Hi guys,

So my A-Spec 3574R for my FD should be shipping soon.

I need to know if I use 850cc primaries and 850cc secondaries with this kit whats the max safe boost I can run. I will be running a walbro 255lph fuel pump. Do I need an aftermarket FPR too?

Thanks guys...

 

That should get you about 12-13 psi safely but each car is different. That turbo is capable of 20 psi+ and runing that low boost with it is a waste in my opinion. We had one on a car with a 550/1300 combo and it was running out of fuel by 15 psi. Get rid of the walbro. Put in a supra tt or bosch 044 pump and get some 1600s at minimum.

 

I'll second what Ihor said. You're wasting the turbo with 850 secondaries. You might as well go ahead and upgrade your system.

I was using 850's for my primary/secondary when I had twins. Even then I was running out of fuel at around 380whp, you can EASILY hit 380 with that turbo off relatively low boost.

 

Definitely get rid of the walbro and look at a Supra pump or the RP upgraded Supra pump:

(8th picture down)

http://www.rx7.com/store/rx7/fdfuel.html

 

I have a new rp pump if you decide to go that route. Im am gonna need to go bigger than planned. G

 

^What's the plan G? Your setup definitely can benefit from a beefier fuel pump

 

driving around with a walbro on a turbo rotary is like working under a car on a jack with not jack stands...good luck

 

why do you say this? i have a 255lph and am looking at getting the 400lph... never had any issues before....

 

i know there are plenty of people driving with no issues. BUT ive personally seen 2 walbros fail on 2 seperate cars on the dyno resulting in engine failures. Why not just spend $50-100 more and get one the above mentioned pumps to save yourself some headache? the saying exists for a reason...you get what you pay for

 

hmmm... i know this but the new walbro 400 is supposed to be pretty impressive...

 

Thanks guys for all the input. Now let me change the question a bit. Ideally what fueling options would you guys suggest I take to have a good idle and capable of around 450whp.

Do I need a fpr
What size primaries and secondaries
Which fuel pump
Do I need new fuel rails

I am going to ditch the walbro and am leaning towards the bosch.

Thanks guys

 

Bosch 044 with stock lines and primaries is fine. Top feed secondary rail, aeromotive a1000-6 regulator and ID2000 secondaries...

 

so which is better in your opinion Elliot? Bosch o44 or the Walbro 400... or just depend on what you are shooting for?

 

Bosch 044.

 

For 450HP I would go with a complete system. Injectors, FPR and rail.
http://www.rx7store.net/category_s/93.htm

The Extreme system we sell is popular and will support the HP numbers.

As far as pump you have a few options. The Walbro 400, Aeromotive, Bosch 044, Supra pumps will all do the job.

 

Guys what are your thoughts on the aeromotive 340lph also how does it compare to nippondenso supra upgrade......

Thanks

 

that good for 500 possibly 500+ rwhp?

 

The factual rating of the Bosch 044 to work on is, in an ideal world, with proper wiring, and a well flowing fuel plumbing.

4000cc per minute pumping into a 4.5 bar head. To interpret this information, understand that 3bar / 43.5psi above pressure at sea level is the maximum base fuel pressure typically used with aftermarket adjustable fuel rails. Some RX-7s may use lower from the factory such as 36psi or so.

Anyway 4.5bar. 3.0 bar will be used by your fuel pressure. Leaving you another 1.5bar for the 1:1 fuel pressure regulator to use to match the intake boost change, and keep 3bar/43.5psi across the injector. This means you can use 1.5bar/21.75psi boost using a 3bar/43.5psi base, and flow 4000cc/min in that operating condition.

It all depends what you can do with ~3.2kg/minute of fuel flow.

 

i have 3/8 lines and planning on -8 which is 1/2" also have an aeromotive rising rate FPR 13301 and will be using a 4bbl TB setup with 4 injectors...

 

Just sayin, I have a Fd with a warblo 255 550/1300 combo, Stock fpr, with a 35r. I run 19-20 psi and see high 90's injector duty, have trapped 98mph in the1/8 on street tires using 93 octane, to indicate HP, as I never put the car on a dyno. I don't drive on the dyno, so y the hell would I tune the car there .

So Basiclly I have a fuel pump and injectors and THATS IT! I actully bought the injector 2nd hand too.

This car has had the same turbo and injector combo since 2005 and has nearly 50,000 miles on it. I have had 0 pump and injector failures. This combo can work and run just fine for very cheap.So people claiming it won't work messed up sumwhere.

Maybe not 450 but damn close. Its more than enough power to make you smile. If you go to Rotary performances hp calculator 550/1300 at 100% can make 570fwhp.

O and don't push stock apexseals hard, they won't last long...aftermarket seal are more forgiving to high hp abuse, +1 for ra super seals.

 

Really?? Curious what your HP output is.... I doubt you could push 500hp with that pump. I know you didnt say you were but i would be really curious. sounds pretty impressive for that fuel pump for running 20 psi on a 35r Because thats what i plan on running and should be making around 500whp.... although my 35r is a t4 exhaust flange and housing and wheel.....

 

i was am running 550/1600 and I was seeing 90% @ 18 psi hmm..

 

It's great that this is your experience but one car doesn't make the case for all 13,000 FDs in the US. When it comes to the fuel system, cutting corners on a modded turbo rotary is a recipe for disaster IMO.

 

agreed... dont think ill chance it.... fuel system is one area overkill is better than just about every other option....

 

I would highly recommend not going with a 850cc primary.

I am currently using:
Bosch 850cc Pri
Bosch 1680cc Sec
KG Parts Rails
Aeromotive FPR
SaRD 280lph pump (Supra)
FJO injector driver

I wish I would have done more research before going with this setup. All works very well except my 850cc primaries. Driveability is a little rough and leaning out my idle is futile. I have tons of fuel but I don't have that OEM smoothness. You can also consider keeping your 550cc OEM primaries, and using a 1680cc Bosch or ID 2000 secondary. The gap is large but a good tuner will have no problem smoothing it out. I will be upgrading to Injector Dynamics injectors once I start my 500whp build. Do some research on the ID injectors. They use a superior Bosch design where atomization and tuneability has far surpassed the old Bosch design.

The new setup will be:
ID 720cc Pri
ID 2000cc Sec
KG Parts rails
Aeromotive FPR
Dual SaRD 280lph pumps (Supra)

No need for resistors or an FJO injector driver with the ID's either. They are the naturalistic high impedance injector that Power FC's love. If you are using a Mictrotech, this will not matter.

https://www.rx7club.com/showthread.p...ector+dynamics