as for the converter topic, especially the rpm drop between shifts, I mentioned the same thing on Thirdgen.org and one of the guys who has been helping me throughout my build replied with this:
" From what I've worked out , both mathematically and empirically is :
6500 rpm 1st gear shift to ~3420 in 2nd.
6500 rpm 2nd gear shift to ~4010 in 3rd.
6000 rpm 2nd gear shift to ~3700 in 3rd.
That's based on the 700R4/4L60 gear ratios of 3.06 and 1.62 (1st and 2nd respectively). This does not account for the characteristics of the converter.
With my off the shelf 10" TCI, I'm estimating about a 10% slippage. There's always been a significant RPM drop from 1st to 2nd. It's not so much from 2nd to 3rd as you can see in the above.
Now the empirical part came from racing with my own Camaro and a similarly prepared 82 Monte Carlo. My 1-2 was always crisp although the ratio split made for a terrible shift. The 2-3 shift was generally slow despite the tighter gearing. That was with a home prepped 700 with the usual stuff and the 10" converter. Now enter the Monte with the same converter and transmission. Predictably the same results. Later that season we swapped in a spec 9.5" Yank. Surprisingly (to me anyway) was that data logs showed that the engine RPMs never fell below 5000 regardless of the gear it was in. 6500 1-2 shift landed at 5000. Same on the 2-3. That car picked up 2/10ths.
This to me demonstrated the importance of having a converter tailor made for the application. And a specific application at that. Not only that but having a thoroughly built transmission pays off too. My home brew rebuild was sent to a specialty shop (an acquaintance of mine actually). I spec'd a pile of Sonax and new GM parts for it and let my guy do his thing. The results are nothing short of spectacular. Shifts are blazingly fast at WOT. Even the previously sloppy 2-3 shift is instant.
Now although I've stepped up in the converter game with another TCI, it's not going to compare to the likes of a Yank or an Edge that's made for my car as you guys have. "
that info and much more can be found on my "engine" thread on TGo :
https://www.thirdgen.org/forums/tech...install-3.html
otherwise
I hope to back to Island on Sunday to experiment with launching from a dead idle. I am also considering removing the cat back exhaust for a day of testing? I know that some of you guys are making due with a 3" exhaust and are making more power than I am, but I became curious about if my DynoDon's mid length headers, Dyno dons y-pipe and hooker 3" full cat back (gutted cat tho) was too restrictive. I do have an electric cutout mid way along the 3" main pipe, and I leave this open while racing, so I never thought much more into it as being restrictive. I played with an exhaust size calculator and in general terms, a 3" single pipe exhaust is really only good for 370 hp. Another calculator shows I would need about 3.6" diameter pipe for 531 hp.
- On my other build thread (the one started a few years ago) I knew I would need to upgrade the exhaust later, but it was not in the budget for this year or for the N/A setup. My plans were/are to put a mufflex 4" exhaust and some long tubes on the car this winter when the nitrous gets installed and along with the roll bar. I am wondering if I should bother leaving the headers and y pipe on but taking the rest of the cat-back off the car for this sunday's test and tune day. Its hardly more than 20 minutes of work and this would remove the two tailpipes, muffler, over axle pipe, and part of the main pipe...removing maybe 40 pounds of weight and possibly freeing up exhaust flow??.. I cant take off the y-pipe and run open headers because of where the o2 sensor is and it would get false readings. thoughts?