"vacuum gauge" to balance stacks?

[kobrabytes]

How large of bore do they work with?

[RICK LAKE]

kobrabytes Len I am running alpha-n on my car since the 482 is in the car. My laptop battery crapped out and kill my laptop. I only have a sloppy disc right now and no way to transfer it to anything. The other thing is every motor is different and my custom setup will not help you at this time. I am running 50 pound injectors with 52 psi fuel pressures. At WOT my duty cycle is 61%. Idle pressure is 44 psi fuel. Fred Kemmer may be able it shoot you a copy of his setup. He's running XFI and 58mm's. May computer in the car is an old Speed-Pro, about 10 years old. Rick L.

[kobrabytes]

Originally Posted by RICK LAKE

kobrabytes Len I am running alpha-n on my car since the 482 is in the car. My laptop battery crapped out and kill my laptop. I only have a sloppy disc right now and no way to transfer it to anything. The other thing is every motor is different and my custom setup will not help you at this time. I am running 50 pound injectors with 52 psi fuel pressures. At WOT my duty cycle is 61%. Idle pressure is 44 psi fuel. Fred Kemmer may be able it shoot you a copy of his setup. He's running XFI and 58mm's. May computer in the car is an old Speed-Pro, about 10 years old. Rick L.

Totally understood. I'm just trying to get a feel for the graphs.

I've got my alpha N set up pretty linear right now. I need to add fuel more mid rage TPS and RPMs to eliminate the hesitation. I'm also trying to get the car on a dyno.

How do I reach Fred?

len

[fkemmerer]

Originally Posted by kobrabytes

Totally understood. I'm just trying to get a feel for the graphs.

I've got my alpha N set up pretty linear right now. I need to add fuel more mid rage TPS and RPMs to eliminate the hesitation. I'm also trying to get the car on a dyno.

How do I reach Fred?

len

Len,

Hi. I am on this forum as Rick indicated in his post. I'm curious why you went to alpha-N vs. sticking with speed-density and solving your problems another way. Alpha-N is great on the drag strip where you run the motor at 2 setting - idle and WOT but its usually not the best choice (or necessary) for the street.

- Fred

[kobrabytes]

Originally Posted by fkemmerer

Len,

Hi. I am on this forum as Rick indicated in his post. I'm curious why you went to alpha-N vs. sticking with speed-density and solving your problems another way. Alpha-N is great on the drag strip where you run the motor at 2 setting - idle and WOT but its usually not the best choice (or necessary) for the street.

- Fred

HI Fred,

In speed density the map sensor doesn't deal well with the low vacuum that I get off the TWM set up, around 6lbs at idle. The idle in SD mode was very eradic, the cursor never sat in a single cell. We even tried buffering the vacuum to no avail. Even with the throttle fully closed the computer would tell me that I was at 60% and always dump in fuel, lots of back fire on deceleration. Plugs continuously fouled. Here in SLC we are at a base altitude of 4500ft, I do drives up to and over 10k ft. Each trip was a guarantee to Checker that I'd be by for new plugs.

FAST says not to use speed density with less than 10 lbs of vacuum.

Currently I have the car running much better in Alpha N than it ever did in SD mode. No backfire and the idle is rock solid. Plugs stopped fouling.

I don't understand what you mean about two step? Idle is tuned really nicely on the first row. I have 15 other rows to define cruse and power...

[fkemmerer]

Len,

It your car is running better in Alpha-N mode, then by all means use it. Alpha-N has somewhat less adaptability to changes in barometric pressure and air temperature than a speed density setup would. The other tricky part of tuning with Alpha-N has to do will the large throttle blade area of most stack EFI setups. In many cases, the throttle bodies will reach maximum air flow at only part open settings below 3,000 RPM. This means that your pulse widths will reach their max values at TPS openings of 70-80% in the lower RPM ranges.

What is your camshaft like?

- Fred

[kobrabytes]

Cam 248/252 at 50 and 112 degree lobe separation.

[Cobra #3170]

Originally Posted by RICK LAKE

kobrabytes Len I am running alpha-n on my car since the 482 is in the car. My laptop battery crapped out and kill my laptop. I only have a sloppy disc right now and no way to transfer it to anything. The other thing is every motor is different and my custom setup will not help you at this time. I am running 50 pound injectors with 52 psi fuel pressures. At WOT my duty cycle is 61%. Idle pressure is 44 psi fuel. Fred Kemmer may be able it shoot you a copy of his setup. He's running XFI and 58mm's. May computer in the car is an old Speed-Pro, about 10 years old. Rick L.

Rick,
why is your idle pressure lower than WOT pressure? My regulator holds pressure at the same level throughout the load range. Do you have lower alternator voltage at idle?
I am running 65# injectors at 45 psi with a Bosch inline pump fed by a Carter electric and the pressure stays at 45 psi no matter what I do with load. I have a Denzo 65 amp 3 wire feeding a 6AL, electric water pump, FAST Sequential EFI, both pumps, PI data logger and a 16" electric fan so fairly large electrical load. I also use Alpha N because cam overlap does not allow
use of the MAP sensor.