I have a 89 Iroc-z 5.7 TPI Auto (700r4). It has the stock 2:73 gears. I want a little more gear. I friend gave me a 3:73 gear set. Is that too much gear for a auto car. I drive this car everyday on the interstate about 20 miles. if you have any input please help.

 

No. Most guys w/ auto run 3.73s. Itll really wake up your car. Low end especially, where the tpi makes its power

 

Highest I'd go with an auto is 3.73's.

 

You are not going to be doing much with that 3:73 gear set unless you are willing to spend a lot of dollars. Think 2-series carrier in car now and gear set (3:73) is 3-series carrirer, result they will not work.

 

I've done it personally and would reccomend 3.42's over 3.73's. A TPI engine makes too much bottom end and not enough top end. Unless you do a drag tire, it'll spin a whole lot. On top of that I think it just makes the engine run though the powerband too fast, especially in first gear. An LT1 or LS1 car is fine with 3.73's and 26" tires but I'd never do it again with a stock TPI car. I'd try a 3.23 or 3.42 with 2800 stall and STICKY tires, goodluck!

 

AutoRoc is probably right about that ... considering the power band of the TPI and all .

BUT, if your friend just gave them to you????? ..............

You need to know whether they're for a 2-series or a 3-series carrier though. You CAN get a 1/4" spacer if they're meant for a 3-series carrier, although it's not "recommended". However, I don't know how many people ACTUALLY use them, and how many ACTUALLY have a problem, it's just been a general "non-recommendation" . For the cost of one though (and considering you were given the gears???)

 

I'll need a spacer. I don't think a spacer will be a problem. I'm not one of those guys that beat on their car, Or waste gas and tires on burnouts or donuts. I just want access to the power i have. I only put my car on the track 2 or 3 times a year and it's only a 1/8 mile track. My car is a daily driver.

 

i have 3.73's in my 1989 formula 350, up from 3.23's. The car is insane in 1-2 spinning full through both gears, third will top at about 100mph, but your top speed will be alot easier to achieve at about 155~mph...before my top speed was hard to achieve once the engine was revving high, there was too much drop off in power and a too much gear left, shortening the OD gear will loose a bit of mileage, but will give you a great seat of the pants rush up to 150+ before redlinning.

 

Autoroc is probably right on this one. But in case you are wondering, my car came with factory 3.73's and I've never wanted any other ratio. 2600 RPM at 70 MPH in fourth gear: It's never been a problem, and gas mileage was an even 21 MPG when commuting. However I had an L69 305 that revved to 5500 RPM just fine. Your motor probably donks out at 4500 RPM before going flat due to the runner design. Because the 700R4 has such a steep ratio in first gear, you will find that launching will only give you a 0 - 30 MPH in first gear. It's a quick runup.
My suggestion is this: It would be better to ebay the gearset and purchase something that fits your carrier. Or else buy a new carrier! It'll probably be as cheap as the spacer. You might even find one that's already loaded with 3.42's. Remember that the gears is the cheap part of setting up the whole axle: You will still need crush sleeves, gaskets, bearings, and someone to set up the whole thing for you. A "free" ring that requires you to stuff around with a spacer doesn't sound economical to me.

 

the guy that is giving me the gear is installing it also for free. he has all of the parts but the spacer. http://cgi.ebay.com/ebaymotors/10-Bo...spagenameZWD1V

 

i bought my set from richmond, and they asked me if i wanted the 3 series with spacer or the 2 series without to replace the 2.73's.

maybe a differant stlye so you dont need the spacer id have to call the guy who installed it to be sure.

 

@elementaltoad- my other car is a WHM-6D.

How about you?