Welp, where to start.

I just want to say the car (not in the heat) feels great, so I'm not sure what's up, but here goes.

Last time I went to the track was in February.. with bolt-ons I was going for the most part 12.9-13.0 @ 103-104 ish all day long. This was in mostly high 60 - mid 70* weather, nice and dry day, and about 1/2 tank of gas. Out of 20 passes that day, only two were 12 second passes, and only one was a 104 mph pass (the rest were 103ish)

Today was a clusterf***. I get there and it's like 85-90* out, and humid as hell. It seems I've lost some lowend with the cam (i mean very very low end) b/c I can't cut 60' times as low as i used to. High 1.7's compared to low 1.7's all day. Track prep was fine, car was hooking fine, I was launching it the same.

On to the meaty stuff. For the most part I cut 12.9's most of the day at high 104 MPH. I managed to cut one 12.89 @ 105 on a high 1.7 60'..

Problems, now I seem to bog after the 60' on a hard launch, looks like I need more gear and a big more stall. I'm thinking 3.73's and a 3200 or 3400 stall. 3rd Gear also takes too long to wind up IMO and starts at a bit too low of an RPM.. any ideas on fixing that?

I'm kinda disappointed, but I'm not. The weather difference in general has GOT to be killing me. I have to say I'm a little disenchanted, especially when I read about people like Ken95Z28 having gone 113mph in a hotcam.. i mean.. HOW.. what is so different b/w cars that way? Is it conditions?

Ugh, and to top it off, the car is set to shift at 6200. After one pass for the most part the car would stay ok. However, if I hotlapped it for a 2nd pass, the tranny would delay shifting 2-3 to like 6500... felt like it was slipping... is the tranny fubar'd? or is this just how it is in hot weather.. I do have a tranny cooler for it.

Suggestions, comments welcome. I really think I could muster a 12.5 @ 108 on a 1.6ish 60'... wish I could go faster like some of these other guys on here though... I just don't understand it.

 

i was there with him. the day sucked. i was down 3.5 mph and was 2-3 tenths slower. and so was everyone else. i think as the car sits with his 2800 stall and 3:23s, it will go 12.5s at 108ish in good weather

 

I've got the same 2-3 shift problem... only my car won't shift into 3rd at WOT, period. But I would still kill to have run times like yours... with 2.73's, stock converter and stock tires I only ran a 13.7 with a 2.29 60'. I need gears and tuning, bad. If you fix the problem let me know how ya did it

 

If you have temp, humidity and most importantly barometer readings you can see exactly what adjustment is for different conditions.
Most drag racers (brackets) have that nailed for dial ins.
A general rule of thumb was .1 tenth and 1mph for every 12 degrees but humidity can make it even more so.
So assume you lost .2 tneths and 2 mphs minimal and you still gained a tenth and 1mph so about 30rwhp from a cam.
That isn't to bad.

 

Unfortunately I don't have the old DA readings to compare, but one of the guys measured DA today at +2515.... it was 90*, 85% humidity.. those were the conditions for my 12.8 @ 105 run.. so I guess you're right, I should be OK.

 

i think that thing will run awesome in some better weather. i am going to be running a similar cam(222/230). crappy weather will KILL your times, especially that humidity

 

You will do better kid. It took a few outings for my car to gel. Also your in need of gears & a higher stall would be nice. That kind of heat & humidity is terrible to the LT1's. Are you on ET Streets?

 

Just for comparisons sake I have a similar cam to yours (224/236xe) and I've run the time in the sig. On street tires with the stock stall. This was with weather in prolly the 70's or so. Your times will get better you just gotta wait for the weather to corroperate.

Joe

 

The last time I went to the track it was crappy for me as well. Mid 70s, but 100% humidity and not so good track prep. Ended up running the times in the sig. I was really hoping for 13.1s. Hang in there.

John

 

Hey Eddie.. nah man I'm on Nitto's for right now.. I know I need to pick up a set of ET Streets instead, but to be honest I was bogging coming out of the hole yesterday, that loss of low end means I need to compensate w/ a higher stall and gears. I guess one thing at a time. In any case, I'm a little worried about the tranny now w/ tht 2-3 slippage issue, I wonder if it was only the heat, or a problem that's going to reoccurr, b/c otherwise the tranny shifted fine 2-3 at WOT when I left the track. I may just have the tranny toughened up and get it rebuilt while I wait for my converter to be restalled later this year.

 

Im going with user error on this one

 

My friend (LS1 A4) just had the same problem in his car. 2-3 would hold for the longest before it shifted. It was knockin' a tenth outta his time for sure. It's like...ok...shift....any time now....come on...THERE YOU GO. I forget exactly what was wrong, but he had a tranny shop rebuild it (race build) and they supplied an old busted planetary from another 4L60E and his warranty covered it...HOW COOL IS THAT?
I'd get it checked for sure. You should see his dyno graph before the rebuild...looked like a kid with a crayon drew that thing!! Catch it now before it starts slipping really bad like his!

 

I know what you mean. The hot weather and humidity kills performance. I went out with more gear and converter and slowed down I came home and checked everything out and all looked well. My car with 3.23's and Vig 2800 went 12.51@107mph last summer but it wasn't a bad day out either. I went 12.60@107mph witha vig. 3500, 52mmT.B. and 4.10's Friday. I will be putting my 3.42's back in and doing some tuning. I did make one N20 60' and went 1.57 60' which felt awesome but my trans is doing the same as yours on both the 1-2 and 2-3 shifts. Goodluck and keep after it. Later

 

I got a buddy that needs some 4.10s...wanna sell em?

 

I am right there with you guys on this.....2-3 will take forever and it even hit the limiter on most cases...So do you think its the trany going south??? I don't wanna put a stall in it because I am gonna have to combat the obd1 high stall issues....I really don't need to get the 2 confused and spend money on trying to fix one and it be the other.....Plus the yank I have I don't really wanna spend the money on another if the tranny screws up....
I believe my best bet is to get the tranny rebuild and then if the issues of the obd1 and high stall issues happen to arise, they won't be mistaken for tranny slippage....
What do you guys think?????