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Posted by: krau911 Aug 4 2004, 11:55 AM

We have been a-xing our 1.8 40,000 75 914. As we are new to the game...we have some questions. We have installed a new front sway bar, 140 rear springs and new rear shocks. Wo turning the car into a pure track car... what are my next steps (other than R tires, new motor and seat time) to improve the car? I was told NOT to change front torsion bars ... as it wouldnt be streetable then??? Comments? Also what is the best tire pressures for AX using my current street tires Dunlops Sports? When I go to Khumos, then what pressures should I use? Thanks from a rookie/beaten too often driver...Karl

Posted by: Joseph Mills Aug 4 2004, 12:33 PM

If your swaybar is around 15mm, with your rear springs being 140#, you should have a good basic setup to start with for now. I would forgo any torsion bar changes right now.

I usually run Kumhos for AX, but ran street Dunlop Sport 9000s a few times. Using white shoe polish on the sidewalls to monitor sidewall rollover, and comparing times of repeated runs, I went from 38# to 30# tire pressure. These tires have very stiff sidewalls and our cars are pretty light. I run 7 & 8" rims, so if you are running narrower wheels, you could need to boost the tire pressure a few pounds. In the end, you just have to experiment in some organized fashion and monitor the results.

As you observed, seat time is a good step to take. Run all the events you can.

When autocrossing, keep your oil level 6-8 oz. above the full mark, bleed your brakes frequently, and don't make too many changes at once! Keep asking questions on this board when they arise.

Oh yeah, remember to have fun doing all this.

Posted by: J P Stein Aug 4 2004, 12:52 PM

After I put in my 2.7L, I ran street tires once....Dunlops....205 X 50 W10s or sumthin'. I got bout 200 yards before I was going ass end first

Next time out was on Kuhmo V racers. I've never looked back. IMO, Rspec tiars are the BEST single improvement you can make...... **even for a beginer**.

I found the Kuhmos are good in the high 20s, pressure wise.

Posted by: Joseph Mills Aug 4 2004, 02:19 PM

JP,

Guess it could've been your "tiars"....

Wouldn't have been the 2.7L would it?

Regarding the Kumhos - 26 & 28# seems to be the "magic" number for me.

Posted by: J P Stein Aug 4 2004, 02:53 PM

Well.....maybe

I had a few AXs with the 2.4L.......bottom 20% of the pack. .......when I put on the Vracers, I wuz amazed how much more controllable/forgiving they were.
I immediately jumped up to mediocre & got serious

Posted by: Joseph Mills Aug 4 2004, 03:31 PM

I just finished my 5th gear/3rd gear swap.
Still mediocre too.

But now I get to mediocre quicker.

Posted by: Aaron Cox Aug 4 2004, 03:40 PM

so that gives you a shorter 3rd and a taller 5th? or a shorter 5th too?

Posted by: tommy914 Aug 4 2004, 04:38 PM

I have found that the 21mm front torsion bars are quite streetable.
It won't necessarily make you faster at the A/X though. It's all about the balance.

Tommy

Posted by: Brad Roberts Aug 4 2004, 05:01 PM

I have said in other posts:

"I'm sticking to the large sway bar stock torsion bar theory. It gives me more room for adjustment"

The Tarret bar or the 27mm Smart bar work VERY well stock torsion bars for anything down too 150 rate rear springs and up too 300lb.


B

Posted by: Dave_Darling Aug 4 2004, 05:46 PM

Jesus!!! 27mm??? That's one big honkin' sway bar!

The 19mm adjustable or the 22mm adjustable should be a good match for 140lb/in rear springs and stock torsion bars. (No rear sway bar.) If the 27 is a good match too, you must be able to adjust it an awfully long way! ....Then again, with Smart Products, even that much adjustability shouldn't surprise me...

I feel that most hard-compound street tires grip best at fairly high cold pressures--in the mid- to high-30s, generally. I know I'm happier with my Dunlop SP2 tires at 36 PSI on my "other car" than at 30 PSI. Ditto the SP8000s on my 914.

My suggestion for the next upgrades: Tires and seat time.

--DD

Posted by: Joseph Mills Aug 4 2004, 06:42 PM

Karl installed a 19mm Weltmeister, so his 140# springs should be a pretty good starting point. But I would "guess" he will have to set them to full soft to induce a bit of oversteer for AX speeds.

Until about a year ago, I've always favored higher tire pressures, so it has been a real surprise to me that the lower pressures work so well (even for my street dunlops).

But like JP says, tiars is a black art...

Posted by: Brad Roberts Aug 4 2004, 06:46 PM

Dave,

I have a 31mm bar in Trekkors car with 175 rears and a stock rear bar... he has now caught all the other BP guy's on Falkens.

The 19mm bar is worthless. People outgrow them in less than 4 months worth of AutoX.. I wont install anything smaller than a 22mm bar. A 22 on full soft is the equivalant of a 19 in the middle.



B

Posted by: Joseph Mills Aug 4 2004, 06:53 PM

Aaron,

Using a 5th gear set in place of your 3rd gear gives you a shorter gear (closer ratio to 2nd). I used a fifth gear set from a donor tranny, so I still have my normal 5th gear also.

But if you do use 3rd in place of 5th, you will also have a shorter 5th (closer ratio to 4th). That's the downside to the "swap". And if you're running lower profile tires also, in 5th gear at highway speeds, you will be floating valves.

Make sense?

It's a great upgrade for AX.

Posted by: Brad Roberts Aug 4 2004, 06:56 PM

He doesnt understand that you FLIPPED the drive and driven gears for 5th and installed them in the 3rd gear spot.

(he does now..LOL)



B

Posted by: brant Aug 4 2004, 07:28 PM

commonly referred to as a KL I believe.
b

Posted by: Joseph Mills Aug 4 2004, 07:37 PM

Oh yeah. I forgot that little part.

I can't wait for the next AX to try it out. It's going to eliminate a lot of shifting for me.

The shift from 2nd to 3rd is sure sweet. You really stay right up on the powerband. Feels like you're shifting a bike.

Course, when you shift from 3rd to 4th, suddenly you feel like you're shifting a VW bug.

Posted by: Brad Roberts Aug 4 2004, 07:41 PM

Yeppers. It works well for "free" basically. I have 2-3 boxes laying around that are converted. One of them has a LSD in it.. fun box. I also have a MSX box sitting around here somewhere.


B

Posted by: J P Stein Aug 4 2004, 07:59 PM

As I said in other posts, I don't have any theories, I go with what works.

Posted by: Brad Roberts Aug 4 2004, 08:03 PM

JP,

Do you EVER adjust your car or do you live with whatever you showed up with ??


B

Posted by: J P Stein Aug 4 2004, 08:54 PM

All I have time for is tire pressures.....2 driver car & all. I've been caught doing pressure changes while the car is rolling towards the lights

I never show up unprepared.....that's why the car never breaks. (I may have just cursed meself here)
I make incremental changes at home depending how the car worked at the last event.

SCCA: NO jacking up the car in the staging lanes. Miss your turn in line and it's tough nuggies.

Besides, It's the driver, dude. Ya'll oughta try it sometime

Posted by: Brad Roberts Aug 4 2004, 08:59 PM

We make sway bar changes in the lanes... turn the wheel hard right/hard left... easy with one wrench.

I watch the cars during the morning sessions and make suggestion to those I think need it (if they buy from me) I normally know who needs what after 3-4 runs. Tighten this... loosen that... they ALWAYS drop a min. of 2 seconds off their times.

I know it is driver... but you also have to make the driver comfortable in the car. If somebody is slinging the ass end around in their 4cyl car... dial in more front bar.... pretty easy.. now they can lay down the power and keep the ass end planted and the front end in the direction they intended.

I do know it is hard with a two person car...


B

Posted by: J P Stein Aug 4 2004, 09:10 PM

SCCA: only the first 3 runs count.

PCA is for fun.

Posted by: Brad Roberts Aug 4 2004, 09:16 PM

I personally have it figured out after the second run.... if I'm driving.

Not sure how many people attend your events, but our SCCA events take all day for the runs.. plenty of time to make changes even with two people.

I guess just drive it...

Posted by: crash914 Aug 5 2004, 05:49 AM

Hmmmmm...

So my set up is very neutral, but....

23mm torsion bars, 22mm sway bar set in middle, 185lbs rear springs on coil overs. Sometimes rear bar, no lsd.....


I kind of like the large sway bar concept..I was amazed at the difference from 22mm sway bar full soft to half hard....now I want more....herb

Posted by: krau911 Aug 5 2004, 05:58 AM

I'm the orignal poster.. thanks to all for your recommendations......... I have a 19 mm Welt. front sway bar installed... did it myself haha.. ok I know there is adjustment, but which way do I move the adjustment for .....soft/hard//understeer oversteer? ? Karl

Posted by: Joseph Mills Aug 5 2004, 06:40 AM

Away from the bar for softness (oversteer) and up towards the bar for stiffness (understeer).

Posted by: brant Aug 5 2004, 08:51 AM

crash...


23mm front torsions are big!
I've always heard that 22's were really about the limit.

I know some damn fast cars running 22's with 400 rears...

just a suggestion
b

Posted by: crash914 Aug 6 2004, 05:26 AM

Yea, but they came with the car...


This car is so stiff, you can jump up and down in the trunk all day and it doesn't give....
I almost got a wheel off the grould once....but not quite.

This car is very neutral, once I stiffened up the front bar.....LSD next

Posted by: cha914 Aug 6 2004, 09:46 AM

While on the topic of swaybars, I need to slap some new bushings on mine (22mm welt bar). Can I do with with gas tank in the car? Just drive the bar out one side, change bushing, same on the other?

Also, are these bushings like the suspension ones where it is recomended to cut groves and fill with grease?

Finally, I have noticed that my bar likes to get "off center" nearly touching the shock on the drivers side while close to the body on the pass side. Is the normal, or is this due to my bad bushings?

Thanks,

Tony

Posted by: airsix Aug 6 2004, 10:55 AM

I know I'm stepping out of line by questioning the big dog, but my concern about this method is that you end up with HUGE weight transfer when braking/accelerating. You have great roll stability, but get hard on the brakes and you'll have a heck of a time keeping the rear planted. IMHO (spinning 914 footage at 11:00).

-Ben M.

Posted by: J P Stein Aug 6 2004, 01:31 PM

Gasp....

You will be ostracized by the bay area 914 Mafia....so I may as well join you.

Here's a guy that could benifit from some staging lane car tuning....IF there was anything wrong with his car's handling....which there ain't.

1m FRUN 60 Jim Daniels 94 Mazda Miata 45.104 > 45.052 45.129

Since he is consistent AND quick, changes to the car would be quantifiable...the driver eliminates himself from the equation by being good. Also, this car is ready to go when it hits the staging lanes......by God, it had better be at a National Tour event . All he does is adjust the tire pressures as needed.....then he "just drives".

Once again (for those who missed it). To improve your AX times.....according to SCCA national champs....the order of importance is:

Driver
Tires
Alignment
Suspension

This is for semi stock cars. Get into the Prepared or Modified class & (IMO) those last 3 get shuffled into one.

Posted by: SteveSr Aug 6 2004, 01:47 PM

To ask a dumb question about sway bars...... what does full soft mean???
No preload???Then as you tighten the adjuster on each side it applys a twisting force that works against body roll???...somebody enlighten me....

SteveSr

Posted by: phantom914 Aug 6 2004, 02:05 PM

No, it is not pre-load. You need an adjustable setup first of all, and slide the connecting point of the droplink (the top end) along the arm towards or away from the swaybar , changing the leverage. Did that make any sense? Someone post a picture please.

See www.tarett.com for pictures

Andrew

Posted by: J P Stein Aug 6 2004, 02:12 PM

With the car sitting on all 4 wheels on a level surface & the down link lock nuts loose, both adjusters should turn freely within a small range...or be slack....no preload.
Preloading is (IMO) best left to someone that really has their shit together. I notice that my 914's front bar will preload itself...or rather the chassis will do it.....this is not good, but I live with it.

Full soft is when the down links are at their maximum distance in the lever arm, away from the bar.

Posted by: Brad Roberts Aug 6 2004, 02:27 PM

Ben,

question everything. I dont have all the answers... but I learn a hell of lot more dealing with 40+ cars/drivers than the person who owns one and has to deal with it. Nevermind that we can attend AutoX's/Road races 40 weekends out of a year...see where I'm going...

I want weight transfer... and honestly the setup is very comfortable to drive. Modulating the brake pedal is easy.. the car really feels no different than the one with 22's/or 23's... we have run 26's in race cars in the past.. they are physically the largest you can get inside a 914 control arm. I also run adjustable shocks.. set the fronts to full firm and the shocks help slow down the transfer of weight... it is really really well balanced.


JP,

I make changes to people cars that are newbies.. they are showing up without a clue. Very difficult to compare them to a SCCA National champ. I have been in the staging lanes in Topeka.. they make changes... they may not on a local level (especially if they are kicking everyones ass in their class by several seconds... why would they ??)


B

Posted by: trekkor Aug 6 2004, 04:15 PM

Here's a pic of the SRP adjusted at 2/3 soft or 1/3 stiff depending how you look at it.

I run it one click stiffer since the photo- Thanks Brad and Randal!

KT


Attached image(s)

Posted by: trekkor Aug 6 2004, 04:25 PM

Oh, you mean like this?

This is my favorite action shot of my car so far.

Now with the rear bar, chassis stiff kit, stiffer bar and properly inflated tires, it doesn't anymore.

Flat and fast is my goal.

KT


Attached image(s)

Posted by: crash914 Aug 7 2004, 07:40 AM

Yea, it is not fast, but it looks really really cool.....My car stays planted, except when I am spinning like a top....

Posted by: J P Stein Aug 8 2004, 01:51 PM

Actually, there are some good comparisons to be made.

Mr Daniels & his Miata showed up at the PCA AX for a test & tune session......got himself some new trick adjustable shocks. He also had street tires on the car.....didn't catch the make/size. He was 2 sec off the pace for once. I have no doubts that when he puts the Rspecs back on & gets the shox dialed, he'll be faster than before.

Posted by: Jeroen Aug 8 2004, 04:59 PM

If you go BIG with a big swaybar in front and stock t-bars, do you need to re-inforce the inner fender / wheelwell (where the swaybar mounts)

Specially with stock springs, I'd think that area would see a lot more stress

cheers,

Jeroen

Posted by: Brad Roberts Aug 8 2004, 05:46 PM

No. The Smart bar has 6 bolts and distributes the load better than the old 3 bolt system used by everyone else. Here is what I have found when 914's rip up the chassis: the owner or the installer has put the bar into bind.


B

Posted by: Jeroen Aug 8 2004, 06:06 PM

thanks!