How much time in your e/t can you pick up in rs 305 tbi by swapping out the automatics 2.73 gears.


They offer 3.08,3.42,3.73,4.10 and if you dare 4.56 axle ratios. I also dont want a broken ring and pinion either because the ratio is too low I just want it to be quicker.


We have lots of backroads and highways 45-70mph and the big 2.73 gears suck always speeding up from a stop 0-50 and 0-70 times.

So what ratio's are pracical and how much time can you pick up by swapping out these super big 2.73 gears?

 

Broken gears are usually from to much HP and to high of a gear. A lower gear like a 3.73 is easier on the launch. Going much lower than that and you engine will be taking a beating on the open road running the higher RPMs.

 

I went from 2.73's to 3.08's and picked up 7/10's. I did a couple other really small mods and bumped up the timing but didnt do that much in the way of HP. I did put some lower control arms in the rear and lowering springs suspension wise.
Now I have 3.42's and I would not go much lower than that on a street car with 26" tires. I recently went on a little drive and averaged 24.24 MPG but I did not go over 70 mph.

 

We don't have enough info to go on, are you auto or stick? I highly recommend 3.42's for the auto and 3.73's with a stick car. Just make sure you get an Eaton posi while you're at it. Check my Cardomain for more info.

 

I have the 305 TBI with 700r4 auto. I went from the 2.73 with a open differential to a 3.42 and Eaton Posi. and could not be happier. Pulls real nice off the line and not to bad at highway speeds in OD.

 

Like everyone has reccomended, upgrade to some sort or lsd/posi. I did a 2.73 open 10 bolt to a 9 bolt 3.27 posi pbr rear and upgraded to Founders Control arms and panhard bar with the GTA Sway bar with energy links and bushings. I can't wait for next summer to take it out and stretch its legs.

 

Great thanks guys, so what are your track times by the way?

 

Best was 14.6 with 3.08's. I ran a 14.7 with the 3.42's and a transmission that wouldnt go into drive. So I was off throttle going across the traps.

 

Your joking right 14.7 is that 1/4 or 1/8 I used to own a 3000gt and no way these are that fast. I would be happy to just run 15 something in these with my auto one.

 

I was running in the 14.1 - 14.4 range with the swirlies and stock cam/1.6 rockers, so it's believable. Then again I have many other "supporting" mods to help the situation. When I'm done tuning low 13's are very possible with my set up. Even on the half *** tune now the car pulls MUCH harder than before but I can definitely tell i'm in big need of my 3200 stall. I myself have DESTROYED quite a few 3000gt's and Dodge Stealth's alike.

 

lol im not joking. Driving like im not in a hurry im gettin 24 mpg also. that is 1/4 mile. once you start running your car at the track. You will always wanna go faster. once I get my tuning equipment I am hoping to run faster. and get even more MPG. I will see.

 

What other mods are you running other than your gears? Im curious as I've never run my car down the track and have a few other mods but stuck with the same 2.73 gear. I'm assuming you at least have headers?

 

For some reason my rs has dual exhaust I keep looking at other ones and cats are still there.

I also dont see many other rs with a/c t tops and I even beat another 305 rs. The only thing I can think of is the aftermarket engine they put in does not have swirls or its a tbi 350 engine since it says from a gmc. Also my emissions tests shows 5.7 but half the recips say 5.0 and those arnt related to any engine repairs.

Either way it is not really that fast its actully slow for a v8 compared to moddern standards.

I have yet to check my casting numbers.

 

on the block behind the drivers side cylinder head it says 5.0 or 5.7 check yours and see

 

My 91 RS came with A/C and T-tops and there are many many many of them.

 

yes i have headers. some head work done myself. camshaft. pulleys. forged pistons (higher than stock compression) timing edelbrock tbi intake suspension work. Now I have a stall converter and a good shifting transmission i need to make it back out to the track

 

You guys are so full of it a vr4 runs 14.00 stock and base model ran 16.3 stock. I drive other peoples cars for living for the auto shop and baught this because everyone talks big about chevy small block.

Had I known they really where that slow I would have just baught another 3000gt with atleast mid trim 222hp v6 or vr4 300hp and there already geared low and do great in the rain here.

I would have spent less and gone faster stock.

 

SBC engines are the cheapest engines to biuld. So you would of bought a faster car off the bat, but to spend $500 on the Stealth/3000GT and not do much for you, $500 on a SBC and you will be doing pretty good. So the 3rd gen is a high to low 15sec car, drop a came, tune and exhuast and you have a whole different car. Plus you can depend on it over 150k miles, unlike the DSM.....

 

f-bodys came configured in dozens of different ways, some tear *** and others are pigs.you have an RS which stock is a pig.if you had a z28 you would be bragging about how quick the car is,both cars have chevy small blocks,but were built for different purposes.the RS was not built to be fast.

dollar for dollar the money spent on a v8 gets you more power,period.

for the money you would spend putting another rubber band (timing belt) on your hotwheels vr4 just to keep the motor from eating itself, you could get a set of vortec heads and intake and add 60hp to your car.

your 3000gt motor is just a four cam version of the 3.0 v6 found in every dodge caravan for the past 20 years.(the ones with the blue smoke cloud following them)

 

Well my 3s car club builds fast 700 horsepower vr4's because they do have twin turbos you can upgrade. The caravan had the sohc with a different cam. Those only require boost controler to up the boost there pretty realible when I owned mine.

check cjbyron.com

People always confuse them with the 4g63 the only difference is that has turbo lag and these dont. many had all wheel steering all wheel drive some of first 6 speed manuls and they all got 4.10 or 3.86 gears. They weigh like 3800 pounds but not bad for the weight and they great for going fast on the highway thats how there geared 1:1 is 3rd gear 120mph. On the highway they build speed like no other to 120mph everyday was not uncommon for me and has awsome brakes.

I like both they are just two totally different worlds I would own both if I could too bad they get 16mpg max on premium nice torque engine.

I like the torque and instance response of a v8 and the gas mileage of big gears you can run however I just dont see it practical. If your drag racing this instant v8 torque is great for best e/t.

How can I make my rs better is buying tpi parts expensive?

 

How can I make my rs better ? Well most would say start from the beginning with a full tune-up , cap,rotor,wires,plugs,etc.(I also "advanced" my timing to 6 degrees because that's the sweat spot for my car.) then open up the breathing with at least a open-air element. Then a full exhaust. Headers,Y-pipe.to a 3in.high-flow cat and 3in. piping to a better flowing muffler.Then last but not least is the posi. unit with at least 3.42 gearing. Those are the basics. I did most of that ( have not installed headers and Y pipe yet.) and it really woke up my car. Especially the Eaton posi. and the 3.42 ring and pinion.Mines a 305,TBI,Auto and it my never be "real" fast but you sure can make it fun to drive!

 

Mine has 4:10's in an Eaton. Unless you like doing burnouts, I'd recommend something more highway worthy. (It came with em, in my case). But with 4:10's, even running like crap, it will chirp, and you can do burnouts without even thinking about it.

 

I have all that and a new block to work with so all I need are a new transmission mount, axle upgrade and some nice heads.

My dual exhaust is aftermarket it has kind of a drone and engine has an air pump. I have an msd ignition.

 

Yeah those twin turbo 3000gt's were low 13's cars stock. No real comparison. Find one of those cars cheap I know someone who wanted to sell his for 15k, or buy a third gen and dump 15k worth of performance parts into it and whoop on that 3000gt