I have the same Dynamic 9.5" that I bought in '99(?) and it's still in good shape given how little my car's been running over the years. However, it was spec'd for the car when it was making maybe 550 HP and running very low 11s. The converter still seemed to work well w/ the 50+ HP increase that put the car into the mid 10s, so I was happy.

However, the new engine is an easy 100+ HP more than the converter was spec'd for originally in '99. It's still going to be my baseline when the car is back together, but at some point I a$$ume it's either going to need to be re-configured for the new engine... or perhaps I'll want (need?) to change to another converter.

So, as my subject line states, whose 727 street/strip converters are you using?

http://www.tcsperformance.com/performance_converters/

have been good to us. good customer service and quality

PTC

The question is "how much torque does the new engine make at the observed stall speed?"
It may have less than the original engine (later intake closing = lower CCP) and will stall lower despite the higher peak power.

If the stall torque is higher, the stall speed will increase (duh) by the ratio of (new torque ÷ old torque)^.5
RPM = K × (T^.5)
Just using easy numbers:
Stall now 3,500, new torque 550, old torque 500
(550 ÷ 500)^,5 = 1.0488, × 3,500 = 3,671 RPM new stall
Stall now 3,500, new torque 600, old torque 500
Same math = 3,834 RPM new stall

Whether this helps or hurts launch...?

PTC.

Converter flashed to ~4500 from 2000 launch w/ old engine combination, so I highlighted the #s at 4500 for comparison. Your formula shows about a 4600 stall w/ additional torque.

Brad ,
I ran a similar Dynamic/Lupo to you for years stalled around 48/4900 . This was with both 440 and 505 footbraking .
Now with transbrake I have a A1 Performance 8" unit , stalled at 5800 with original 505 and 440 . When I went TF270 head stall went to 6000 , but car went 0.25 faster so the heads obviously helped the motor HP wise.
Drives fine daily . Even drove to a race in Mildura on the other side of the state - 12 1/4 hours on the highway no dramas . Tis was 2 weeks ago .

Tex

I have loads of street miles on a Turbo Action 8" 4500 when I had my 727. My 904 had a 8" 4800 until the snout broke but that is getting repaired. The 4500 behind the 727 flashed to about 5500 and the 4800 with the 904 flashes to 6400. I did 5 drag weeks with the 727 converter and 1 with the 904, car weight on the road for drag week is around 4000ish.

The street manners of them don't bother me at all.

8" ATI Tree master about 18 yrs old with one refresh it has great street manners also

That's not "my formula", it's the one the transmission and converter manufacturers use.

Regardless, it calcs right at 100 RPM increase.

Know of any formula to help quantify converter slippage increase resulting from torque increase? It would be interesting to know if there is a way to help predict at what point you are likely to start "driving through" a known converter when the power level is stepped up.

Turbo Action or PTC, never had any issues with either one.

ptc is very good,they have a mopar guy that is real good with converter combo!!!

hi ,

the dynamic worked good for 20 years and you want to know where to get a converter ?

My Dynamic has worked very well so far. My friend's sucked. Nobody hits 100%, and converter tech & good builders can change over 20 years. If the new engine and the old converter aren't a good match, I'd like to know what other people's experiences have been.

When I bought my 8" vert from Dynamics I told them I wanted it to flash 5200. It was dead nuts 5200. Can't get any better than that.

PTC
Mopar racer owned

For my A518 I had PATC custom build mine, told them my engine combo & they nailed it, so far so good, 3500miles of abuse .

ATI here......Getting one for a big engine like mine wasn't easy....Love it.

FTI - great Service! Switched from a 9.5" PTC with 3200 stall to a 9.5" FTI with 3500 stall. Day and night difference! Much better.

My Dynamic has worked very well so far. My friend's sucked. Nobody hits 100%, and converter tech & good builders can change over 20 years. If the new engine and the old converter aren't a good match, I'd like to know what other people's experiences have been. [/quote
]by your power numbers i would geuss your new combo will want a 7000 to 7200 shift and 6200 stall. As low as 5200 may work well. I would run what you have. I didn't see a lot of change fron 5500 to 6000 stall on my deal. So the problem becomes; if you mess with it you may go backwards. Test the car with the old one and if you want to know if a change is needed buy a new one to compare.

ATI is in Maryland about 60 miles from me, but I've never done any business with them.

Dynamic is in Delaware about 120 miles from me.

If there are other "close" converter companies, I don't know of them. And until what I have now is tested again, this is all "for informational purposes only."

+1 for ATI.

I have used the ATI treemaster 8" and now a 9.5" - the 8" converter seems to be going the way of the dodo bird pretty quick due to the availability and supply of new cores. The new converter of choice seems to be the 9.5" and is much more durable piece when the HP goes above 800. I also have used a local company called Perfect Converter with some very good results - its nice to be able to drop a converter talk with the owner of the company about it - have them make an adjustment and get it back in a couple of days . A strip/street converter is really a compromise on both ends of the spectrum as you tend to go with a lower stall to accommodate the street behavior. General I have found good results matching the stall with the peak torque of the motor as a base starting point - right now I have the converter at 200 rpm above peak torque and the car really picked up in the sixty - I may try more stall next year. The other side of the equation is efficiency at top end and for me it seems the sweet spot for the converters I use is about 1000 - 1500 above the stall before it becomes less efficient and MPH falls off. Chasing the ideal converter is never ending - I have watched Marco Abruzzi test 5-10 converters in his dragster in a single day in order to find the right one - I am not that ambitious !

I am using a 9.5" PTC that they built for my combination and street / strip . I have no complaints . But, It would be interesting to try a higher stall .

I run the Luppo Dynamic 9.5 street/strip converter in my 63. And it was not built for the eng in the car as I bought it in 2006 for my old 440 that was about 100 less hp then my 440/493. . But it works fine behind this eng and is still working fine after 13 years of street driving and some drag racing. Ron

Call PTC and see what they can do.
I sent my 9.5" back to them after 13 years of running it, $150 + shipping to polish the hub and a refresh.

I used an A & A 10 inch medium stall behind my 408 Dart motor. 517 tq at 4600 and it stalled 4,000. There are three stall versions, about 400 rpm apart. Mine was the middle one. It had decent lockup. 2600 rpm at 60mph with 27. Inch tires and 3.55 g e ars.
$700.

In my previous posts, I said that I had a 9" that I had originally gotten from PTC. But I see that they actually have it listed as a 9 1/2".

Lenny had told me that I needed a larger converter to get me where I wanted but that meant the elusive 11" core was needed.

Is it possible that the 9", 9 1/2", and 10" converters being mentioned here are in reality based on the same core?

I run a Turbo Action 11" with 7/16 thread flexplate bolt upgrade (I couldn't keep the 5/16 thread bolts to stay tight despite being arp and loctited). 2800 rated stall as I recall.

Surprisingly, it has run a 1.37 60 ft.

Turbo-Action. 17805T if I remember correctly. No complaints.

I also run a Dynamic 9-1/2”. To the OP, I’d send it back to Lupo and explain to them exactly how the engine and car has changed. No one will know that converter better than them.

I've used Atlantic Coast Converters for the past 15+ years w/ great results.

Not from what I have seen... but I ain't in the converter biz, either.

If I'm not mistaken, I think the 9" and 9.5" converter are the same. I remember my converter builder mentioning that, but it's been years ago. He's always built 9" converters for my stuff.

Brad...FWIW, my guy really likes ATI and buys a lot of parts from them.

I did speak with Sean once before the last round of engine changes. At that time he mentioned a stator change would be likely, but things have changed even more since then.