'Trust'

iTrader: (24)

Interesting points, noted on the timing too, thanks. It doesn't seem like the MPH is as off as I thought. The group I was with said their MPH's were down a little, but still, just trying to think it through.

Next question, should I be locking up the triple disc in 3rd? PI says it's ok, Yank doesn't see how the converter could survive. Thoughts anybody?

kp

iTrader: (34)

Certainly cant hurt to try, high speed retard/lean is just another tool, gas or methanol.

kp

iTrader: (34)

Unless you want to buy a new converter soon I wouldnt lock it up at WOT too many times, but if it were me I'd try it Be a good way to see if its either down on power or blowing through the converter but I've smoked the lockup clutches out of a couple converters with way less power than you are making.

I dont get really too paranoid about mph unless it changes a lot the same day, there are tracks around that vary 2-5mph in 1/4 mile mph. Thats why it would have been nice to see some 1/8 mile times. The air is getting better and I'm sure yours will improve soon so may as well experiment some.

'Trust'

iTrader: (24)

That's the thing, it was locked up, PI and Yank said the lock up clutches (I assume there is more than one on a triple disc?) could be letting go. I have a free re-stall with it, so I may just have them freshen it up and go in with a good converter.

98Z28CobraKiller

iTrader: (17)

Make sure it's done doing most of the slipping before you lock it up. Like KP said, the 1/8 mile slip would help determine what is going on on the long end.

kp

iTrader: (34)

Just have to experiment a little, untl you get a few more passes on it and get a baseline I wouldnt change much or assume something is wrong just yet.

If the converter was locked at 6500rpm (and held) it should have been going closer to 145mph with 3.70s and 28" tires. If you have real 28" tires, 6500rpm and 130 mph will put it at 12% slippage which isnt that uncommon from some converters. I was never able to get one to lock tight, either the PCM was unlocking it for some unknown reason on mine or the clutches just couldnt hold. As stated dont lock it until 1000' or more - otherwise you will kill the lockup clutch.

'Trust'

iTrader: (24)

Well I happened to get the pedal stuck to the floor when I was logging on accident today. It looks like my shift extension (avg between 2 runs) is 281 RPM from 1st to 2nd, then 766.5 RPM. Not sure if that is good or bad, but curious on everyones thoughts.

I don't remember shifting twice, but I triple checked the spreadsheets and they say 100% throttle on both drops in RPM from the peak. It is over a period of about 4 seconds. Also, 0 knock on both runs.

98Z28CobraKiller

iTrader: (17)

The 2-3 shift should have a 900-1200 RPM extension. The converter is definetly slipping.

'Trust'

iTrader: (24)

Hmm, interesting. The first run the 2-3 shift extension was 717, second run it was 816, if that helps. Nice part is IAT's were 104 before the 100% throttle, and 84* during the run, I love meth.

EDIT: Something else too, the car is set to shift at 6500, but on the 2-3 shift it was at 6,3XX one run, and 6,2XX on the other. Does that indicate anything to anybody? It also may not have captured that grain of detail though as far as the recording capabilities of HP Tuners goes I guess.

helicoil

iTrader: (104)

Just some thoughts.......

If you went 134 with less power, which I think that is correct (based on what I can remember), and now you are making more power and trapping less MPH..... I would think it is the converter not holding the additional HP up top. Without track data where the tires are stuck it will be really hard to tell. BTW that 1-2 drop seems very low. Mine drops 900-1000RPM between gear changes. Right about where you would like to be.

I can understand your strong 60' though. You are stretching the converter way out with all that power and heavy mass.....Kind of hard for it to be inefficient with a 3.08 low gear and 3.70 ring and pinion in 1.1 seconds.

Yank recommended to me to not lock the converter at WOT, ever. I know PI has another thought on this, but I can't see how or why. IMO that lock up clutch in the converter cannot hold that kind of power at that weight. No way.

If you have been locking it, I'll bet it is burnt, and now you are just at the mercy of how inefficient the PI's are at big HP.

Your car should be no less than 135 in the 1/4. More like 138-140. With that kind of 60' I would expect 9.80's if it were efficient on the other end regardless of the weight, hell it is already rollin at point. The hard part with weight is getting it going, you've got that figured out.

Also, that loose converter is why you are 60' footin at 1.34. If they tighten it, that could go down. It is a compromise. That was a beauty launch BTW!

Small Procharger cars are all about first 100 ft. They leave hard characteristically, especially in a car with a 3.08 low gear and 3.70's out back. If the car sticks, it will do what yours does and run a good et.

A nice high dollar race converter that was more efficient and built specifically for your car (power/weight) would help a bunch, but that can be pricey and a crap shoot. The Yanks and PI's are off the shelf pieces that fit a wide variety of combos, definitely not the BEST choice for MAX et's at the dragstrip.

I would just be happy with it. 9's for a complete car such as yours is stout!
You can spend thousands more chasing tenths at this point. And if you don't have 300M shafts in that 4L60E you probably won't want to turn it into a track car anyway. Racing at that weight too many times will lead you into a
4L80E or TH400.

'Trust'

iTrader: (24)

^^ agreed on the $1,000's for 10ths, not worth it to me at this point. If the converter is hurt, which it seems it is, I'll get it rebuilt, sell it, and throw the Yank in there. Tighter is nicer to cruise at anyway!

Pro Stock John

iTrader: (34)

Run the rpm info by PI, but it sounds like the converter is on the loose side/ a bit inefficient for your car. But you have to start somewhere and a 9.9 rocks.

'Trust'

iTrader: (24)

Well it looks like something is slipping, the 281RPM "shift extension" looks like it was slip when the car was working its way up to the 2-3 shift, I knew I didn't shift twice. I'm pretty sure it isn't the tranny, I'd assume I'd have hit the limiter or blown through the shift if it was, I think it is just slowly hurting the converter.

I'll call PI this afternoon and see what's going on.

Photochop

iTrader: (74)

Unless you wanna build a new tranny to go with that new converter, I think I'd share your findings with the companies and leave it be as far as running it goes til you get in there and see how bad that disc is burnt - more debris in the fluid getting into the tranny is no bueno.

I know you wanna pick up MPH, and based on that data you've collected and can give either company, I'd think they'd be able to get pretty close to right on with a converter that won't kill your 60' but hold the power up top.

'Trust'

iTrader: (24)

With which companies?

RS_SS69

iTrader: (31)

I think he meant with PI or Yank

'Trust'

iTrader: (24)

That's what I thought, but I said that at the bottom of my post, lol.

RS_SS69

iTrader: (31)

Id say get it restalled and tighted for your new power to hold down low for the 60ft but still be just tight enough up top not to blow past the stall. Try that then look at the trans for a freshening.

tomz28

iTrader: (20)

very clean 60 foot man
the car left the line very well i like that better than the ET lol
but im all about the 60 foot

'Trust'

iTrader: (24)

I'm going to go with a Yank, flush the trans, add a cooler, go back the 2nd and cross my fingers. I'll log the runs with the Yank and call them to see what they think. I guess I may lose some 60' but that's ok if it picks up up to.

If the stall speed on the Yank isn't good enough I'll send it off in the winter to get rebuilt then let Brett go through the trans. Should have the new converter in this weekend.