4.10 to 4.30's

[daveyboy]

Thinking about swapping my 4.10's for 4.30's or maybe even 4.56 depending on what is available. My 4.10's are not that bad on the street but i'm not sure about the lower gears. The reason I am concidering the change is when the car shifts into 4th i still have a fair bit of the track left(well before the 1000') and would like it to pull 4th a bit harder. As a side note I am trying to get max ET with out any performance mods. Except the ones I already have or ones that are required.(ex. tune.. for correct speedo reading...ect) Would it be beneficial to adjust shift points a little higher perhaps? What do you guys think?

 

[86GT351]

Thinking about swapping my 4.10's for 4.30's or maybe even 4.56 depending on what is available. My 4.10's are not that bad on the street but i'm not sure about the lower gears. The reason I am concidering the change is when the car shifts into 4th i still have a fair bit of the track left(well before the 1000') and would like it to pull 4th a bit harder. As a side note I am trying to get max ET with out any performance mods. Except the ones I already have or ones that are required.(ex. tune.. for correct speedo reading...ect) Would it be beneficial to adjust shift points a little higher perhaps? What do you guys think?

Can you be a little more specific on max RPM? What are you going through the traps at? What size tire are you currently running? What about your combination? NA car?

 

[daveyboy]

Oh yeah. good point. NA car, I don't like to go over 6500 rpm, 26" tire(stock size 235 55/17) and the exact rpm i don't know i'm guessing between 4000-4500 rpm. I wish i could be a little more exact but i honestly haven't looked. I know stock I was trapping around 3800, but that was with 3.31's

 

[86GT351]

Oh yeah. good point. NA car, I don't like to go over 6500 rpm, 26" tire(stock size 235 55/17) and the exact rpm i don't know i'm guessing between 4000-4500 rpm. I wish i could be a little more exact but i honestly haven't looked. I know stock I was trapping around 3800, but that was with 3.31's

No reason why you can't do at least a 4:30. You need to go to the track again before making a change and verify shift RPM and Trap RPM.

 

[daveyboy]

Yeah I agree. Im tossing up the Idea of bumping the third gear shift point a couple MPH higher then the rpm drop when shifting to 4th will be closer to where it needs to be....I think

 

[86GT351]

Also what Stahl is your TCI Converter?

 

[daveyboy]

It would be a 3000 tci (the cheap one)

 

[86GT351]

It would be a 3000 tci (the cheap one)

Might want to consider a better one! It works but you can get much better to maximize performance!

 

[daveyboy]

Ugg I know but they are so freaking exspenive.

 

[86GT351]

Ugg I know but they are so freaking exspenive.

Performance unfortunately comes with a cost. When building a car you need to maximize the dollars the best you can!

 

[conexion914]

What's your MPH in the 1/4? I have 4.10s and an auto with a PTC converter. I may be able to help figure out your rpm and mph.

Sent from my SGH-I747 using Tapatalk 2

 

[daveyboy]

104 on the average with an occasional 105 Probably depending on the DA

 

[conexion914]

With a 27" tire that puts you between 5300 and 5400 rpms at that mph

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[daveyboy]

Just remesured. My tire is 26"

 

[GTAmuscle]

Just remesured. My tire is 26"

235x.55x2/25.4+17 = 27.17 inches. Probably getting a little squat but at full speed there will be none and you'll be realizing full tire height.

4.30's will get you through the traps at about 5600 rpm
4.56 will be 5900

 

[daveyboy]

Oh that's interesting.

Looking at upgrading to This and selling the TCI unit I have
Unless of course TCI can upgrade my converter cheap enough

 

[conexion914]

I have a PTC single disc I bought here on the forum. It stalls between 35-3700 or so. It locks up in 4th gear only. The car has been 12.48 with a 1.74 60' on 255/50/16 et street radials. I don't think the jump to 4.30s would be worth it in my opinion. If I ever got to getting another daily driver I would consider a 4.56 for track purposes. I bracket race so going fast doesn't matter so much, but who doesn't want to get the most out of it. If you can change your own gears I say try it out. Otherwise put the money towards a better converter. Just my 2 cents.

Sent from my SGH-I747 using Tapatalk 2

 

[daveyboy]

I have a PTC single disc I bought here on the forum. It stalls between 35-3700 or so. It locks up in 4th gear only. The car has been 12.48 with a 1.74 60' on 255/50/16 et street radials. I don't think the jump to 4.30s would be worth it in my opinion. If I ever got to getting another daily driver I would consider a 4.56 for track purposes. I bracket race so going fast doesn't matter so much, but who doesn't want to get the most out of it. If you can change your own gears I say try it out. Otherwise put the money towards a better converter. Just my 2 cents.

Sent from my SGH-I747 using Tapatalk 2

I do my own gears so that's not really an issue. I probably will wind up doing suspension mods before changing converter or gears. I am thinking a 3500 stall and 4.30 gears would be perfect to maximize my combo. Not sure If I would like them on the street or not. Could also raise shift points a bit higher to stay in 3rd a bit longer. I really need to do testing. sigh

What motor and mods do you have

 

[NotQuik]

Maybe GT.350-R will chime in but if I remember correctly he went from 4.10's to 4.30's and now runs 4.56's with a 28" tire with a stock longblock 3v and as far as I know has no regrets. I want to say he is going through the traps at just under 7k with the 28" tire and trapping around 114 give or take alittle.

If I planned to stay n/a, that's probably the path I would take as well.

 

[Mike K]

I think he is running 4.88's now that he got sponsored by currie. I plan on 4.56's when I get a chance.