View Full Version : Direct Port DynoToday (544/540 on 150-shot)

04-27-2003, 09:10 PM
OBTW, this setup can be yours for $2500 (see classifieds)

Red graph is motor pull and blue graph is 150-shot pull (155/175 gain with 12:1 a/f ratio).

04-28-2003, 12:05 AM
Do you still have the TH350 in the car, those are some good #'s...:)

04-28-2003, 08:21 AM
Do you still have the TH350 in the car, those are some good #'s...:)

Hey Bos...TH350 is gone. This was through an MN6 with stock rear (3.42s).


04-28-2003, 10:43 AM
Thats one hell of a lean spike around 3600.

Sure is...Reckless, did you purge the fuel side before you made these runs??


04-28-2003, 11:02 AM
Yeah I noticed that too. Did not purge the fuel. What is a good way to do that? Other than arming with the bottle closed and flooring the car.

The fuel system/pump is already running when I hit it. It has a built in return to keep the pressure up. But it takes a secong to load into the rails. I don't know if there is a good way to load the rails without the vacuum from the motor pulling the fuel out of the rails :(

04-28-2003, 11:29 AM
I would think the motor would suck the fuel in. One solution could be to run fuel solenoids directly off the rails that way you don't have the 12-18" of lines and the long fuel rails to fill up before it starts going. You could probably leave the nitrous side the way it is now and things might click together at the right time then (or at least closer than they do now).

04-28-2003, 11:52 AM
This is a main reason why I stepped out of the nitrous world, but even now that I'm in the F.I. world, I'm still having issues, even built motors can be destroyed off of spikes like that...hes got enough fuel, its just all in the setup...:)

04-28-2003, 02:07 PM
I don't know if there is a good way to load the rails without the vacuum from the motor pulling the fuel out of the rails :(

I know that MagnaFlow just came out with a fuel line bleeder that will bleed the air out of the line up to the fuel solenoid. The best way to feed a rail is from both ends. Remember that a Fogger fuel pump is only about 19-25 psi.

04-28-2003, 02:19 PM
Reckless....yes, with the car off and the system armed, you can activate the kit for a split second with the bottle closed. Also, right before the line goes into the fuel solinoids, you can install a T fitting with a bleeder in it, or a very small jet. Does your fuel system come on when the kit is "armed", or when its actually activated?


04-28-2003, 04:52 PM

Heres my NA graph ;) No nitrous, no power adder, Same spike. Its because the Exhaust from the car before the pull is still in the copper tubing, Do the pull, and its taking readings from the old exhaust before the fresh stuff makes it to the WB. Use the WB in the actual collector, and it will be gone.


04-28-2003, 05:13 PM
Chris...the fuel system starts pumping when the system is armed. Fuel should be up to the noid while armed. But it is at such low pressure right now. I had to back it down to 6.5psi to get to 12:1 afr.

Maybe I should jet down on the fuel and run a higher pressure?

Louis...we were using a tailpipe sniffer on the dyno, but old exhaust? Are you sure you haven't been sniffing some exhaust yourself? :D

If this is true, why is there no lean spike on my NA pull?

04-28-2003, 05:26 PM
OK, I know its not easy to understand over the net, find me at the NvS, and Ill explain ;)

If you decel before a pull, say-go up to 4k in 4th, and then decel to 3k, then begin the pull- what happens is that the lean exhaust from decel ( Read: OLD EXHAUST :p) is just gettting to the WB when your pull begins- thats where the spike comes from. The WB through a tail pipe will allways be behind a few hundred rpms due to the fact that it takes time for the exhaust to travel from the tailpipe to the WB.

PM Me your # and Ill explain it a little better in person if need be :usa:


Chicago Z06
04-29-2003, 02:23 PM
another reason for the spike is the NOS which operates at a higher pressure actually hits the cyl first for a brief half second or so. this is why some of the big NOS users actually shorten the length of the lines from the solenoid outlet on the fuel side to the nozzle as opposed to the NOS side. this will minimize the lean spike. again it is all in the setup. Most dry systems are prone to this unless DFI, FAST, etc activated.