Mar 2004: I just attended a Dyno day with the Baysho group yesterday and had a chance to sit down for about 75 minutes to do some tuning on my car. The rest of the group was doing 3 pulls for $50 (with A/F monitoring). I learned some very cool stuff about my car and the software and the tuning time allowed me to get a good level of additional performance as well as get the curve for my 80mm MAF to something a lot more correct than I got on the original mail-order chip.

First, mods on the engine so people have an idea of what I'm doing.

I have a 3.2L block; internals from an ATX inside of a bored-out 3.0L engine with 3.0L heads that had new seals, guides, and valve springs put on them when it was rebuilt (~20k ago). No performance porting or anything. I also machined out the fuel rails and dropped in a set of Ford Motorsports 30lb injectors.

I was after top-end power so I dropped a set of Sho Shop's stage II cams into the motor and installed ShoNut's adjustable cam sprockets. They're setup up with 3 degrees of overlap reduction (exhaust advanced vs. 0 timing) and the baseline runs had 2 degrees of overall timing retard (I believe his markings are in cam degrees but I may be wrong). The intake manifold has been extrude honed and port-matched to the heads and to the surge tanks. I had a writeup about this earlier -- I was surprised how much material needed to be removed from the surge tanks to mate to the long runners. I have Sho Shop big-bore butterflies installed as well.

The exhaust is a standard cat-equipped Sho-Shop Y pipe (old style), modified for a 3" catback, which consists of one 4" Dynomax bullet muffler and one enormous 5x11x22" SS Magnaflow in the tail.

The intake has stock airbox with the outer removed and a 4" PVC pipe to the fender well and a 80mm MAF (in some runs) and a K&N (in some runs).

The engine runs pretty well but has suffered the same fate my other engines have though I'm not sure if it's for the same reason. I'm burning about a quart of oil every 500 miles, no matter what my driving style. I haven't checked the compression, so I can't assume it's a little on the low side, though it probably is.

I have my own tuning software that I developed from some documents I found online vs. the original code in the chip. I have a LPM with a removable 32-pin DIP byte-wide EPROM/flash/EEPROM, which makes do-it-yourself tuning possible (vs. the black Autologic plastic modules which one of the other SHO attendees had).

The first thing to do was to make sure that my fuel injector setting was right. I installed the 55mm factory MAF and made a LPM program with the larger injector value (300cc/min) and the stock MAF curve. This would give me a baseline A/F curve to compare against what the computer was programmed to give.

First two runs were this way (first run on a lot people's dynos seems to be a little low -- not sure why):

We strapped the car on the dyno:

Then we ran it:

The A/F ratio was basically about what the factory computer was programmed for (11.4 @ 6800 RPM). I was pretty sure that the 300cc injector sizing was about right. Next order of business was to attach the 80mm MAF and optimize the curve in the LPM.

When I first got the chip the car didn't really run that well and seemed to learn some pretty wierd habits. A simple voltmeter-on-O2-sensor-lead test showed it was pretty lean at WOT, so I added MAF in the LPM until I got something that felt better. My last dyno (Nov 2002) was all based off of this type of tuning, and yielded 233whp (no EH intake at the time, and a 2.5" exhaust -- cam timing was the same).

The 80mm MAF is on now, though you can't really tell that well in this pic (I only took video and don't have any stills):

This chart has the first two passes with the bigger meter. The first pass was pretty lean so I upped the MAF curve for the second pass and it's now fairly close to correct, at least for relatively high flows.

It's hard to tell exactly how close it is to the right curve on the bottom end. Here's the 55mm MAF vs. the mostly-optimized 80mm MAF. You can see a 7-8HP gain.

At this point the MAF curve is pretty close. I actually put in another 3% (~0.4pt difference), then made a run with the secondaries opening at 3800 RPM vs. 4150 RPM, and pulled a little bit of spark out on the bottom end as I was getting a little bit of pinging (not really evident in the dyno charts). I also changed the commanded A/F ratio to lean out the mixture on the top end a little bit (not much).

The 3800 RPM opening is obviously too early. Where I had it before was pretty close to correct. I then tried a program with a 13.2:1 or so A/F from 4000 RPM and up. The secondary runners went back to 4150 RPM.

Not much difference there. I decided I'd try adding 4 degrees of spark advance to see if there was anything to be gained. This was 4 degrees on anything over 3650 RPM. In retrospect I probably should have tried this on the richer mixture. It may have showed some gain there though probably not. I zoomed in on the torque curve for this one since that's where you'd see anything (if there were anything to see).

I think I'm about done with computer tweaking. I pulled the spark back out (back to dynorun10's settings), and dropped in a K&N panel -- had a Purolater filter on up to this point (I was trying to break 250):

1.5hp gain, which is within the dyno accuracy (the A/F curve varies a bit between runs, perhaps due to the computer adding fuel for coolant or air temp changes). FWIW, the paper one is going back in since I'm tired of cleaning the MAF. Note that the dyno software at the shop reported this as 249.7 whp, so I hadn't hit 250 yet (not sure why the runviewer7 software shows it slightly different with the same SAE correction algorithm)

The last and maybe most interesting change was the cam timing. Dynorun #13 is with the cams advanced 2 degrees, dynorun #14 is retarded by ~3.5 degrees. Baseline (#12) is retarded by 2 degrees.

The shop showed 251.2 for the last run, woohoo! Figuring the normal correction for wheel hp vs. crank HP, that should be a healty 295-305 HP. Not bad for a 3.2L junkyard motor that burns oil.

Interesting that the torque differences in the cam adjustment are mostly confined to the 4000+ RPM range. There may be some difference at ~2200 RPM but there isn't enough data there (I was trying to get 1700RPM and up but the guy was a little late hitting the go button on some of the runs).

You can see the somewhat soft torque curve on the stage IIs. I'm not sure what it would look like without the sprocket overlap change (advanced exhaust cam by 3 degrees relative to intake).

A nice shot with the car redlined (well, a little past red line, since it was hitting the 7800 rev limiter in this shot)...

Anyway, I had a great time and had a lot of fun running the car out. There's probably more power in there that people more experienced could get, but it's probably not a lot. I'm a lot happier now that I know I have a MAF curve that is closer to what it should be (though the low-end, part-throttle area is a bit hard to tune on a dyno this way).

Just as a comparison, on the first dyno day there were two other 3.2Ls there; mine was making 233whp at the time (blue line):

The second dyno day there was one, but I left the old 217hp dyno run on there and I added a stock 3L (just a Y-pipe for modifications) to compare. Again, the blue line; gained 17whp and few ft lbs of torque everywhere between the EH intake, port matching, tuning and exhaust changes.

Lastly, the comparison between the 233whp and 250whp run -- they're 15 months apart and about 10F different. Again, changes between the two are tuning, the 3" catback, and the Extrude-honed intake. The 4-5 ft.lb torque gain is noticeable throughout the low-mid RPM range widening at higher speeds. I gained 10hp at 6200 RPM and the peak HP difference is around 20hp, which extends from 6800 RPM up to the end of the dyno. I have since upped my rev limiter to 8200 RPM based on the results here -- 7800 RPM is far too low given the power output of this motor setup and the wide spacing of the SHO's gearbox.

Recently I had some cooling problems at the track so I decided I would modify my bumper.

The front license plate stays on except at the track; the other holes don't look quite as ridiculous so a little touch-up paint should be all it needs.

Update 1/25/2006:
Added Sho Shop headers. Swapped in a different motor (10:1 pistons, shaved heads) because my old one died due to a stupid mistake on my part. Run #13 is old exhaust. Run #17 & 18 are headers. Note here that I did this on a different dyno which had no fans for the engine and the car was packed in with the intake side of the engine surrounded by walls -- the car's computer was logging >110F air inlet temps, while the dyno was corrected to ambient (70F), so the #s are low by about 7.5% based on standard gas density physics (530 rankine correction temp / 570 rankine actual temp).

Update 07/12/2006:

Took the beast out to the drags at Infineon. Cool night, but 20-30mph headwind all night kept things slow. Stock cars were all running quite a bit slower than normal -- C5 vettes in the high 13/low 14s, Evos running high 14s @ 92mph, etc. I felt like the car did pretty well, but I have a lot of work to do on the launch and need to replace the clutch since hard shifts = clutch slippage for 1-2 seconds. Fine for road courses, but not so good for drag racing. Anyway, here's the slip -- I'm car #141; a fellow BaySho owner is driving a gen1 (stock + Ypipe, basically) in the other lane.

-Lance