DINAN 3.91 Limited Slip Differential initial impressions & review - Page 4

ACG · 19th March 2012, 18:18

Quote:

Originally Posted by 5.7 silver bullet

Also it does cruse at 2700-3000 on the hwy so what is the stock gearing rpm at 70-75mph?

Not sure what the stock gearing is for that speed but I do know that I can go up to 95 in 3rd in mine.

I presume that is in 7th gear to keep the rpms around 2700-3000? I know my rpms are around 2400-2500 at the same speed in 7th gear.

EuroCarFan · 19th March 2012, 19:12

Nice review Yaphet! Glad you're enjoying the new mod. I've also been going back and forth with this mod for a long time. Almost pulled the trigger on the 4.10 BMW Motorsport gears offered by Turner a couple months ago but was worried about 1) the whine and 2) the reduction in top end speed. I think the extra shift needed for the 1/4 and 60-130 runs made me reconsidered the upgrade. That said, not sure if I'll ever take this car to the drage, or will be getting a V-Box to work on my 60-130 times or how many times I will ever do a max speed run so maybe those things shouldn't matter. I can definitely use the low end torque.

Hmm..........

C's Bimmer · 19th March 2012, 19:23

For those that remember LI-M5, he went through 4 Dinan Diffs, which is why I was a bit hesitant a few years ago to do this. However, he always swore this was the best mod on his beast and if you look at some of the old video's of he and some others doing some runs, he was always ahead.

ykjones · 19th March 2012, 19:43

Quote:

Originally Posted by ACG

Do you have a pre dyno as I would like to know what kind of trq you gained from this mod. Like John said I have kept my distance due to the compliants of the whine but if you can let us know after the break in period has been complete that would be great.

Sorry I haven't done any dynos as I'm never done them and really don't have a desire or need to. As long as I can feel the difference (which I most certainly can!), I am really enjoying the new grin on my face now when I'm driving the beast.

EuroCarFan · 19th March 2012, 19:50

How does the improvement in torque for the diff show up on a dyno since it's not like the diff increases overall torque. It just brings more of it sooner in the rev range right?

messex · 19th March 2012, 19:56

Quote:

Originally Posted by EuroCarFan

How does the improvement in torque for the diff show up on a dyno since it's not like the diff increases overall torque. It just brings more of it sooner in the rev range right?

I would think, if you overlayed the 2 Dyno graphs, you would see the torque sooner in the RPM range. Max Torque probably wouldn't change, but you would just reach max Torque sooner - maybe not - just my guess.

Vodyk · 19th March 2012, 20:30

Quote:

Originally Posted by 5.7 silver bullet

I have the 3.91 and I'm considering selling it, but have not desided yet so don't ask. With the stroker and the way the shifts fall I would like to get to 130mph in 4th and save a shift in the 1/4 mile run and 60-130mph.

+1 was thinking about selling mine but can't make up my mind! After reading this thread and how many people want one I think their must be something to it!

Most of my IRL car friends will always make the argument that the added time shifting isn't worth the benefit and some days I agree!

ykjones · 19th March 2012, 20:45

Quote:

Originally Posted by Revo

yk - you'll definitely have to give me a ride at the next meet. Would love to feel the difference.

As for the break in, you are NOT limited to 5500RPM! Rev all you want (though I wouldn't do full throttle or hard shifts). Think of it this way, how does your diff tell whether you are doing 60mph at 2000RPM in 7th or 7000RPM in 2nd? It can't - since your transmission outputs the same rotational speed to your diff either way.

Revo - Consider yourself in for a ride at our next GMR meet sometime in May. I will definitely have it broken in well before then.

ykjones · 19th March 2012, 20:49

Quote:

Originally Posted by Fiftytwoeighty

I love my Dinan 3.91. You will be spinning well into 2nd looking for traction.

Let me know if you want to do some WOT with my broken in 3.91. I have to make a run out to Temecula this week to see my CPA.

~Woody

Woody - Let me know when you are planning to be up this way in Temecula. Maybe we can do a meet up at lunch or something as there are some other beasts here too. I'm retired, so I'm pretty flexible.

Yaphet

ykjones · 19th March 2012, 20:55

Quote:

Originally Posted by EuroCarFan

Nice review Yaphet! Glad you're enjoying the new mod. I've also been going back and forth with this mod for a long time. Almost pulled the trigger on the 4.10 BMW Motorsport gears offered by Turner a couple months ago but was worried about 1) the whine and 2) the reduction in top end speed. I think the extra shift needed for the 1/4 and 60-130 runs made me reconsidered the upgrade. That said, not sure if I'll ever take this car to the drage, or will be getting a V-Box to work on my 60-130 times or how many times I will ever do a max speed run so maybe those things shouldn't matter. I can definitely use the low end torque.

Hmm..........

Thanks Tony and thanks for the DINAN Intakes as well. Loving them! I did give some thought about going with 4.10 from a couple of other vendors but decided to stay consistent with my DINAN mods. Really loving this diff so far and about to take her out on the freeway in a few. Gotta take it kinda easy as I'll have our 10 week old boy in his car seat in the back. Trying to get as many miles as I can to break the diff in while mommy is at work ;-).