Which One?

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MOPARJ

MOPARJ

What can I upgrade now?
Joined
Nov 3, 2006
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Location
Thousand Oaks, Ca
At this point, with the near stock compression 318 in my duster, with Comp XE268 cam, holley 650 car, hookers, 904 with shift kit, 8 1/4 rear with open 3.21s and new stock converter, which one would be my best seat of the pants, performance gain that would help out my power combo the most:

1) Upgrade the converter to 2200 or 2400?

2) Add 3.55 gears with Sure Grip

I should also question bang for the buck.......
 
I'd would think if your willing to upgrade to 3.55's "with Sure-Grip"

4.10's "with Sure-Grip" will do more for the same $$$.

Otherwise, a 150 shot is just begging for low buck bang.
 
I think 4.10s are too steep. I drive this on the highway and am turning 2750 at 65 right now with 3.21s.
 
If you really want to feel a difference put 3.91's in it,for a good compromise between them and 3.55's put 3.73's in it...
 
What size tires are on your car now?

Gears would be the best bang for the buck. 340'srule makes a good and valid point. Your gear increase is very mild while 340's would provided a better banf and a ratio more suited to the cam and future stall speed you mention.

I went from 3.21 to 3.55's in my Magnum (w/a 400 B engine) It is noticable, but a very low return vs a stall conveter like you want to do.

It feels more like, ummm, closer to a good tune up after I changed the gears.
 
rumblefish360 said:
What size tires are on your car now?

Gears would be the best bang for the buck. 340'srule makes a good and valid point. Your gear increase is very mild while 340's would provided a better banf and a ratio more suited to the cam and future stall speed you mention.

I went from 3.21 to 3.55's in my Magnum (w/a 400 B engine) It is noticable, but a very low return vs a stall conveter like you want to do.

It feels more like, ummm, closer to a good tune up after I changed the gears.
Click to expand...

Well, my tires are quite tall, 245/70/15s I believe on the rear. It helps bring the revs down on the highway right now at 65 mph, about 2750. If I can get a 3.73 unit for the 8.25 rear and get it to turn no more than 3,300 on the highway, that would be the way I want to go. I can just slow down a little on the hwy.

If the picture shows up, the orange duster closest is mine, while the yellow cuda on the end is as well. You can see the tires on the rear of the duster.

3946760888ec3.jpg
 
I went from 3.23 geared 7 1/4 to a 3.55 geared 8 1/4. There was a difference but it was not dramatic.

I would think the converter would be the way to go. The XE268 cam in stock relatively low compression 318 would be pretty soft on the bottom end.
 
Can someone come up with a diameter of his tires?

I have 255/60/15's on my Cuda with 4.10's. Thats the approx. rom I turn on the Hwy. It's not to bad to live with. Just not everyday for me.

I say gear would be it, just not 3.55's. Thats why I ask ties size/diameter. Otherwise, If your set on 3.55's, the conerter would be it.
 
rumblefish360 said:
Can someone come up with a diameter of his tires?

I have 255/60/15's on my Cuda with 4.10's. Thats the approx. rom I turn on the Hwy. It's not to bad to live with. Just not everyday for me.

I say gear would be it, just not 3.55's. Thats why I ask ties size/diameter. Otherwise, If your set on 3.55's, the conerter would be it.
Click to expand...


Rob, I think you are right with the idea of 3.73s to make it worth it and very noticable. These tires are tall, so it does sap rpms down, but like I said, if I can stay around 3300 on the hwy, even if I have to drive 60 instead (just to cruises and on weekends; usually 20-40 miles on highwaqy), then I want to use the 3.73s.
 
I have used a few calculators, and I confirmed that I do have 26" tall tires. With 3.21s, the calcs show 2775, which is pretty close to what I am turning currently. I plugged in 3.73s and 3.91s for the hell of it, and I got 3,250 and 3,350 respectively. Both are not too excessive and I can always slow down 5 mph and be at 3,000. I think I can live with both and I think the little teen' can take it. Shouldn suck too much more fuel, as it should be in the torque range of the cam, relatively speaking.

With that neglegable number of a difference in rpm, would 3.91s be the best choice, or should I just go with 3.73s and have decent gains still?
 
Heres a simple formula for calculating tires sizes your self,they are usualy a little shorter when installed since most rate them at maximum tire growth.Section width times series divided by 25.4 (to convert mm to inches) times two plus your rim size equals the tire size.For exmaple,245/60/15,,,245 times .60=147 divided by 25.4=5.78 times two =11.57 plus 15=26.57.
 

I haven't added stuff to calculate ideal tire diameters from sidewall info (ignoring rim width and such), but I made a calculation spreadsheet a while back to figure speeds and engine displacement (including bushels!). There's a formula to calculate fuel cost on roadtrips as well.

Do the right-click -> 'Save As' thing here for countless hours of mathematical enjoyment.

Note: the cell noted as 'OD' can also be used for ratios of other gears. This is handy for various things such as comparing shift points to torque and/or horsepower curves. I got tired of calculating the stuff the long way.
 
I have decided to go with the torque converter, as I want to keep my low cruising rpms. The converter will help on the bottom end. I am thinking 2200-2400. Would this be a good range to shoot for to help this motor out of the whole and wind her up quicker? It is a bone stock converter currently(1600?)
 
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