Supercharger vs. gears. Either? Or? Both???

[Spenser]

O.K. trying to decide which way to go here. I live in Phoenix and do 80% of my driving in the city and under 60 mph. I'd like a little more pep without having to always put my foot to the floor, you know, normal driving, smoother acceleration without a minor flat spot after shifting into second. I've added headers and exhaust, cold air box, and programmer, but would just like a bit more. Now, if I add the supercharger, my highway driving will surely be much better, say, driving up the mountain to Flagstaff, etc. But will I notice a large difference in normal driving conditions below say 2000 rpm? On the other hand, if I go with the 4.56 gears, I'm certain the town driving will dramatically improve, but will I lose the ability to drive say, 80-90 mph on the highway without really winding her up? I appreciate the thoughts and response. I'd consider both if there were a real benefit here. Thanks.

Kevin (casey2)
2005 Stealth Gray H2 SUV
2006 Ford Expedition Limited

[Spenser]

O.K. trying to decide which way to go here. I live in Phoenix and do 80% of my driving in the city and under 60 mph. I'd like a little more pep without having to always put my foot to the floor, you know, normal driving, smoother acceleration without a minor flat spot after shifting into second. I've added headers and exhaust, cold air box, and programmer, but would just like a bit more. Now, if I add the supercharger, my highway driving will surely be much better, say, driving up the mountain to Flagstaff, etc. But will I notice a large difference in normal driving conditions below say 2000 rpm? On the other hand, if I go with the 4.56 gears, I'm certain the town driving will dramatically improve, but will I lose the ability to drive say, 80-90 mph on the highway without really winding her up? I appreciate the thoughts and response. I'd consider both if there were a real benefit here. Thanks.

Kevin (casey2)
2005 Stealth Gray H2 SUV
2006 Ford Expedition Limited

[LasVegas]

The supercharger will probably give you what you're looking for without the need of gear changes.

[H222]

well if cost is no matter the supercharger although 5-7 thousand for a supercharger or a cool grand in gears. intake, catback, and a chip/programmer will get you along ways too

[Induction Concepts]

As others have said, if cost is not an issue, get the supercharger.

BUT, what I would do is get the gears first, since you're only talking a few hundred bucks. It will definitely make an improvement in the seat-of-the-pants-o-meter and its cheap.

THEN, if that isn't enough, you could go for the supercharger.

The lower gears (higher numerically) will affect fuel mileage, but I'm guessing that isn't much of a concern.

If it turns out that the gears alone aren't enough, and you add the supercharger, you may want to put the stock gears back in because the SC will give you the power that you want, so why lose the extra mileage of the low gears, plus the SC will decrease mileage itself from parasitic losses. So don't give your stock gears away until you decide for sure.

Gears won't hurt performance with the SC, in fact they will improve it over just the SC alone, but you may decide you don't need/want both, and you can always sell the lower gears pretty easily.

Gears are a great bang for the buck.

[Spenser]

I understand that the gears are a lot of "bang for the buck", however, my concern would be how will they actually affect my top end, I mean, has anyone done the math regarding the difference in rpm at say 80 mph? I believe that currently I have a 4.10 gear set and would be changing to the 4.56 set. Now if the supercharger can provide the added "zing" under normal driving conditions then all the better. I've added the exhaust, cold air box, headers, and programing, and they made a noticable difference, (however, I've been told that with the addition of the supercharger, the headers need to go bye bye) I'm just wanting to add a little more "zing" under normal driving conditions, and a hell of a lot more when I really need, or want it. Thanks for the response.

Kevin (casey.2)

[Induction Concepts]

I didn't know it had that low of a gear already. A change to 4.56's from 4.11's isn't going to make that big of a difference, in rpm or performance. If you were running a 2.xx or a low 3.xx, like a 3.27, then it would make a difference in both.

So, I'd go for the supercharger. Headers won't hurt a supercharger, anything you can do to make it easier for the engine to get more air in and out, will help performance and efficiency.

[KenP]

Spencer, I'm looking at 4.88's or higher. I'm waiting to find out the math for the 1/4 mile to decide. I don't want to top out early. BTW, I have stock height tires.

Going to 4.56's is like putting 33's on and really doesn't do anything.

[Induction Concepts]

Ken, here are a couple of links that might help.


Speed for RPM Range - This formula will calculate the speed of the vehicle at a RPM. You enter your tire diameter and your rear end gear ratio and it will display vehicle speed an RPM range from 1000 - 8000 RPM.

Speed for RPM range comparing rear gears - This calculation will display two tables with mph vs rpm range for two different gear ratios. It's handy for comparing different speeds for two different gear ratios. In other words how will changing my stock 2.73 gears to 4.11's effect my cruising speed. Same as Speed for RPM range below except with an additional gear ratio input.

And here's one more to help calculate tire dimensions:

Tire Diameter This formula will calculate the tire diameter from the tread width, series, and wheel diameter. In other words the stamping on the tire, example 275 60R15.