graebz28

iTrader: (5)

Getting very very close now. Just a few more hours and I'll be ready to begin initial break in. Hopefully everything breaks in and does not break out.

Got an xtreme 50mm, 90# inj and a top down solution AFPR from a long time ago that never made it in the 305. Should I use the spring that came with the new injectors ..... I think set at 13 psi.

or

TDS spring: Application: Top-Down Solutions tested the stock spring (orange in color) that comes with the GM 17113186 vacuum adjustable fuel pressure regulator (used on GM TBI equipped engines) and found the spring rate was too high. We were unable to adjust the fuel pressure below 18 psi at WOT (Wide-Open Throttle). Swapping this spring for the stock spring (tan in color) that came in the non-adjustable fuel pressure regulator wasn’t acceptable either. This spring was found to be too low of a spring rate. We were unable to adjust this spring beyond 13 psi at WOT. This aftermarket spring is an ideal solution, It is rated at 15.5 lbs/in. and will give you an adjustment range from 12 psi to 20 psi at WOT. The spring is zinc plated to provide years of corrosion protection.


I got the excel spreadsheet from RBob, but hel if I know what the hp is going to be. A quick search just now says about 394. I am thinking 375 to be conservative.

thomas1976

Souds like its going to be a fun car

According to the excel, 17-18psi, sounds like a good start point. TDS spring a must.

If then DC% happens to be to high or to low, its preatty quckly adjusted with AFPR and EBL.

BronYrAur

iTrader: (1)

err on the high side for pressure, be conservative by having too much pressure not too little. I'd probably go right for 20psi, that's a 71.54 BPW and should give you room. You always want to be higher than what you NEED, with AE additions and PE you can easily go over what your engine is "supposed" to require.

graebz28

iTrader: (5)

Thanks! I'll see what the max pressure is that I get out of the AFPR and shoot for a few #s less than that. Somewhere around 18?

A 350 @ 20psi gives me BPC of 75?!? 22 = 71 My cells are locked to integer precision.