the stock PD with or without putting an after market PD into the system. ie. Marrin PD.

I was not implying the FPR would cause a lean condition outright but that since the stock regulator, per Mazda, operates at 38psi, below the 43.5psi the injector shops test with, I won`t be getting the rated output of the upgrade injectors.
I`m going with primaries 696cc actual flow at 43.5psi each and secondaries 724cc and 728cc actual flow at 43.5psi each. Maybe this does not come into play and as I said I`m being overly cautious, hence that first sentence.

 

Here u go:
This formula calculates the effect of changed fuel pressure on injector flow:

(SQR(SysP2/SysP1)]*Statflow1=startflow2
*SQR means take the square root of the value in parentheses

For example say u have a injector that is rated at roughly 20 pounds per hour at 39 psi.
[sqr(25/39)]*20=16lb/hr at 25 psi
At 25 psi it would be 16 pounds per hour a 20 percent differance.
The same injector at 55psi would flow 23.75 pounds per hour a 19% differance.

Here is a link so u can figure it out you're self the easy way.
http://www.mkivstore.com/index.php?t...e_id=443355888

Fyi 72.5 psi (5bar) is for the most part the max u can run w/o affecting the ability of the injector's internal spring to force the injector closed against fuel pressure. Also at higher line pressures or lower voltage the fuel pump will deliver less pounds per hour. At 10 volt's rather than 12 volt's a 282 lb/hr pump will flow 220 lb/hr. The same pump at 12 volts and 40 psi will flow 282 lb/hr and at 12 volts and 50psi will flow 260 lb/hr at 13.5 volts and 50 psi it will flow 320 lb/hr.


So yes, less pressure mean less fuel and or the injector thinks its smaller than it is. As far as running lean goes u have a ms just tune it. If u get to close to a 80% duty cycle jump the pressure up or change the injector. For the most part u are better off, running a smaller injectors and a higher pressure around 50 psi cause it gives u a better spray pattern and makes it easier to atomize. That is if you're pump can handle it!

 

Thanks for the link, its a big help.

I have not done an actual pressure test on my fuel pump and won`t be able to until
it warms up around here. Once I can get back to work I still need to finish tearing apart **** (ABS pump) so I can get the original turbo and manifold off. Sometimes in the next two weeks I will be sending my S5 turbo thats on the bench on down to BNR to get the stage 2 hybrid work done.
I`ve even considered having the S5 manifold as well as the hot side of the turbo
coated with some type of heat rejection coating. (though not sure what at this point)

Also the forum server is sure acting slow, anyone else notice this today.
I can get anywhere else I want.