slomove

Normal cruising noise is actually not that bad. But at some occasions I took the opportunity to demonstrate the engine rev limiter in 3rd gear. Unfortunately Jonny had declined the earplugs that I offered him before we took off.....

Nah, piece of cake....this was a fun drive and Jonny is a very nice guy. The "incident" happend when I tried to pull a 180 degree semi-donut back into Decker Canyon. I really should not do such bragging with 2 day old tires that hook up a little better than the old ones and took me out to that rainwater runoff berm. It was only 2 or 3 inches tall and did not do any damage to the suspension but when trying to pull back I forgot about the rubber mud flaps which got caught between the berm and the wheel. Consequently my persistent escape attempts pulled down the wing, bent the brackets and made the wing block the wheel. As you can see from the pics I used the jack and a deep socket to bend the horizontal tube back and a few foot kicks to adjust the vertical one. That got us going again. This weekend when I replaced my shocks I straightened out the tubing and spackled/repainted the nicks in the wing. Looks like new http://www.usa7s.com/aspnetforum/images/emoticons/smile5.gif I was really lucky that I brought my full tool complement. Would have been even more embarrassing to take the trip home on a flatbed. Gert

If you don't feel ready to build one or don't have the time (like myself when I got into this 4 years ago) get a pre-owned car. The market is small but you will see a good Se7en with few miles and a modern engine once a while. This is often the cheapest way to get some nice upgrades because they don't usually get their value back when selling. Contrary to common belief these cars do lose a bit of value from new. However, it becomes pretty stable in the long run. Another advantage is instant gratification. Instead of only building for anything between a few weeks and a decade you can drive it right away and upgrade and tweak as you go (which I did a lot). BTW, I bought a Birkin back then because the business transaction side of the heritage was irrelevant for me. I was looking for similarity of appearance and concept, also quality of workmanship. Gert

Thanks, maybe I just keep them right side up. The steel rod and piston are probably not much lighter than the ali tube, anyway. I will post how they drive but at least the shocks look good: http://www.usa7s.com/forum/uploads/20070209_181357_ProtechShocks.JPG Also the price, customer service and turn-around speed (2 weeks for custom length and end fittings) are hard to beat. Shipping costs a bundle, though. Gert

Just got new Protech shocks and about to install over the weekend. I was wondering if there was a real benefit of installing the front shocks upside down with the shock body attached to the chassis. Are the few ounces difference important? Protech told me the shocks don't care. Thanks, Gert

Maybe not exactly these but similar ones have the TENAX brand. >Here Just read a little more.... you can even have British or German TENAX fasteners. Of course not compatible..... http://www.usa7s.com/aspnetforum/images/emoticons/confused5.gifslomove2007-02-05 21:55:01

Sometimes you just have to admire persistence, willpower and good clutch http://www.usa7s.com/aspnetforum/images/emoticons/smile5.gif

Jeez, what else is coming down on us? Highway patrol in UFO's ? Maybe for PNW2007 we should stay close together. The wolfes always get the sheep roaming alone... Another thing I noticed last summer in NorCal is the radar detector went off all the time even in remote places (sometimes when police was visible but mostly without apparent reason). Don't know what that is and I don't have it here on SoCal highways. Gert

Another interesting one (clipped from www.automobilemag.com): Philosophy: Automobile tests cars for a variety of reasons. While many makers offer a few snippets of acceleration, top-speed, and gas-mileage information, many do not. Conducting our own tests fills in gaps and adds trustworthy information about passing ability, cornering grip, and stopping performance. Having accurate performance profiles helps us pass judgment when we compare one contender to the next or draw conclusions at the end of a Four Seasons evaluation. Since there is no industry-wide standard for car testing, every maker has its own pet procedures. Some test with less than a full tank of fuel, some with two passengers and luggage aboard. Doing our own tests is the only means of leveling the playing field. Some publications strive for the quickest, fastest, or most spectacular results. We make no attempt to emulate quarter-mile drag strip results by subtracting the roll-out portion (the 0.3-0.4 seconds required to move the first foot) of the acceleration run. Drag strips divulge nothing but the speed achieved near the end of the quarter mile and the time required to accelerate that distance. Since the strip reports no other time-to-speed information, subtracting roll-out from 0-60 mph results is never warranted. Many magazines do adjust all of their acceleration results by subtracting the roll-out. We do not because, even though that yields quicker, more tantalizing performance figures, it presents a less accurate picture of the car's abilities.

I am not a drag racer but this roll-out business has something to do with the point you stop at when the stage lights triggers at the drag strip. If you stop immediately you stage "shallow" which gives you a good end speed but bad reaction time. If you roll a few inches beyond that point you stage "deep", giving better reaction speed but worse overall time. For me that all means if it gets into the 3 or 4 seconds to 60 everything becomes subjective.... Gert P.S. more info >here

I suspect when Ariel and the likes go out for acceleration testing to print in their literature they make sure everything is right, like nice warm drag strip, sticky warm tires, an experienced drag racer, shedding all junk from the car, engine optimized etc. Then they may do some dozen runs and pick the best. After all this is one of the most important marketing figures. I guess the chance for the normal driver to get there is pretty slim. The 1/4mile figures are probably more reliable. Gert P.S.: I am happy when I get 4.5 seconds....Even then my times vary wildly +/- 0.3 seconds, depending on how fast I shift. I am also confused because I read the car companies and most magazines use a 12" roll-out before they start the timer. There is already abou 0.2 to 0.3 seconds. slomove2007-01-28 13:24:45

Well, I would not say it that harsh....I found the accelerometer function of the G-Tech Pro functioning quite well, that means for 0-60 or 1/4 mile comparisons it seems to be pretty accurate. It allows for roll-out setting to compare with published tests (I believe most car manufacturers use a 12" roll-out which makes a huge difference). The horsepower calculation is a different story...You need not only to plug in the (honest) car weight including load but additionally the linear equivalent of the moment of inertia of rotating masses which can be significant for a Seven as a percentage and difficult to estimate. I am using 250 pounds as wild-ass guestimate for wheels, driveshafts, diff, gearbox, clutch, flywheel, crank and pistons. That gets me somewhat close to what is probably the power. Another error source is the RPM pickup. The G-Tech does not connect to the ECU or crank sensor but measures the ripple noise on the 12V power with the idea that the alternator spins proportially to the engine. Very clever but if this noise is filtered too much or if the RPM are not calibrated correctly the HP result can be anything. But, in my car the RPM reading is pretty good. Finally, I am trying to do a coast-down deduction. When you get to e.g. 60 mph the air drag, tire and drive train friction are quite high. Therefore I look at the positive acceleration at the moment just before I take the foot off the pedal and the negative acceleration (without braking) just after. I use the ratio of negative/positive accelaration to correct the calculated HP figure After all, I like the G-Tech as a comparative measurement tool to asses e.g. engine improvements and knowing the limits it does a reasonable job for the money. Can it measure engine power precisely? No way, but even on any given dyno the numbers can vary wildly. Gert P.S.: I use a low cost bicycle GPS gadget with automatic lap trigger for track timing which is kind of O.K. but only accurate to 1 sec. I believe the more expensive data loggers with GPS can do 100 updates per second.

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You could get the ACB10 in a softer A30 or even A24 compound but that is probably an expensive proposition in terms of wear and maybe a special order. But >Roger Kraus has them on his tire list. Gert Edited: I lied, to a degree....I just weighed my wheels again ad found the following: Front(new) Rear(50% tread wear) Rim Width 7" 8" Wheel weight (lbs) 23.4 23.6 Rim weight (lbs) 10.4 10.8 Tire weight (lbs) 13.0 12.8 nominal Inches 7.0/21.0-13 8.0/22.0-13 M nominal Metric 195/50-13 245/45-13 max width @19psi 210mm 245mm tread width 170mm 210mm So the weight difference to typical 13" radials is not as dramatic as I posted first but still significant, maybe 16-20 pounds total. Also interesting that the nominal tire sizes have only remote resemblance of actual measures. slomove2007-01-24 19:07:55

I am selling two > G-Force 5-point harnesses with cam-lock buckles. Shoulder and lap belts (pull-down) are 3" black, 2003 vintage, very good condition. Driver cam buckle has right attachement and passenger cam buckle has left attachment. Mounting plates included. $100 for the set (new about $290). Please PM. Reason: I am upgrading to 7-point harness with pull-up lap belt

I can not compare the ACB10 with the Ecsta710 in driving behavior because I never driven the 710s (it looks like they have softer compound than the "Caterham" ACB10 compound A33). However, one of the reasons I picked the ACB10 is weight (besides a lot recommendations). The 8" ACB10 (245/45-13) is about 11 pounds vs. the 18 pounds for one 215/50-13 Kumho. Extrapolated for all 4 wheels I would guess a difference of more than 25-30 pounds unsprung and rotating. That is substantial and in terms of accceleration it almost counts double. So my thought process was why spend money on light rims and waste this with heavy tires..... Obviously the ACB10 are no fun on the road due to tramlining. Gert

You don't have a scope, by chance, to watch the drive voltage of the coils?slomove2007-01-23 21:51:14

Another interesting data collection would be for road tires. For that purpose I am not looking for ultimate dry grip and super light weight (got 13" ACB10 for the track) but reasonable performance and price, acceptable wet behavior and at least 10-15k miles durability. I was shopping lately to replace my balding Bridgestone S03. But the general trend to bigger wheels has shrunk the selection of performance tires for 15" rims from many suppliers. For my preferred road combination of 195/50-15 and 225/50-15 about the only ones I still found was the Yoko ES100 and Goodrich G-Force. Fortunately at $55 and $90 the Yokos are quite inexpensive. Gertslomove2007-01-21 10:44:06

Not sure about webcon ecu but if the crank pickup was intermittent the ecu should anyway fall out of sync and not really know what to do. IIRC the 2nd and 3rd cylinder are on the same coil and spark at the same time. Maybe the ecu output driver is damaged or the wiring between ecu and coil? Gert

Hmm, have to think about that..... but on the other hand I heard that progressives are standard issue for some Caterhams. That means it can not be totally wrong? Gert

I am in the process of ordering a new set of shocks for my Birkin from Protech in the UK and doing that wanted to uprate the rear springs from currently 150lbs/" to 175 lbs/" (I have ball-jointed radius arms). For convenience reasons I could order those from ProTech, too and they suggested instead of a fixed 175 pound rate to use a progressive 150-225 pound spring, which they offer at same cost of GBP 20 per spring. In my simple mind I thought that is a good idea, keeping the smoother ride when the road has only little bumps and the springs stiffening up when the prop shaft is in danger of hitting the hoops (which happens sometimes now in deep dips when I have a passenger). Would anybody know why I should not do this (like vehicle dynamics on the track or something like that)?? Thanks, Gert

We still have a few slots free on the Pacific Northwest Sevens Tour in August! More information here: http://www.usa7s.com/forum/forum_posts.asp?TID=308 And here: http://www.californiacaterhamclub.com/chat/showthread.php?t=686 If you are interested (and can decide within a week) please send me a private message! Gert

Sounds like a good starting point but I guess you should not design for regular driving loads only. Most parts fail when somehow abused and I think you should allow for hitting the occasional curb. I am not sure if there is an analytical way of doing that without a big research department. The safer way may be to take and modify a known good design. Gert

Busa, I have a bog standard Raceline wet sump under my ZX1. That would leave me something like 3" clearance with the 15" road wheels. However, the local mountains are crumbly and rocks abundant, so I made a well armored sump guard that reduces the clearance to about 2". This means more ground contact but less damage: http://www.usa7s.com/forum/uploads/20070109_210340_SumpGuard3Years.jpg Obviously the clearance is even less with 13" track wheels. But so far no problem. Gert

Aargh, why do the pics come out so monstrous when I link to my web site?? Gert