Convertor help

hbr509 · 08-09-2023, 08:56 AM

I have a 1986 Camaro Ed Quay built , I race it in bracket form now , Has Nesbitt 531 ,power glide 180 straight cut , 4.56 rear weighs 3200 , When I bought the car it would go 5.91 1.27-60ft and put it on the bumper , Convertor broke PTC , Car was shifting 6500 and would go 116.mph . I have been through 3 different companys and all convertors stall 6200 -6400, 1.37 60ft 6.10et 114 mph .Peak torgue @5900hp and 7400 max hp . There are a ton of these cars running SS . I,m at a loss need help please . My thinking is it needs 5500 stall . I sent the new PTC back to lower stall 500rpm ,going to test this friday and see Thanks

dragracerray · 08-09-2023, 10:08 AM

What did the old converter stall when the converter was healthy? Ray

hbr509 · 08-09-2023, 12:49 PM

I don,t know , I only know shift is 6500 and so had to be somewhere around 5500. I called PTC and gave them the number stamped on convertor to duplicate but what they sent was to loose ,as soon as i left the starting line it was in high gear

dragracerray · 08-09-2023, 03:17 PM

It is very possible that PTC did not make the last change to the old converter. If so the stamped number is meaningless. I would try to learn what you can from the broken converter. If you don't know who changed it last send it back to PTC, cut it apart, and see if they can determine how it was built. I would agree from what you are saying that you need a tighter converter.

Adger Smith · 08-09-2023, 03:32 PM

With the MPH down I would say the converters are too loose (% of Slip not stall) compared to the broken PTC.
I like the idea of sending the broken converter to Lane and Kenny at PTC to cut open and study. There is a lot more to getting a converter to work correctly than just getting stall correct. ( Fin size and shape and angle, stator degree and back angle, ect) Like said earlier Your broken converter may have some changes that the numbers don't reflect.

Mike Pearson · 08-09-2023, 04:17 PM

Quote:

Originally Posted by hbr509

I don,t know , I only know shift is 6500 and so had to be somewhere around 5500. I called PTC and gave them the number stamped on convertor to duplicate but what they sent was to loose ,as soon as i left the starting line it was in high gear

You cant have a converter that stalls 6300 and shift at 6500. you said your engine made max power at 7500. That is where your shift rpm should be and that would match up pretty well with the 6300 stall speed. When you ordered the new converters did you tell them the engine max power was 7500?

L.Fite · 08-09-2023, 04:34 PM

So...
I know nothing...
But stall should be around peak torque and shift at or above peak H.P.
I would send a dyno sheet to whomever you have build your converter...
They should be able to get you real close...
I always had good luck with Coan, and ATI...
Like I said I know nothing, just my going by my experience...

hbr509 · 08-09-2023, 05:25 PM

Thanks for the replies , The original PTC that blew up was sent to FTI and they said it was not salvageable, My fault for not getting it back , and yes I,m sure it was changed from original specs, I sent FTI, ABRUZZI AND PTC dyno sheet and motor build sheets all convertors where 6200-6400 on racepack also all ran the exact et and mph Great for bracket racing but 10th slow in 60 ft does not wheelie anymore so no rotation . I shifted at 7200 with those convertors , My thoughts are this car was very popular for SS racing and seen alot of them leave harder then what i have . peak torgue is 704@5900 and 804hp @7400

Adger Smith · 08-09-2023, 08:36 PM

6500 is too low to shift.
converter guys all built them for an engine turning 7500+ by looking at the dyno sheet. your 6500 shift makes the RPM fall way below peak TQ. The converter is hanging and can't climb RPM back over peak Tq. If your going to continue to shift at 6500 you need a converter built for the power curve from peak TQ to 6500 on the dyno sheet. Your leaving power and ET on the table.
Shift it at 200 above peak HP on the dyno sheet with the converter you have and look at the ET/MPH.
You need to have a serious conversation with a good converter guy.. not a salesman.

tavirace · 08-11-2023, 07:45 AM

This may not apply but just thought I would share. I raced a stock eliminator Chevelle for years and it suddenly lost all it had, 60ft's, consistent lights,winning rounds were gone. I tried tires,converters, gears, rear suspension,shocks, nothing worked. I was telling a very talented racer my problem and they said, How old are your front springs ? They were Morosos at least 20 years old, I replaced them and everything went back to the way it used to be. If I was chasing something it's the first place I'd go.

08-09-2023, 08:56 AM	#1
hbr509 Junior Member Join Date: Jul 2023 Posts: 4 Likes: 0 Liked 3 Times in 2 Posts	Convertor help I have a 1986 Camaro Ed Quay built , I race it in bracket form now , Has Nesbitt 531 ,power glide 180 straight cut , 4.56 rear weighs 3200 , When I bought the car it would go 5.91 1.27-60ft and put it on the bumper , Convertor broke PTC , Car was shifting 6500 and would go 116.mph . I have been through 3 different companys and all convertors stall 6200 -6400, 1.37 60ft 6.10et 114 mph .Peak torgue @5900hp and 7400 max hp . There are a ton of these cars running SS . I,m at a loss need help please . My thinking is it needs 5500 stall . I sent the new PTC back to lower stall 500rpm ,going to test this friday and see Thanks

08-09-2023, 10:08 AM	#2
dragracerray Member Join Date: May 2017 Location: Webster, New York Posts: 157 Likes: 311 Liked 122 Times in 57 Posts	Re: Convertor help What did the old converter stall when the converter was healthy? Ray __________________ Ray Bassett I/SA 1687, SS/DA 1687 "SuperPro is both", unknown

08-09-2023, 12:49 PM	#3
hbr509 Junior Member Join Date: Jul 2023 Posts: 4 Likes: 0 Liked 3 Times in 2 Posts	Re: Convertor help I don,t know , I only know shift is 6500 and so had to be somewhere around 5500. I called PTC and gave them the number stamped on convertor to duplicate but what they sent was to loose ,as soon as i left the starting line it was in high gear

08-09-2023, 03:17 PM	#4
dragracerray Member Join Date: May 2017 Location: Webster, New York Posts: 157 Likes: 311 Liked 122 Times in 57 Posts	Re: Convertor help It is very possible that PTC did not make the last change to the old converter. If so the stamped number is meaningless. I would try to learn what you can from the broken converter. If you don't know who changed it last send it back to PTC, cut it apart, and see if they can determine how it was built. I would agree from what you are saying that you need a tighter converter. __________________ Ray Bassett I/SA 1687, SS/DA 1687 "SuperPro is both", unknown

08-09-2023, 03:32 PM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,351 Likes: 435 Liked 678 Times in 262 Posts	Re: Convertor help With the MPH down I would say the converters are too loose (% of Slip not stall) compared to the broken PTC. I like the idea of sending the broken converter to Lane and Kenny at PTC to cut open and study. There is a lot more to getting a converter to work correctly than just getting stall correct. ( Fin size and shape and angle, stator degree and back angle, ect) Like said earlier Your broken converter may have some changes that the numbers don't reflect. __________________ Adger Smith (Former SS)

08-09-2023, 04:34 PM	#7
L.Fite Member Join Date: May 2020 Posts: 390 Likes: 390 Liked 353 Times in 177 Posts	Re: Convertor help So... I know nothing... But stall should be around peak torque and shift at or above peak H.P. I would send a dyno sheet to whomever you have build your converter... They should be able to get you real close... I always had good luck with Coan, and ATI... Like I said I know nothing, just my going by my experience...

08-09-2023, 05:25 PM	#8
hbr509 Junior Member Join Date: Jul 2023 Posts: 4 Likes: 0 Liked 3 Times in 2 Posts	Re: Convertor help Thanks for the replies , The original PTC that blew up was sent to FTI and they said it was not salvageable, My fault for not getting it back , and yes I,m sure it was changed from original specs, I sent FTI, ABRUZZI AND PTC dyno sheet and motor build sheets all convertors where 6200-6400 on racepack also all ran the exact et and mph Great for bracket racing but 10th slow in 60 ft does not wheelie anymore so no rotation . I shifted at 7200 with those convertors , My thoughts are this car was very popular for SS racing and seen alot of them leave harder then what i have . peak torgue is 704@5900 and 804hp @7400

08-09-2023, 08:36 PM	#9
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,351 Likes: 435 Liked 678 Times in 262 Posts	Re: Convertor help 6500 is too low to shift. converter guys all built them for an engine turning 7500+ by looking at the dyno sheet. your 6500 shift makes the RPM fall way below peak TQ. The converter is hanging and can't climb RPM back over peak Tq. If your going to continue to shift at 6500 you need a converter built for the power curve from peak TQ to 6500 on the dyno sheet. Your leaving power and ET on the table. Shift it at 200 above peak HP on the dyno sheet with the converter you have and look at the ET/MPH. You need to have a serious conversation with a good converter guy.. not a salesman. __________________ Adger Smith (Former SS) Last edited by Adger Smith; 08-09-2023 at 08:39 PM. Reason: add

08-11-2023, 07:45 AM	#10
tavirace Junior Member Join Date: Oct 2021 Posts: 31 Likes: 6 Liked 18 Times in 13 Posts	Re: Convertor help This may not apply but just thought I would share. I raced a stock eliminator Chevelle for years and it suddenly lost all it had, 60ft's, consistent lights,winning rounds were gone. I tried tires,converters, gears, rear suspension,shocks, nothing worked. I was telling a very talented racer my problem and they said, How old are your front springs ? They were Morosos at least 20 years old, I replaced them and everything went back to the way it used to be. If I was chasing something it's the first place I'd go.