While I was in California I got a chance to talk to Steve Millen about their 3.90 gear. Here's what they laid out for the forum, and I'll post my thoughts below:
Stillen said:3.9 Gear Ratio
Stillen has finalized the R&D process on a 3.9 gear ratio upgrade for the venerable Ford GT. We are interested in your feedback before we begin production. It is our goal to produce the type and quality of products that you are most interested in for your vehicle and want to focus our efforts accordingly. Do you see value in this product? Would you be interested in purchasing such an item? This is your chance to help bring an amazing product to market.
Why would I want to change the drive ratio?... you ask:
During development of the GT, Ford set many performance goals some of which were for the sole purpose of achieving specific “paper” milestones. As almost every driver knows paper goals don’t always jive with real world practicality and fun. One such “compromise” was Ford’s insistence that the car reach 60mph without a shift. This was to insure that any editor, journalist or critic that got his hands on the car would achieve blistering 0-60 times by removing as much driver input, and potential error, as possible – a paper goal.
The compromise with the shift-free 0-60 goal is that gaping spans of rev’s must exist. This results in large RPM drops between gears forcing the engine to work much harder in the unavoidable low rev’s as the car claws its way back up into power. The GT currently overcomes this obstacle with brute force. This is all the work of the stock 3.3 ratio that creates something of a no-mans-land at speeds and shift points that are critical in the real world. Track days and spirited driving benefit most from a nimble drive ratio that allows the driver to keep the car in peak horsepower range as often and as quickly as possible. One should not have to decide between pinging the rev limiter or plunging the RPM under the power band and waiting as the supercharger hustles at full boost to push the car back up into power.
Now you don’t have to. Steve Millen, fresh off his grueling, week long, track experience with the GT, had had enough of this torque shuffle and teamed up with Ricardo to develop a gear ratio more befitting a car that demands to be driven. After all, the world is not paved exclusively with straight lines, turns are inevitable. In fact true enthusiasts typically seek them out. The race prep of Steve’s GT included Penske coil-overs, Eibach springs, an AP Racing clutch, AP Racing 6 Piston front calipers with 2 piece cross-drilled and slotted front & rear rotors, Stillen performance exhaust and race pipes, and a Stillen/Eaton blower upgrade, and yet the car’s performance still suffered substantially from the black holes in the drive ratio. Immediately upon his return Millen and Ricardo put to work at solving this deficiency. The result is a perfectly balanced 3.9 ratio upgrade that can be installed on any GT by STILLEN’s specially trained master technicians. Why? Superb agility and more fun from a car that sets a high standard right out of the box.
This product is near production ready and we would like to know what you think before we invest in mass production. Please post your opinions here or, if you prefer, please email them to smillen@stillen.com. Thank you for your interest and participation.
Factory 3.3 Ratio Redline Speeds
1st: 62mph
2nd: 95mph
3rd: 131mph
4th: 171mph
5th: 210mph
6th: 255mph
STILLEN 3.9 Ratio Redline Speeds
1st: 53mph
2nd: 81mph
3rd: 112mph
4th: 146mph
5th: 180mph
6th: 220mph