I finally got my ALDL to RS-232 cable put together and hooked it up to my laptop and monitered my car with Craig Moates software.

I was noticing that with the Paxton on my 305 LB9 my car did not really feel any faster.. maybe even slower. There was good increased throttle response down low, but up high it fell on it's face. I figured I was starved for fuel up high because I have 100K 19lb injectors in my car. So, I bought some LT1 24 lb injectors and they should be here tommorow or the day after, i'll put them in as soon as I get them.

I also bought a new NOS inline fuel pump in case my pump couldn't supply the fuel. It should get to me by the end of the week. I don't know if my FP is dropping because I don't have a guage, i'll order one soon. I also bought a CRANE HI-6 w/ timing retard (also has rev-limiter) so I could adjust my timing inside the car to dial in the correct timing and keep my car under 4800 rpms so to not destroy my paxton. That will be here soon too I hope.

I figured that with a blower, tuning is everything, so I started to read up on eprom burning, and am getting myself ready. The first step was to get some kind of scanner for my car. So I made an ALDL cable, got a laptop, and scanned my car for the first time tonight.


On my car basically stock (just a cat-back and free mods) I ran a 9.7 in the 1/8th with a 2.4 second 60ft about a month ago. I think if I got my 60ft to a 2.1-2.2 I would be much faster, i just suck at driving and need to work on my launches. So my car wasn't super slow before I put the blower on.

The first thing I noticed was how many knock counts were showing. Before I got out of my driveway, I already had one count. By the time I had gone 1/2 a mile I had 4 (driving slowly). By the time I was done w/ my 15 min "test", I had over 50. But I wasn't showing any timing retard?!

The second thing I noticed was how rich I was running. I was pretty much always at 14.7 air/fuel ratio. I also have been noticing a very distinct gas smell when I let the car idle.

I also noticed that when I floored it, it only showed 60% throttle?! I took my NOS throttle body plate off and left the linkage moved forward, maybe that is not letting my throttle body blades open all the way. I'll check that.

There was also a lot of other things that didn't look good, but I don't have a spreadsheet program installed right now so it's hard to interpret the data. I'll post some more as soon as I can look at the date better. What other things should I look for when I am looking through my data? I have a feeling that either I am throwing some false knock or that my 305 is almost dead. I think the latter might be the case. Maybe I'll have a mechanic look at it? Maybe I'll go buy a shortblock 350 and start building.

Any suggestions on what to do? I am going to run my car tommorow on the scanner with the s/c off and see what happens. I'll post more data when I get it.



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1989 GTA w/ 305 LB9 w/ T5 - Stock TPI/LB9 w/ iron manifolds, Paxton SN2000, N.O.S. Throttle Body Plate Kit, Eibach Pro-Kit, bunch of other little stuff.

 

I would venture to guess that you're falling flat on the top end because of fuel pressure. Do you have a stock in-tank pump? Install the in-line fuel pump first. It's strongly advisable to get a fuel pressure gauge too because you really need to know that you're supplying adequate pressure at WOT, not just for testing purposes, but ALL the time.

Don't waste your time (at least initially) installing the larger injectors, especially on a near-stock 305 even with a blower on it. To date, I still use 19# injectors and there is nothing stock about my 305. Record O2 values at WOT after installing the in-line pump and get some baseline figures. Then adjust fuel pressure as needed. Larger injectors are necessary only if you've exceeded 85 percent duty cycle after bumping up the fuel pressure to ~54 psig AND the O2 readings are on the lean side (i.e. 800mV or lower).

------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig): 12.57 @ 111 mph.
Former Paxton (6-psig) & former 50-hp nitrous: 12.04 @ 114 mph.
ATI D1SC (5-psig):
12.26 @ 113.55 mph
ATI D1SC (10-psig): Projecting high 11's.
Future ATI D1SC (15-psig): Gotta catch them pesky 26-psig boosted TTA's!!

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

[This message has been edited by Willie (edited June 13, 2001).]

 

I agree with Willie! From experience, my Z28 did the same thing as you car is doing.....fallig flat on its face above 3500rpm's! Once i installed the aux. fuel pump, it made all of the difference in the world! Before i installed the aux.fuel pump, I too added the ford svo 24lb injectors thinking this would solve the fuel problem.....wrong! I think they are a needed component, However, The stock fuel pump does not have enough UPMH! for the needs of a supercharger. Once you put the aux. fuel pump and 24lb injectors, you may beleive me and willie. Take it from me and my exp......my sypmtoms were the same as yours and since i added these components, my car runs awsome! I would like to know how much all of the DIY prom kit cost?

 

I just looked up results on a spreadsheet. It said over 100 degrees of timing retard at 4000 rpm sometimes, no wonder my car is slow.

I have a bunch of problems.. too rich (always 14.7), 02 readings seem erratic sometimes, idle is erratic, TPS sensor voltage isn't the same as actual tps voltage.

I got the fuel pump today, so I am going to try to install it tonight (I have work tommorow so that might not be the greatest idea, but I'll try anyway). It came w/ 2 relays and wiring and some rubber hose as well as some fittings. So I don't have to hunt down any parts.

 

Well, I think I am going to sell the paxton. I found thirdgen w/ a T56, new L98 w/ edel headers, hotchkis springs, new interior and a straight body.. that I want. It comes w/ a superram, edelbrock lower, bbk tb, injectors and some other stuff too. I think I am going to get that one, get it dialed in w/ superram and then put a 150 shot, sfc's, stb, bushings, lca's, konis, and a rollcage on it (already have NOS 5151 and alston sfc's and stb).. and see if I can run 11's.