70 RR
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I have heard guys saying they run 15lbs in their ETs. Does this sound about right?
ET Street 295/55R/15 drag radials psi?
- Thread starter 70 RR
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That depends on the car. I tried 8lbs once because a guy in a Cuda was doing that and hooking up nice. Trouble is my GTX had more overhang at the rear and different weight dispersion, didn't handle well at all. Ended up running around 13-15lbs. Once again, different factors determine pressure - heat in the track, ambient etc...
70 RR
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I will try 13-15 with my roadrunner and adjust from there. Thanks for your input, l appreciate it very much.
66Satellite47
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Used 12.5 - 13.5 in my 325/50R/15's. Car is 3850# w/me, 500", 4.10, 10" 3200 conv. Try 13 - 15.
Car hooks well at 17-18psi, 1.40 60 foot.
Doug
Doug
Mike Gaines
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I talked to tech at M/T and they told me NOT to run less than 12-13lbs in any M/T tire that is 28" tall or less" with a HEAVY CAR...such as 3500lbs or more. M/T TEC told me that lower than 12-13lbs with a heavy car would just crush the tires and make the center cup up and get contact on the outer sections of the tire. But with a tire that is TALLER THAN 28" can run the lower air pressure even with a heavy car. This is not my opinion...just what M/T Tech told me.
66Satellite47
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Good to know. I tried 15 to start with and seemed greasy, but like with lots of things a little verification goes a long way. I use 18 -20 on the street.
Shocks are a big influence with the radials. With sidewalls being stiff the shock has to hit the tire hard early and then stiffen up very quickly afterwards. With custom shock valving we picked up consistency and 60 ft. With the old shocks we had to limit the power at the hit. Occasionally we could get in the 1.5 range, usually 1.6 and inconsistent. After the shock change with the exact same pair of tires we could run 1.40 effortlessly w/o spin.
Doug
Doug
SUPERSTOCKRACER
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SUPERSTOCKRACER
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383man
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I actually run radial slicks all the time and they hook good for me at about 16 psi. It took some getting used to when years ago we would run like 8 lbs in the old bias slicks. I run my tires up to 28 and drive them on the street and then drop them to 16 at the track where they work good. Ron
Mike Gaines
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Ron, My life will be complete when I get my new stroker motor in my Coronet and pull the left front wheel on the launch like you do. My new 512" motor is being built to my specs to be right at 600HP and 650FTLBS of Torque. I don't really want more because I want to take it easy on my trans and my 8 3/4 rear end. I just installed a complete CAL TRAC system with MonoLeaf springs/Traction Bar Setup and their 90/10 front shocks and their rear shocks. I also just put on a brand new set of M/T ET DOT slicks 28x13.50x11.25 wide and have them screwed to my Weld Wheels. I plan on running 12-13 lbs. I am hoping for 10.70's.I actually run radial slicks all the time and they hook good for me at about 16 psi. It took some getting used to when years ago we would run like 8 lbs in the old bias slicks. I run my tires up to 28 and drive them on the street and then drop them to 16 at the track where they work good. Ron
383man
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Wow that Cal Trac setup looks real nice. And so do the tires. I figure I make right about 600 flywheel hp by my et , mph and weight of the car. Thats about what the calculator said I used to run 10.70's at almost 125 at just over 3700 lbs. Good luck with the 512 as you will love the torque it makes as it will plant you back in the seat very nicely ! Ron
70 RR
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You say you used Cal Trac shocks both front and rear? 90/10 front and 50/50 rear correct? My car is primarily a street machine, I am not going to set it up as a full race car. I have cal tracs with the super stock springs to try and help launch my 542....BTW, all off you have awesome cars, thanks for your input!
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I placed 2nd last weekend at the Summit Piston Powered Autorama Show at the Cleveland IX Center. I was in the Conservative Hardtop 70-79 Class.
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sorry not to get off subject
Calvert CalTracs recommends not using
Super Stock Springs combined with CalTrac Bars,
kind of defeats the action/function of the S/S springs,
IIRC they said use/recommended
either use the stock type OE multi leaf,
or their mono leaf springs &
not the S/S springs
doesn't mean they would work, just not recommended
Anyway carry on
when I was running M/T Drag Radials 315/50/15's with my 479ci 68 RR
I ran them mid 20's psi on the street, if I was on curvy roads like 25-28psi &
usually got best results at like 16psi at the lowest point,
I tried with any success on concrete starting pads,
little loose & washed out/wandering feeling on top-end thou &
18-20psi was pretty good/optimal for @ the track, depending on specific tracks,
that's if there was decent prep done
Calvert CalTracs recommends not using
Super Stock Springs combined with CalTrac Bars,
kind of defeats the action/function of the S/S springs,
IIRC they said use/recommended
either use the stock type OE multi leaf,
or their mono leaf springs &
not the S/S springs
doesn't mean they would work, just not recommended
Anyway carry on
when I was running M/T Drag Radials 315/50/15's with my 479ci 68 RR
I ran them mid 20's psi on the street, if I was on curvy roads like 25-28psi &
usually got best results at like 16psi at the lowest point,
I tried with any success on concrete starting pads,
little loose & washed out/wandering feeling on top-end thou &
18-20psi was pretty good/optimal for @ the track, depending on specific tracks,
that's if there was decent prep done
70 RR
Well-Known Member
My mistake, I have stock springs and not the super stocks....
383man
Well-Known Member
Talking about awesome cars that 70 Roadrunner you have is as or is more awesome then mine is thats for sure ! I love the 70 Runners and thats a beauty you have there. Have you raced it yet with the 542 beast in it yet ?? My 63 is a streetcar also that gets raced once or twice a year when I can. I built it with good quench in the eng as I wanted to be able to drive it anywhere and get pump gas anywhere I went with it. I do agree with you as these guys on here have some awesome Mopars including that fine Roadrunner of yours ! Ron
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