foru2nv4

Right now I am looking at installing 4.10 gears on a 2003 mustang that has a twin screw supercharger. My question is that right now with the stock 3.27 gears there is no passing gear in 4th. when you need to pass at 45 mph on a road you have to down shift to 3rd gear to get passing power at 45 MPH. well I did not have this problem when it was stock V8, 4th gear worked fine but now it seems with the SC install I lost that and I am wondering going with 4.10 rearend gears would get me back to as if it was stock?

jwarner0297

it will increase the rpms you are at in that gear at that speed so you will have more power.

foru2nv4

Thank You for your answer. I have gotten people at work that don't own a v8 mustang tell me that is to much gear for a v8. I disagree with that because with the engine being a 281 4.10 gears would be just right to get it back to as if it was stock. The supercharger I put on it has changed the gear ratio and I want it back to as if I was driving it normal. I could understand 4.10 gears being to much in a supercharged camaro that has a 350 engine in it which mustang does not. Right now even supercharged on a 281 engine you have to run the rpms up to 2500 rpms even before the SC kicks in. Right now on take off without reving the engine up it still lacks power so I am hoping 4.10 gears will fill that space plus the passing gear space at 45MPH and I can leave it in 4th gear to pass without down shifting to 3rd. I am hoping it puts the car right where it needs to be.

defconfire

Wait... you are saying you lost low rpm torque with a positive displacement supercharger?

What brand of supercharger?

ddmsgtr1

For an N/A 4.10s are not too much, you can even do pretty well with them on a centri car. But on a roots or twin screw, the consensus is 4.10s are too steep. And +1, how are you loosing low end power with a blower that is known for just that?

foru2nv4

I have no Idea can you explain that to me I have a saleen series IV twin screw supercharger and I am loosin lots of power in 4th gear at 45MPH have to shift down to 3rd gear to geat any passing gear speed at 45 MPH. Some how with the stock 3.27 gears and saleen series IV SC in a 2003 Mustang GT I am loosin power in 4th gear for passin what is going on its a brand SC. I am thinkin that the SC sucks with 3.27 gears?

pcs

so you have an auto tranny?
any ways 4.10 can be to low for a screw type blower usually centri s.c go that low to get their rpms up, with a screw you dont want to low or youll just burn out all the time. if you car is losing low could it be your tune?

pcs

so you have an auto tranny?
any ways 4.10 can be to low for a screw type blower usually centri s.c go that low to get their rpms up, with a screw you dont want to low or youll just burn out all the time. if your car is losing low end power could it be your tune?

defconfire

Have you have you dynoed it yet?

Yellow Fever had a Saleen S/C and was running like 12psi and could only pull 294 rwhp.

I honestly was expecting you to say it was a saleen.

But it should NEVER feel slower after a supercharger particularly w/ a positive displacement one at low rpm, one of the biggest benefits you get with a Positive D. superchager is nearly full boost and more torque at every point in the rpm range. (Idle to redline)

foru2nv4

I have a saleen series IV supercharger on a 281 engine with 3.27 gears stock. it has an upgraded catback exhaust system made by spl 1 and an upgraded pulley to a smaller one from 3.10 to 2.90 pulley on the saleen supercharger and a 75mm KBB throttle body upgraded from a stock 58mm TB so the car feels good but only if you rev. the engine up to 3200 RPMs before take off with 3.27 gears stocks. I am lookin at puttin 4.10 gears in with this saleen SC without revin the engine up to 3200 RPMs, I want to be able to take off from the stop light with never rev.in the engine up will this(4.10) gear put me at what I need to b at if the engine was stock? That is the QUESTION?