THS_Steed06

Hey guys,

Just doing a gut check here but am looking for a rear end upgrade this winter. Found a t-lock for $350 and have been sitting on it waiting to decide between 3.73 and 4.10. So I'm looking for those of you who already did it and if you can really say (honestly) you would do it again?

I'm considerjng just doing the t-lok and leaving the 3:31s, because honestly its a good compromise gear for a daily driver you want to have some fun with. The added traction alone I think will be great improvement. I also run summer performance tires that are slightly shorter than the stock Pirellis so my effective final drive ratio is 3.46 which I have already noticed because I can now consistently chirp into 2nd gear. Plus I think I'd rather spend the gear money on a Zex 75HP system that I can install myself, which will give it plenty of punch.

So that being said...

How was your mileage affected?

How well are you liking the driveability?

How's the top end?

Would you do it again the same way or differently?

Thanks,

Tom

2007StangV6

I went from the 7.5" 3.31 to the 8.8" 3.73 and I would do it again no questions asked. The 3.73's suit me for what I need, daily driving, way faster acceleration than stock, and the prep for when I (eventually) throw on a x-charger.

The 7.5" rears are pretty weak to begin with. I would imagine that if you are going to add a 7.5" t-lok and then add in a 75 shot of nitrous, you are going to break it. For the reason alone, I would say save up the money for the 8.8" and which ever gears you decide on.

THS_Steed06

Oh also wanted to add..

That currently my car runs about 1800 RPM in 5th at 60MPH, at this speed my exhaust drone is very minimal but at 2k it starts to get obnoxious. At 2500 RPM it quiets down a little and frankly sounds frikin amazing. That's why 4.10s are even on the radar but I moticed driving my car in 4th at 60 MPG dropped about 10-15%.

If I change gears I'm concerned my mormal commute speed will fall right into that 2k-2300 zone which will kind of suck. I love the sound of these Dynomax ultra-flow mufflers and don't realky want to change them to something milder.

That's the other reason I'm considering sticking with 3.31

Thanks,

Tom

JimC

In the long run it is cheaper to swap the 8.8 to your car than it is to pay a shop to crack open the 7.5 and try to build it up.

And with a shot of nitrous your 7.5 won't last long. Nitrous adds a big torque hit all at once, lots of fun but the 7.5 won't handle it for long. So you will break it after spending the money to build it, only to spend the money on the 8.8.

All it took to break my built 7.5 was a CAI, tune, and a set of drag radials.

Murgatroy

Ideally I think the gears are a much better upgrade than the juice.

I have seen way to many people think that juice is the cure to all their woes and make the car more fun. However the low entry cost is going to break parts, and with refills added, it will be more hassle than it is worth for a street car.

If you are not racing, you don't need juice.





There is a reason gears are one of the first things mentioned on the path to upgrade. With gears and a tune, you will get more usable power immediately without the hassle of installing or trouble shooting performance parts. Nearly factory reliability with a 10%-15% increase in usable power.

THS_Steed06

Hey Murg...

Thanks for chipping in here. I've read that using no more than the 75 shot of NOS isn't likely to damage things as long as you dont do it 10 times a day. If you have some anecdotes to share please do, maybe I need to re-consider theat route?

I actually talked to some guys at a show last summer who said gears are better than NOS in the long run, but cost about twice as much and you get about the same benefit.

I'm starting to think of pricing out the 8.8 swap because I could get a 3.55 or 3.73 already in there and be ready to go. Last time I priced this it was about $300 for the axle plus shipping and $6-700 for installation. That would mean it costs about $300-400 more for the 8.8 swap vs. 7.5 build up.

If I'm not going past 300HP not sure its necessary for the 8.8, but definitely a risk in the lo ong run.

kput

I run a 75shot and have run 8.8 @ 85 in the 1/8

My next mod will be an 8.8 rear and 3.73's.
The nitrous is fun. The only concern and problem
Is not being able to spray until you're 100% sure you have sufficient traction when you flip the switch.

With the 8.8 and gears I'm hoping to jump my times to 8.4ish. It's the off the like acceleration that kills your ET.

Murgatroy

Let me preface this by saying that I haven't played with N2O in at least 10 years. I ran a 250 plate on a bracket car and a 50 shot on a street car.

The problem with having that much power 'on demand' is that it is a lot of fun to use it. If you are out hooning around, it is completely feasible to run through a 10lb bottle in a day. That is an extreme case, but it is possible to run through a bottle a week. Especially if you are racing.

At the time it cost me between $35 and $50 a fill.

With the bracket car, it was built for the power, with the spray being planned from the beginning. I STILL tore transmissions out of the car though. Dumping an extra 200+HP at demand is not easy on the drivetrain. You can build up for it, but in the end, even the little things, like an external transmission cooler, or a rear girdle, simple safety measures, will run the cost of the juice up. Sure, you are talking $400 to install the juice. But then you can tune for it (micro switch at WOT with the tune designed to compensate and dump more fuel, etc...) you are now into the $700 range (if you don't have a current tune.) A tranny cooler is just makes sense. More power means more heat. Then you have a smaller rear end that isn't designed to handle 300HP, much less if you dump 75 of those 300 ponies at the push of a button. You don't get a purge kit with your common kits. You don't get a fuel pressure gauge either. These are again, simple safety precautions.

I am not saying you HAVE to have these items. But I am saying that having them will make your spray safer, if not more effective.

So your safe install of the juice just got you to ~$1000.

But, I can not tell a lie, that smile you will get when you go full tilt boogie is gonna be awesome.

But there is more wear and tear.






With a gear (and a tune to go along with it, that is part of the price to play,) you aren't adding power other than what the tune will give you. That means that your engine and transmission are still running at factory intended efficiency. They aren't hotter, they aren't being forced to put out more power (N2O is similar to forced induction in that it introduces more air/fuel into the combustion chamber.) The gear makes your power curve more street or strip friendly. From the factory your car is geared for efficiency. Lower revs on the interstate/highway, better mileage. With a gear and a tune, you can customize how your car reacts to your driving style.

The benefit to this is that you aren't stressing the drivetrain more than factory. That is a bit of a misnomer though, because if you hotdog it, and you will, you will be stressing it, but you aren't dumping more power to it.






As to anecdotes, anyone that has been around a drag strip much can tell you at least a dozen stories about the cat that showed up with spray installed and popped a gasket at the line. I hate to say this, but in my experience there are two cars this happened to the most, Mustangs and Civics, but then again they are the most popular. The myth is that if they get the kit, and keep it below a certain HP everything is safe. They strap an extra 100HP on a stock engine with 200,000 miles on it, romp the hell out of it, then stand there shaking their heads when something breaks.

C-clips in the old Chevies, CV joints in the Hondas and head gaskets all around. Those are the first to go.





To end this, if I had to choose only one mod to perform to my car, without a doubt, it would be a new rear gear and a tune.

2007StangV6

It's been about a little over a year since I bought my 8.8". If you found a $300 axle, I would have ran to the bank and bought it immediately. That is a good deal, I would say.

Then again, that may be the current price of them. I'm just judging on how much I paid.

I will also say that you won't be able to enjoy your nitrous all the time. With gears, they are there all the time when you step on the gas.

THS_Steed06

That may be the best explanation of NOS I've seen, thanks! I think gears are definitely the way to go.