PTC converter users
- Thread starter V6POWER
- Start date
Maybe I can get to the track over the weekend.I went to test and tune today to try out my new 10", 2800 PTC tc. It worked well but did not give me the mph I got when I locked my PTS 9-11 tc. The best run I had today was 7.154 @ 96.83 with a 1.608 60' and I did not lock the tc. With my PTS 9-11 I ran 7.1x @ 99 mph when I locked it but only 94.5 mph when I did not lock it (same et). So it looks like I gained 2+ mph with the PTC over the 9-11 when not locked but I lost 2+ mph over the locked 9-11.
I had 600 rpm drop at gear shifts, the same as I did with the 9-11 when unlocked. When locked, the 9-11 would drop 1,000 rpm.
Attached is a screen shot at '0' mph. It shows the tc stalls a lot higher than 2800 and I could really build boost off the foot brake.
I had 600 rpm drop at gear shifts, the same as I did with the 9-11 when unlocked. When locked, the 9-11 would drop 1,000 rpm.
Attached is a screen shot at '0' mph. It shows the tc stalls a lot higher than 2800 and I could really build boost off the foot brake.
You reduced your e.t. Thats most important. In first you are shifting the car at a higher mph more than likely vs the 9-11. You have to consider that at the eighth trap your right in the middle of 3rd gear. The converter is not even close to coupling yet. If you continued to the quarter trap you would gain a lot back. Get us some quarter numbers so we can look at the efficiency in the top of 3rd.
That 1-2 shift at 26 is a huge gain right there. What tire height are you running? If you dont have a 28" or taller tire then you are leaving a lot on the table as far as eighth e.t. You will have to leave with more boost to make up for the taller tire. There are a lot of variables that can effect stall. Compression ratio, cam selection, a/f on spoolup, converter fill, and timing are some of them. Based on your sig you need a 5500-5600rpm shift point and wold want it to fall back to about 4700 on shifts.
Thats not too far off. Looks really good actually. If you manually shift it a little later you will probably go a little faster. Get us your slip numbers if you can.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
The 2800 is a base rating. So many other variables inside the tranny and motor can affect the final stall speed. I can use engine combination to predict how a converter can act, the tranny is a whole new issue which can't be predicted.
Your cam and converter will work better with a little higher shift point but overall it looks pretty good. The 10" can't be as fine tuned as the 9.5 so I could only go 400 rpm tighter if you wanted more mph but that could be too tight down low and hurt the 60'.
Your cam and converter will work better with a little higher shift point but overall it looks pretty good. The 10" can't be as fine tuned as the 9.5 so I could only go 400 rpm tighter if you wanted more mph but that could be too tight down low and hurt the 60'.
I think you need some 28" tall tires to get that converter lugging down. I know when I take my 26" tires off and put my 28" with my weld wheels I can feel the engine staying in the powerband longer. But I dont have any track times yet with my 2800 10" so dont take my word as gospel.:redface:
I will be going in October....
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
Generally a taller tire or higher gear will put more load on the converter and cause it to act a tad looser. The tire in your case may be affecting the tranny in a way that makes it hold the shift a little later. If he shifted another 200 rpm higher he could see some gains in both mph and e.t. The rpm will help it couple.
Dusty--The tc seems fine as is. I really like how it drives on the street, especially at downshift. :biggrin: I hope to return to the track Thursday night for more test and tune.
Will the car respond better if the shift point is 200 rpm higher? Can I get there by removing weight from the governor? Thanks.
Will the car respond better if the shift point is 200 rpm higher? Can I get there by removing weight from the governor? Thanks.
remove .5g from the governor as a starting point. The smaller weight.
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
Two things
It seemed like you compared the unlocked PTC to the locked 9-11.
What psi are you running as that can affect shift rpm a little.
I had Jimmy trim a touch out of my governor and it went up about 150rpm so you can do small amounts if you are concerned.
It seemed like you compared the unlocked PTC to the locked 9-11.
What psi are you running as that can affect shift rpm a little.
I had Jimmy trim a touch out of my governor and it went up about 150rpm so you can do small amounts if you are concerned.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
The car should respond to a higher shift point. 200-300 rpm would be about right. Small steps on the governor weight.
As far as the 10" matching a locked converter mph wise...I doubt it will. The 10" is still considered a budget converter and was built to e.t well and drive like a stocker with lock-up while not requiring lock-up to et well at the track. The 9.5 was built to et and mph.
What is your rpm at 0# and 5# of boost?
You will almost always mph higher with a locked converter. He picked up a lot of efficiency unlocked with his 10" vs. the 9-11. Therefore the car can stay in 1st and 2nd longer and benefit from the better coupling efficiency the converter has vs the 9-11. Thats why he went faster with the unlocked 10" vs the locked 9-11. Id like to see the mph gain on a 5 disc vig vs my NL 9.5" PTC. I bet it wouldnt be more than 1 mph. Im slipping about 4.5% at 135mph. Im almost positive it would not e.t. as well with a 5 disc since they suck when unlocked. Giving up way too much in 1st where the car isnt moving fast yet. The 1-2 shift occurs at about 50 mph and the 2-3 is at about 87 mph in the car in my sig. This really helps the cars e.t.
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