At what speed does the problem of rear lift become an issue with a non spoiler 3.2 with IROC front?

Then how 'severe' as in big, does the spoiler need to be to address the problem?

 

How do you mean 'an issue?' The car will feel more planted with front and rear spoilers, but it's perfectly safe and acceptable without either, even at autobahn speeds.

Worn bushings and out-of-spec suspension/alignment settings are more often the cause of high speed darty-ness or drift.

 

Paul Frere's book "Porsche 911 Story" covers the lift numbers of the various types of spoilers very well. Porsche apparently used wheel scales and a wind tunnel. I don't recall seeing any info on the IROC front though. There is a casual mention of cross winds stalling the wing shape of the front hood. I experienced this wide-open on a sweeping turn on Highway 46 on the way to the central coast (same road James Dean died on), and it was very scary.

 

As Jack said, there really is no issue, but rather a difference in feel or manners. My Targa, with stock front valance and no spoiler got a bit light and squirelly at about 90+. With front factory spoiler and my old Carrera tail, or my current duck, it feels much more planted at the same speed. Gets a bit light at 140 or so.

 

What Ed said. Squirrely at 90 + with a crosswind. Not so bad at 100 on a still day.

 

When I lived in Europe with a non-tail 911S in the good old days I used to drive fairly fast on the autobahns. If you're doing straight line stuff the downforce is nice, but not nearly as critical as when in turns (banks). But I do recall a trek down to Switzerland for lunch one Sunday when I went over a curving bridge joint at about 120 mph and sure WISHED I had a tail. Those cars get floaty above 90-100 mph.

 

hi jack, suspension is freshly aligned and re bushed.... 'issues' as in at what speed does it behave like a sea vessel, all floaty boaty.. In fact I'm glad you chimed in I noticed you ran a 964 lid and a duck tail. Whats your thoughts on both?

chris

 

My 911 with front and rear tail does not get light (rebushed and euro height) at all. Before it got light at 130 ish.

 

My 1985 with a factory chin spoiler and no tail has been stable for me up to 130mph.

 

Check this thread....

https://rennlist.com/forums/911-foru...in-at-all.html

 

Ian, comes back as a duff link?

 

They're similar. Both help with engine cooling, too.

 

Thanks - Fixed It

 

Granted this wasn't the wings fault but I always keep it in the most aggressive position now.



http://www.youtube.com/user/mussberg.../4/py6lO8jiubE