Using Super AFC type of add on computer or using a fuel pressure regulator? If via regulator, should have by-pass the stock regulator all together or run it inline?

 

Well the only true way to adjust fuel pressure is with an Adj. FPR. The AFC's ony adjust injector pulse width. But I know what you are trying to do. I would say that if you are staying with the stock fuel pump that the AFC would be the best way. At ~200 the Fields Fuel controller is a bargin.

I did the Adj FPR thing, I removed the factory FPR and ran to a Paxton universal FPR. I had to do this because the fuel pump I run was way too strong for the factory regulator to control. I had to lower the pressure! Total cost ~200 for the fitting and regulatorw/adapters and hose.

If you just want to increase the pressure a few points than you can just install the Adj FPR after the factory regulator. You would remove the vacume line from the factory FPR and attach it to the Adj.FPR.




With either of these you should do some dyno time witha wide band O2 sensor to get it optomized.

[Edited by MardiGrasMax on 12-01-2000 at 09:48 AM]

 

Thanks for the info Matt. I can't wait until I get all these details work out and start on the Direct Port kit. Do you think the factory pump will able to provide enough fuel flow for me? Are most of the adjustable fuel pressure regulator the same? Any major differences I should look for?


[Edited by 1MAX2NV on 12-01-2000 at 10:43 AM]

 

The stock fuel pump should be ok with the direct port kit up to about 50hp, I would recomend a pump upgrade for saftey sake with any NOS aplication, its cheep insurance. As long as you dont want to increase the fuel pressure to ultra high levels like ~80psi (dry nos) a 190lph pump would work just fine and it should be compatable with the stock FPR. The direct port kit should be set up to operate at the stock fuel pressure level of 43psi @WOT. I have to run ~80psi for a 100hp "dry" shot so I need a strong high pressure pump. I have a 255lph "high pressure pump, Walbro GSS342, it fit just like the factory pump, cool! I dont know the part number for the 190lph pump put who ever you order it from should be able to cross it over from my GSS342. You will need a new gas tank gasket from Nissan.

You can get the pumps from here
http://www.forcedperformance.net/
or here
http://members.home.com/syclone/APE/...mp.html#fp_faq This site has good info on them! It shows "kit numbers as part numbers. you dont need a kit, just the pump because it fits perfectly with the factory hardware.

As far as regulator go... I really dont know that much about them. The Paxton and the SX regulators are the same darn thing. Their are others, but they get more expensive. Basically you need one that can handle the 43psi range and has a vacume reference port. Be sure you order a fitting kit with the regulator so you can plumb it correctly. I ordered the Paxton kit that allowed me to plumb to 5/8 fuel line.

Gladd to help!

 

Just to make sure I got this right.

1. With a dry kit like yours, the extra fuel are added by increaing fuel pressure. The higher the fuel pressure. The more fuel the stock injectors will flow. The more nitrous you use, the higher the fuel pressure needed ~80psi.

2. With a direct port, since it has it's own fuel jets. As long as I can keep a WOT of 43psi, the fuel jets can provide the needed fuel. Even if I increase my fuel pressure via regulator, it's still going to flow the same amount =). If FP drops below 43 at WOT, I'll need a bigger fuel pump. I don't need a regulator because it will just confuse the stock injectors and I will end up running too rich.

 

<img src = "http://www.overboost.com/images/297/full/DSCN2369.jpg">

 

1) yep! The higher you can get the fuel pressure on a dry kit the more NOS you can run. Example, for ~40hp NOS ~55psi of fuel is needed. For 100hp NOS ~87.5 psi of fuel. I'm still working on the 100 shot but thats pretty close on the FP.

2) yep! as long as you can maintain the 43psi when you engage the NOS you are cool. Their are jets that go into the fuel side of the fogger nozzle that you will use to fine tune the system to your desired HP level.

2A)"Even if I increase my fuel pressure via regulator, it's still going to flow the same amount =). "

Nope, it will flow more.

2B)"I don't need a regulator because it will just confuse the stock injectors and I will end up running too rich."

If you tune the wet kit correctly you should not need an Adj FPR. However if you do use an Adj FPR, this is what the wide band O2 sensor and dyno tuning is for. At WOT the extra fuel pressure can not be compensated for by the ECU because it is in closed loop mode using the pre programed fuel map, it may cause a rich condition. You can tune it (adjust the pressure) using the dyno and wide band O2 to get it just right. Under part throttle open loop mode the ECU will use the factory O2 sensors readings to adjust the fuel injector pulse with to compensate for a rich condition caused by a higher rate of fuel flow due to the higher fuel pressure.

Hope that helps!

 

I spoke to you earlier by email dealing with info about your Walbro fuel pump. From the link you gave I guess I'll just have to call Forced Performance directly hoping they'll be able to get the Walbro pump. Now for the Jun regulator off fitting, no go on that part. Would you happen to know of a company I can call directly that might be able to help. And for the adj fuel press reg. I've seen
a Paxton unit like the one you have in the Summit Racing catalog

 

Jun cant order the fitting for you? Hmmm

If you want to bring the FP up you can plumb in after the factory regulator like I discribed above. You could use the Paxton Adj.FPR, I got mine from summit!

Forced Performance can get the pump, give them a call.