Why does my Miata understeer?

[Geo212]

I have a stock suspesion equipped '91 Miata with 16x6 Konig Moonsoons rapped in Avon 205/45ZR16 tires. I experience this sensation that when i turn into corners at fast speeds my front wheels screech and the car continues to go straight . I know it is not my skiils or going to fast because i have tried the same corners at same speeds in several cars( '99 Eclipse GS-T and '84 Rx-7 13B all wearing stock rubber) I have the trie pressure set a 32psi and i was wondering if that was to low. My tire wear is fine although i think my main problem is unsprung weight. Could anyone help me out.?

 

[jflo]

it might be your tire pressure...try inflating it to 34. if nothing happens then maybe its the different tire sizing

 

[Geo212]

I will try that and get back to you.

 

[flat_black]

RWD cars can and will understeer, too. =) Keep this in mind. That being said, keep an eye on your rear inflation, too... Try and keep it a bit higher than your front, to cause the tires to break free evenly... If you experience understeer, try counteracting it with a jab to the accelerator to see if it starts to oversteer. If so, your problem is probably just rear/front tire inflation. High unsprung weight would be cause for a small amount of 'plow' affect, too.

 

[Geo212]

Your right because when i hit the accelerator i oversteered, right into oncoming traffic and almost off the edge of the road and into a 15ft ditch! I will try 32psi front and 34psi rear and post my results.

 

[flat_black]

Damn, dude! Be careful! o.o Don't want another Miata trashed, let alone a dead board member!

Oh! That reminds me; Welcome to the boards. =)

 

[Geo212]

Thanks, nice RX-7. Always wanted one but never had enough $$. Does your car have the 13B that is fuel injected with an intercooler?

 

[flat_black]

Thanks on the compliment. =) Yeah, my car has a J-spec 13BT. Being a Turbo II, it came with a 13BT, but I just replaced the engine. And yes, it has the top mount intercooler, too. Hehee. More or less stock, too. Only the audio stuff has been stripped out, as the previous owner had amps and speakers and stuff all throughout the car. =) Now it has two speakers, and the factory tape player. Hehee. That'll be gone soon, though. Once I get un-lazy about it.

 

[rowan]

If you are understeering on corner entry obviously you are going too fast ! wtf?

 

[Geo212]

I set the tire pressure 36 front and 38 rear and the problem dissapeared. My tires were to low at about 28psi all the way around, thanx for the help. No i was not going to fast.