Help me win at autocross, I wanna be a top 10 car and driver! Options

[crash914]

ok, I need help. currently I am about 3 to 5 seconds off the pace in my local club events. I know most of the time is due to the driver. I think that there is some time in the car also as it is mostly set up for the long track.

Here is what I know so far, if more info is needed..ask...

73 914, blue. bolt in cage, just the 4 plates plus the seat belt for tie in points.

stiffly sprung, Koni yellows, I think 250 lbs in the rear and 21 or 23mm torsion bars in the front.

Delrin bushings everywhere, I have needle bearings, just not installed.

lowered, see pictures for height. 4 inches in the rear to the bottom of the engine mount bar, 4 inches in front to the bottom of the front floor pan.

205 50 15 tires, not sure of the wheel width, 4 lug.

my tires are about 8 year old khumo v710's that have been in the garage and have 4 autocross days on them now.

air pressure I have been running, 22lbs front, 20 rear. see pictures for chalk. looks like I am using all the tread.

Camber is close to -2.4 degrees front and rear. Front toe is 0, not sure about the rear, perhaps 1/4 inch toe in.

Motor is 103 by 80, nickies, split cam, le200 heads, tangerine header, 6800 rpm redline, 11:1 compression, so plenty of grunt.

Megasquirt with twin throttle bodies.

Transmission is open diff, with a flipped 5th gear for 3rd and standard 5th.

no camber plates,

See pictures in the following posts..

[crash914]

pictures....

[crash914]

Video of the loose nut....I had a good run until the cone jumped out in front of me....

https://www.youtube.com/watch?v=54uULzcLg4s

[koozy]

1- Lose as much weight as possible (car and driver)
2 - Toss the old tires and get some Hoosier A6 tires under there (wide as ya can fit)
3 - Get some toe out in front
4 - Get the car corner-balanced and make sure you are not running the car too low (a-arms and axles need to be parallel to the ground when static)
5 - Lose more weight (if it don't make ya go faster take it out)
6 - You need to know what the spring rate is up front to balance the suspension so guessing on T-bar size won't cut it.

That should make a HUGE difference

[crash914]

I know about the weight thing...I did corner balance some time ago...I am going to do it when I replace the bushings.

I did forget...no money...got to be done on the cheap...this is still a street/track car...

I am about 1900 lbs now without driver.

I agree about the tires...old rubber...but, no money!
The car is pretty balanced, I can throttle steer very well. I did get lots of understeer when taking that sharp left in the video, but was just too hot into the corner. Otherwise, both ends let go pretty much the same....
Is my air pressure too low?

working on the driver weight....got another 25 lbs to go...
thanks!

[koozy]

If you machined the Delrin bushings properly and lubed them prior to install they should work fine. Bearings will be better but properly installed Delrin is light years better than rubber.

I just watched the video. You are coasting too much. If you are not on the gas you should be on the brake. Those tires are probably worse than soft compound street tires at this point. You are overwhelming them with little to no effort. Also, you are in third gear where you could probably be in 2nd most of the time. Find some fast drivers and ask them to get in and instruct you a bit. Then, seat time is your friend.

The "no money" thing will keep ya from the pointy end of the field, if for the lack of competitive tires alone.

Good luck in your adventures.

[mskala]

I sure as hell don't know everything, but:

1) It looks like there are several places there where you are coasting up to
the braking zone, when you should be full on the gas and then hard on the brake
(these look like straights in the video, if not then my bad, but you will still need to
push the limits more)

2) I'm in favor of hands at 9 and 3 (ish) and if a corner gets too tight, you leave
the outside hand in position (but it can't grab), take your other hand off, move it
across and pull the wheel the rest of the way. This way you will always know where
the wheel is. Easier to show than to explain.

If you are that far back as far as times you're getting vs. your goal time, then keep
those tires if they haven't aged out while you improve.

[koozy]

Also, this book is money well spent.

Secrets of Solo Racing: Expert Techniques for Autocross and Time Trials

http://www.amazon.com/Secrets-Solo-Racing-...s/dp/0962057312

[koozy]

Hand technique is explained in that book. Get a tire money jar and throw $5 every chance you get. Do a side-job or something. Tires are critical in this game.

[koozy]

Also, tire pressure should be slightly higher in the rear than the front due to weight differential. I would swap those tire pressures front and rear

[Alice]

Also, tire pressure should be slightly higher in the rear than the front due to weight differential. I would swap those tire pressures front and rear

What about a new set of good race shoe s ?

[crash914]

all good info. Thanks!
I know I need rubber, but I figured it would be worth 1 second or so...not 5..

As far as 3rd gear, you are right. this was a long 911 course, FTD was a cayman with a 42.something. I was 47.x

the previous courses, I tacked out at 6500 rpm several places..thus the pull in 3rd gear. I was about 4500rpm in 3rd. Remember it is a flipped 5th gear.

I did have on my lucky autocross shoes.

Since I have a full set of Shine suspension bearings, I am going to install them...then I will know my T-bar size and sway bar.

I do really like the idea of a solo instructor...thanks for looking at the videos....I learn a lot from everyones videos also.

I will post the link to the FTD video of this event..you can see the difference. I wish I knew how to do a side by side...that would be awsome....thanks all...

[crash914]

Here is a link to the FTD...

FTD run

[koozy]

You said top 10. What was the tenth place time?

In your case the tires would be worth more than one second. Sticky street tires would give you a full second over the stones you have on there now. 8 year old race tires have gassed out years ago but are fantastic for learning car control since they give up so easily.

[ChrisFoley]

Your car is already too low for good suspension movement.
The lower CG won't make up for loss of contact patch from the wrong dynamic camber.
You don't really need toe in at the rear for AX. Some toe out at the front will help turn-in.

[wobbletop]

Keep your hands at 9 and 3.
Get new tires.
Be more aggressive... go for ride alongs with guys that are faster than you.

www.youtubedoubler.com btw

[crash914]

All good info...my street tires are 10 years old also....so at least the soft rubber is stickier.

I plan on running these tires this year and will look at wheels and tires for next year...practice, practice and burn them up..

I did have a fuel problem during some of the last runs, my inlet air temperature sensor was flakey and was reading -40 degrees to 140 degrees. Really threw off my AFR.

I really get no body roll. this car is STIFF. the front A arms are just lower than horizontal...but the suspension doesn't move...

could I bee too stiff?

[naro914]

Tires, tires, tires... yes, tires can get you more than 1 second. Difference between my soft 'street' tires and A6's is more than 4 seconds. You will be amazed at how well A6's grip. My first time using them, I couldn't hold the steering wheel I went through the turns so fast and held so many G's.

Using !6's, I can usually compete for or are within top 5 of FTD in our region with nearly 100 cars running - some purpose build SCCA or full track cars. Without them, I am middle of the pack...top 30 or so...

And NO COASTING....gas, gas, gas...brake brake brake. One or the other...never neither.

[drgchapman]

As a driving coach, I find the most time can be made up by working on the driver and his habits.......
Check out evolution driving school, very good instruction for autocross.

[crash914]

ok, see this thread is helpful already!

Chris, what do you recommend for ride height? A-arms horizontal?
I have our next ax mid July...hopefully I can have some of these ideas in place...

I am currently top 20, around 16 to 18th. this years goal is top ten, then for next year......I might have to run with the big dogs...just for fun. my problem is my motor pushes me out of any stock or improved class...I have to run modified..its all good though.

I would like to go to one of the driving schools...I feel that would be the biggest bang for the $$....
thanks all...