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  #91 (permalink)  
Old 11-28-2010, 01:59 PM
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but the street radial is the tire i was referring to and you guys both said drag radial cause they are two different tires did you mean street radial

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  #92 (permalink)  
Old 11-28-2010, 02:02 PM
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Quote:
Originally Posted by abigassbowtie
but the street radial is the tire i was referring to and you guys both said drag radial cause they are two different tires did you mean street radial
Nope, the Street radial (SR) is worthless from a strip standpoint, hard as a rock, just like a BFGoodrich Radial TA. The SR is a wide street rod/cruizer tire.
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Old 11-28-2010, 02:37 PM
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fair enough guess ill order a set of the drag radials what size would you suggest being as though i only have 4.10 gears would you go with the 28x13.50s or the 30x13.50s thanks for the advice eric

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Old 11-28-2010, 02:48 PM
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oh yeah do you run tubes in your drag radials ?

I do drive it on the street but mostly just to the drag strip and back wich is MAYBE 5 miles from my house other than that maybe 5 times a year and i really dont want to run tubes
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Old 11-28-2010, 02:55 PM
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The Drag Radials are tubeless tires. My guess would be you will want the 325/50R15 for its 28" height, unless you need to lower your finish line rpm.
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Old 11-28-2010, 03:47 PM
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well i dont know what its gonna do now I was running 106.4 mph with 3.73s crossing the traps at about 5500 but im hoping to get a little better than that for my mph this year but i had horrible horrible traction problems last season but i am gonna manually shift the tranny this year and get a shift kit in it hopefully that will pick up a bit of my mph and et with the new tires and lower gears

eric in one of your posts you said that you started shifting your car at 4700 to slow down your e.t. now when you do that does your mph drop as well
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Old 11-28-2010, 03:52 PM
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Quote:
Originally Posted by abigassbowtie
eric in one of your posts you said that you started shifting your car at 4700 to slow down your e.t. now when you do that does your mph drop as well
It impacted the ET far more than the MPH, finish line MPH dropped very little, only 1 mph or so. Hp made pretty much decides MPH regardless of gearing, but ET will change a lot with gearing or shift points.
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Old 11-28-2010, 07:19 PM
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so best case scenario for my truck would be mid 12s? till i make more power
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Old 11-28-2010, 07:21 PM
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so best case scenario for my truck would be mid 12s? till i make more power or get more power to the ground

when the truck shifts into third it will slip for a second unless i let off and stab it again makes me think it needs a shift kit!! any thoughts
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  #100 (permalink)  
Old 11-28-2010, 08:47 PM
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Quote:
Originally Posted by abigassbowtie
so best case scenario for my truck would be mid 12s? till i make more power or get more power to the ground

when the truck shifts into third it will slip for a second unless i let off and stab it again makes me think it needs a shift kit!! any thoughts
If it slips like that, a shift kit won't fix it or help at all , it needs a rebuild, at least that clutch pack(direct clutch) in the trans if not the whole thing. Shift kit just speeds up and more firmly shifts the trans, it won't fix a slipping trans and will often cause one that is in poor shape to tear up even faster. The instructions even tell you it won't fix a slipping trans.

You correct mid twelves may be all it has, but it depends a lot on gearing, tuning, and tire slip. 4 tenths in the first 60'(from say 2.1 to 1.7 seconds) will be nearly double that much gained in the quarter - 8 tenths or so, so tire slip really impacts things. The first couple hundred feet of track are the most important for ET.
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Old 11-30-2010, 08:13 PM
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well hell i was thinking it was just a soft shift from 2-3 but i have an extra tranny that works good in my crew cab so when i get my cummins in that this winter i will just use that tranny and rebuild the other in my spare time i guess

as for the e.t. I would really like to hit 12.0s but my machinist told me there is not enough meat between the top of the piston and the top ring land to run nitrous but do you think a 75 shot of nitrous would hurt it keep in mind i am running stock crank and rods

for my mph and weight at the strip the calculations say im only making 375 or so horsepower to the wheels wich is **** compared to what i was expecting I was thinking the calculations would say at least 400 hp to the wheels so maybe the tranny is screwing me more than i know or i just need to spend some more time tuning it I just dont know what else to do to me it seems like it runs great wish i had somebody that knew what the hell they were doing to help me

thanks
jeff
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  #102 (permalink)  
Old 11-30-2010, 09:00 PM
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my brother in law gave me a jeep th 400 that has a trans brake in it but got water in the trans due to the jeep being under lots of water and the tranny quit working I would really like to use the trans brake out of it but was curious if they make a trans brake with a forward shift pattern cause thats what i would like to do since i am still running a stock column shifter I have a floor shifter but its not for reverse pattern neither

thanks eric you have helped me more than you will ever know
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  #103 (permalink)  
Old 11-30-2010, 09:15 PM
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No one I know of makes a forward pattern transbrake valvebody. Nobody wants one racing because it would have you moving the shifter towards the neutral gear, nobody wants to hit that by accident.

Even a stock cast piston will handle a 75 hp nitrous shot without a problem. Small blocks w/cast pistons will generally be safe at 125hp, big blocks at 175-200 hp according to Nitrous Oxide Systems(NOS). Crank and rods will hold it no problem.

If you are having to get out of the gas to get the trans to hold in gear you are losing quit a bit.

The more a vehicle weighs the harder it is to make gains, or conversely the more hp you need to find just to get a noticeable gain.
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  #104 (permalink)  
Old 12-01-2010, 10:24 AM
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Quote:
Originally Posted by abigassbowtie
for my mph and weight at the strip the calculations say im only making 375 or so horsepower to the wheels wich is **** compared to what i was expecting I was thinking the calculations would say at least 400 hp to the wheels...
Until you're able to run the engine out to its HP peak before shifting to a higher gear, there's going to be some discrepancy between the actual HP and what you've calculated by allowing the trans to shift by itself in Drive.

As you've calculated it, you're likely north of 450 HP at the flywheel. This may not increase by a huge margin by shifting later, but I would be surprised if you didn't see more than that. I'd even go as far as to say 500 HP @ the flywheel isn't out of the question once the tuneup is right.

Unless you've modified the 1-2 shift valve, the TH400 will shift out of first by itself- regardless of where the shifter is at. This can happen as soon as 4000 RPM in a stock trans, so it's important if you want to hold first gear until you (not the tranny) is ready for the shift to second.


Image from Jakeshoe.

I would suggest the Trans-Go shift kit (BTW, don't forget a trans cooler), but as has been said- a shift kit is NOT a cure for a bad trans and will often hasten the demise of a marginal trans. But if all you're feeling is a slight "flare" on the 2-3 upshift, it can tighten this up- again, as long as it's not caused by wear or low line pressure, etc..
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Old 12-01-2010, 10:18 PM
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honestly i am thinking it is just a "flare" on the 2-3 shift it only does it for maybe a second at the most and it is just a bone stock trans out of a 91 1 ton chevy truck so i think i will try sticking a shift kit in it while its in the truck and seeing what it does since that is easier than pulling two trannys and putting one back in and then having one truck not running
and if that dont work ill build one and put a trans brake in

and thanks cobalt i do plan on doing that mod to the valve body just out of curiuosity does that also make it to where you can down shift at any speed also ???
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