60ft times on dart

[swingerjack]

hi there sorry about the mistake dont post much my question is i put a altercation frontend in my 71 dart swinger was runing 10.1 10,2 134mph 60ft times where 1.41 1.43 after installing the front end i lost 1.5 tenths in the 60ft which is 3 tenths in the 1/4 i have caltracs wth the single mono leafs rancho schocks ten way adj 10.5by 28 slicks any help with my new frontend setup would be awsom thank you the front end makes this car a treatto work on .very nice quality

[Blue]

I have exactly the same problem, I think in my case it's down to lack of front end travel. Calvert say you need 5" of front end rise to get the caltracs to work, I have nowhere near that with the Alterkation. I did speak to Bill about it some time ago, he said there was a longer shock he could supply to fit my early kit, must sort that out at the end of the season.....

[doug 371]

hi jack... any issues with the new launch pad?

[bOb shingler]

hi jack... any issues with the new launch pad?

[doug 371]

hi jack... any issues with the new launch pad?

new cement launch pad at the track he races at... oh well...hopefully blue was some help to him...

[PureGTS]

  I have the same issue, as far as losing front end rise. Before Alter-K the front end would leave the ground. After I installed it I expected it to become even worse, losing 87lbs off the nose and all, I figured I'd see more sky under the front tires... but I didn't. Don't get me wrong it's the stuff as far as I'm concerned. I'll trade control for less transfer any time so long as the ET remains good and it does. However, I fail to see how a longer shock is going to help. It is a coil over shock; it has limited travel. Now a longer spring AND shock maybe, but just shock alone... I don't think so.
  Here's how I got this, correct me if I'm wrong. Let's say the shock's max length is 20" with no load, fully extended. With the shock and spring installed, car weight on it, it is 15" long. The spring, unloaded, is 12" long and 9" long with the cars weight on it. The only travel you will get is those same 3" when it tries to transfer weight. You can make the shock as long as you like but, to me, the spring, and its travel, is the problem not the shock. If the body comes further up at launch, won't the spring rattle around lose in the now unrestricted space beneath it as the suspension just fell away? And yet it doesn't. Not to mention what would happen when the suspension came back down with the spring out of place. It is the spring's length and the shock together that is causing the problem, not just the shock alone.

[Blue]

I agree, The spring length needs to match the shock or else you'd gain nothing and give yourself another bunch of problems. This is one of the reasons I have'nt bought new shocks yet, the new motor will be lighter than the one that's in there now, so not only will the new springs need to be longer, hopefully I'll need a lighter spring rate too. Still can't see me getting 5" of rise though, even then.....

[Bill_Reilly]

The key isn't so much how much the front end moves, but how high it goes. The higher it goes, the more weight on the rear axle. For the last couple of years I've been using the longest shock possible, and to gain anything we add 1" extensions to the shocks. With the extensions, it's best to go up to 10" springs instead of the 9's. Doing this gets you about 3/4" extra travel, which is the max amount the a-arms will move.

The strange thing I can't figure out is caltracs' 5" travel recommendation. The stock stuff will only travel 7" top to bottom, so they basically require the car be set almost bottomed out to have enough rise. Don't think of transfer as "flinging" the nose up, but more the side-view angle of the car. Nose up, rear down. If the rear is up higher, the front must rise higher to maintain the same angle and hence, the same amount of weight on the rear. Cars with SS springs set a foot off the ground wil see the biggest loss, as the angle changes the most. The lower the car is, the better it performs, primarily because of that side-view angle. The alterk gives up 1.5" of up travel, so that's really all you lose as far as transfer. Adding the extensions gets half of that back, and a common gain is to soften the rear a bit. Allowing the rear of the car to drop some has the same transfer effects and has been showing some guys substantial gains - basically they recovered their times plus a little. Obviously this is harder to do with leafs than it is with coils and bars in the rear, but alot can be done with just the shocks. With leafs, adjustable rear shocks go a long way. All other rear suspension types actually work better with less front travel, so tuning things together becomes important. Some guys have to go down to a shorter shock to limit travel to just a couple inches to keep the nose down.
  I always send out the extensions for free, but the 10" springs are a cost if you need them - I think 90 a pair. The springs are available here, or anywhere else also, like summit and jegs too, the 10" coil-over springs are about the most common spring. Depending on how high the springs are up the shocks, the 9's sometimes work fine. I still prefer to mess with rear tuning first to get the most out the existing, and if that doesn't help enough, throw the extensions in.  Ideally, you want the lightest spring possible, so it's compressed up the shock as much as possible without binding. If the 9" rate is right, the 10" spring rate will still be the same because the travel range isn't increased enough to make a spring difference. If the gain was 2" or more, the rate would definitely go down with the longer spring, but gaining 3/4" isn't a big enough change to warrant a lower spring rate.

[Blue]

Bill, a lot of guys running Mopars with caltracs are suffering from "porpoising" on launch, the cars rocks back and forth on the springs unloading the rear tires. The only thing that seems to work on the higher horsepower cars is to increase the front end travel. With a stock front end and a 28" front tire, you can lower the torsion bars so the car sits about 1/4" off the factory bump stops, this gives enough rise to cure the problem. I too suffered from the same problem, I have managed to tune it out for now on the back suspension, but I know it will come back to haunt me when I up the power. However, my 60 ft's are too high for the ET I'm running at the moment, so I'm sure a longer front shock/spring than I have in my early style Alterkation is the answer, I'll call you to discuss.

[Bill_Reilly]

Yea, Blue, I do believe you have the early one with the shorter shock - the shock we use in all of them now is 10" closed and 14.25" open - I think yours is like 9.5 closed and 12.5" open.... The longer one in your case will be a sizable change.

[bOb shingler]

porpoising is caused be the front and rear springs being to close to each other in the rate per inch. they occilate ( vibrate ) at the same frequency. the only way to care the problem is to change either the front or back spring rate. 

[68_Val_Sedan]

I am certainly no expert on the subject but whe nmy car was porposing with the cal tracs all I did was add longer rear shocks ... the ranchos that caltracs recommended to me were not long enough and they would bottom out on a launch.  just my 2 cents

[bOb shingler]

I am certainly no expert on the subject but whe nmy car was porposing with the cal tracs all I did was add longer rear shocks ... the ranchos that caltracs recommended to me were not long enough and they would bottom out on a launch.  just my 2 cents

i don't reckon that's the ture diffinetion of porposing.

[PureGTS]

I am certainly no expert on the subject but whe nmy car was porposing with the cal tracs all I did was add longer rear shocks ... the ranchos that caltracs recommended to me were not long enough and they would bottom out on a launch. just my 2 cents

That sounds like a different problem all together. The suspension should grow, not compress. At worst remain same, but never bottom out or compress to that point.

Bill - How would I know if I have the "early" Alter-K (purchased May 2004) and need to get the longer shock set up? Would the new shocks be the double adjustable ones or are they an option unto themselves? I have the QA1's right now.

[68_Val_Sedan]

I am certainly no expert on the subject but whe nmy car was porposing with the cal tracs all I did was add longer rear shocks ... the ranchos that caltracs recommended to me were not long enough and they would bottom out on a launch. just my 2 cents

That sounds like a different problem all together. The suspension should grow, not compress. At worst remain same, but never bottom out or compress to that point.

Bill - How would I know if I have the "early" Alter-K (purchased May 2004) and need to get the longer shock set up? Would the new shocks be the double adjustable ones or are they an option unto themselves? I have the QA1's right now.

If I needed LONGER shocks don't you think the suspension was growing ?   When I said bottomed out I meant they hit the end of their travel in the extension direction that is why the post said I needed LONGER shocks

[Blvedere]

To me bottoming out is fully compressing the shock, topping out is fully extending shock.

[PureGTS]

68Val Sedan - My mistake; I got lost in the confusion of bottoming and extending. But as you can see I'm having similar issues with geting the front suspension to grow on the Alter-K. My best 60ft is 1.52, so it's not too bad, but I still think there's more to be knocked off.
  I've had the whole Cal-Tracs set up sitting on my shelf, for 4 years now at least, but haven't convinced myself I cant live without putting them on. The OEM 4-spd springs seem to be doing quite well at this level of performance. If/when I finish the 572, I'll probably have to do something out back too. (Thank goodness that isn't tomorrow!)