jacob300zx

Read up on how a miata VLSD works, then go wtf was Mazda thinking. I currently am DD one now and it literally works some days and some corners or not at all. Try to get a 4.30 Torsten out of a VVT car.

DaveC

Have you considered the possibility that the track car is on the rear bumpstops when cornering under power?

wannafbody

iTrader: (1)

Yes, that is why I traded shocks between the 2 cars and added the ISC top hats on the rear of the track car for more travel. It seems to have helped. I decided to add another 3mm packer on the front shocks to see if that makes any difference in feel. I plan on hitting a trackcross event at Pitt Race in a couple weeks.

One difference between the two cars is that the street car seems to have a bit more suspension travel.

DaveC

Yeah, I guess I was being a little sarcastic. I think your entire problem is that you're hitting the rear bump stop under power. It's worse with the more powerful car because the rearward weight transfer is greater so you're hitting the stop sooner/harder.

I know that people riding around on the street with soft springs take it for granted that they'll be on the bumpstops when they get frisky so they tune them front/rear to balance things. I can't help much with that, but adding the packers to the front will cause the front bumpstops to engage earlier and supposedly bring some balance. I'm not qualified to tell anyone the best way to set up a car for track, but I'm pretty sure that's not it.

The ISC top hats helped increase rear wheel travel. Great. I would try raising the rear ride height to increase available travel even more. I know it goes against what Andrew suggested, but I'd give it a try anyway. He won't know if you don't tell him.

wannafbody

iTrader: (1)

Well, I'm currently using the 1 inch top hats in the rear, I have a set of 1.5 inch top hats in the garage, I could swap them over winter.

wannafbody

iTrader: (1)

I figured I'd update this again. Since the last track day I added 3mm packers up front, lowered the rear of the car slightly and took off the Star Specs and installed the Yoke AD08's. I went to Pittrace to do a trackcross. In September the temp was mid 70's and the car was really loose. This weekend the temp was 45 and cloudy with gusty wind and the track lacked grip. Surprisingly after a couple laps the Yokes warmed up enough to provide adequate grip. The car seemed easy to control and wasn't prone to over rotation as in the past. Overall I was pleased with the feel of the car and was able to drop my times by 3 seconds compared to September. Even though I made more changes over the last month than just tires, I was impressed by the grip the AD08's held in the cold.

miatauser884

iTrader: (11)

I think you touched on a good point about knowing when your tires are warmed up. My RE-11s took three laps at barber before everything came together.

glade

iTrader: (2)

Just so I got this straight......you've ignored every suggestion from qualified persons, made your own changes based upon anecdotal evidence suggested by local dirt track racers....and finally noted that tires up to "temp" made the car predictable......yet no use of tire temp gauge......on a short course where speed and cornering forces are limited...

You must be a colossal idiot.

wannafbody

iTrader: (1)

I've tuned the car based on advice setup from the 949 page and from the advice of some members here who have contributed. As for you *******, If you don't have something of substance to add then STFU.

Based on what I've read of Emilio's Xida setups he doesn't have much shock travel until the front bumpstops start to engage. That would suck on the street but it seems to work quite well on the track. Looking at the Xida photos you can see the rear bumpstop is quite a bit shorter than the front one. That caused me to conclude that adding a second 3mm packer up front might be beneficial. Adding the ISC tophats in the rear increased travel and seems to have made a difference as well.

Savington, your suggestions seem to have helped, thanks.