Silly suspension question...

scrming said:

Ok... drawing on my limited automotive/physics knowledge...

When I punch my car from a stop the front end lifts up ALOT... It takes energy to rais the front of the car up. Wasted energy? Today I put in some H&R Sport Springs which were supposed to lower the car 7/8 inch. Now when I take off from the line the front end stay pretty flat... no BIG lift... so where did the engery that used to lift the front go? Is it now useful energy and help the car get more power to the pavement?

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Nope!! Just the opposite.. Typically, what you want is a weight transfer from the front to the rear at launch to help the rear-wheels grab for traction.. With out it, the car is more prone to spinning the rear wheels..

So you may have just killed your good launch capabilities, especially now that you have the nitrous.. With the nitrous, your previous setup would have been better because from the line the car voluntarily squated allowing for a weight transfer from front to back like it should be.. Now, the chances are you will spin the tires on launch which will show that the Nitrous system is stuck with making up ground on the old setup, and posibly going just as fast, or slightly faster.. Your ET may be pretty close to the same as before, or worse.. You basically will have to feather your launch now...

Not good in my opinion.. You should have waited on the springs until after testing was done to get a good impression of just how much time you shaved off your ET with the nitrous.. Now we will be in the dark just how effective your new install was... Damn! LOL!! Oh well...

But yeah, you will smoke the tires with street tires now, because your not getting a good weight transfer to the rear onto the portion of the car which needs it most..

You could slap the old springs back in, in the rear of the car, because they are easier to do.. But that lifting of the front end was really good..

If you order a drag-pack suspenion setup, the rear springs will be softer than the front, allowing for the weight transfer to take place..

Keep in mind, this is all relative to the amount of traction your tires are getting, based on track temp and stickiness.. So you may still get a good launch if the springs installed still allow for some type of weight transfer.. But it will be hard to judge if the suspension has actually helped or hurt your ET because you dont have a baseline run with the nitrous which will increase your launch torque to more than 2 times what it used to be..

Before Launch torque was around 240 RWTQ... Now it will be about 425 RWTQ plus.. So if you didnt spin them before, that was good.. But now we must wait and see if they will spin with 2x (425+ RWTQ) the increased torque with a launch from 2400+RPM with stiffer springs in the rear...


Pwrhws launched his at 2800RPM..

scrming said:

ok... just back from a short Taco Bell run... I didn't do any hard launches... but my butt dyno thinks the new springs helped with the take off... It certainly help the handling and ride... Improve ride is important since this IS a DD and probably won't see much of the track...


Well, I can always make a run at the track WITHOUT the Nitrous and compare it to my previous times...

BTW... There is no way I can launch above 2000RPMs with my Torque convertor and set up... I usually launch about 1800 or 1900... So the Zex manual says don't hit the nitrous until at 2500RPM??? What is you opinion on the best way to do that... Launch with out going WOT until 2500RPM than go WOT... or should I plan on installing a window switch (which i have sitting right here... LOL)

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I would say let Lidio handle that portion... He will have to tailor the SCT to accomodate the nitrous.. I'm quite sure he will know what to do.. With the automatic, you cant just rev it to 2800, and pop the clutch.. Launching the front wheels into the air and making a grandstand in front of thousands of on-lookers!

LOL!! That what you want huh scrming! You want the croud to Scream your name.. Scrming...Scrming!!!! LOL!!

Oh yeah, then as the auto transmission shifts to 2nd and 3rd, it shoots the front wheels back up into the air about 1 or 2 inches!! LOL!! That would be awsome!! A half track pull up usually means you wil get there first..

Most springs will lower the car more in back than in the front.. dont see how this would hurt the ride. Performance springs are also stiffer, so they should be putting more weight towards the ground, holding it down more. If the nose is comming up less Id say the rear springs are giving less and doing their job. But thats just my 2cents.

John,

Check with Lidio on the Automatic Transmission Cooler bud.... No joke. Last thing you need is to cook the tranny fluid.

Powerbrakeing to achieve launch is a tricky little thing to figure out in the 05. Finding her G-Spot in relation to the stall point to obtain optimum launch is going to take some work. I work on it daily. Hahahahahahah...

Just don't do hold it for very long. Your main enemy here is temperature. The A/T fluid temp increases, as a rule of thumb, 5 degrees/second^2 at a standstill with throttle.

temp = temp(0) + 1/2 (5) (time)^2

So fluid temp can raise 62.5 degrees in 5 seconds of powerbraking.

A higher stall converter/torque converter allows the vehicle to accelerate better from a dead stop. Our stall converter is set to around 2000rpm, if I recall. If a 2400rpm model (I like B&M Racing's TQ Converters ) is installed, you should be able to footbrake stall the converter to about 2400 RPM. This should provide anywhere from 500 to 1000 more RPM to launch the vehicle from a dead stop, as compared to the stock converter. This increase should substantially improve your acceleration capability.

Again, temperature is your enemy. Check with Lidio on the Automatic Tranny Coolers. The stock cooler may be fine. All I know is that it was NOT in my 03 GT. I powerbraked that SOB to a line blow at around 2600 RPM and it was not good.

Let me know what Lidio says.. I really want to make sure I don't cook the fluid in this tranny and have to get rid of it like I did the GT after the dealer fixed the cooler under warrenty and replaced the upper and lower control arms (a lady wouldn't be out draggin now would she - Blink-Blink-Smile). LOL I would have never trusted that GT tranny to last long after that.

Jenn

Jenns05Stang said:

Finding her G-Spot >>> *

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what'a gal ....

I have to say shooterm that I find it a tad interesting that out of my entire post that is the main point you walked away with.

I just can't win fellas.

Jenn

Jenns05Stang said:

I have to say shooterm that I find it a tad interesting that out of my entire post that is the main point you walked away with.


Jenn

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Its a guy thang I guess . . .


but no matter what, you're always a winner here Jenn.