body lift
 

I wanna get a body lift for my 2 door blazer so I can fit 31s? Would my stock gears be enought sence I'm gonna put a e-fan on it and cool air intake?

Should be fine, but the Speedo will be off a little..

What gears do you have? They all should handle it fine, but 3.73s will be a lot better than 3.08s.

I wouldn't expect much from the fan and intake. The factory intake is a cold air intake. Look where it pulls air from. And the e fan puts more strain on the charging system, making the alternator work harder, and thus more power is needed to turn it.

I forget the p code but ABS will kick a code at 10% vehicle to wheel speed error.

How much will my mpg be effected with 31s if I'm getting 17 right now?

You might get 15-16 with an average of 17 now

I have a 2 inch body lift with 31s and my mileage has decreased by 1 mpg

Dont agree with e fan comment. Screwy fan clutch set up robs horsepower an d wired right it doesnt use any more power from the electrical system

Wait, Bigger tires roll farther with one rotation, how do you get worse mileage? Especially on the highway

Bigger tires will carry you further in one rotation but also bigger tires also weigh more & cause more rolling friction plus the increased height means more wind resistance. & mine only dropped one mpg and with 3.73 gears my speedo was 5mph at 60 I was really doing 65mph

I remember a comparison Hot Rod mag (or maybe car craft) did a few years back with different kinds of fan setups. They tested a clutch fan, e-fan, and a non-clutch flex fan. They ran all three setups on the same car on a chassis dyno. All variables were the same throughout the test.

The flex fan came in last, making the least power. The e-fan came out ahead of the clutch fan, but only by a couple horsepower. So, technically, you will gain some power, I guess. But I wouldn't want to spend that much money for a couple horsepower that you won't be able to feel, anyway.

Now, if your fan clutch is all old and messed up, maybe it's costing you something. Maybe it's hooked up and blowing on the highway when it's supposed to be free-wheeling. I would still spend maybe $50 on a fan clutch than a couple hundred for an e-fan setup.

What about the flex a light fan?? Would it give me some power.
And a flowmaster 40 series?

The flex fan came in last

So I'm thinking about flowmaster 40 series? Does it have a loud interior sound?

The non-clutch flex fans were the worst. The engine is still having to turn them even at highway speeds. With a properly operating clutch fan, it will disengage at speed, since you have 60 mph wind blowing across your radiator while driving down the highway. The clutch should only be engaged at idle and slow speed driving.

If you do end up doing the e fan, at least document your mileage before and after, and do a good write up on here. That would be good, real world information that would benefit people thinking about doing the same thing.

Also, if you end up doing it, try and pull a set from a junk yard car. I've heard guys like (I think) Taurus fans, and possibly some Chrysler application, but I can't remember. They pull as much if not more cfm than some of the slick aftermarket ones, and are much cheaper used.

I have no clue about the flow master. If you do get some drone, some sound deadening material above the muffler might help?

The Taurus/sable fans and the Chrysler application (from the intrepid) are the ones I've seen used most for s10's in general. Really the most expensive part of an electric fan setup is the fan controller to set which temp the fans kick on at would be the most expensive part. Just source everything else from the junkyard. I've seen guys on other forums hook them up to a 3 way switch. Gives them an off, temp sensor only, and an always on option. If you spend 100 bucks, and get 1 more mpg, it'd pay for itself after like, 30 gallons of gas? Something like that anyway. Point is, buy **** at the junkyard.

Bigger tires also means a taller end gear ratio which results in less torque, and worse city fuel mileage because it requires more engine power to get the truck moving from a stop. The taller tires may help a bit on highway mileage because the taller end gear ratio will probably result in a lower RPM for a given cruising speed. This may be negated if you live in a hilly area and your transmission ends up shifting more often due to the loss in torque. That was certainly what happened to me with 3.42 gears and 31's. I swapped to 3.73 gears and it evened things out a lot, and my mileage went back up.

I'm now rolling on 32's with 3.73 gears, 3.5" lift, and I average 17mpg with 60%/40% highway/city driving. I do tend to have a heavy foot too, so I would probably be another 1-3mpg higher if I granny drove.

I barely average much higher than 17 mpg, and I'm on 235s, 3.73s, maybe a couple inches lift, over half highway driving, and I DO drive like a grandma! I figured 32"s, and the lift required to clear them would kill ones mileage. Guess what it takes away in town, it gives back on the highway from a lower cruise rpm.

will my blazer be better with 4.11 gears than stock?

It totally depends on your tire height and driving style. If you are running 31's then 4.11 gears will be too low, and will KILL your highway mileage. I'd suggest that the 3.73 gears that many S-series trucks come with from factory are very well matched to 31" tires, and will net the best mileage for both city & highway driving.

ok thanks so just keep stock gears with 31s? And im gonna get a bored throttle body will it help with the horsepower i loose?

Do you know for sure that you have 3.73 gears? What rear end RPO do you have? The 3.73 would be RPO GT4. If your RPO is GU6 then you have 3.42 gears.

ill check on that and how can you tell the difference between RPO'S?

Look in your glove box. There will be a list in there. They normally are in alphabetical order a-z. You may be able to find a website that can give you an RPO printout from your VIN number that will detail all the factory options and equipment. Those are handy to have too.

Ok thanks

Found out my truck has 3.42 gears and a locking rear axle. So when I get 31s ill be puting 3.73 gears in it.

Would it be better to just buy a zr2 rear end to save me the money of puting the gears in?

Swaping the rear axle would be a lot cheaper that swapping gears. You can get an axle for $100-$200, and it can be done in the driveway with hand tools. If you want to upgrade to a ZR2 axle this would be a good opportunity too.

A zr2 rear axle is like 3" wider than a normal 4x4 axle, which I think is like 3" wider than a 2wd axle. You really should just start one thread and stick to it, cuz you've got like 4 different threads going about all the same things, but you only mention its 2wd in 1 or 2 of them. It helps people provide more accurate info when you give detailed info on your ride. If you wanna gain 6 inches of width for just the rear axle, swap the zr2 axle in, but they have a 8.6" diff, and its longer then a stock 7.5" diff, so if your rocking a 2 door or 4, I can't remember, but if its 2 door, grab the driveshaft from whatever zr2 blazer you take the axle from. If you take it from a truck, you'll have to have your driveshaft shortened a couple inches.

What if I get a 2 doors 4wd rear axle would it be 3.73 ratio or not?

You'd have to check the rpo codes in the glovebox, but it might not have the g80 posi unit. The cheapest and easiest thing to do, would be to pull the gears out of a 7.5" rear and put them in yours. Get the ring, pinion and the posi. I'm pretty sure all bravadas came with 3.73 gears and posi's, but I could be wrong on that. Once you pull them, or even before, look into a rebuild kit for the posi. Really, in all honesty, if you have a posi and 3.42 gears already, the 3.73 gears may work with that, but I'll let someone who knows more about that to chime in on it. Got any pics of your ride? We like pics here. I think you should look into that rough country kit you asked about in the lifting section and a 2" body lift. Fack gears, man, if your only going up to 31's you'll be fine for awhile. If it dosnt perform like you want, save up 300 bucks and buy a set of 3.73's later on.

+1 on what Sickman said here. It used to be encouraged and almost policy to put a description of your truck in your signature (year, doors, 2wd vs 4wd) to help people give better info. It's a really good idea.

From what you were asking, and the way you were talking I thought you had a 4x4. You don't want a ZR2 axle if you have a 2wd. It will be way too wide. If you want a wider axle get one from a regular 4x4 Blazer or Bravada and check the RPO's in the glove box to confirm the gearing and if it has the G80.

If he already has the g80, wouldn't it be possible to just take the ring and pinion? Seems simpler and easier than trying to find a 2wd axle with a posi and 3.73 gears.

I'm not sure. My understanding is that it's not as simple as simply swaping the new ring & pinion in. I believe you have to set lashing or something like that? I have zero experience with this, so I'm not the best source. Hopefully someone with more experience can chime in here.

Gears are not an easy install, if you have no experience with it you should get it done by a shop which means a good chunk of change. They have to be set up properly or you could easily ruin the all the internals. Swapping the complete diff is much easier for the average person to tackle.

so would it cost alot to get 3.73 gears put in a 2wd?

My guess is it would be in the $4-500 range for just the labour. You'd have to go get some quotes to know for sure. I was charged $600 for my locker install, but it shouldn't have been that high... that's a rant I won't get into though lol.

Well check pick and pulls. I don't think it'll be as bad as you think if your looking at 30's or even 31's with a 3.42 and a g80 already. 31 inch tires are 2 inches over 235/75r15 on my 4x.

I see the RPO codes on here for the ratio but can anyone tell by the RPO codes as to what size the diff is. PS every time I see a new RPO code on here I make a mad dash for my 97 blazer 4 door 4WD only to bring more bad news . I don't have the g80 and I have the gu6 3:42 gears and not the 3:73