G3 HEMI Aussie Valiant Ute

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I use caltracks :)
I think i lose time because of shifting times going into 4th.
You think shifting earlier (lower rpm) and going into 4th is a progress? Power peak is where around? 6000 rpm? That's tight but will give it a try...:)
 
Mo- Cars - for every 1" tyre diameter..its roughly the same as going up or down 1 gear ratio.

Eg - 26" tyre / 3.23 ~ 27" tyre / 3.5s. If that helps.....

Buschi - so is your 60ft a teaction issue or just slow launch?
 
Rat Patrol said:
Mo- Cars - for every 1" tyre diameter..its roughly the same as going up or down 1 gear ratio.

Eg - 26" tyre / 3.23 ~ 27" tyre / 3.5s. If that helps.....
Click to expand...

I think you might have that reversed 26" tire would be 3.55 while 27" tire would be 3.23. A taller tire would equate to a lower numerically or taller rear end ratio.

Otherwise, you bring up an excellent point. Assuming you have the room making changes to tire height can play an important role in tuning. Thus if you wish to go through the traps near redline in fourth gear you can tailor your speed with a change of 1"- 2" in tire height.

One other thing to consider. Given two tires with the same width, the taller tire has a larger contact patch. So if you reduce your tire height from 28" to 26" to put a little more gear in your car, you could end up with a traction problem because of the smaller contact patch. You might erroneously believe that your new found traction problem is because of the now lower effective gear ratio when the smaller contact patch might be the culprit.

You can play around with different tire and final drive ratios here:

http://www.csgnetwork.com/multirpmcalc.html

Regards,

Joe Dokes
 
Thanks guys , in my case lowering the effective gear ratio numerically is the desired out come .

Bushi340 , Yes I think try these things , It will do no harm .

Give me a couple of days I will upload a stock 6.1 dyno printout .
 
i don't see me much from outside but a buddy said the speed of 178 kph is saying high 11s. He also said tracktion probs are visible. and mostly when I am launching with higher rpm ( 2500 around ).
and I thought a 60ft of 1.9 sec is super good... hahahaha. because the MT Semis and caltracs brought me down from 2.6 to 2...
ok, launches i will try again. using 4th gear i will try. smaller front (195) tires will help I bet. currently street tires all season 215/60. And a diet.... :D
 
Buschi you don't need to side step the clutch at 4500. I have A VALIANT CHARGER with 410 small block. When I dump the clutch at about 2500 rpm I can get no better than about a 12.2 ET. It took me a long time to learn that when I dropped the clutch just a little above idle, 1200 rpm it just jumped out of the hole and did a 11.7 @ 117 mph with a 1.68 sixty foot. Every time I dumped the clutch with more revs on it would just wheel spin all the way through first. I have m/t drag radials and caltracs. I have purchased a set of m/t drag slicks in 235x15s (26 inch) and hope to be able to be more agressive on the launch revs and maybe do a low eleven.
 
can also caltracs adjustments making those differences? I currently turn them 360 degree ( full turn ) and lower hole

( i am sorry for crashing this thread but it is so interesting and helpfull right now !! )
 

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Wade UhCoog on here has the Megasquirt thread on here, and it was him who sent me the timing maps, I give him the credit. He based his off of a factory Gen III. They have like 10* at idle.
 
Joe - What Im saying is that running 3.23s and a 26" tyre, is almost the same as running a 27" tyre with 3.55gears - the rpm at 60 mph is very close.
 
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