Mach 1 Autcross make over!

[Bmeagher]

I should have results this weekend. I'll just play with my pressures, since last year I had them set from what the door jam said.

 

[blacksheep-1]

The biggest gain will come from driver experience

 

[wmfateam]

^Aaaaaaaaaaaaagree

 

[Bmeagher]

The car handles great but when I corner/brake hard, a rear tire comes off the ground and hops. The gearing is also hurting me, 4.30's with a 3.38 first gear tops out pretty fast. Ideally I need 3.55's or 2.66 magnum first gear....I'm hitting 6800-7200 a lot.
I'll pick up a torque arm next year, and completed the Panhard bar with it. And maybe some nt01's before the airport autocross in August.

 

[blacksheep-1]

Find a single gear you can run the course with, then just leave it in that gear and work on driving, unless it lugs real bad, just work on the driving aspects. I usually run mine in second with a 3.55 most of the time.

 

[Bmeagher]

Is wider tires always better for autocross? Right now I know I don't have the right tires for the job. Nitto 555 245/45r17's on stock 17x8's, and nitto 555r 275/40r17's On 17x9's.
I was thinking about picking up 2 more 17x10.5 afs rims, and getting 315/35r17's, and putting the 17x9's on the front.
I'll be going with NT01's on all 4 corners. 275/40r17's in the front , 315/35r17's on the rear....
Opinions?

 

[wmfateam]

Bigger tires on the rear will increase rear grip, which generally causes a push.

 

[Bmeagher]

Bigger tires on the rear will increase rear grip, which generally causes a push.

So what's the ideal tire sizes for autocross.... 275/40r17's on all corners?

 

[mgsullivan]

Whatever size you pick use the same size for rotation to get the most out of the tires.

 

[Bmeagher]

I want to get the max out of the car, 275 on all corners would do better then 275/315 mix?

 

[mgsullivan]

I liked my car on a staggered set up but didn't like the wear. The staggered set with 315's would be great for rear grip. Just be prepared to tune out the understeer.

 

[Bmeagher]

To tune out under steer, -2.5 caster, a little more toe out, lower front end more....stiffer rear swaybar.
Would you think more rubber the better? I want this car to hang with the best, and handle like on rails. I do notice right now, there is major understeer.... It just plows with the steering wheel cut.

 

[mgsullivan]

Don't do any tires until you do your best to fix the understeer.
In no specific order...
1. Slow in fast out
2. More rear ride height
3. More rear spring rate
4. More rear sway bar (I don't run one but that's another discussion)

 

[blacksheep-1]

FWIW the tri 4 link is known for going into snap oversteer on corner exit as the upper control arms try to force the diff back to it's neutral center. I might point out that some of what you are experiencing is just the nature of the beast, our mustangs are nose heavy and therefore "pushy" then they snap oversteer on corner exit, it's my opinion that you must be a better driver with a mustang, (especially on these short rice burner slot car tracks) than with most other cars. Several years ago I finished 3rd in the Tampa NASA autocross, there were 2 S200s ahead of me and 1 S2000 behind me in 4th. Those are some pretty impressive cars to be paired with and infinitely easier to autocross fast than our mustangs. Again ..driver experience will be more important at this point than any changes you can make on the car, and you may find that as you gain experience, you went the wrong way with those adjustments. (in other words, they are a crutch for your current level of driving).

 

[Bmeagher]

I tried staying in 1st, then starting in 2nd.....I had zero difference in my times. I was averaging 26.2, with my fastest time of 25.95.
There's another event here this weekend

Crutch.... What would you have done for suspension?

 

[blacksheep-1]

I tried staying in 1st, then starting in 2nd.....I had zero difference in my times. I was averaging 26.2, with my fastest time of 25.95.
There's another event here this weekend

Crutch.... What would you have done for suspension?

Well say, as an example, you loosen up the front sway bar so the car is not so pushy, then you find (with experience) that taking a wider line, and having the sway bar tighter is faster. OK let me tell you an old karting story, I used to run a Yamaha kart, one of the biggest turds on the planet, I worked my azz off driving that things, every week, I'd go to my engine builder and tell him to order me a new chassis. His comment was ALWAYS "Are you getting the most out of what you have?" the answer was ALWAYS "no" I needed more experience. After beating myself to death with this kart for over a year (I cut the spindles, re engineered the brakes, changed everything at least 20 times) this guy comes out of his shop with a brand new Coyote Bullet..says "It's yours" I won my next 6 races. SO I have to ask...with your experience level "are you getting the most out of what you have now?"........

 

[Bmeagher]

Very good point, I think I am. But I'm just missin one piece of the puzzle..... Gears are too short / brand new 555's on the front roll over. Maybe if I grabbed 2 NT01's for just the front, I'd be able to hold the line and not get pushed out.
I also think your right, I need more seat time. Maybe I'll throw my stock uppers back in before he event, and see if it helps any

 

[jpmotorsport]

Very good advice in this thread. If you're talking about throwing stock suspension parts back on I don't think you have the full answer to the question blacksheep asked...

I caught the bug this year too and frankly I find it very hard (as it sounds like you too) to resist the urge to play engineer and fiddle with suspension parts I really just don't have the experience to know...

at this point I took the money I was saving for new sway bars + LCA's and put it towards the tire fund and an SCCA membership (even though we end in Nov here in NYC I will still get the $$ back in savings and more so...). After a lot of soul searching and asking myself that same question, I found that's the best investment for me right now.

 

[mike1530]

Did you have issues fitting the 6 piston calipers to the stock wheels

 

[prokill00]

Just ran my Mach 1 for the first time in an Auto X today. What a blast. I've been slowly setting my car up for turns instead of straight line, but today was the first event I participated in. I noticed 2 other Mustangs there. One guy in a 2011 was running amazing times. He used to have the NT555's then went to NT05's and is now running NT01's. He said the 01's are his favorite so far. I'm not a pro in this area but I'm just forwarding on what information I saw and heard today.
The other Mustang told me it would be better handling to run a square setup with 275s on all 4 corners instead of the 275/315 setup like I am currently running.
One thing I noticed was a ton of body roll and the rear end kept wanting to kick out. I have factory sway bars and H&R race springs, Koni adjustables up front and Billstiens in the rear. I'm also running an IRS from an 04 Corba.
I think I might want upgraded sway bars and a change of tires for next season. Full bushing kit from FTBR is a must for the IRS. Also bought a cast iron housing to beef up the rear a little more. 4.10's are probably gonna go in favor of 3.73 or 3.55's...not sure yet. It would be awesome to do coil-overs on all 4 but right now the funds wont allow all of this at once, gotta pick and choose for the time being.

Needless to say I am hooked though. Had a blast and cant wait for future events. Eventually I'd like to get into road courses but $45 for an auto x event is a bargain and a hell of a fun day spent with friends.