Organized Drag Racing and AutocrossDrag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.
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The spectator who took pictures of my car last night sent me 5 pictures today and said more will arrive tomorrow. These are fantastic pics but he also had a really good camera. Check out the tire growth as I go past the 1/8 mile at 113 MPH. The pictures were sent to me in mega pixel format so I resized them down to 800 x 600 instead of the typical 600 wide as I usually do for the forum. I may have to use one of these for my new sig picture.
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Hardtail Racing
All engine, no power adders! Bests: 9.029@150.45 (at altitude)
Theoretical sea level performance 8.623@157.05
They are some good pictures. I would definetely use one for your sig. It's good to see a powerglide car with the wheels in the air. It means your converter works well.
__________________ 1986 Camaro SC - SOLD
383/T-350/4.10'S/PUMP GAS
10.71 @ 126 W/ 1.52 60FT
I was launching at 5500 rpm and the converter stalls just over 6000. I'm still debating a gear swap. I currently have 4.57 in the diff but still have a set of 4.86 that I was using last year. All the software programs I try recommend something closer to the 4.57 gears.
Along with the gear change, I also changed the heads over the winter. I went from unported 310's to massively port 360's.
Last year I was shifting at 7400 and crossing the finish at 7400. I still shift at 7400 but now cross the finish at 7200. I swear within the last 100 feet or so, it feels like the car is picking up speed as the rpms are peaking out. It just feels like it wants more rpm. The camshaft's powerband peaks at 7600 and I have the rev limiter set at 7800.
I think these new heads really want the rpms to breath but the camshaft and now the gearing are holding them back. Current cam in the engine is a Comp Cams 11-740-9. Although it makes good power, it's actually a bad choice for the rest of the engine. An 11-733-9 would be much better along with going back to the 4.86 gears to get those rpms up higher. I haven't been able to punch in the cam specs yet to see how well it would perform.
Nope. If I pre-registered for $75, there's a dyno shootout tomorrow at a car show. You get one pull on a dyno and the vehicle with the most HP wins $1000. I sent an email to the business holding the event last Thursday asking if there was room for my tow vehicle and trailer and never got a response.
I was playing with Camquest 6 tonight to see what different cam grinds would produce. Swapping to a better cam might gain 20 HP and about 15 pounds of torque but the majority of the cams, even the ones that peak over 8000 rpm, all will make peak power in my engine at 7500 rpm and peak torque at 6000. 2 better suggestions are 11-733-9 which I already knew was better and 11-721-9. the biggest thing about swapping similar cams is how they move the powerband around. Peak numbers will move higher or lower a little but they're usually determined by the heads. The peaks can be moved up or down in the rpm range based on the cam grind. The reason I feel my current cam isn't good enough for my engine is that most cams are not designed for a tunnel ram.
Now that's camquest. It's a ballpark number. I'd love to get my hands on Desktop Dyno5 some day to see what else I can tweak.
There is one suggestion that I'm not sure if I want to try or not. Instead of shifting at 7400, short shift at 6800 and go through the traps at around 7600. You get into high gear quicker to use HP instead of torque to move down the track.
What air pressure are you running? Those tires are folded up pretty well. It might pick up some with more air, I know your worried about consistent but if its faster and consistent then its a win win.
I put the 4.86 gears back in today. We'll see how well they do this weekend.
Real pain swapping the gears over. I forgot I was using a Daytona pinion support which has a large inner bearing. I didn't have a spare for the 4.86 pinion but somehow managed to get the bearing off the 4.57 pinion without damaging it. From jacking the car up to putting it back on the ground took about 4 hours. I think at least an hour of that was just trying to get the pinion bearing off.
The Moser aluminum center section, aluminum spool and aluminum pinion support sure made the swap a lot easier. I didn't have to bench press the center section in and out of the diff. Just about took it out of the diff with one hand.