Go to the 3, 5 and 3 day races in December at local track. Due to a multitude of reasons, head out with new setup. 406 SBC, 11.5 CR, mild engine. Rebuilt T/C with new sprag after sprag failure. Originally stalled on TB at 4500, now at 5000. 4.10 gear in Moser 9" and 28' slicks.
Car, remarkably ran slow but killer consistent in competition. Feels like TC is spragless, virtually no torque multiplication. But runs steady, regardless of weather. Missed dial when guessed with weather better but car still ran same. Cannot complain about ET.
Reaction time diff issue, Early on RT time steady .025 or better early (no box segment), then 3rd round, goes away .065 to .085. Same pattern every day except last day when 1st round bad. Last race tried again, terrible lights and swapped in fastest button for a .005 tree, which during the prior races would have put me super red. I been running Nobox a lot of years and feel something amiss that may/or may not be me.
Everything from engine/trans temp steady, plugs same every pass, even fuel usage identical pass to pass. Nothing unusual other than constant soft feel on brake release. Converter stalls higher, 5000 vs prior 4500, actually feels more like a fluid coupling than automotive torque converter. I even tried new set of another maker tires between 3 day and 5 day. Same everything, same pattern.
I lean toward converter. The 5000 vs 4500 with same displacement says something diff. With smaller 357 same converter sent me to IHRA world finals in 2020 stalling at 4350 to 4400 behind smaller engine.
Trans seems fine, has new drum/band combo and 225 at port. Fuid (type F) looks new.
Is there anything else I should be looking at beyond converter? Is always possible, at past 65 a is me but Leaving off 3rd bulb is usually I get faster on tree in a day unless something failing.
Any ideas what else? looking for a .040 to .060 loss in RT is tough without sophisticated data gathering.
Posts: 3114 | Location: Florida | Registered: February 21, 2005
Is it possible that early rounds it was lifting the tires out but being less aggressive as the track changed it was rolling out? I ran into this with my Footbrake car. Mine wasn’t rolling completely but not popping up and my driver side was hanging down further so it stayed in the beams longer as I left when it didn’t pop right up.
Posts: 3648 | Location: KIEFER, OK. | Registered: August 17, 2007
Originally posted by CURTIS REED: Is it possible that early rounds it was lifting the tires out but being less aggressive as the track changed it was rolling out? I ran into this with my Footbrake car. Mine wasn’t rolling completely but not popping up and my driver side was hanging down further so it stayed in the beams longer as I left when it didn’t pop right up.
That would be verified by corresponding differences in the 60' and other incremental ET's. ?? In my opinion.
"Despite the high cost of living, it remains popular." Dave Cook N375
Posts: 2182 | Location: Indy | Registered: November 21, 2008
60' abd 330' times very tight. I shift manually at 5500 and due to limited time runs did no changes beyond tire pressures and button/2step. Is possible tire lift or rollout changes, just not showing at 60' and 330'. I was concerned about small tire slip and added 130 lbs, car lost .012 on every pass steady and lost RT 3rd pass again.
I used to run TH400s with TCI brake. When RT tailed off some used to pull sol, plunger and spring to extend spring to restore. This glide is pro brake. Is there anything inside like that?
I have run this car for over 20 years, 18 off brake and when I pattern develops outside my usual errors it gets me scratching head.
Posts: 3114 | Location: Florida | Registered: February 21, 2005
Originally posted by muggs:new setup. 406 SBC, 11.5 CR, mild engine. Rebuilt T/C with new sprag after sprag failure. Originally stalled on TB at 4500, now at 5000. 4.10 gear in Moser 9" and 28' slicks. I shift manually at 5500
2 questions. What rpm is the launch 2 step set at? Why shifting at only 5500?
Posts: 3183 | Location: 53056 | Registered: December 30, 2009
Logical question. Was pre entry 3 day and 5 day races. Tried to get to TNT ahead of 1st race and blew out header gasket. No full pass except 1 time run first day. Start with 5500 shift point and 4000 launch. Car was solid on ET, remarkably so.
2 step set between 3800 to 4200. Only other change is shims in Terminator button and tire pressure. RT solid 1st and 2nd round along with ET. Then 3rd round always slow. Lost 1st day when actually expected car to slow when it did not. Another round expected to pickup with weather and it did not. I was watching temps and trans not getting hot at with lots of time between rounds.
Another interesting thing, 200 on 2 step did not seem to change 60' or ET, granted slow car was 7.14/15 all 11 race days.
Posts: 3114 | Location: Florida | Registered: February 21, 2005
