Super Stalker V6 and 2.73 gears for Road Racing

[searya]

Hi I have been running my Brunton SuperStalker (pontiac 3800 v6 supercharged) for years now at track day road racing events. The car is fantastic but as the years go on I find my lack of top end speed and 5th gear being useless (I have a tremec t5) an issue when I try to keep up with with all of the 600-800 hp cars out there. I can catch them in the turns but damn do they make a gap on every straight!

 

So I am toying with the idea of changing out my 3.23 rear end with a 2.73.

 

Using my t5 a 5500 rpm max shift point and 23 inch tires this would increase my 4th gear from 117 to 138 which should be enough for most tracks.

 

Wanted to find out if anyone has done this and what they thought or if not if folks thought this was a good idea?

 

Below is what the current and new gearing would give me using this calculator (https://www.tremec.com/calculadora.php)

 

[TABLE=class: grid, width: 500, align: left]

[TR]

[TD]Gear[/TD]

[TD]Trans Ratio[/TD]

[TD]3.23 Top Speed[/TD]

[TD]2.73 Top Speed[/TD]

[/TR]

[TR]

[TD]1[/TD]

[TD]2.95[/TD]

[TD]40[/TD]

[TD]47[/TD]

[/TR]

[TR]

[TD]2[/TD]

[TD]1.94[/TD]

[TD]60[/TD]

[TD]71[/TD]

[/TR]

[TR]

[TD]3[/TD]

[TD]1.34[/TD]

[TD]87[/TD]

[TD]103[/TD]

[/TR]

[TR]

[TD]4[/TD]

[TD]1.00[/TD]

[TD]116[/TD]

[TD]138[/TD]

[/TR]

[TR]

[TD]5[/TD]

[TD].63 (useless)[/TD]

[TD]185 at lemans[/TD]

[TD]219 just before i die[/TD]

[/TR]

[/TABLE]

[JohnCh]

Are you only concerned with track days, or do you use the car on the street? If the latter, I'd wonder if increasing the diff ratio by that much would dull the fun? I did a quick search and found a couple of mentions of 0.80 ratio 5th gears available. That would give you a slightly taller gear than 4th with the 2.73 (146mph) and provide a far more reasonable gap on the upshift to 5th. 1.00 to 0.63 is enormous!

 

-John

[fastg]

It looks like there is a range of 5th gears option for the T5, from 25t to 33t.

 

Contact https://www.midwesttrans.com/t5-world-class-5-speed-manual-transmissions/

 

Graham