My R2

Ok, I have the appointment..now I just need the details...

I have the PFS Intercooler and catback. I do plan to keep both of these items as it is TOO much money to upgrade at this point in time.

What else do I need to go single... I am getting the T04E or S I am not sure but it WILL be one of the two.
Could you guys/girls give me some direction as to what else is needed to keep the car reliable and safe. The engine WILL NOT be ported.
Thanks a million!

P.S.
No I am NOT going to PFS to get the work done!!
Oh yeah those in the NE don't forget the meeting

Bacon

iTrader: (12)

for a single..youll need a stand alone ecu..either haltec or pfc or such
since you on the east coast theres no one out here who can tune the pfc woth a damn..so haltec looks to be the best right now
youll need larger secondary injectors
a rrfpr
a upgraded fuel pump
and the turbo itself

so you looking..
1k ecu
600 for injectors and rail
350 for rrfpr and fuel pump
3k for the turbo

personally id buy a better ic..the pfc imho opponion isnt big enough to support a single

also you only mods are a ic and a cat back?

you should do all the rest of the mods on the stock twins and see if that isnt enough ...then look @ single..


singles a big jump

My R2

I have the intake and downpipe and all that but I am having turbo problems..and instead of a re-build of the turbos I think I may like the single much BETTER!

What is a rrfpr?
So the PFS is not that good for a single application? It is (I think) 100% bigger than stock. Do I NEED a front mount? I really wanted to stay away from haltec...b/c the installation is just too much. Also I am not looking for BIG horsepower just a streetable killer. Could I get the Supra fuel pump? Do you know how much those cost?

turborotarypower

Rising Rate Fuel Pressure Regulator

My R2

rrfpr..is that something that goes into the engine bay or the cockpit?

Mr rx-7 tt

iTrader: (5)

You will need at least....rrfpr,blow off valve, hipo fuel pump, turbo kit which includes dp, turbo manifold,oil lines,clamps,etc..,large ic, haltech computer,aem etc, also an a hd clutch and pp, full exhaust to include midpipe, larger injectors, The car will also have to be dyno tuned with maps..

SilverR2

.

maxcooper

I wouldn't get a RRFPR. You don't need it with a programmable engine management system, and it can be inconsistent in its operation. You can run with the stock regulator, but an adjustable FPR (which is quite different from an RRFPR) might be a good idea as I have noticed some inconsistent behavior with the stock regulator on my single turbo car.

I would get:
- PowerFC, AEM computer, or Haltech (do a search to compare) $1000-$1400
- big fuel pump, from Denso, Walbro, Bosch, or A'PEXi $150-$400
- enlarge secondary injectors to 1300 cc/min $280-$350
- turbo kit (XS E or S is a good choice) $3000
- consider an FPR and hoses $180-$300
- electronic or manual boost controller $30-$500
- new fuel filter $40
- consider a larger radiator $400
- custom piping to your IC?
- Santoprene hose from http://www.mcmaster.com/ so your air filter will clear the IC?
- dyno tuning with wideband $400+ and well worth it for power and reliability
- plan on another $1000 of misc stuff you decide to do

-Max

My R2

WOW that is A LOT OF FREAKING MONEY!!!! MAYBE I WILL JUST KEEP THE SMOKING TWINS nawwwww

My R2

Ok here goes this is what I am getting...

This has/will be ordered soon...
Koyo Radiator
Nippondenso fuel pump
2x 1300cc injectors
Power FC

Future ASAP
T04E Single Turbo Kit
SX Adjustable Fuel Pressure Regulator
Greddy Profec B
High flow cat (? which one would hold up well)

This will be on a stock motor. What boost should I run on this turbo? How much RWHP should I be expecting? Ok one more...IS THERE ANYTHING THAT I HAVE FORGOT?

THANKS A MILLION GUYS/GIRLS

My R2

Oh yeah thanks for the replies so far...
maxcooper
Mr rx-7 tt
SilverR2
turborotarypower
Bacon

Keep them coming...

Maxthe7man

Maxcooper: You can only get away without a RRFPR, if you have almost double the size injectors required with a RRFPR. As boost pressure increases, the effective pressure across the injectors decreases, meaning that an injector instead of flowing say 50 lb/hr at 43 psi, with ten pounds of boost the injector only has effectively only psi of drop across it, so the flow rate of the injector starts to go down, this means that you then have the problems of larger injectors at idle, and running more injector staging.
With a RRFPR, you can calculate our injector sizing and staging across the RPM board by knowing your injectors are always capable of flowing 50/lb/hr of fuel.
SO it would go like this.. with a rate of rise of 1:1

Boost psi Fuel pressure pressure drop across injector capacity
0 43 43 50 lbs/hr
1 44 43 50 lbs/hr
2 45 43 50 lbs/hr
3 46 43 50 lbs/hr

now if your injectors are a little tight on the the upper end , you change the rate of rise to give you more fuel pressure and hence a little more injector capacity, if you ran into this with only a FPR, you would have to swap injectors to remedy the problem. The other beauty is that with vaccumm on it, you can cut the pressure right down at idle , to effectively make the injector smaller during light loads and idleing, making the use of larger injectors easier to tune..
Now without and RRFPR, just an FPR, this what happens

Boost psi Fuel pressure Pressure drop across injector Capacity
0 43 43 50 lbs/hr
1 43 42 48 lbs/hr
2 43 41 46 lbs/hr
3 43 40 44 lbs/hr

Now I did some lazy math in the capacity section but you get the idea, now some would argue that by increasing the base fuel pressure you could overcome the issue of dropping the overall injector capacity as boost increases, but there are 2 negative effects of this
say you needed a base fuel pressure of 75 psi to overcome the losses of higher boost, this now means that at low speeds and idle , you are running with a an injector flowing 75 psi of pressure drop or more, so your injector becomes a lot larger effectively, meaning harder to tune, and the chances that fouling and flooding is a problem, the other effect is that fuel pump output pressure is inverse to flow capacity, so if your fuel pump flows enough for 500hp at 43 psi, at 75 psi, it would only flow enough for about 350hp, you get into an area, where your fuel pump cannot flow enough at the psi required to make your injectors flow enough, and your injectors do not flow enough at a lower pressure to make your fuel pump flow enough at the psi... Max

maxcooper

I understand the issues of fuel pressure and flow very well. I even wrote a fuel calcs web page, here:
http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

Any adjustable FPR for turbo applications will have a port for the manifold reference pressure. An adjustable FPR will maintain the same pressure across the injector no matter what boost you run. It raises the fuel pressure with a 1:1 rate relative to manifold pressure. It's job is simply to maintain your base "effective" pressure no matter what boost you are running. Here's what it looks like:

Boost / "gauge" fuel pressure / "effective" fuel pressure / capacity
0 / 43 / 43 / 50 lbs/hr
5 / 48 / 43 / 50 lbs/hr
10 / 53 / 43 / 50 lbs/hr
15 / 58 / 43 / 50 lbs/hr

An RRFPR raises the fuel pressure by some multiple of the boost pressure. If you set it to 2:1, it looks like this:

Boost / "gauge" fuel pressure / "effective" fuel pressure / capacity
0 / 43 / 43 / 50 lbs/hr
5 / 53 / 48 / 53 lbs/hr
10 / 63 / 53 / 56 lbs/hr
15 / 73 / 58 / 58 lbs/hr

Few pumps will supply the fuel flow you need at 70 psi rail pressure (which is roughly 80 psi to the pump, including the pressure drop of the fuel system). Also, the rise rate changes slightly with air temperature, so you have some new and unwelcome variability to deal with when tuning. And someone might decide to twist the adjustment **** while you aren't looking, which is a bit unnerving.

I have used a RRFPR in my car, and my conclusions are that this type of unit has no place in a car with a programmable computer and adequate injector sizes. It is a reasonably good solution if you need a little more fuel under boost than your injectors will support, and you can't or don't want to remap for higher base fuel pressure. It might be legal in competition classes that disallow an ECU change as well, which makes it an attractive option for adding fuel under boost but not screwing up your off-boost fuel maps. But on a single turbo, you are much better off with adequate injector sizes, a reasonable fuel pump, a programmable ECU, and an adjustable FPR.

-Max

Maxthe7man

OK, I am not trying to pick on you here, but you kinda missed the point, the rising fuel pressure you talk about and the reference to manifold pressure is a rising rate regulator. A base FPR, maintains a set fuel pressure reguardless of manifold pressure, they are adjustable to one pressure and thats it, any time its referenced to manifold pressure in a ratio of increase, its a rising rate regulator, be it 1:1 or 2:1, most are adjustable via springs and discs to pick the rate of climb, and the total fuel pressure. Most stock oem regualtors are just that Fuel pressure regulators, they hold it at a fixed pressure reguardless of RPM or load..Some are a two step regulator that holds 25 psi at idle, and 43 at load.
The lower you can keep your fuel pressure via properly sized injectors the better off you are. When you start getting your rail pressures into the 75+ psi, you are asking for problems with fuel lines, and the power consumption of the pump goes through the roof, also most pumps fall off drastically past the 65 psi point.
The adjustment is typically a set screw with a lock nut, and if you saw one that was affected by air temperatures, it was faulty to begin with. I don't have to explain the benefits or rising rate to you, because it appears you are using one now, you just didn't realize it, if you were using a base FPR, your rail pressure would be the same all the time, since you suggest that yours climbs with boost, I would have to surmise its a rising rate its just on a 1:1 ratio......Max

My R2

Ok MAX guys can we get back to the subject here

This will be on a stock motor. What boost should I run on this turbo? How much RWHP should I be expecting? Ok one more...IS THERE ANYTHING THAT I HAVE FORGOT?

maxcooper

A 1:1 regulator is not a rising rate regulator. The stock regulator has a 1:1 rate as well. It is not a rising rate regulator. You are confused about regulators.

Adjustable FPR = 1:1 rate with an adjustable base pressure

Rising rate means you can adjust the rate, and it is pointless unless you use a rate higher than 1:1. Most allow you to adjust continuously to 2:1, 3:1, or even 4:1.

RRFPR = adjustable rate, often with a fixed base pressure (though there are regulators that can you can adjust both the base pressure and the rate, and even ones that allow to set the pressure at which the rate takes effect)

I imagine there are a fair number of regulators that are as you describe -- they hold a constant pressure relative to the atmosphere. But no one uses these on turbo cars for the most part. The common adjustable regulators from SX, Aeromotive, etc. all have adjustable base pressure and a fixed, 1:1 rate.

The RRFPR that I used had an air bleed that you could adjust with a little **** that set the rate. It was very easy to adjust.

Perhaps it is just a difference in terminology, but I am quite certain about the specifics of the regulators, and what their common names and behaviors are. Lots of people are confused about this topic.

Sorry to be off the point My R2, but confusion about regulators is widespread, and I want to make sure this posts contains the real information. Your parts selections sound excellent to me.

-Max

maxcooper

I attached a picture of two aftermarket regulators. The one on the left is the SR Motorsports RRFPR and the one on the right is the Aeromotive Adjustable FPR. The SR regulator has a fixed base pressure and you can adjust the rate with the bleed valve ****. The Aeromotive FPR has a port for the manifold reference pressure on the right and a nut to adjust the base pressure on the top (well, you turn the stud with an allen wrench and the nut is to hold the setting). The appearance of these regulators are typical of their breed.

Maxthe7man

Umm,,, no...
If its reference to manifold pressure, its is a rising rate regulator.. period.. What you are arguing here is that because the rate of rise is not adjustable its not a rising rate, which is not true, a basline adjustable FPR gives you just that, a baseline fuel pressure, my truck has one, its set at 9 psi, its not a rising rate, its an FPR and thats it, it is not referecend to manifold pressure. the stock tII fPR is a rising rate, however the rate of rise is fixed and its span is also limited , but its still is a rising rate regulator, some RRFPR's have less adjustements than others however that does not exclude them from being RRFPR's its just the adjustability that is excluded.
Rising Rate means they have a rate of reset of fuel pressure against manifold vacuum or boost, some are adjustable, some are 1:1, 2:1, 3:1 4:1, it doesn it really matter its still a rising rate regulator, so some people would ask why add an RRFPR to a car that already has an RRFPR, mainly for adjustability, the stock ones have no adjustments, base, rise rate, or total, buts its still an RRFPR..
the non adjustabiltiy of a manifold fpr in terms of the rise does not mean its not an RRFPR, it just means its a non adjustable RRFPR..Max

maxcooper

No hard feelings on the posts here; just trying to get to the truth of the matter.

I am quite sure that the stock regulator and the "regular" adjustable regulators are not considered rising rate by their manufacturers, or any tuner than understands their operation. The term "rising rate" is sort of confusing, but I have been thinking about its meaning, and I think I have found a reasonable definition for it:

A rising rate regulator is one that increases the flow rate of the injectors in proportion to the manifold pressure. This means that it increases the fuel pressure by some multiple (larger than 1) of the manifold pressure. Thus the flow rate of the injectors rises with the manifold pressure -- a "rising rate" regulator.

A regulator that holds the flow rate of the injectors constant is not a rising rate regulator. This includes all 1:1 regulators that are commonly found on turbo cars, and adjustable regulators from SX, Aeromotive, etc. You might think of a 1:1 regulator as a "constant rate" regulator in the sense that they hold the flow rate of the injector constant no matter what the manifold pressure is. The rate doesn't rise, it is constant.

I am aware of the fixed pressure regulators you speak of, but they aren't used on turbo cars very often because of their inability to keep up with boost pressure. If we needed to find a name for these that includes the word "rate" in it, we might call them "falling rate" regulators. But "fixed pressure" is probably better.

I hope that offers a reasonable explanation why a 1:1 regulator should not be considered a rising rate regulator. It makes sense to me, and it matches the common names of the components with their behavior.

-Max

peejay

SHEESH.

ALL cars with port fuel injection reference the fuel pressure to manifold pressure. That way the differential pressure between the intake manifold and the fuel is the SAME. If it was any other way, fueling would be quite inconsistent. (Setting pressure to 38psi "base pressure" means fuel pressure will always be 38psi higher than manifold pressure - if the intake manifold is at 15 inches of vacuum (-7psi) then fuel pressure will be at 31psi for a 38psi pressure differential, and so on)

A rising rate fuel pressure regulator is just that - the rate of adjustment of fuel pressure rises out of proportion to manifold pressure. So instead of adding 1psi of fuel pressure to compensate for an added 1psi of manifold pressure (to keep the same pressure differential) the fuel pressure goes up by a factor of 2:1 or whatever it's set to, once intake manifold pressure is above atmospheric (even that is adjustable).

Just make a graph of fuel pressure. A standard fuel pressure regulator alters pressure in step with manifold pressure, going up one PSI for very manifold PSI. A rising rate regulator will have a CURVE - the rate of fuel pressure increase rises once past a certain point, usually above atmospheric pressure.

Maxthe7man

Peejay I can't agree with that either really, I have the brochure from the original nash rising rate fuel regulator that has the ratio fixed at 1:1, so if its fixed at 1:1 , how do you explain that?
Max cooper: I see what you are getting at, the term means different things to different brands, I read a series of notes from the SAE on fuel pressure systems, the original FPR's had a baseline setting, that they stuck to, but with blow through carb systems, the need to compensate the fuel bowl inlet pressure to boost pressure, gave way to what was called the rising rate regulator where they referenced the top side of the diapragm to manifold pressure instead of atmospheric, it seems the rising rate was in reference to rising the fuel pressure at the same rate of manifold pressure, but as Peejay sees it, its in reference to the ratio of gain on the diaghpram. I guess it depends on what manafacture you want to accept the terminology from, I myself and probably more old school than new school, so I accept the older definition. I noticed in some furthing reading that guys like Cartech, vortech and paxton have steered clear of the Rising rate name tag, calling their products, FMU's and then listing the features, as adjustable and auxilary. If AEM and what not sold the original Nash piece, they would term it boost sensitive instead of rising rate, but under the Kinsler definition its a rising rate.. I can see both terms being used, I guess its what you term to be the meaning of rise and rate.
I also found some stuff in some of my old books on stock fuel pressure regulators, for efi cars kind of interesting, they do not use a linear spring, its conical in shape and the spacing in the coils is uneven which suggest a non linear fuel increase or decrease in reference to vaccum, but have a positive stop at atmosheric pressure, that would explain the need for adjustable replacement regulators called "boost sensitve" for cars that were not originally equpipped with a turbo, but seeing as the off bosst characteristics of the engine would stay relatively the same, the aftermarket regs would most likely retain the non linear curve of the stock regulators, so in essence, most companies are selling a reg that is the same as stock but with added adjustabiltiy and the zero guage pressure stop removed, but when they add a **** for the gain, they call it a rising rate, when it fact as you put it via dropping rate, it already was one....Max