4.10s back to 3.55s ???

[vladasap]

hi guys ... im having a serious debate here
its a 95 gt with a mild HCI (gt40s ported polished, gt40 upper n lower......) & of course the 4.10s ***dynoed 275rwhp & 307rwtq

when i just got the gears i loved them but having to shift at 5600rpm or so im only at ~90ish and through 4th gear already and i feel that im through the gears waaaay too quiclky, as if i dont give the car enough time in the gear to make the power....

i am debating going back to 3.55s cause a friend of mine has a 95 cobra with less rwhp & rwtq than me with the 3.55s and we are neck to neck with my damn 4.10s on the highway (and even off a dig we are not too far apart)

am i crazy for thinkin of going this route??????

is it possible that having to shift so soon is causing me to actually run slower???
i cant stop believing that if i had longer gears that the car would get upto higher speeds quicker

help pleaseee :SNSign:

 

[final5-0]

I would think you could pull a bit higher than 5600 in each gear

Perhaps the OEM intake is holding you back

I guess I'm trying to ask if you still make power
or
If you are starting to fall off at the 5600 point

Got any dyno charts or strip data from different shift rpm's???

Grady

 

[Pokageek]

When I went from 3.90's to 3.27's the car held the gear longer and the power band longer. I know what you are talking about and it depends what speed you are at and what gear. The 3.55's will relatively hold and then pass the 4.10's HWY. QM and slicks different story but I dont do QM.

 

[vladasap]

unfortunately in my move to school last semester i lost all my paper work so i dont have anything to post. As far as when the car looses power.....the power band drops significantly btwn 5600 and 5800 rpm so i figured 5600-5700 was the perfect shift point in my case.
The car really doesnt see the strip all that much (twice in the last two years) so yea it is the highway that im concerned about.
Basically im not crazy for thinkin of going with a longer gear right???

And Pokageek, did you regret making the switch from 3.90s back to the 3.27s?????

BTW the reason all of this came to mind was youtube.com as well. I see all these guys get upto 60-65 in 2nd gear and it seems to me like it takes me a lot longer to get up there with all the shifting. On their videos it just looks like the car hauls ass and gets up there really quick...(and not to mention they still have 2 gears to go through)

 

[final5-0]

No ... I'd not think you are crazy for considering a gear that does
not produce as many rpm's at highway speeds

Like a lot of things ... Application dictates reason for doing a mod

If you do a LOT of highway driving .........
A steeper gearset will rev higher as the speeds are higher

I absolutely love steep gears for my hot rod
but
Since my senior year in high school .........

All my hot rods have NOT been my daily driver

Most of my cars had 457's in a 9 inch rear
and
Back in those days ... 4 speeds only ... so ... final gear was 1 to 1

If you only got one car
really steep gears can cause more of a compromise you could say

Grady

 

[Pokageek]

3.27's were great in my o. When I switched them I still had my 306 running around your rwhp..290+rwhp and 310rwtq with cats. The car held the power longer and as a result, I liked it better.

My 3.55's are perfect for my powerband and trans set up. I have had a 302 , 306 and 414 and with your set up 3.55 would be perfect. I had my 5th custom made more hwy than the stock trans. I am running .64 instead of your .68 5th gear and I wouldnt want to rev any higher. 3.73 would be too high for my taste. I am in the process of making the car street friendly. THAT is what makes the car fun to me. Gears are a part of that.

For another example, I am going over 500HP and the car gets louder the more power I add. I am sooner or later getting those corsa muflers to get the loudness out of the cabin and dyno-mating the floor. Right now its too loud for me. Sooooo-> Too steep a gear AND too loud a car = Not my style. I dont care if it makes it 2 tenths faster in the QM.

 

[BlackVert]

heh, i've been all over the map too. in my 1996 gt, it had 3.27s and was a dog. then i had 4.10s put in, and while they really woke up 3rd gear, i grew very tired of the high rpms on the highway and the almost nonexistent 1st gear. i also didn't like not having an accurate speedo and odometer.

then when i sold the 96 and bought the 95, it had 3.73s already installed. i liked them, but again, the speedo and odometer were still off which i didn't like.

then when i went to the 410 (cubes, not gear ratio), i also went back to 3.27s, thinking that that was a better fit for the power band and my goal for a very streetable, easy to drive, ride that had accurate gauges.

i like it this way, but i am still considering going back to the 3.73s (they are sitting in my basement) because i am sure it would wake up the car. even though it is easy to smoke the tires from a stop, i can feel it bog a little after it hooks.

but then i'll feel even more like stepping on it, and i'll start winding it up more, and then the fact that my upper intake (typhoon) doesn't flow well enough will be much more noticeable and i'll have to get a new intake, and then my STB won't fit and my hood won't close so i'll have to get a new hood, ...

so maybe i'm better off just leaving it alone

 

[Pokageek]

Hehe yea I hear ya. I'm tired of fooling with it too. Chris also has a auto - FYI.

 

[Zero Signal]

If you feel you're going through the gears too quickly then definitely change them. You really only want a steep gear if you can sustain really high rpms. A steep gear is not much of a replacement for more HP. It's too bad you don't have a dyno chart for us so we can at least calculate your shift points.

My personal theory on choosing a gear comes down to what gear did you want to max at the end of the 1/4 mile. So if your're trap speed is in the 90s, it might be best to stick with a gear that you can trap in 3rd with. If you'r trapping 105+ then 4th might be best so choose a gear that will use all of 4th to make best use of that extra shift. That's just MY way of thinking of it. In the past when I ran the numbers, it almost always came out to 3.55s or 3.73s for cars trapping under 100 and 4.10s and up for quicker cars. Typically, the quicker cars are revving into the 6.5+k rpm range though too.

 

[sick95gt]

I am honestly in the same boat as you. I am about to finally do an engine swap. Probably something that will put down 300-350 RWHP and I am ditching my 4.10's so quick and going to go with probably 3.55's. I could not stand the highway cruising at such high RPM. Also, 1st gear is worthless, so there is pretty much an unnecessary shift every time I came to a complete stop. For non aggressive driving, I would have to shift at 15mph everytime I was at a dead stop and that was pretty much annoying as hell. I had a supercharged RSX Type-S for a while and I loved how I could just drive it like normal and not have to worry about shifting so soon. Then when I got in the stang, I felt like I wasn't going anywhere because I would either spin through first, or have to baby it through first then shift to second. Either way, it was an extra shift. By the time I got to third in the stang, it felt like all I was doing was shifting and only doing like 40mph.

 

[Al J]

I have a similar H/C/I set up on my Mustang & my primary build purpose was to have a good street performer.
I had big gears in my previous ride (Sunbeam Tiger) and hated freeway driving, so I went w/355s.
Perfect for a 5 speed car & decent gas mileage, too.
Most of the board advice extols high horsepower hobby cars---few are daily drivers. You need an overall purpose before building---many here do not.
Take advice from whence it comes.