Paging 'Mike Comp T/A #57' /NOS Dry kit Q

Hi there,

I see some of you run the 5176 NOS kit with very much succes, especially Mike with his mostly stock engine T/A and high 10' ETs :)
I now there was a change in the 5176 kit some time ago, they changed the bypass jet from 42 to 59.
My question is, did the 'old' 5176 kits come without the inline pump, or why had they 42 fuel jets?
If so, I have a 5115 kit which is like the 5176, only without the inline pump.
I am using 59N/46F jets, and it nets me about 100rwhp. Can I spray a bit more with my stock fuel system? I would really like to go with the 67 jet :)
Thanks in advance for your input!

My #5176 came with the 67N and 42F jets along with the inline fuel pump.

So I HAVE to run an inline booster pump with the 67 jet...
Ok, thanks again!

Mike do you have some pics or kind of explain how you installed the inline pump and where? I bought the pump off of a board member w/o instructions. I am running a wet kit and want some insurance that stock pump can keep up. It looks like you would hook it up to the fuel filter. LMK thanks Clint

Not Mike (wish I had his 10-sec time slip :D ).... but I have the NOS install instructions, for both the fuel piping and the electrical. I can fax them to you if you want.

I would appreciate that Fred. 337-988-8410 is my fax#. Thanks Later Clint

Hi,

Now, that Fred and Mike, aka the dry kit specialist are here, :D I would like to ask the following form you guys:
Let's say I'll change my intank fuel pump to a Walbro or Racetronix pump, which has like 255lph or so. Does it "boost" the fuel pressure like the booster pump in the 5176 kit? So, with that, do I have to change my bypass jetting?
Also, if I do heads/cam to my LT1, do I have to play with the bypass jetting, since more fuel is going to the injectors?
I don't really get this, and I'm afraid I can't use my dry kit after doing heads/cam.

Thanks!

The 5176 kit raises fuel pressure to increase flow through the injectors. When I bought my kit originally, it was simply quoted as "120-130HP and 160-170 ft-lb". It had an 0.067 nitrous jet, and nothing in the line to the fuel pressure regulator. The design of the kit was based on doubling the stock fuel pressure, to about 85psi, which nets you 40% extra fuel flow to match 40% extra HP.

To achieve this, you need a fuel system that can flow about 220 #/HR = ~36 Gal/HR = ~ 135 L/Hr. The key is, the system not only has to flow 135 LPH.... it has to be able to do it at 85 PSI. In general, a pump has a flow vs. pressure curve, and as system pressure goes up, the flow goes down. Apparently, the stock pump won't flow 135 LPH at 85 PSI, so NOS added a booster pump.

Therefore, for a stock setup, to run only a single in-tank pump, and no inline booster pump, you need to check the curve for your replacement pump to insure it will flow the required LPH at 85 PSI. Simply saying you are using a 255 LPH pump isn't enough info, because that is probably the pumps rating at 43.5 PSI. You need to get more into from the manufacturer.

And, all the "jet" sizes for fuel are based on the assumption you are running the 5176 kit on a stock engine, with stock flow rated injectors. If you increase your NA HP output over stock, or change to a different injector size, you need to refigure the fuel jet sizes. Not sure exactly how you do it, since I bought the "adjustable" fuel jet "kit" from NOS, but never really used it.

Fuel pressure is controlled by the fuel pressure regulator, so if you simply go to a larger capacity pump on a stock engine, you don't have to change any jets. The FPR should still produce roughly the same fuel system pressure when you are spraying.

Not swure if that helps or confuses.......

Thanks Fred. What do you think of my stock intank pump + this NOS pump for my fuels system. I plan on spraying a 200 wet shot next year. I currently run a 125 shot and it works fine. LMK Later Clint.

Fred, thanks for this detailed writeup!
I think I'll stick to the 100 shot. There will be some testing and tuning with the heads/cam combo, I will definiately post my results as soon as I'll have some good jetting setup.
Thanks again!