I actually would prefer constant pressure across the board, and then add fuel and remove fuel as needed across the map via eManage tuning. I prefer electronic control of the fuel, rather than effecting fueling by pressure changes...which is very hit or miss at times.

One reason most aftermarket turbos use rising rate FPR's, is to help "overpressurize" the stock injectors at higher RPM's to accomdate the extra fuel needs of F/I. But in a perfect world, I'd rather have pretty normal fuel pressures, but have the ability to enrich fuel via bigger injectors, or ECU/Piggyback tuning.

 

gq_626

You hit it on the spot. the only time you use a pressure riser is when you have smaller injectors. the 440 injectors that greddy came with are ranked at 43.5psi. at 52psi they run as if they were 507. that is well enough to run 500+rwhp. A constant fuel pressure with larger injectors for manipulation is always better the using a fuel pressure riser. I had to go this way because TS won't make a fuel curve for the 440 injectors. I pretty sure JWT will come out with there version soon. Hopfully is will run constant pressure with like the nismo 510 injectors

 

Adam and Spaz I PM'd you if you get time.

I have the ATI Tuner kit with TS and 380cc's at 9-9.5 PSI

My A/F is maxed out in open loop mode for the stock pump but in closed loop mode I get an occassional (and irratating) CEL code 175 rich bank two. TS does not touch this area. Danny says it is not a huge concern unless one of my 02 simms go bad.

If you watch my video you will notice that I hit 875-900C on both WOT runs and would like to add more fuel via a larger pump but I don't want to get too complicated with drilling etc I am way too deep into my car and not real rich right now due to an IRS raping.

I can live with being a little rich in closed loop (I already am) for safer settings at WOT. A happy medium of sorts. I knew it was inevitable but with my new torque converter the boost is coming up much faster because of the added torque.

What would you reccomend for someone like me with the 380cc's and the SCer tuner kit (no dfmu or booster?)

I am not racing regularly this year because of my new schedule so I would like to keep it as simple as possible or even wait if I can. My measuring bung is post Borla header and pre RT cat with a Borla TD.

Has *anyone* with a SCer run the ATI tuner kit and just did a direct swap on the pump without the FPR after raising the fuel at the ECU level and increasing the injector size?

Max

 

Max,
I have just gotten back into town and am going to test my car witout the FPR(SARD Type R) connected. I do have the TS flash for SCer(8lbs) and 380cc injectors. I did get the walbro 255 installed a couple weeks ago but have been out of town since. I should be able to give some results by tomorrow as to what happens, maybe even tonight but I'm on east coast time. I already got the 175 cel three times with the stock pump as well. I am sure it will be there still. I also have a fuel pressure gauge installed to monitor what happens.

How do you plan on passing OBD2 inspections with the ECU putting out a cel or not have all the test parameters completed? Have you viewed your test parameters with a scan tool? I bet more than one of the parameters is unset or not ready which would fail inspection here in NC. I am currently battling that problem here in NC since we have to get an OBD2 reading once a year.

MIKE

 

New cars here require smog 4-5 years after purchasing. I have never kept a car that long in my entire life.

Hey let me know about the 255l without the FPR I will wait and watch here.

Thanks!

 

I am never moving to NC.....ODBII tests every year??? Holy Smokes!

 

you most certainly do not want constant pressure across the board . A FI setup should have a linear rise to fuel pressure. 1 psi of fuel added for every 1 psi of boost it sees. This is how ever forced induction (from factory) setup I have ever seen does it, and its the industry standard. In order to do this, you also need a fuel pump that can support the fuel demand, and in this car, the usual Walbro 255 lph pump (part # GGS342 does not make pass the muster).

With this setup, you then use the E Manage to fine tune the curve to suit the particular needs of the engine. last I checked the Emanage does not have its own injector drivers. So it is simply adding or subtracting IPW by manipulation of the MAF or MAP sensor - same as every other piggyback does. teh Emanage is a superior unit to the HKS SAFR or the Apexi SAFC2 maninly because of the resolution it has in this regard. It's other benefits are the ability to adjust timing as well, among some other things. But as for how it goes about adding or taking away fuel, it does it no differently than any other piggyback

I think you guys are confusing what I mean by a RRFPR with the ones sold by Vortec, etc which are more than a linear rise in fuel, but rather an exponential rise in fuel. These regulaors are "old school" in their approach, and are generally tuned to add between 2 and 8 psi of fuel for every psi of boost they see - this worked well engouh in the old days, but stock engine mgmt tends to freak out when it sees such sjy high fuel pressures (ie a 4:1 RRFPR on a Z that has 6 psi means the car sees 76 psi under boost - that is retard amounts of fuel pressure, and will certainly wreak havoc on injector seals in the long run).

I think the first thing you guys need to do is have the stock injectors tested at 53 psi (the abse pressure the Z runs at). I know its been said they are 290 cc - but was that at 43.5 psi (the industry norm for rating and testing), or at 53 psi (what the car actually runs at idle).

 

Max,
My Walbro doesn't pump any gas at all when installed but the stock pump still does once I put it back in. I already have another pump being shipped two day, so It should be running by the weekend hopefully.

As far as the OBD2 it is a fairly new law here and it sucks b/c it's pretty strict. Thats weird that cali doesn't do this so I would be prepaired for incase they do any time soon. I will find the solution once I get some time.

MIKE

 

Z1....i disagree with this statement on a couple of different fronts.....

First, the eManage does NOT increase fuel with MAF coinditioning. It is not tricking the ECU by altering an incoming MAF signal. It is actually adding IWP by tapping the injector signal wires and adding pulse-width to the stock ECU signal. It is not touching the MAF signal at all to enrich fuel. This is about as accurate as you can get without going full stand alone.

Second, I still feel a stable, yet HIGHER fuel pressure level is the best way to tune. Think about it. We are probably almost saying the same thing. For instance, if the stock psi is 50, and we run 8psi of boost, with your formula, we'd gradually add 8psi of fuel pressure which gets us to 58psi of total fuel pressure. I dont like this method becuase you are enriching fuel via fuelpressure changes, instead of increasing IPW. With my strategy, we keep a constant 58psi on the rail, and then lean out the entire map to get to the equivalent fuel of 50psi (but the pressure still remains at 58psi), and then I would add IWP as the boost increases. This is the more accurate approach to fuel mangement...in my opinion.

I guess we can agree to disagree......

 

I got you on the E Manage..but how is it adding pulse if it does not have drivers? How does it do it?

As for the pressure.I suppose for a relatively low boost setup this could work. Problem is it becomes a tuning nightmare, as you have so many more adjustments to make (such as no load conditions, where you'll have higher base fp but still ahev to make big changes to IPW. Does it work? I suppose it could be made to - I have never seen nor heard of it done this way on any car though, so would be interesting to see in practice.

 

It has drivers...for both injectors and timing. Remember, there is a seperate harness for injectors which taps the stock ECU injector wires, and another harness for timing which taps the stock ingition wires.I dont know exactly what happens in that box....but it does it. It can even display the factory pulse width, and the total pulse width (factory plus the added IPW).

The eManage is very powerful, accurate, and capable. There are folks running Supras with eManage and putting down close to 800whp.

 

Z1 is right on this one. What you are missing is that the rise in pressure 1 for 1 only equals out the change in differental pressure across the injector. So it's not there to "add fuel" but to maintain a ratio of pressure.

If you don't add this 1 for 1 as boost rises it's like the fuel pressure is going lower compared to manifold pressure. Thus each pulse supplies less fuel for the same given duration. Thats one of the reasons even with the 440's we run out of fuel at such low power levels with the stock fuel system.
Gary

 

Gary - you wrote it better than I did..thanks

gq - thats pretty neat then I have one coming for my car, so it likely will get put to good use...I have a whole host of brand new stuff going into my car in the coming weeks...all in the name of NA goodness, though i am out to set some records if I can

 

Thanks Mike,

I will see how yours does. My A/F is 11.5 to 12.1 on the Dyno Jet at the tail pipe.

The car gremlins sure have been hitting you hard lately. I went through that, hang in there man and it will all be perfect.

Max

 

hmmm...maybe i dont understand what is happening in that manifold. But I thought the fuel pressure ends at the nozzle of the injector, and that manifold pressure would have no effect on net fuel pressure.

I would still...obvisouly..need to add additional pulse width as the boost increases. I just see more of the rising rate stuff on cars using stockish sized injectors.

 

GQ,
The manifold pressure does have an effect. The compressed air is putting an opposing force on the nozzles, putting more pressure on the fuel that is trying to come out of them. This means you would have to add fuel pressure to match, or overcome a higher manifold pressure. You can still maintain a constant net fuel pressure, but you still add fuel pressure under boost so the difference is 58 psi.

Also, your strategy sounds good. The only tough part is keeping the pressure at a constant 58 psi.

I have the dfmu and under part load my car will sometimes see 80 psi. A lot of pressure you say...yes, but at WOT that 80 psi will drop to around 60 psi, keeping my A/F at around 12:1.

I think you are still going to have to rely somewhat on fuel pressures because I don't think the IPW is going to be able to supply the amount needed under full boost.

I would like to see how it all works out though since I will be getting my e-manage shortly. Keep me informed.

 

actually, pulsewidth inherently should DECREASE as rpm's increase.... cannot see how you would ever get enough pulsewidth out of your injectors (unless they are HUGE) to ever tune the car the way you are intending to.

Also gq, regarding the 1:1 rising rate regulators, we left something important out! The regulator is used to increase line pressure as boost presents itself. However, the difference in pressure between the rails and the engine stays the same. This is how the actual amount of fuel injected into the engine per injector pulse (measured in milliseconds), stays the same, no matter how much manifold pressure there is, and regardless of what rpm you are at.

pulsewidth needs to be at its longest at the torque peak, which tends to occur midway throught he rev range

 

Thanks Max. Yeah things sure have sucked lately but I can see it coming to an end soon. Should be able to post some results this weekend I hope.
MIKE

 

Max/Mike,
I spoke to Danny (at TS) yesterday about adding a pump and a new flash to my car since I am increasing the boost with a 9lb pulley. He said it was not necessary to do either. He said to keep the stock pump and run a fuel regulator like sard or areomotive. Areomotive regs can be had for $130 on Summit's website. Max this might be an option for you if you ever want to increase the boost.

 

Whosdaddy,
Dump the stock pump for Walbro 255. The stock pump will loose pressure after 5600rpms for sure and the regulator won't be able to boost pressure. The pump is cheap, about $90. It fits really good after shaving the plastic bottom off and is easy to install.
MIKE