Davemk1

Cool. It totally makes sense when you think about it. There is going to be movement up there most any way you look at it. If the suspension is too stiff then something else will take up the load.....like the tires or chassis flex. In either case it's undamped movement with a very rapid rebound. So by softening up the suspension you are allowing it do do it's job so the other stuff can do the jobs they were intended to do. Cool. Dave

If I understand this right it started after you changed the uprights and some brake components. Is that right? If that is the case then we can rule out things like weight distribution and the like since it didn't do it before and you haven't appreciably changed that with your front end work. I assume you've got adjustable shocks and that they have a dial for adjustment. If that's the case then take it out to an empty lot and lock them up and make sure it happens with the current set up and then make a huge change to the damping and see what it does. You might not want to run the car full soft but try it and see if it goes away and you'll learn something. If you don't have the luxury or spinning a knob to make the adjustments things just got less convenient but it's still worth trying anyway. You'll also want to play with rear shock settings. Not enough rebound damping can cause too much weight shift and funny things to happen. You also need to verify your suspension settings. Make sure that your camber is set with your weight in the car. It changes a lot once you drop you butt in the seat. Check the caster too and make use both sides are close to the same and make sure there is enough caster overall. Too little caster can have negative effects under braking. Is your brake bias adjustable? If so you'll want to confirm that you haven't given the front end such good braking that the tires are overwhelmed. That's all I've got. Dave

Sounds like a geometry issue (caster?) or a damping issue. Dave

As you've read there is no clear answer. I'm a bit over 6'4" and weigh 180. I bought my Birkin never having sat in any Seven ever before. The first time I sat in it (after it came off the truck and too late to do anything about it) I thought to myself....."oh lord, what have I done?". I didn't really fit. But I made some changes and now it fits perfectly. I ditched the stock Birkin seat (sucked anyway) and put in an Ultrashield race seat. I modified the seat a bit to get it to drop down lower and go back just a shade more. Before putting the race seat in I took out the stock seat rails and now my butt is right on the floor and pretty comfy at that. After that was done I made myself a new taller roll bar. The stock Birkin bar is pretty short. I made the new bar a full 3.5" taller than the stock bar so it's over my helmet. And lastly, after that, I had a new top made to fit over the new tall bar. Now with the new top I can roll in comfort to the races or anywhere else I want to go with little regard for the weather. And I even fit in the car with the top up and my helmet on. I very nice thing I must say for those wet autocross events. What type of Seven are you considering? Dave http://www.usa7s.com/aspnetforum/upload/1346459251_DSC_3695.jpghttp://www.usa7s.com/aspnetforum/upload/1150602935_DSC_5646.jpg

On what have been one of the last warm and dry days of the fall I took some time and went for a cruise. I saw this fresh cut field a bit off the road and couldn't resist taking a few photos. One more race this season and then the engine comes out for a bit of work. Enjoy the Fall. Dave http://www.usa7s.com/aspnetforum/upload/54927240_DSC_7148.jpghttp://www.usa7s.com/aspnetforum/upload/751944381_DSC_7158.jpg

Glad to help a bit. You're right those guys with the big wheels are using something. If you have a choice find the lightest tire you can. Not only for the weight but for the flexibility. Most of those tires are meant to carry a car twice the weight of a Seven and can be too stiff in the sidewall. About camber and bias ply tires.........I agree in a big way. I'm running 1/4* camber and it works very well. Dave

If I'm not mistaken we are speaking about two different types of slicks here. DOT slicks (like thee Hoosier A6) and true road racing non-DOT slicks. If you need to drive to the event on the tires you are going to race on there is only one choice from where I stand and that's the Hoosier A6. If you are driving to the event on street tires and the race tires will be put on at the event then Hoosier road race slicks can not be beat. I've used Goodyear, Michelin and Hoosier and the Hoosier are in another class altogether. You can think of it this way........with each bump up in tire you are going to see about 2 seconds of difference on a one minute course. So with high performance street tires you might get a 60 seconds flat. Move to DOT R compounds and you'll be in the 58 second range. Move from there to Non-DOT race tires and you'll be able to get into the 56's. The big difference between an R compound DOT tire and a real race tire is weight and suppleness. A true race tire will weigh much, much less than any DOT tire. They don't have to pass the same (or any) tests to pass the DOT deal so they have a very thin carcass. This makes them light but also allows them to contour to the surface much better resulting in much higher traction. All that BS said................most true road race slicks don't come in a 17" size. Most are in the 13", 15" or 16" sizes only. If this is the case then you are getting road tires. I could be wrong on this. In the end it's much faster on real race tires. They are so good that you need to reset your "what's possible meter". Dave

My Birkin has a heater that might be better referred to as a warmer. It makes warm air but you won't e driving in the cold in a T shirt that's for sure. I use a full top and side curtains in the cold and it works well. It's chilly here in the morning no matter what time of year it is. This morning it was 42* at 7:00 but will be in the low 80's this afternoon. Such it is with such low humidity. I don't end up driving it very often when it's seriously cold but this past weekend I drove it 1 1/2 hours to a race and it was in the low 30's. So I use the full weather gear fairly often when going out early to an autocross. This is what it looks like. This shot is taken on one of my favorite roads right where the road leaves the Bridger mountains and head across the Shields valley toward the Crazy Mountains in the distance. The road goes from very curvy and dead flat and straight.....which is of course the road you see. Dave http://www.usa7s.com/aspnetforum/upload/806709342_DSC_3839.jpg

We have the room for you. The state's population is less than 900,000 in total and the distance form the eastern boarder to the western boarder is the same as from Washington DC to Chicago..............in other words it's huge and empty. If the event was centered in the South West part of the state you could see both Yellowstone and Glacier national parks. Yellowstone is about 1 1/2 hours south from Bozeman and Glacier about 5 hours north. There are wonderful places to stay and lot's a first class driving with the only other thing on the road being cows or elk. I'm an active member of our SCCA club and I'm sure we could arrange for an autocross event to be held during the time of the event. We've got a few national class drivers in the area and the events are fun and fast. If folks would like info on roads or places to stay I'd be more than happy to supply whatever you all want/need. I don't want to be too pushy so if the group is interested let me know and I'll do some leg work and present you all with some info. One closing thought................a group of Sevens going over Beartooth pass early in the AM would be over the top fun. Dave

My Dad sent me this link. I don't know anything else about is but I can tell you it was some barn find deal in Europe. A good number of Lotus in there. Unbelievable. Dave http://WWW.intuh.net/barnfinds/afa70.htm Edit - I just got the below from my Dad in another email that explains it a bit more. Sounds a bit urban legend like but who knows. Cool cars any way you slice it. A man retired. He wanted to use his retirement money wisely, so it would last, and decided to buy a home and a few acres in Portugal. The modest farmhouse had been vacant for 15 year.; the owner and wife both had died, and there were no heirs. The house was sold to pay taxes. There had been several lookers, but the large barn had steel doors, and they had been welded shut. Nobody wanted to go to the extra expense to see what was in the barn, and it wasn't complimentary to the property anyway......so, nobody made an offer on the place. The New York guy bought it at just over half of the property's worth, moved in, and set about to tear in to the barn.......curiosity was killing him. So, he and his wife bought a generator, and a couple of grinders.......and cut thru the welds. What was in the barn...............? Go to; WWW.intuh.net/barnfinds/afa70.htm http://WWW.intuh.net/barnfinds/afa70.htm> and start wishing you had bought the place. When the picture comes up, click next to see all the cool stuff he unknowingly purchased. [And, unfortunately the author of this piece doesn't know American cars at all, nor is he/she interested. One of the most valuable finds is the 1931/2 Chrysler Imperial convertible coupe (a Custom Imperial? - or a LeBaron???).]

I believe that would be Hazel. Dave

Nice R/T ! Dave

Amen to that. The Beartooth highway needs to be seen to be believed. I've been over it a number of times and the beauty is hard to describe. There are some other wonderful driving roads in this area and I feel it would be a wonderful place to hold a get together. I can give details of some of the drives if folks are interested. I'm also very active in our local SCCA club (region 52 which for the third year running is the fastest growing SCCA region in the country BTW) and I'm sure we could arrange it for our club to organize an autocross event for that weekend. Food for thought. Dave Bozeman MT

My car is the fastest car on the planet.....bar none. End of discussion. Dave

A Seven is like porn........I'm not sure I can fully define it but I know it when I see it. The Atom is stunning in it's own way but it's not a Seven. Dave

I agree 100% - the bathroom scales should be more than accurate enough to get reasonable results. It's interesting to me.......in retrospect it seems surprising that my car doesn't have issues with this. It completely makes sense that it would. But, in my car's case, I don't have an issue. It's a curious thing. Dave

Absolutely. It makes sense to me but in practice they lock up at the same time everytime. My records show that the left front is carrying 50lbs more than the right with me in the seat. Only thing I can figure is that there is enough weight transfer to make that 50 pounds a smallish percentage of the overall weight during hard braking. I'll toot my own horn a bit and say that with this set up I just two weeks ago won the Top Gun Meet in Helena MT. The Top Gun event is our state championship and pits the three SCCA regions in MT against each other. Our region (SCCA #52) took the most "first in class wins" and so won the overall trophy for the 3rd year running. Not bad for the smallest (and fastest growing in the country!) SCCA region in the USA. I won my class (DM) and took FTD both days of the event. That was fun. The course on day tow had a 4th gear 85mph slalom. That was the shit. Dave

I'm in the same boat. Stock Birkin with 50% cross weights and both front tires lock at the same time. Stops on a dime. Dave

I'm running a Birkin and I found that having it properly corner weighted really helped in autocross. I can feel it handling more consistently in slaloms.........the right and lefts are the same. For me it was worth the trouble. I made my own corner weight set up with cheap bathroom scales and a lever of sorts. The hard part about using a lever is that the exact placement of the tire on the lever is hard and if it's off it will change the reading a great deal. So I added a pivoting pad on top of the lever. The tire sits on the pad which in turn sits on the lever. This allows for a precise location of the weight on the lever. The underside of the pad has a small inverted "V" on it to allow it to pivot to allow for tire camber. This way a tire with camber won't change the leverage ratio. I used them and they seemed absolutely repeatable even with the cheap scales I used (less than $10 a piece at Target). Months after I did this a good friend bought some Longacre scales and I checked the set up going back and forth between set ups and they were very, very close. I was getting less than a 5 pound variance between the two set ups. The digital Longacre set up was over $1000 and mine target set up was less than $75 all materials included. It's well worth the time and effort and the car will work better at the limit. Davehttp://www.usa7s.com/aspnetforum/upload/556173090_DSC_6960.jpghttp://www.usa7s.com/aspnetforum/upload/1620524268_DSC_6961.jpghttp://www.usa7s.com/aspnetforum/upload/939962813_DSC_6962.jpg

I've been told by folks in the know that my set up should have about 145hp. And if one uses the 15% drivetrain loss correction as recommended by my Dynotech friend (126 x 1.15= 144.9) then my numbers come out just right at 144.9hp. So in my case it all seems to add up. As I recall Dynojet systems correct for altitude as well as temperature. Dave

I could see the heat hurting you a little bit but not nearly that much. I'm lucky to have a good friend who is head engineer at Dynotech here in Montana. Yes the Dynotech dynos are built here. He let me on the dyno for a six pack and it's was interesting. I have a 1997 ZX1 with hydraulic lifters. It's running Webers and headers in my Birkin but it's otherwise stock. I got 126hp @ 5500 rpm and 123 lbs/ft from 3000 - 5400 rpms at the wheels. The air/fuel stays pretty darn flat being between 12.5 - 14:1 all the way. I figured this might give you another data point to help or confuse. Dave

Very interesting. Thanks for sharing. I suppose my Birkin would have more of a rearward bias too with a passenger. My 51-49 is with my skinny butt in the car alone. Dave

As cool as the Atom is (and I do think it's very cool) I just can't se it ever overtaking a Seven in the handling dept. Having more than 60% of the weight on the rear wheels has it's effects any way you look at it. 51% rear - 49% front - Dave

The tire should not be any wider than the wheel. If it is you get the tread rounding out and lots of sidewall flex. It's slower by all accounts. It's tempting to stuff big wide 9" tires on your 7" rims but it will suck. I learned the hard way and the tech guys from Hoosier set me straight and he was dead right. I use 7" tires on 7" rims in front and 8" tires on 8" rims in back. This makes for a very stable sidewall and allows for the use of lower pressures and a bigger footprint without the tire rolling over. Have fun, Dave

I suppose it could be. I think it was sold not last fall but the fall before. Late October maybe. I do think that the guy who got it did so in the last 10 seconds or so. Were you in the bidding? Dave