I thought I'd share the results of my chassis dyno testing last week. The motor is a DZ302 with an original (unblueprinted) bottom end, 11:1 compression, 247/254@.050 cam, Edelbrock RPM aluminum heads, stock intake, 4053 carb, 1 3/4 headers, and 2.5 inch exhaust.

After 14 pulls, the car made 283 hp at 6,000 rpm and 278 ft lbs torque at 4,000 rpm. Figuring 18% drivetrain loss, that's an estimated 345 hp at the flywheel. The motor ran best with 37 degrees total timing, #70 primary jets, #66 secondary jets (with secondary power valve), .031 shooter, and a green pump cam in #2 position. I had to jet up the primary from #68 to #70 to get the cruise A/F ratio right. The secondary jetting had to be leaned out from #76 to #66 jets to produce an A/F ratio of 12.7:1 at 6,000 rpm (it was around 11:1 with stock jetting). Leaning out the secondaries gained us about 10 hp and 8 ft lbs. The green pump cam was needed to cover a lean spot during the transition to the secondaries (a secondary spring change is probably a better fix). I'd love to hear other 'real world' 302 street car dyno numbers.

graemlins/beers.gif

Way to go! That must be fun tuning your car and seeing immediate (and better) results. Also, Im looking for a chassis dyno to tune my car once I get my combo finalized. Can you get me some info on the shop? Did you bring your own carb calibration kit or did they provide the parts? Thanks!

sik68,

I went to Advanced Dyno Technologies in Suisun City, CA. It was a great experience. They allow the car owner to be as 'hands on' as they want to be. Contact Larry Bennett a.k.a. 'H.H.' at (707) 425-DYNO. H.H. even met my request to put towels for padding between the tie down straps and my car's undercarriage to prevent scratches.

I brought my own carb jets, tools, and timing light, but they had misc. carb parts available when needed. I recommend bringing your own timing light because they all read a little different.

We were mighty impressed with Neil's car. Extraordinarily clean in and out, everything underneath was painted and immaculate. One of the hook-ups on the dyno is a ground strap that grounds the chassis of the car. With Neil's car, there was not one unpainted nut or bolt to latch on to, so I finally found a brake line exposed that I could get the ground clip on.

Neil's approach was very methodical, making a pull after every change, analyzing the results and plotting the next move. We were a little surprised at how the jetting ended up, but you have to follow the instruments.

Looking at the results, I noticed that the midrange had a saddle, probably due to the 1-3/4" headers with 302 cubes. This shows up as a large spread between the torque and power peaks.

We get some interesting cars on the dyno. Yesterday we had a supercharged 2003 SVT Mustang, very impressive. Earlier we had a Whipple blown 454 Chevy pickup that had a drywall screw come out of the rear tire at about 140 mph. We are presently preparing a 496" 70 Vette for a session.

I second the "Way to go"! graemlins/thumbsup.gif
I can't help but wonder if the hp peaked at 6000 or was it still climbing? Seems like that cam in a 302 would give a hp peak at a higher rpm.

Hey onovakind67! I didn't realize you were out here on Team Camaro. Thank you for all of your help getting my car dialed in. I had a great day out at the shop, and the car runs great now.

Bob_T, I agree that the motor should peak higher than 6K, but it doesn't. It peaked at 5,900 on a different dyno last year. Even though the cam has 247/254@.050, it's advertised duration is only 287/291 (much smaller than the 30/30). I want to try a Victor Jr. or cross-ram intake on it to raise the torque curve on the RPM scale and really make some HP. However, it's probably more fun on the street right now with the strong mid-range torque curve. My Flowmaster exhaust system with stock-style transverse muffler may be bringing the peak down a few hundred rpm as well.