I will message you on FB

 

131mph

 

I'll give him 135

 

High 130s to low 140s would be great. 60-130 makes it seem promising. Geared for 145 in the 1/4 at the top of 4th so that should work nicely for what I’m hoping to trap

 

Okay I know I have not been on here in a while but I am interested to hear if anyone has data on this. I have talked about doing it for years but never took the risk. The 3.01 (or 2.97) 1-4 gear set vs the 2.66 close ratio set, and why? I have the stock 3.01 wide set and always had a terrible bog hitting that 4th gear in the mid 5000s, the car really seems to come to life about 6500 in 4th. If I swapped to the 2.66 close ratio set this would bring me up 600rpm ish of where I land in 4th gear, getting me past that hump in the bottom of the gear. But is it going to be a major change on starting line ratio where it will be a major loss out of the hole? The car is not near 3900-4000 like factory, just looking for insight. I am expecting to hear that it depends whether I want to dig race or roll race more, but I should be at the top of 4th gear in the 1/4 if that helps. Some people chiming in with experience on both seems like a long shot but would be awesome info. TIA

 

I switched to the 2.66 trans. I went from a 26" to a 28" tire too. My 100-130 was .2 faster with the 2.66/28". That's also the difference between shifting into 4th at 110mph and shifting into 3rd at 98mph. Acceleration seems pretty close. All things equal, with tire size, I think the 2.66 will be slower for you. My 60-100 is faster on the 2.66 only because I can use, somewhat, 2nd gear, instead of leaving in 3rd.

 

this basically perfectly sums up what my thoughts were. I was talking with a buddy this morning and verbatim told him I would expect a .2 gain factoring in shift time, and that gain being from a 2nd gear start vs 3rd gear. I’d probably gain about the same, I start in 3rd for 50 rolls and higher.

 

Going to a 28" tire should mimic the 2.66/26" pretty closely, at least in 2nd/3rd. You can see how that affects your 60-130. Only thing that will suffer will be that 3-4 shift. But much cheaper than swapping the trans.

 

that’s the whole reason I’ve wanted to ditch it was to rid of the 3-4 bogging and be able to try 2nd gear leave. My guess has always been .2 gained on the 60-130. So the bulk of the gain to you was the 2nd gear leave and not so much the closer ratio 3-4? Just making sure I understand correctly

 

Here is a good site to see the gearing vs speed charted out

https://legacypic.uk/transmission/graph.php

 

oh yea I have been glued to the screen on legacy, blocklayer, and gearcal. One of those things where you drive yourself crazy until you just try it yourself. Unfortunately that is a bit more spending for an experiment than I would normally care for. Plus if I was to decide to switch to the 2.66 set, I would do it to my current trans. I would do the 2.66 1-4 and try to keep the 3.01 5-6. Would make for a perfect split trans imo - at least on rolls.

 

I guess for me, just trying to shorten the shift point between third and fourth would be the biggest thing.

 

Yeah I always hated the drop off from 3-4, really noticed it badly next to cars I was really close with but they had modern 10 speed transmission. Glued together in my 2nd, 3rd, and top of 4th gear, but always fall back when it falls to the bottom of 4th. Now another internal battle being do I want to focus on roll race gearing or potentially look into drag racing the car more. The drag racing is coming back to me, but may have me prefer the 3.01 gear set.

 

This is what I get with my combination on the 26. To me, it seems like it won't be a large falloff on the 3-4 like it used to be with the 3.42. I am also planning on giving it about 1k more shift rpm though.

Then again, maybe I am not reading this right and it will still be a noticeable lag in acceleration once in 4th. My biggest issue on the old sbe ls6 combo on motor, was that 3rd gear was just lazy unless I was already moving. The new motor is going to make a lot more torque, so that coupled with the 3.90s vs the 3.42s should make a noticeable change.

 

Here is my comparison that I run with the 3.01 gear set (left), vs the 2.66 gear set (right). Both are using 4.10 gears and running a 25.7 tire. Redline is 8200 but figuring on a realistic 8000 shift. Even keeping the shorter tire on the 2.66 test shows a usable 2nd gear on a 60 roll, even better if I went up to a 28''. The 3-4 is where I feel I would really make the difference. The car hits 3-4 like a slug and does not feel alive until about 6500 rpm. My current setup shows to land to about 5600 in 4th and the gear set change would land me around 6200. I feel like that would be an amazing change on my personal setup. If I start doing more 1/4 mile stuff then my opinion starts to change on what is best for me.

 

What about the 2.66 ratios and a shorter rear gear?

 

Apologies if I missed it but are you still running the original 2 piece driveshaft? Recently, I've installed a couple of once piece DSs onto this platform (1 Carbon and 1 Chromoly). Along with the DSS upgraded axles.

 

My current 4.10 is the deepest rear gear you can get for the 8.6 IRS rear end. I could always entertain a solid axle swap and my choice of gear for a small 10-15k, lol. Ultimately a 2.66 gear set with a 4.56-4.88 on a 28'' tire would be money imo

 

I do have stock axles in it and always have. I have gone through 2 driveshafts (one custom steel, one DSS) and never had much luck, so I reverted back to the stock 2 piece again. Should be okay on highway stuff. I have my doubts of it doing well if I get back to the track.

 

How long is that driveshaft?