Davemk1

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

I've had a few over the past few years. I'm down to a single toy car now with my Birkin. I previously owned and restored this 1966 Lotus Cortina. A wonderful car and a cool slice of history. While owning this I got into autocross and didn't want to risk damaging the Cortina so I bought this 1976 Mazda RX3. It was in a farmers field sunk up to the hubs in the dirt with something wrong with the clutch. It turned out that it was a small spring that holds the clutch fork to the throw out bearing had come unclipped. Stuck it back on and it was good to go. Fully stripped it was pretty darn light and quick. I sold it to a local friend who is still racing it and doing well. Both of these are gone now and I miss them. Dave http://www.usa7s.com/aspnetforum/upload/2028647937__2039.jpghttp://www.usa7s.com/aspnetforum/upload/1696887103_Camera_1962.jpg

I'm not the end all be all of info on this subject but I do have a reasonable amount of experience in autocross. Tire width can be a funny thing. Keeping in mind that the runs are short (about 1 minute in most cases) you'll realize that getting heat into the tires can be a real issue. You are in effect running on cold tires most all of the time. Here in Montana we run plenty of events where the morning temps are in the 50's. I feel tire width choices need to be made considering your temperatures and your horsepower. I'm running a Birkin with about 140hp and 13x7 wheels in front and 13x8 wheels in back. I'm also using Hoosiers (25A compound) in a 7" width in front and a 8" width in the rear. This is a bit narrow compared to national class cars which run 10" in many cases. The narrow tire allows for a much quicker heat build up and in the end better grip than I'd have with a wider tire. If I lived in Texas the choice would be different. So a narrow but warm tire will outgrip and wide cold one every time. I also feel that the choice to run staggered sizes or not depends on your driving style and the cars power and balance. As basic as it sounds, if the car is loose or tail happy then wider rubber in the rear would help..........if it pushes then having the same size all round would benefit. If you have plenty of power then wider rears might make sense. At over 200hp I'd put you in this camp. I drive pretty aggressively and tend to steer a good bit with my right foot and the slightly wider rear tire keeps me from spinning and wiping out cones with the back end of the car. FWIW I've used a few different tire brands over the years and have come to realize why about 90% of the winners at Nationals are all running Hoosier 25A's. They are simply the best for autocross. They stick hard and have a very progressive breakaway which you can use to your advantage. I love them and will never run without them again. So......if I owned your car I'd lean toward running wider rears. I hope that helps and doesn't confuse the matter more. I've attached a photo of my car cornering hard on the Hoosiers. This event was last weekend and I took second fastest time of the day about .3 seconds behind a 125cc shifter cart. Hoosiers rock. Dave http://www.usa7s.com/aspnetforum/upload/161956215_DSC_6475.jpg

I feel a bit like a dummy but here goes - I completely understand the foam around the tunnel deal and that is something I plan to do myself. My question is what does the foam around the radiator do to keep your feet cool? Thanks for sharing your results. Dave

Engineer and first head of the SAE William Stout said (in the 30's as I recall) "Simplicate and add more lightness". He designed a mininvan in the 30's that had suspension geometry that made the vehicle lean toward the inside during corners and demonstrated it's effectiveness by cornering hard with a glass of water on the dash. We was more than a bit ahead of his time. Dave

I've been pulled over only once. I knew I wasn't speeding so I was ready to argue. Turned out the cop just thought the car was cool and wanted to tell me so. Here in the 3rd world country of Montana if it rolls and has brake lights it's legal so I don't get much trouble from the MAN. Dave

I hadn't thought f that. That makes good sense. Dave

That's a strange one isn't it. I remember seeing that car on eBay and then it was gone. Seller ended auction early and sold it to WW. Strange as I'm sure they would have gotten MUCH more if they let the auction run it's course. Is it true that WW got it for 12K. I wonder how they did that? Dave

I bought my Birkin from Dick Brink and would do so again. FWIW there are a few things about later cars that might be better. My car, a 1999, has the transmission tunnel riveted to the chassis and would be a total PITA to remove. Later cars have lot's of little bolts. I wanted to remove my tunnel to put in driveshaft safety hoops. I still will do it someday when I feel like drilling out nearly 50 rivets. I hear that later cars also have a wider footwell than mine has. I wear a size 11 and there is no extra room in there. I can only drive it in driving shoes or barefoot. Not a big deal for me but if you have big feet it might be. I like my Birkin very much and think it's well made. I'll bet you'd enjoy one. Dave

Sorry about posting in the wrong place. I wondered about that RIGHT AFTER posting it. Thanks, Dave

The lot we were racing in is fairly small. I was the one who set the course and my aim was to make it as open and flowing as possible for the size of the lot. We made two laps and my best time was 42.9 seconds. The fastest thing out there was a shifter cart. I was the second fastest car behind a very well prepped and driven Neon ACR and a few seconds in front of an Elise. Not bad. I did my usual thing and drove better AFTER the event was over while we were doing buck laps and set FTD then..........not that it counts. Oh well Hard to say how many turns there were. It was all small turns with no real straights. There were 4 major turns with a Chicago box and a slalom tossed in. Most all of us put it in second gear after the first turn and were able to leave it there. Thanks for reading, Dave

Good Morning, I don't think that is the case. The fronts are 7" tires on 7" rims and the backs are 8" tires on 8" rims. The handling is very good and neutral. I like it very much. I think the angle of the photos shows very well how much the tires move. I don't notice the squirm while driving and the grip is very good. Thanks, Dave

That is a truly stunning vehicle. Makes me wish I did something for a living that really paid well. But I love my job nonetheless. But that car can make one second guess everything. Dave

We had a fun event here in Bozeman today on the campus of Montana State U. The lot isn't too larger but at least it's slippery. My wife came out and took a bunch of photos and I liked these as they show how much the slicks distort under hard cornering loads. Looks cool to see such a stiff sidewall tire getting sucked under like that. Anyone else have autoX shots?http://www.usa7s.com/aspnetforum/upload/2041696780_DSC_5631.jpghttp://www.usa7s.com/aspnetforum/upload/2096090050_DSC_5656.jpg Another event in Helena next weekend where we get to get deep into 3rd gear. I love driving there. Dave

Do you want a photo of the rack mounted on the car sans tires? If so I don't have one but the rack goes on this weekend for a race and I could take one. Let me know. Dave

Hi Mike, I bought my car used from Texas Motor Work (Dick Brink) and he treated me well and fairly. I'd do it again. My car has what I believe to be a stock Zetec and it dynos at about 145hp. That is more than enough power to have lots of fun with. Would I like more? Yes. Do I need more? No,not at all. I had one issue with my car. For some reason whoever converted the Zetec removed the windage tray. God knows why but it wasn't there. I found out because every time the car was spun up toward redline it would puke oil out the breather into the catch can. I tried everything to fix it to no avail. I finally dropped the sump and found out the windage tray just wasn't there. $25 later it had a tray and no works perfectly. I don't know who did the original work but I do know it wasn't Dick Brink. I've seen both cars in question on the website and it money was no object I'd buy the green one. I think it's worth the $31K. But both cars look good. I feel the Birkin is a well thought out car and I enjoy it very much. I put about 6k miles on mine last summer and loved every mile. let me know if you have other questions. Dave