have to shift to over drive before end of track need some help on what to do

[GrandNational87]

while im in third gear near the end of the track i start to hit red line.. i have a new tranny and shift kit made for low 12.s but i seem to be running out of rpm's so i shift into OD.. dont know if thats to good, but what can i do.. ive also heard that different tire size makes a difference but i dont know.. if any suggestions that would be great thanks..

 

[GNsQuick]

either change to taller tire, change gears or shift slightly to higher RPMs in each gear if u can. Dont like to shift to OD!

 

[XLR8]

What size tires are you running? 100 mph is way to low to have to shift into OD - unless you have very small tires or a taller than stock gear. I have a stock long block and was running 113 mph with 275/50/15 Nittos and now have been 118.9 mph with 27" tall QTPs. I think I'm around 5500 through the traps but I don't have a tach. (I don't think I'd have time to look at it if I did)

 

[UNGN]

Lock the torque converter.

Switch to 28" tall tires.

Also know that the fatory tach is worthless. Do not use this to judge RPM. Use a scan tool like turbolink to determine RPM/mph to check for converter slippage.

 

[GrandNational87]

ok thanks i get my scanmaster in i think like friday or hope so, then i will check that out.. thanks for the help

 

[REDS HOT AIR]

yeah no way at 100 mph are you at redline unless youre converter is trashed

what size tires and what rpm are you shifting at?

 

[GrandNational87]

225/50/16.. it wouldnt be the converter cause i just had that and a tranny done a month ago or so...

 

[UNGN]

Those tires are too small. They will limit your top end potential by at least 5 mph in the 1/4.

255/50's will allow 110-113 mph. 225/50-16's are only 25" tall.

If they aren't hurting you now, they will be soon.

 

[GrandNational87]

so whats a good tire size to get for 16 inch wheels

 

[UNGN]

Originally posted by GrandNational87
so whats a good tire size to get for 16 inch wheels

255/50's are the same height as stock. You can run 110-113 mph before you have to worry about them hurting top end.

 

[GrandNational87]

alright thanks