after being told and told and told to upgrade my fuel pump I went ahead and did it. Let me tell you (anyone listening) if you are using Nitrous and don't have an upgraded Fuel Pump, then you are just not using the right equipment. I took it on its first ride with TOOLROCKS in the car, and that engine just came to life when the WOT switch turned on.

My only questions are,
1. My pressure boosts about 97-90psi. is this normal?
2. the power feels like it surges in higher RPMS.

 

Your optimal fuel pressure depends on how many shots you are spraying. What size jet(s) are you using & what is your bottle pressure?

A surging sensation means uneven nitrous pressure or fuel pressure. Again, what is your bottle pressure? A half filled bottle could cause the surging feeling. A clogged nitrous filter could cause the same. On a side note, it took a few days to break in my Walbro pump. When it was first installed, fuel pressure wasn't consistant until after a few days of driving. I dunno if others had the same problem.

 

90+ psi is way rich, it's over what you should have for 100 shot. What shot are you running btw? What is your N/A fuel pressure at regular driving and also at WOT?

 

WOT N/A is around 48-50 and cruising is around 36-38.

I had about 850-900 psi. I don't have a bottle heater and it was cold out side maybe the loss of overall pressure and the bottle cooling due to the ambient temps? I would like to think that its the fuel pump breaking in. I did notice that the pressure N/A wouldn't rise evenly it would go up then suddenly it would peak at the 48 psi.

I'm currently running the Kit#5124 70shot with the alike vacuum bypass jet. I'm wondering if I could just not run the vacuum booster for the dry manifold.

Thanks guys.

Andrew- do you think I could heat my bottle with your heater for tomorrow after you test?

 

70 shot I believe is the .036 jet, are you using the .042 jet for the fuel bypass jet?

Regardless of the factors involved, 90 psi is way too high for your current setup but your slightly elevated N/A pressure readings seem consistent with N/A readings w/ the Walboro fuel pump. I'm not an expert on this matter yet, but I believe that people get an aftermarket fuel pressure regulator such as the SARD model to adjust accordingly.

As for tomorrow, you're welcome to use it. Steve is going to help me install my fuel pressure gauge after my runs so I'll be there after. There isnt much slack in the wiring, so either I can take my bottle out or you can just kind of hold your bottle slightly above mine. I hope you have a bottle mount nitrous pressure gauge, the heater I have doesnt have the thermostat and it gets hot fast.

See you tomorrow.

 

Also, have you zip-tied or clamped all your vacuum hoses? That surging in power is usually related to a vacuum leak. Make SURE all vacuum ends are zip-tied or clamped.....

 

yes they are zip tied. One of the vacuum hoses is twisted a little but not occluded. the bottle was pretty light coming out of the brackets yesterday so I think it may be the excessive hight Fuel pressure and low n2o pressure?

 

I dynod and my a/f mixture is off the chart rich so I'm assuming its the fuel press regulator thats my problem.

I dynod 228fwhp and 282lb tq.
70 shot w/ 700lbs of psi

 

Time for the 100 shot