07 impala build

In reply to MadScientistMatt :

That's a lot of reading   lol  something to do at work tonight. I have thought of the police parts as well just hard to find at the junk yard. As it is a claimed class  have to try and keep costs down.

Brad76 said:

In reply to MadScientistMatt :

 I have thought of the police parts as well just hard to find at the junk yard. As it is a claimed class  have to try and keep costs down.

That's why you go to the yard and measure everything. Being a GM there's a lot of parts sharing and you may find the cop car parts on another vehicle you would never expect. Around here G6's dominate that class (FYI)

In reply to Mr. Peabody :

The g6 is a good car for it . But being in southern Ontario any car 10 or 15 years old that meets spec and isn't rotten into the ground is a good car   lol

Brad76 said:

In reply to AngryCorvair :

It would be as I get on the gas coming out of the corner  I watched a video of my race and when I got on it the inside tire was smoking. I think it's because i was running a smaller tire on the l.f.  with the open dif. Should I be running the same size tire? And just play with air?

so you need less spin / more acceleration from LF (inside) tire on corner exit. generally speaking, you can break this down into two goals.

more weight on LF tire.  more weight can come from things like lower ride height, softer front springs, softer front bar, stiffer rear springs, stiffer rear bar, and maybe moving some things around as long as you don't break any rules.

more grip from LF tire.  more grip can come from adjusting front end alignment, ie static positive camber so the tire is more perpendicular to track surface when cornering, maybe changes to tire tread and inflation pressure, etc.

maybe there's some driving technique improvements to be had as well.  if you can rotate the car earlier so it's pointed down track sooner, you can unwind some steering earlier and start accelerating earlier?  IDK, i've never done this kind of racing so i'm just looking at it from an overall vehicle dynamics POV.

are you keeping good notes of what changes you've tried and whether those changes were faster or slower?  i'd be really interested to see that info.

He needs to go stiffer in the front.  Much stiffer

Mr. Peabody said:

He needs to go stiffer in the front.  Much stiffer

stiffer what?  and please explain the effects which will lead to putting power down better with the inside front tire.

Stiffer springs. They're so soft that at speed the LR will actually come off the ground, the RF will bottom, and start the car bouncing back and forth.

The effect of having the wheels on the ground will increase traction.

In the event that doesn't happen, you're still transferring too much weight to the RF

Mr. Peabody said:

Stiffer springs. They're so soft that at speed the LR will actually come off the ground, the RF will bottom, and start the car bouncing back and forth.

OP didn't complain of any of those things.

The effect of having the wheels on the ground will increase traction.

stiffer = more weight transfer

In the event that doesn't happen, you're still transferring too much weight to the RF

Yes, and making things stiffer will transfer more weight away from the inside front.  

In reply to AngryCorvair :

I don't have many notes from last year as I'm not sure how the car was built and didn't change much from that. We can't change camber at all so I can't work with that. Putting more weight on the right front sounds like it should work and I think a bigger left front and disconnecting the sway bar should help it roll a bit onto the left front as well? 

In reply to Brad76 :

I want to make sure I'm on the right track here.  This is a roundy-round car, yes?  And it's all left turns, yes?  

In reply to AngryCorvair :

Yes to both it's a 1/3 clay oval   I have street tread on it now with about 27 to 29 psi on the front 2 tires and 10 in the left rear and 38 in the right rear. Not sure off hand the tire sizes 

If you're looking for police Impalas in the junkyard, keep your eyes open for trunk locks about two thirds of the way across the trunk (starting from the left.)  Civilian Impalas normally open the trunk with the fob (no visible lock cylinder.)

Also, consider looking for old police Impalas in the back lots of taxi companies, not just in junkyards.

In reply to Stealthtercel :

I have a cab company just down the road   my have to hit them up.  Good idea thanks. 

Brad76 said:

In reply to AngryCorvair :

Yes to both it's a 1/3 clay oval   I have street tread on it now with about 27 to 29 psi on the front 2 tires and 10 in the left rear and 38 in the right rear. Not sure off hand the tire sizes 

OK just wanted to be sure i was understanding the problem correctly.

Your stated problem is limited acceleration out of corner due to left front wheelspin.

tire force equation:  F = mu * N.   force equals grip of tire on that surface, multiplied by the weight carried by that tire.

so if you want more force from the tire, you can increase the grip of the tire on that surface, or increase the weight carried by that tire.

grip is influenced by suspension alignment, inflation pressure, rubber compound, tread design, and maybe some other stuff.

can you tell us the exact wording of the rule(s) regarding suspension alignment?

are you required to run "street tires"?  do they have to be "car" street tires?  any chance you could mount up a motocross tire on left front?  :-)

In reply to AngryCorvair :

The suspension has to be stock everything as it comes from the factory. So no moving of the strut tower or mounting points also no caster or camber changes. As for tires they must be car tires. We can run a m.and.s tire this year. That's new for this year. We are allowed to run a mix and match of tire and rim sizes. 

Dang.  Maybe you'll just have to be more gentle on the throttle.

try more air in the front tires.  Go up 4 psi and see what you get.  If no difference, or if faster, add another 4 psi and try again.

In reply to AngryCorvair :

I am going to look for a bigger softer tire for the l.f and ay with air a bit  the problem is we don't get hot laps and only one day of practice  so  not a lot of seat time before the races.   And what's this crazy talk about less throttle?  Never heard of that before   lol

Apologies for butchering the terminology. I guess I meant body roll.

Nonetheless, he was running a little tire on the inside, which is a big contributor to his traction problem, stock suspension aside.

The cop suspension will stiffen it up everywhere, which is what it desperately needs, so you're going in the right direction.

Mr. Peabody said:

Apologies for butchering the terminology. I guess I meant body roll.

Nonetheless, he was running a little tire on the inside, which is a big contributor to his traction problem, stock suspension aside.

The cop suspension will stiffen it up everywhere, which is what it desperately needs, so you're going in the right direction.

It will be interesting to see if reducing body roll by stiffening the suspension will improve the contact patch on LF enough to offset the reduction in weight being carried by the LF.  I know that works in cornering on some camber-challenges FWDs, but acceleration loads the tire differently than cornering.

i agree that a taller LF tire should help. 

I was thinking a new or stronger r.r strut my help as well?  And matched set of tires on the front 

If the struts are worn, it will certainly handle a lot more predictably with new ones, but if they're in good shape with stock springs - the closest thing to a performance shock out there is the KYB AGX. There isn't all that much aftermarket support for W-bodies, although there is some interesting junkyard mix and match possibilities. Your '07 model already has most of the good parts, though.

Thanks folks for all the tips and hints.  I will be starting the work soon and looking over everything  and after the tune up ( plugs  oil air filters  and nut and bolts checks) I will go thru the springs shocks and tires to see what improvements I can make and what I can sneak under the radar  lol. 

I used to drill a hole in the shock or strut body, drain the oil and replace it with heavier suspension fluid. It works,  but I don't know if any of your available or stock shocks or struts are non-gas shocks

This thread has me wondering about more W-body parts interchanges. It appears that in 2007 there was a sport suspension (and possibly police?) package that used stiffer rear struts and springs. The front struts (but not the front springs) are the exact same part number as on my '98 Regal.

Interestingly, on Buicks, the base model suspension only differed from the sport suspension by what sway bars were used.

In reply to MadScientistMatt :

I do know there was a 07 police pacage for the impala  I'll have to go to the local parts guy and start getting part #s I would like the stiffer rear spring on the right side. Have to look and see if it has a rear sway bar or not