Will my converter keep me out of 10's??

[87LtdT]

Best run is 11.30 @ 120.95...with converter locked. However, I don't think it really locks. I know it locks at normal driving speeds either automatically or if the ALDL switch is used....however, at the track I never feel it lock nor can see any rpm drop on Direct Scan. I can see that it is commanded to lock via Direct Scan...have never tried to use the ALDL switch at track.

Running my best 1/4 numbers (11.30 @ 120.95 w/1.688 60') on Chuck Leepers calculator (5650 28.0 3.42 1.00 120.95) results in 13.8% slippage in a supposedly locked converter.

So a few of questions arise...

1) why does it definitely lock up at normal driving conditions but not when at full throttle ven though commanded to do so via T+ chip setting??

2) will this slippage keep me out of my goal of high 10's??

3) if answer to #2 is yes, what lock up converter is recommended??

Thanks, Bob (preparing for 10's next year )

 

[TurboBob]

If its like my old Yank, at that power level it locks about "half way" meaning that your slippage is cut in half.

When I sent it in for a freshening, the clutch still looked "great" so I think you will be fine running it that way.

Jim Hicks ran his like that and went mid 10's. TE45A at 30+ psi.

Bob

 

[TurboBob]

post your DS file and your tire height and rear axle settings.

Bob

 

[D's GN]

How much boost and timing? Get that 60' down and feed it some more boost if the tune up is safe. My converter was slipping @ almost 15% unlocked and it still went 10.89@124 with low boost. You have enough turbo and heads to get you there if you do not feel like swapping converters.

 

[87LtdT]

Thanks for the advice....

Timing: 25/27
Boost: 27
Tire height: 28.0 (MT 275/60-15 Drag Radial)
Diff: 3.42


Not sure if the DS file will work as .txt may need to rename at something else.
Thanks, Bob

 

[Blazer406]

Thanks for the advice....

Timing: 25/27
Boost: 27
Tire height: 28.0 (MT 275/60-15 Drag Radial)
Diff: 3.42


Not sure if the DS file will work as .txt may need to rename at something else.
Thanks, Bob

That DS file shows you were not in it all the way down the track.... about 4 sec worht of WOT.... the TPS voltage was hovering around 2-1/2 volts the rest of that run.

Timing was 19/17...... what fuel are you running? If race gas.... you are leaving alot of HP on the table with such low timing IMHO.

I can't decipher anything else from the run since it doesn't appear you were at WOT....

 

[Underboost]

That DS file shows you were not in it all the way down the track.... about 4 sec worht of WOT.... the TPS voltage was hovering around 2-1/2 volts the rest of that run.

Timing was 19/17...... what fuel are you running? If race gas.... you are leaving alot of HP on the table with such low timing IMHO.

I can't decipher anything else from the run since it doesn't appear you were at WOT....

Check TPS?

 

[87LtdT]

Sorry guys...I picked the wrong file...during the previous file I saw that I'd set the boost too high so was trying to continue with the run by adjusting throttle to hold boost at 27 psi. It was an 11.40 run.

The attached file is the 11.30 @ 121.

And I'm adding 8 degrees of timing with the T+ so the timing is 25/27.

Running C16

Bob

 

[Blazer406]

DS file

Observations:

1st and 2nd gear could be leaned down some. 02's were above 800 mv for most of 1st and 2nd gear.

You had absolutely no knock. I would bump timing up another degree. If still no knock.... i'd lean it down a couple percent on the fuel. As long as there is no knock... i'd lean it down a percent or two at a time.... watching closely.

The converter is plenty loose. 350 RPM drop at the gear change means it isn't coupling very efficiently at that RPM. (In your case.... approx 5000-5100 RPM).

Depending on your heads/cam..... if she makes good power at 4000 RPM.... I'd shoot for a tighter converter....I think it would really help..... some on the ET... and a pile on the trap speed....

IMHO... if you are running a 215 or below cam... and stock or ported heads.... your motor will make good power well below the 5000 RPM shift recovery point you have now.....to take advantage of this "area under the curve".... you can choose a tighter converter.

Maybe someone else can add and/or draw another conclusion....

HTH

 

[turbows6]

I agree with what blazer 406 said. I think your converter may be a little loose.

I think your TCC is working though because at +6.59 seconds the TCC was activated and rpm was 5375@93mph. It actually takes a split second for the clutch to engage and at +7.30 seconds the rpm had dropped to 5275 rpm's and gained 4mph. I didn't calculate slip, but the TCC is working for sure.

 

[GNVYUS 1]

Time to yank the Yank, I would sell it if want a converter that will lock up at that power level, Precision 5 disc.

Or go with a PTC non locker, great price, great stalls available and guys are running super tight up top, hard to beat considering it's also lighter and no worries about clutches.

 

[Mr.Spool]

87ltdt,that 60ft has to come down to run 10's regardless of a converter change.if you stay at basically a 1.70 a better converter would have to knock off 4 tenths on the top end to run 10's.inmo try to cut the 60ft down before you invest in a new converter,tune,play with the suspension,better tires, etc. then re-evaluate.

 

[Quick6'n'-K.C.]

Anyone want to help me out to open this, ive never been able to view these and the power logger files.

Any help is appreciated, i think you guys have a grasp on it, i just want to get a view of it.
BW

 

[87LtdT]

Bryan...appreciate your interest.

In order for me to upload the file I had to rename the extension to txt. However, I later found that a .txt file does not show up in Direct Scan. So you need to rename it to anything except .txt . Do you know how to do that in DOS?? Maybe there are other ways to rename or to view it...but I only know how to rename it so that DS will see it. Let me try to upload with a different file extension name.

Odd huh ??

Bob

 

[87LtdT]

This is the same file...just renamed with a different extension that is viewable by DS.

Bob

 

[murphster]

Just looked at the run on DS. I agree that you look rich down low, take some fuel out in 1st and 2nd keeping an eye on it as Blazer406 said. I've seen shifts like that on other DS runs, where the converter efficiency point rises up in rpm depending on the power level. In your case, your converter is coupling at around 5100 rpm at the power level in your DS run. Having only a 350 rpm drop doesn't mean as much, because if you shifted at 6000 rpm, you'd have a 900 rpm drop.

For example, with my white T with an older 9.5" Art Carr unlocked converter the rpms would drop to 4800 or so when in was running mid to high 11s on a stock engine with a GT61 turbo. With the new engine and bigger turbo making more power, the same converter drops only to around 5200 rpm on shifts.

As Blazer406 also mentioned, one thing to consider is whether the rpm range you are seeing on your shifts is in your powerband for your cam. My converter seems to be more efficient with the higher rpms I'm running now (around 6000 on shifts), but the stall is too low for the bottom end. Overall, it could still be more efficient on the top end too. The higher rpms on the shifts are good for me though, since I'm running a bigger cam. You may want a tighter converter depending on where the max power is for your cam so that the rpms after the shift drop to a lower rpm. If your cam makes more power at higher rpm, you need to raise the shift points or shift manually to keep it in the powerband longer.

I'm leaning towards a new high quality nonlock converter that will still be very efficient. From what I understand, the good nonlocks are also lot easier on the tranny, especially for those without all the bulletproof goodies.

Everything else looked pretty normal to me on DS. I got 11% slippage for your converter using another calculator. I don't think its too bad, probably not locking 100%, but not awful either. My very loose converter gave me 13.5% slippage while a friends locked converter with 1100 rpm drops on shifts gave 9% slippage on the same calculator.

 

[87LtdT]

Running a stock, never removed, cam.

Because of that I'd think my power band would be 4500 range...not 5500...agree??

If so, then I need a tighter converter don't I?? I am contemplating a PTC non-lock...read a big thread on this forum...PTC sure looks good and efficient.

Thanks, Bob

 

[murphster]

While I'm no expert by any means, I would think that what you are doing makes it a little more difficult than most. On one side, you have a stock cam where you don't want the rpms to get too high. On the other hand, you have a turbo and combo that probably benefits from the higher stall. Making as much power as you are, the stall of the converter is going to rise pretty high no matter what. And you really don't want too tight of a converter or a larger converter (as in diameter) because it will hurt the spool of the turbo.

It seems like a bigger cam that shifts the rpm range about 500-600 rpm higher would be the best bet, since you already have good heads and it would match the rest of the combo better. Maybe another option would be to use a smaller turbo or maybe a BB turbo along with a tighter and more efficient converter that will work better in the lower rpm range if you're set on keeping the stock cam.

I'm also looking at a PTC converter, seems like a good unit. I'm anxious to see what my car would run with one for comparison before I start turning the boost up.

 

[murphster]

One other thing.... Lets say you work on the chip settings so that you take fuel out of 1st and 2nd and the car 60fts better and you run faster in 1st and 2nd. This probably means you'll run faster overall and run even higher rpm at the end of the track than you were before. You'll gain ET but probably won't gain much mph as it will be falling flat on its face at the top end. Maybe shifting into OD would help?

 

[Quick6'n'-K.C.]

I renamed it, still wont open it. Yes we all have our idiotic moments :redface:

Brian Dykes- Send it to me wanner@kc.rr.com if you can....

I think that if the convertor is 1/2 way locked then replace that solenoid, we ran into that here on a few cars. 1/2 way locked and the MPH was down alot, as your car is missing alot of MPH. It might be making some decent hp, and the PTC might be the way to go.

I will try and keep this short.

Guy from Georgia calls me about a week ago and had a customers/ friends car that just always had a slight miss or stumble to it, he was all over it and it just didnt run perfect.
When he told me that the car ran and drove fine, just felt like it was running on 5 1/2 cylinders, the first thought in my mind was a flat cam lobe.
The owner of the car had no idea, but it turns out the car had 2 flat lobes and when dealing with a 21 year old cam, dont rule it out.

A good stock cam will run 10s with heads and a turbo, so something isnt perfect and you need to find it.
BW