help! boosting 5th gear?

phen0m

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Hello all,
I searched around but could not find a good answer for my question. I have a kb 2.4 with a 10 pound pulley (520/480) and am running 3.90 gears. I'm thinking I will run out of 4th gear before finishing the quarter mile and was wondering if its safe to boost 5th. I'm running a stock 03 motor (sct dyno tuned) with a head cooling mod, bigger radiator and heat exchanger. Not that it matters but the tranny and rear end are built. Any thoughts? Thanks!
 

phen0m

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Have not been to the track yet with the new setup was hoping to make it before it gets too cold. I'm running nitto 555r 17/9 wide
 

Posi

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You might have to tach it up a little bit but you should easily still be in 4th gear.
 

BO TY KLR

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With that HP I'm guessing you'll be fine in 4th in 1/4. But to answer the 5th gear question. I have pulled 5th all the way to 6500 a few times. Just make sure you don't make back to back pulls and give it plenty of cool down between long 5th gear pulls.
 

cobracide

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Don't boost in overdrive gears 5 and 6. Closely monitor temps and add power if you want to push the edge and go further. Low 300's head time to cool.
 
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Posi

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I ran my 2.3 Whipple up to 6,800 rpm's at the track when it was on there. Powershifted at that rpm too. Just get the car cooled down and if you have to tach it up in 4th it should be perfectly fine.
 

mustangman36578

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should be fine. i have similar numbers (472 rwhp 500rwtq) and a 4.30 gear with 28" tall tires. the tires bring the gear about .3 so it would be like running a 4.00 on the normal size wheel. Im trapping 124 mph and going through at about 6,800 rpm. if you spin a lot off the line you may end up hitting the limiter going through the traps. only real way to know is run it.
 

phen0m

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That's true, I do need to run it and see where I am. I try not to rev over 6,000 rpm per KB instruction which is why I thought it would be so close.
 

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