Big Eldorado 0-60 improvements (a reply to Cadman88's' email letter)
The information from the tranny guy came from the assumption that the engine was less than 400 HP. He did not buy that info, and was being nice about it. The 3.73 gears will do a small block Chevy some good, since that is a horsepower gear that keeps the RPMs up. If you keep 28" tall tires on the car, and keep the cam that works in those high RPMs, then 3.73s may not be too high. I know of several drag racers that use 3.50 gears in their 500 Caddy powered drag machines, but those cars are also lighter. I would check with that guy that runs 11s in the 4800 pound 53 Caddy that visits the board a lot. His machine is in the same weight class, and I'm sure he can give better advise than I can on gear ratios. If it was me, I'd use the stock gears, and 27" tall 255/60R 15 tires and call it good. ( but then again, I hate to buzz a motor in high RPMs) My guess---and I do say guess, is that your perfect combo will be 27" tall tires and a 3.50 or 3.23 gear. No harm in keeping the stock gears for a while and run an initial test. You might find after running the stock gears, that 3.73s do improve the 0-60, but may not be worth enough time in the quarter mile to justify dropping the MPGs from 10 to 6Miles per gallon. If it is a street car, you do have to keep fuel costs in mind. Due to the weight of the car- my Eldo, got 8.5 MPG city, and 13.5 MPG interstate with the 2.73s and 28" tires. (that's why I'm building my '82 Eldo as my daily driver--- should get 20+ MPG)
I know yours is not for daily use, so MPGs may be meaningless.
Since your air leveler does not work, Gabriel High Jackers with an air line separator kit are a good choice. You can air up the shocks individually and can compensate for any spring sag to make the car level, and you can air them up so much if you want to that the back bumper will level with your knees! (the car will look stupid funny jacked up like that, but in a drag race, all of the weight will be on the front, and it will be harder to loose traction. As it is now, your stock shocks, do not hold air since the air leveler is not working. when you take off, the air will "whoosh" out of them and the rear will squat, the front will point at the sky, and the front tires will fry. ( hey, I made a rhyme!) lol I have a picture that I want to get online soon of my car doing that with the stock suspension. It makes for a good smoke show if you want to use the car as a fog machine, but traction is poor. You can even buy and install the air line separator kit and use it with the stock shocks for now, since the kit will cause those stock shocks to hold air, and you can pick the back end up. It might even be a better application for the drags, since you can put about 150 PSI of air in them and lock the back shocks in the up position for the race. That will keep weight transfer from happening, and will keep the car from looking so high off the ground in back. In my Mustang, I ran the air line kit to the trunk, so when the trunk was closed, the nozzles were protected from tamper. ( Some people find it hard to resist letting your air out when you are not looking, and in the Mustang, that would have caused the fenders to shred the rear tires.)
The gears are in the front differential, and that can be removed and replaced separate from the trans, so there is no need to worry about the diff at this time. Also remember, you can use a smaller torque converter, which will allow more slippage, which will cause the car to act like it has a higher gear. those 2.73s can possibly act like 3.23s with a small enough converter. At any rate, the converter will play just as much a part of getting your 0-60 times down as the front gears, and if you are going to run slicks at the drags, the stock torque converter may need to be changed anyway to prevent breakage (just a guess) because I have heard that they are weaker than the rest of the trans. ( again, that is hear say, and I would check it out before I acted on that one.)
I will also post this information in the Caddy clubs, I hope you don't mind if I use your letter as a reference in the post.
thanks, lots of valuable tips i'm going to consider!My Eldo i am intending primarily for street use, notso much an everyday, but something i will put on theroad in the spring & cover in the fall. Something ican pull alongside Chevy's, Ford's, Lincolns, Japcraps& whatnot at a Highway light & smoke em' when it goesgreen & hopefully leave them in the dust..When i bought the Eldorado, i never registered it,thus i never drove it, thus i have no idea of what a1970 Eldorado is like to drive!. I kind of regretdoing the modifications, because i will have noappreciation of what kind of power this car has in itsstock form.I Do want to bring it to a track, not to race it persay, but to get some accurate 0-60 & 1/4 mile stats. Ialso want to attend local car shows as well & instilla little "Cadillac Pride" in non-believers ;)I'm definitely looking to have the front suspensionbeefed up, as it is going to need it. The level ridedoes not work in the car, and i am definitely lookingfor the car to ride a little higher than the stockshocks place it.For the Tranny, i say a shift kit should do it, maybei can have the gear ratio changed to 3.73's?Speaking of trannys & what shops say about Cadillacs,this is funny, because i just got this e-mail at thesame time a Tranny shop got back to me regarding aquestion, The tranny guy doubts that an Eldorado camewith 400 Horse stock!. Here is the text of hisresponse word for word."T.C. -Don't know that much about the Eldos, although the HPand torque figures you mention do not sound like anystock GM big block they would be likely to use in anEldo. The Torque sounds about right, but I wouldexpect less HP. Building the motor is the 1st step.The FWD Eldo uses a variation on the GM TH400 trans,it can be beefed up using many of the rear wheel driveTH400 parts. If you want to make a hot rod out of it,then you probably want to change the diff ratios to3.73. Any more than that, and with all that torque andFWD, you will just light up the tires.Greg MillerHigh Impact Wheels / Transmission & GearToll Free 888-898-4331www.high-impact.net"Now, i am not the most mechanically versed when itcomes to cars, so what do you think of his suggestionfor changing the gears??, Are the gears located in theTranny or in the Axle itself?, If so where would i beable to get 3.73's & how much $$ do you think thatwould run me??, and is it a big job??. It sounds to melike that would edge a little time off the 0-60 run?Let me know!,Cadman88
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