Hi guys is there any way to know what the rear gear ratio is? I'm running a T5, with a 347 stroker, at 70mph Im turning 2,000rpm
Visit our community sponsor
Hi guys is there any way to know what the rear gear ratio is? I'm running a T5, with a 347 stroker, at 70mph Im turning 2,000rpm
I am assuming you are in 5th at the time. I would say ether a 3:27 or 3:31
99/2000 NASA PSO Champion-2005 west coast FFR challenge series Champions
Sponsor Tony B's 2007 ST2 National Championship
2009 NASA TTC runner up-2010 NASA TTB runner up
I’d say Gordon is right on... with a 308 year you’d be going about 77-78 mph at 2k
FFR 5136 Started as a donor...donor guages, engine, trans,etc. Now...TFS street intake,stage 1 cam, GT40p's,24# injectors and 80mm MAF,70mm TB,Z-spec t-5, and PSE Halibrand wrapped with Nitto 555 G2’s. My ever evolving dream car!!
Since there may be some speedometer error try this---jack the rear of the car up, mark the tire and the driveshaft and count how many revolutions the driveshaft makes for one revolution of the tire. 2 3/4 turns=2.73, a little more than 3=3.08, 3 1/4turns=3.27 or 3.31, a touch more than 3 1/2 turns=3.55 and about 3 3/4 turns= 3.73.
Jeff
For reference, as Gordon states, my stock 302,T-5 with 3.08 does turn 2,000rpm at 78mph.
Dave
Mk 3.1 - #6882 - 5.0L 302 - FiTech EFI - 3-Link - 3.08 Ratio - 15" Wheels
Greenhorn and doing the best I can
My photos are at: My Flickr acct
Videos are at: YouTube Videos
Your GPS speed will be accurate. If you get the RPM in 4th gear (which is 1:1 ratio) at 70 mph you can plug those numbers into this calculator to figure your gear ratio.
http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php
You'll also need to measure your tire diameter to assure accurate results.
Mk IV Roadster, 347/516 HP, 8 stack injection, Holley HP ECU, Astro Performance T5, 3-Link 4.10 gears, A/C, PS, PB Purchased 08/2015, Graduated 02/2017