cheap power improvements to the 425...

[Night Wolf]

Here are some videos and stuff of my stock 425, these were taken in the winter, I have since change some things on the car (interrior stuff etc...) I copied and paste this from another site, so I dunno if I may be talking about off-topic stuff, but it explains all the videos and I don't have to re-type it all


Once I fianlly get the miniDV camera, I am going to take some cool videos, these were taken by my digital camera in video mode (no sound)

plus the rear tires are completly bald now.... so I need to wait until i get new tires before I do much more of anything (some nice burn out videos will be coming soon though

0-65:

http://inoventionseast.com/1979%20DeVille/'790-65.wmv

highway (can't see the tach):

http://inoventionseast.com/1979%20De...;79highway.wmv

highway with tach:

http://inoventionseast.com/1979%20DeVille/'79speedo.wmv

^I coudln't tell how fast i was going when I shifted into 3rd.... the speedo was burried and the GPS wasn't with me.... but I shifted at 4,000RPM, I could have held it out to 4,200 or so and got even more...... it is fun

This is why the tires are bald:

http://inoventionseast.com/1979%20De...Caddymovie.wmv

^was for a contest that I didn't win (hence the short time)

Here is the sound form in the car, windows closed doing 0-85 or so. I just left it in drive, and it shifts into 3rd at 3,400RPM (when in drive) The ticking is the leaking left exhaust manifold, and the only reason why you hear the engine is because of the open element air filter, with that on, when the secondaires open, it sounds like it does int eh video. Witht he stock air clenaer, it is quiet. Also despite the high torque fo the big block, the car itself bogs from a stop, both due to the carburator needing to be rebuilt, and the gearing, you can kinda hear it bog a little in the sound clip. Besides the open element air filter and the cat. conv. that I drained the beads out of (still there though) the car is comeplty stock. Has a full tune up but that is it. With 90k miles, it runs great, but the enigne inside is kinda dirty, look in the valve covers it is sludgey, the new oil is really dirty within 3,000 miles or so.... but you really can't kill a big block Cadillac.... although you may go broke feeding it

http://inoventionseast.com/1979%20DeVille/VOICE010.MP3

All in all, not too bad for a 26 year old daily driver from the land of emmission-loaded, low compresson engines.... I am just holding off until I put a built up 472/500 into this car, get a nice 2.78 Posi w/ rear disc brakes from a similar year limo, and then we will be talking

[djcwardog]

Rick,

No need to pull heads to do what I'm talkng about. I agree (from reading the MTS web site) that the MTS 5 and MTS 10 cams move your power peak up the curve - and may not give you much extra peak power without head mods, etc... However, I believe that the MTS 3 cam will move your power peak to LOWER RPM's than stock. That is the idea behind that cam - gobs of low RPM torque at the expense of some high RPM power. If you can confirm that your stock valvetrain (springs, etc) will work with that cam, then it seems a great idea. Give MTS a call and let us know what they say. As you seem to agree, who cares about high RPM power with such low rear gears? Torque off the line is what this is all about. I like your videos! Does the tach on the column hide anything important? Were you able to find a nice one-piece strap with rubber sleeve under it or is it still the radiator hose clamp trick these days? I may do that if I get a similar car.

[Night Wolf]

the 3 series cam is not what I would want... it is a cam made for fuel efficentcy.... I really don't want the powerband LOWER then what is is stock, the engine has enough low end power, it is the top end where it lacks... so taking away from what it already dosn't have much of adds to that.... For my intentions with the 425 (mostly stock, some tuning etc...) the stock cam isn't a factor right now.... Maybe I can pull the thread that I was talking about swapping the cam.

The location of the tach does not block anything, not even the left blinker directional arrow, in fact it kinda matches the car, black background with white letters and a red/orange needle. having the redline at 4,000RPM is neat though... it is soo different then any other car I have been in, like my friends '01 Jetta 1.8T, or even my fathers '99 GP GTP, it goes thru the revs so quick, 100RPM means nothing.... but just look at the tach on the '79, the speedo moves faster then the tach! Not only that, but 100RPM on the 425 makes a world of a difference etc....

I have it on with double sided tape, which has now fallen off, so I will just put one of those big plastic pipe tie things on it and be done for now.

Also, the tach goes to 8,000RPM, so if I put it on 4cylinder mode, it doubles the real RPM, it is pretty cool to see it wind up to 8,000 or move so fast in this car

2 cool things I have noted though:

under WOT in drive, the 1-2 shift happens at 3,900RPM, and the 2-3 shift is 3,400RPM..... which is why when in drive it goes into 3rd around 85mph, but if you manually shift it and hold it out longer, it'll completly burry the speedo, and then go. I think I remember gearing the "redline" of the engine is around 4,200RPM.... I have shifted my 425 into 2nd at 4,600RPM (doing 65mph in first!) and it didn't like it too much.... by then the power is dropping way off though.

Also, the stock torque peak is at 2,000RPM, you would be very surprised to see that under normal acceleration form a stop, going from 40-60mph, or anything, when you hit the gas (not to the floor, but normally) the tach goes right to 2,000RPM, then sits there.... while the car is accelerating... the tach moves very slowly, but it just, for the most part sits there.... it is pretty cool how these engines move these cars with the gearing they have.....

[abcdefg]

To made an update:

My original catalytic converter finnaly plugged up (you cant blame it, it gave 29 years of reliable service).

I took my friends sawzall, and took care of that problem. I stared the engine up after that and mashed the gas in park a few times... Oh man, did it have a nice gurgly roar to it.

I installed about 10 feet of small fence post pipe (2" outer diameter) and rigged it up to the old exhaust hangers. The fence post pipe really toned down the bad-assness of the exhaust, but made it sound like a WWII propeller airplane with a 3spd auto. The exhaust noise under a heavy pull sounds nothing like a V8 untill the secondaries pop open.

As a side note to those wishing to remove the catalytic converter, check with your local state patroll... I was given the A-Ok on my car (because its older than dirt and we dont have emmssions testing). Emissions and exhaust noise violations can add up. Also, the gasoline and sulpher smell is pretty strong.

The acceleration from 0-50 really grabs me by my underwear now. I can leave long long strips of rubber with both tires in parking lots (the whole lenth of them doing a slight turn). Power braking is no sweat, flipping cookies also is easy.

I had my friends freaking out in the car (doing 55mph in a parking lot), they called it a piece of crap and said their toyotas were better... or so they thought .

I would be doing some real engine work.. But umm... Well, gas is TOO EXPENSIVE for 7mpg, so I just blew my cash on a diesel VW (50mpg).

Im low on cash (down to $1200, and unemployed). If I get some good income, im giving the caddy hell.

Btw, is the 425 engine a weak candidate for hot rodding? Im worried about the crankshaft, cooling, vavles, rods, pistons... Im looking for a lot more Torque under the 2000rpm range, 500Ft-lbs would be nice without forced induction or nitrous .

[abcdefg]

Originally Posted by Night Wolf

I have shifted my 425 into 2nd at 4,600RPM (doing 65mph in first!) and it didn't like it too much.... by then the power is dropping way off though.

If I put mine in drive and stand on the gas at about 35-40, It will shove me in the seat, rev and roar up to 60mph, pause for a second, then go into 2nd gear. thats having it D and flooring it. Is this normal or is something adjusted wrong?

[davesdeville]

Originally Posted by abcdefg

Btw, is the 425 engine a weak candidate for hot rodding? Im worried about the crankshaft, cooling, vavles, rods, pistons... Im looking for a lot more Torque under the 2000rpm range, 500Ft-lbs would be nice without forced induction or nitrous .

It's a good engine, I'd say up to about 500hp. Once you hit those power levels (or if you're aiming for those power levels) it's time to think 500 or 472.

[davesdeville]

Originally Posted by abcdefg

If I put mine in drive and stand on the gas at about 35-40, It will shove me in the seat, rev and roar up to 60mph, pause for a second, then go into 2nd gear. thats having it D and flooring it. Is this normal or is something adjusted wrong?

Sounds like the vacuum modulator in the tranny isn't hooked up to a vacuum source. On the back of the carb, either over or under (can't remember which) the brake booster vacuum line there should be another, smaller vacuum line which leads to the tranny. Make sure it's connected and if it is, pull it off and check to see if it might be leaking transmission fluid. If it's not connected, plug it in, if it leaks ATF you need a new vacuum modulator for it to ever work properly even though it's obviously still driveable.

[Night Wolf]

Here I am running the Caddy thru 1st gear... all stock, about to turn 90k.

The sound is from the 14" Edelbrock open element air filter

the carb needs to be rebuilt, the engine dosn't run as good as it should... and 2.28 gears suck. I just bought 4 new, kinda used tires, so I went out tonight doing my best to get some rubber.... but gosh! the car did not want to listen.... in this video the tires hardly spun from a stop, I wasn't able to do a brake stand (tried aobut 5 times) or even a power slide.... wasn't a very productive night

But i finally got my miniDV cam corder! still trying to figure out how to get the video ont he tape on the comp0uter, so these are form the little SD card... quality is bad, but there is sound

http://inoventionseast.com/1979%20De...ddy1stgear.AVI

[Night Wolf]

see.... she just didn't want to go along...

between the very high gears, and the 235 tires on it.... and the hesitation form an idle.... there isn't much overall low end power... it takes alot to get the 2.28 gears spinning... and stay spinning...

http://inoventionseast.com/1979%20De...dy1-3drive.AVI

she was in drive, so it shifted into 3rd at 3,400RPM instead of 3,900RPm it shifts into 2nd....

[Night Wolf]

I go the tire to spin... but no nosie, just the enigne revving when I looked int he rear view there was a trail of smoke tho.....

http://inoventionseast.com/1979%20De...etspintire.AVI

[Night Wolf]

well, I think alot of it has to do with 2 factors:

1) to really get the car going sideways, I gotta throw it into the turn, but with all the foilage now, I gotta slow up to see if any one is there... not enough momentium to get is going...

2) I really need both hands on the wheel when trying to put the car sideways, it just helps me alot... and only haivng 1 hand ont he wheel and the other holding the camera is kinda hard in that respect

[terrible one]

Tape the camera to the right of the headrest or something

[Night Wolf]

Originally Posted by terrible one

Tape the camera to the right of the headrest or something

Yeah, I defintily need to get a way to mount the camra... I do not want to drill anything to the dash, and there is no where my tripod could go....

I'll have to see, maybe I could use the 3M velco stuff on it like i do my radar detector.... but then I would have to put more of that stuff on the dash since it is all the way at the front, near the windsheild for the radar detector... maybe a temp. way to mount it to the passenger side headrest?

[TorqueInc]

To pump up the power of a 425 do you really think you need a 4k kit to do it ?

I know you dont

Just a good rebuild will get you where you wanna be with some head work and thats the key.

another thing....do not ever replace a cam without replacing the stock springs at a minimum.
they have been there long enough and are always mush..TI

[Night Wolf]

well, I want to open up the 425 a little... what I really want to do is an all out performance build on a 472/500

For the 425, as far as performance goes, I want to install the modified 472 intake manidolf (once it gets modified) and the rebuilt carb (once it gets rebuilt) then get a nice free flowing dual exhaust on the car, which will stay on the car even with the 472/500, so that'll be a good investment.

Then I would like to find the rear end from a commercial chassis/factory towing package car... I want those 2.78 gears, Posi, and rear disc brakes just to show off

I know a cam and head work would do wonders.... but I really didn't want to get *that* involved with the 425....

Plus I'll be in FL in a couple months, with no cash to do anything with the car (in tech. school) so sooner or latter the car is going (back) to Florida.... so the 425 will power its way down there, I have always wanted a '77-'92 RWD Deville/Brougham to do a nice build up with, and I got one hell of a steal on the car a little over a month ago.... so now that I have the car, I can wait.... well, I really want to get a 472/500 just to "have" it, but now i am just waiting on funds.

Plus, I think between the carb/intake manifold and dual exhaust, the 425 will be running better already.... I know as it is right now, the carb is already causing (performance) issues...