hey guys, in a couple years i plan to build a 5 window A coupe with some serious power and very low weight. right now im thinking choped and chaneld over a scratch built frame ect bla bla bla anyways its going to be pushing a good 5/600 hp with a four speed behind it and i dont want this to all go to waist, what would you recomend for a rear suspension set up so this thing will hook up instead of smoking the hides all the way threw the quarter? its going to sit fairly low if that makes any differnce and i plan on running some slicks when i want to make a run, but not sure what ill run on the street tia tim
Copy a current Funny car chassis. No Im not kidding. If you really want to competetively hook up and WIN races you have to be state of the art. Second place ain't shit! (Stroker Ace)
Variable pinion angle Triangulated 4 bar with coil-overs has worked just fine for me. I've seen many different set-ups work for others though. But there are other variables to consider to make a light car hook-up..., such as what type and size of tires are you going to run, the gear ratio, as well as the optimum torq and Horsepower curve on your engine. As "Reeves Calloway" has said many times..., "You can have all the Horse Power in the world..., but if you can't get it to the ground it's no use...!
i would have to agree with that quote, thats why im trying to figure out how to get it to the ground. any opions are welcome tim
With a light car you won't need the torque to accelerate it, so build it for horsepower. Set it up so the power comes in after you're already rolling (High RPM) and you'll have good luck
Hot Rod To Hell speaketh da truth! I see lots of cars that are excercises in waste...high revving small blocks in 4000 pound hulks, tourquey 502s in Camaros, and all sorts of other bad combinations. If you can think in abstract terms, try to imagine that your entire vehicle is a mathmatical equation. Whenever you alter one variable, it will effect all other variables and throw the formula off balance. You have to compensate. My old math teacher explained it best....whatever you do to ONE side of the equation, you must do an equal change on the opposite side to keep it balanced. For example: Say, you have a bone stock 68 Camaro with a 327 automatic. The car was built by GM and everything from camshaft profile, to carburetion, to tranny and rear axle gearing has been engineered to work as a package for the best all around performance and driveability. Now, you come along and stick a big ol' cam in that motor. Your new camshaft changes the engines characteristics and it's fuel and spark requirements, as well as moving the powerband further up the RPM scale. The result is that you have a nasty sounding car that falls on it's face out of the hole and runs SLOWER times than it did stock! What do you do? Well, you will need a better flowing intake, a larger CFM rated carburetor, more spark advance, and free flowing exhaust headers to make the most of that new cam. In some cases, higher compression may even be required, but let's assume that you didn't go THAT far out! Okay...now that engine has snappy throttle response, revs like a beast in neutral, so you line it up for another pass down the old 1320. Hmmmm...it's better...but still lagging and not running much, if any quicker times than it did stock...what the Hell went WRONG??? The other side of the equation! You worked on the engine's variables and balanced THAT side out...but you didn't do a THING to the rest of the car...the 'other side' as I think of it! With your powerband moved up the RPM ladder, your stock torque converter is effectively "lugging" the engine, and not allowing it to rev into it's optimal powerband fast enough. You need a "looser" converter with a higher stall speed. So, you swap in an 11" street converter with an advertised 2800-3200 RPM stall speed. Let's say you also install a shift improver kit and a ratchet shifter while you're at it. Good for you! Back to the staging lanes. Bring up the revs against the brake as the amber lights come down...then nail the pedal and dump the brake just as the last yellow light winks out! DAMN! It spun one tire halfway down the track! You're getting more power to the rear axle...but it's going up in smoke as you overpower the one drive wheel and the 3.08 gears keep that motor in it's "sweet spot" long enough to incinerate the tires for a long ways...putting on a Hell of a show...but not gaining you much! Now, you opt for a positraction unit and steeper 4.10 gears to allow the motor to wind through it's optimal range in every gear in the quarter mile length of track. Then you trundle back to the starting line to see what ya got! Not bad...you blaze both street tires off the line for a few feet, then you're screaming through the gears just as planned. You're getting there! Next, you bolt on a set of slicks and the required driveshaft loop, and stage the car after a nice smokey burnout. The lights come down and you launch it hard! The resulting wheel hop damn near gives you whiplash as the mushy 35 year old leaf springs wrap and unwind violently! If you're lucky, nothing broke! Okay...now you install a set of Moroso drag springs with a set of Lakewood J-bolt traction bars, as well as a set of 50/50 rated shocks for the rear. The next launch is much harder...but you still get a little wheelspin. Your ETs have finally dropped a respectable amount, and you move on to optimizing the FRONT suspension with softer springs, 90/10 rated shocks and removal of the sway bar for increased weight transfer. Now you're diggin' hard off the line and gettin it ON...but the creaking and groaning you hear everytime you leave the line tells you that the chassis is flexing under the stress. To capture the torque being wasted by twisting the unibody chassis, you have a set of subframe connectors and a six point roll bar welded in...and replace the stock motor mount that broke on your last pass with Moroso solid mounts! Now, you come to the point where to go any faster requires either more power, or less weight. You increase horsepower in proportion to decreasing weight and low end torque. (Bigger cams will kill of low end power and help high RPM horsepower, etc). You want to keep your weight reductions consistent with your horsepower increases...taking weight off the FRONT of the car but not off of the back...as doing so would limit traction. If you keep going, you will need to build a stronger short block, install better heads and a more radical intake design and so on down the line. Then, to some degree, the whole process starts over again and you must make changes to your torque converter, gear ratio and weight balance to keep everything balanced. You see how you must consider what one change to any one part of the total vehicle combination will do to the whole equation??? You can't alter ONE variable without throwing things out of whack..especially if you start with motor mods like so many people do! (I for one advocate making the most of the chassis and suspension on a drag car and then bringing more power into play later...but that's just ME!!!) Anyhow...hope some of this rambling makes sense...it's still early on Sunday morning!!!
Unequal length adjustable four bar, panhard rod, coil over shockers, limited slip diff, fat tyres, high end power motor (No 'max power at idle' cams, go wild), stock convertor(If you running an auto) keep your weight at the rear, battery, fuel, fat friends etc. Don't forget the front end either, good brakes, decent 'working' suspension etc Don't go running 8psi in your rear tyres thinking it makes 'em grip. Eyeball the black mark it leaves when you launch, and go for full width, full darkness marks, remember that tyre pressure, as it'll be far higher than you'd think on street tyres. THEN, go out and test launch it at a real track, checking 60ft times, and adjust, and test again etc etc. Here's a little buggy I built in the Philippines a couple years ago. 350 Chevy Powerglide, ladder bars, 9" rear etc. Not finished in the pic, but man, that thing would come outta the hole like a scalded cat on speed
OK model A 5 to 6 hun HP 4-speed and dont spin the tires. I suggest you go to the drags and start lookin at super gas cars. Get a Chris Alston catalog and about 10,000 later you will have all you need. Really your gonna need a drag chassis not a street chassis.--Feder
thanks for all the info guys, i realy apreciate it. i know this thing is going to cost me an arm and a leg thats why i want to make sure everything is what i want and that is done right the first time so i can just sit back and enjoy it. preety much planing a big block mopar powered FED with a model A body and make it preety close to street legal if that gives you a clearer picture of what im thinking so race chassi stuff and links are more then welcome. low, loud, and waaay more power then any one should realy have under five toes tia tim
I hopes your gonna use that car somewhere wiiiiide open, cause things come up real quick when you get hooked up with your foot deep into the loud pedal. 20mph to 80 mph in, like, two seconds type reeaal quick! That half assed yellow buggy of mine used to scare me shitless sometimes, and that was just 400hp, and thrown together in two months.
I'd say FatHack pretty much nailed it. I've beat a lot of cars over the years that had me whipped on power but couldn't USE it! Also, Samyam would probably tell you it's knowing what the car has and how to put it to use. I had a buddy with a G.T.O. back in the 70's. I was consistantly 1 and 1/2 seconds faster thru the quarter than he was in that car. You just couldn't teach him how to launch or drive the car to it's advantage. I've seen a blown 427 glass hiboy that couldn't run faster than high 15s and a crate engine SBC 72 pickup that would do high 12s. It's 1/2 having the parts work together and 1/2 knowing how to make it do what you want it to do.
alright, so how would you go about putting the frame together to take the abuse and work corectly? sounds like un equal 4 link and coils with a pan hard bar is the way to go in the rear, and im thinking a droped and suicide mounted axel in the front. figure the frame would end up preety much ladder shaped basicly, what way should i go with this? thanx tim
I really would get ahold of Chris Alston, Chassis Engineering, or somebody like that and get a 4 link kit. I have Chassis engineering ladder bar / coil over kit in my car, and I wish i would've gone with a 4 link. It has more room for error, but WAY more adjustability. My ladder bars with a diagonal link SUCKED ( I kept bending the diagonal link, shock brackets, and even the ladder bar mounts), so I switched over to a panhard bar and I love it! Haven't bent a single thing, it has a lot less body roll, and just feels more "solid".
Tim, It's obviously going to be a car with a few bucks in, so a pro built chassis will be the way to go. All depends on how much expertise you have with engineering yourself. You can look at a bunch of websites and pinch ideas and build your own, or you can cut to the chase and spend a little bit more and get a pro built one. 600hp can do wierd things to steel Have a look around in this site: http://www.baiengineering.com/chassisengineering/
For what you're talking about, a tubular chassis with built-in roll cage surrounding the driver is the only way it'd even be CLOSE to practical. A four link out back with alot of tire and a gusseted 9" axle housing on coil-overs will work, and a dropped axle front with a suicide mount spring could be employed to hold the front wheels on. You're also gonna want a serious braking system...likely race car stuff...four wheel competition discs with adjustable proportioning valve. The chassis should be constructed to use motor plates for mounting the engine, and you'll want as much set-back as you can get. A sedan body might be best here...move the seats back and recess the firewall to gain proper weight transfer. My brother-in-law's 26 T is built pretty much as I just described with a 406 Chevy in it (for now). It has been NHRA certified legal to I believe the 8.99 ET mark (although it's not THAT quick!) and it was professionally built by a shop in Minnesota. (Classic Metalworks maybe?) That's the only type of chassis I'd even consider for the kind of power you're contemplating! As mentioned...get ahold of Chris Alston's Chassisworks to help you plan, design and build a tubular chassis with integral cage that can handle this type of power without flexing or tearing itself apart.
Equal length four link and diagonal link work fine for me. You get so much scope for tuning the way the car launches with a 4 link. If you really want to learn about getting cars to hook up then get yourself a copy of "Doorslammers: the chassis book" by Dave Morgan ISBN NO 0-963-1217-0-7
great posts guys, fat hack thats more of the kind of stuff i want to here im not going to go all gold chainer or anything but thinks will be done right and it will sit years before i put low grade b.s. on it. not worth risking lifes just to save a buck or have it on the road i actauly do have some mechanical enginering back ground, and would plan on conversating quite a bit with proffesional chassi builders when it came time to put it together, and with it obvosioly being a large part of the safty of the car a certified builder will be puting it together. not saying its all getting farmed out or anything but you just have to have comon sence in there some were viva da hamb tim
Tim heres My BB mopar with a Chris Alston chassis.The tubes are .084 wall thickness.For street duty You would want the .120 wall.Hes really got the stuff.-Feder
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