marty can u help me?thank you in advance!!!

One of the most critical areas of a automatic race car

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572 BBC
Posts: 105
Joined: Wed Nov 26, 2008 1:43 pm

marty can u help me?thank you in advance!!!

#1 Post by 572 BBC » Sun Nov 30, 2008 11:46 am

i have a 572 with big shot kit.i only shoot 275 shot of nitrous.question is...can a converter have best of both worlds?what i mean is stall to say 4000-4500 on transbrake and still be tight on the big end so as to say have only 5% converter slippage???

my motor builder says its typical for converters on nitrous will slip more than if not on spray...they said 500 to 1000 rpms more

my math says 160 mph on a 33" tire and 4.11 gears should run quarter at about 6700 rpms. and with 5% slippage , i should be @ about 7000 or so. but last time out i think i hit my rev limiter chip is 7600 before end of run and i let go of throttle before end of track.this is only second pass for me on nitrous and i probably should do more research.i will camcord tach next time out with a bigger chip in msd box

current converter is a TIGHT 9" .on transbrake it stalls only to 3200-3300 rpms.cam is 286/296@.050 on 112.

on motor only the math proves perfect and i go thru traps on formulated rpms!is it typical for a converter to slip more with more power(nitrous)and if so how much????

thank you for your time!!!

Marty Chance
Posts: 193
Joined: Fri Sep 19, 2008 6:34 am
Location: Cheney, KS

Re: marty can u help me?thank you in advance!!!

#2 Post by Marty Chance » Mon Dec 01, 2008 8:19 am

unfortunately this is not the answer you want to hear. Your motor is two completely different motors with totally different torque curves on and off nitrous. It is possible to build a "compromise" converter that will work ok with motor and small amount of nitrous , but it will never be perfect for both. Nitrous increases the stall and slippage of a converter because you have increased the torque and the torque of the motor verses the resistance (weight,gear,ect) is what dictates stall speed . if you want the car to run to its full potential on and off nitrous , you will need two different converters.
Neal Chance Racing Converters
Home of the World's Fastest Automatic Doorslammers!
www.racingconverters.com

572 BBC
Posts: 105
Joined: Wed Nov 26, 2008 1:43 pm

Re: marty can u help me?thank you in advance!!!

#3 Post by 572 BBC » Mon Dec 01, 2008 9:42 am

thanks marty!!!

my last thought is this,i can live with a tight converter formed to tailor nitrous,cause i can putt on the street what little i do(2 car shows a year)...if im seeing like 15% roughly converter slippage when on nitrous,and on motor it runs the exact or darn near formulated rpm, is this 15% slippage typical of a (quarter mile) nitrous pass???

thank you in advance,russ

Marty Chance
Posts: 193
Joined: Fri Sep 19, 2008 6:34 am
Location: Cheney, KS

Re: marty can u help me?thank you in advance!!!

#4 Post by Marty Chance » Sat Dec 06, 2008 9:41 am

the 15% slippage would be typical in the sense that it was 5% on the motor and it gained 10% when the nitrous was added but a converter designed for your car on the nitrous will have less slippage than 15%
Neal Chance Racing Converters
Home of the World's Fastest Automatic Doorslammers!
www.racingconverters.com

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