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Thursday, February 28, 2008


C4 Corvette speakers - what really fits

There's a couple little things on C4 Corvettes that their owners generally don't like - the skip shift feature in 6 speed transmissions, the Optispark distributor, and leaky weatherstripping are some offenders. But if I were to take a guess as to which part actually gets replaced the most often, it would probably be the Bose sound system. Many Corvette owners have dubbed it the Blose. That's a pretty apt description of mine - one speaker is blown, and the radio only turns on half the time. In all fairness, most 20 year old stereos have probably broken. But it's high time for a new stereo. I had originally planned on putting in a used one, but after having trouble with two used ones I went and bought a new if cheap JVC head unit.

Now, the trouble with the Bose system is that it's usually recommended you replace the speakers along with the head unit, because Bose put amps in the speakers. So I went speaker shopping. Unfortunately, the various stereo guides I've found online and in stores all say conflicting things. I checked at Wal-Mart, Best Buy, and Crutchfield, and no two guides said the speakers were the same size! So, tonight I went and measured the speakers to find out the truth. Here are the [i]real[/i] speaker sizes for a 1986 Corvette with a Bose stereo system.

Up front, Wal-Mart said the speakers were 4", Crutchfield said the closest size would be 6 1/2", and Best Buy said that the speakers were 6" x 4" ovals. The truth is that they are 7" square grilles with 4 1/2" round speakers behind them. So the win goes to Wal-Mart, with Best Buy's recommendation being close enough to fit hidden behind the stock grille without a hack job. The 6 1/2" speakers could possibly fit, but it would be tricky to make it look right as they don't look like they'd fit behind the stock grille or completely cover the opening. (It appears that a lot of people on Corvetteforum.com have made 6 1/2" speakers fit, however.)

In the back, Wal-Mart didn't list a speaker size, Crutchfield said that 6 1/2" would be the closest size, and Best Buy said the closest size was a 9" x 6" oval. The grille is a large irregular shape, but behind this was a set of 4 1/2" round speakers, again. However, they are stuck inside a 9" x 6" cutout with an adapter! And it also looks as if it wouldn't be terribly hard to cram a 6 1/2" in there while leaving the original grille in place. So Best Buy takes the win for the rear speakers, but this time Crutchfield's recommendation is easier to follow.


Tuesday, February 26, 2008


Some pictures of the Ram 50

Here it is, in all its beaterific splendor, parked outside DIYAutoTune.com headquarters. The car behind it is "The Grapemobile," one of the many development mules hanging around the building.

I've found a pretty interesting forum at Project Zero G, a site dedicated to rear wheel drive turbo Mitsubishis. They've got the largest library of RWD 4G63 information I've found online.


Saturday, February 23, 2008


One of the downsides to owning a Corvette...

...is that you can easily spend $1,000 to get a new set of tires for one. On the upside, that did make that unnerving 60 mph vibration go away.


Thursday, February 21, 2008


Mad Scientist Matt's Lair - The Book?

Well, it's not going to be a book version of this blog, but Jerry Hoffmann and I just signed a book contract with HPBooks for a book on EFI installation and tuning. It's likely to be a while before you're able to buy it in a bookstore, and may even be a while before you hear anything more about it on this blog. But I just wanted to share this with everyone.



The Lotus of gas mileage?

Philip emailed me this link to an interesting effort at building a 150 mpg car. It's not from one of the big automakers, but from an upstart called Loremo. This one isn't a hybrid, either. Instead, in the great Colin Chapman tradition, they've decided to "simplify and add lightness." It's not exactly fast since it only has 20 hp, but with a sub-600 kg (that's 1,320 lbs), it's not much heavier than a typical Lotus Seven knock-off. Only a Seven doesn't have a roof, or air bags, or a back seat - all of which are standard on the Loremo. It's kind of like a revived CRX in many ways, and might even be fun to autocross.

But one thing worries me: It uses a front-opening door, Isetta-style. This sounds like it would create the same safety hazard it did on the Isetta - if you're in a head-on collision, how do you open the door to get out? It looks like it may be possible to get out the hatchback in a Loremo, which could be a way around that problem.

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Sunday, February 17, 2008


I didn't really need another project, but it happened anyway,

Yep, I've blundered into another car project. I have a friend named Roy who had an old Dodge Ram 50, a little pickup truck that Dodge imported from Mitsubishi. (They were also sold as the Mitsubishi Mighty Max.) He gave it about the minimum permissible maintenance, and it seemed like he was determined to drive it until the wheels fell off.

Yesterday, he had a wheel fall off.

Technically, he had a lower ball joint break, so the wheel actually stayed on the truck, but the wheel was canted over at a crazy angle. The police complained he was blocking the road with it, so he had pulled it off the road with a lawn tractor. Still, he was kind of worried that the cops wouldn't like it sitting on someone else's property with a broken suspension.

Roy wondered if I'd be interested in it. While Kelly didn't want it around the house (quite understandable; wait for the pictures of it), I thought it might make an interesting shop truck at work, and the price was quite attractive, since it was free. I originally thought I'd probably have to call a wrecker and have it towed. But when I got to the truck, I saw I wasn't really in for anything that difficult. The ball joints were simply attached to the control arm with three bolts, and the bolts weren't even too rusted. The weather report warned of storms coming in, but I saw my chance and went to work. I managed to remove the ball joint, so Roy and I then went searching for new ones. To my surprise, the local AutoZone had two. (I wanted a second one since I figured the other side has to be equally shot.) So I bought them and managed to get the broken ball joint installed on the side of the road before the storm hit. I'll take it up to work sometime later this week. Right now it's parked at Roy's house.

The truck had an interesting surprise. I checked it for stickers or part numbers under the hood to see if I could figure out what sort of engine it had. Sure enough, there was a sticker in the back of the engine compartment saying "Engine code: G63B." For those who don't speak Mitsubishi, 4G63T is the Mitsubishi engine code for the motor found in the turbo Eclipses and the Lancer Evolution. Wikipedia seems to think it had a different engine altogether, but I suspect that's about as likely as the claim it will run happily on E85.

I'll get some pictures up soon.


Wednesday, February 13, 2008


A fairly minor setback

On occasion, I've been lending AutoFab a hand with some of the cars ahead of the Dart. Yesterday, they ran into a bit of a problem with a project with a Megasquirt installation on a Dinan BMW M6 (yes, you read that right). They were using monster 750 cc/min low impedance injectors, and concluded it needed the Hi-Res code. Trouble is, this code keeps Megasquirt from being able to limit the injector current, so they needed an injector resistor pack and couldn't whistle one up on short enough notice. So I let them transplant the Dart's injector resistor onto the Dinan M6, leaving the Dart's current V2.2 ECU unable to run the injectors on there until I can find a replacement.

Except that, given where I work, it makes a bit more sense to whistle up a different ECU out of our small collection of unsellable units than to go and hunt down a resistor pack. I'll need a V3.0 or higher unit to get that crank trigger working anyway.


Monday, February 11, 2008


The gas mileage evildoers of eBay

The mad scientist is feeling a bit belicose today. So I thought I'd go take on a few of the automotive evildoers - those who use impressive-sounding pseudoscientific claims to convince people that a worthless trinket will improve their gas mileage. It's my opinion that the products they sell are scams, and today I'm going to unmask a few of these evildoers and show what is wrong (and often patently absurd) about their claims. So I decided to do a little bit of patroling on eBay to see what I could turn up. There's always a couple good automotive scams on eBay.

My first target is what appears to be a cheaply made knock-off of a product I've blogged about before, the Tornado Fuel Saver. Not only is it cheaply made, it's cheaply photographed, too. Seller couldn't afford more than 72 by 80 pixels for his photo. (This guy appears to be selling the same thing but with a bigger photo, allowing you to see just how poorly made this thing is.) I've blogged about the "genuine article" reducing performance when tested on a dyno before. Since there's already a lot of notes on why the Tornado and its ilk are scams, I only feel it necessary to comment on one particular issue with this knock-off. They've used slit bends to form the vanes. This significantly weakens the base of the vanes and invites cracks to form. There's a good chance that the vanes could break off and get sucked into the engine. Perhaps that's why "Peter Pan" used such a small photo. The Tornado may be flim-flam, but at least it's well made flim-flam.

This guy puts the names of some better known rip offs into his auction. So he's not only ripping off consumers, he's ripping off trademarks (couldn't happen to a nicer bunch of trademark holders, though, could it?). This one is good for a few laughs if you're into material science, such as "Made of strong alloy zinc." Zinc's mostly used for cheap castings where strenght is not a big concern, stuff like the metal emblems on my Dart. Extra giggle points for using the phrase "cambusting chamber." Sounds worse than getting metal shards sucked into your intake.

This auction is for another gas mileage scam that refuses to die, the gas line magnet. The EPA's tested these fuel magnets time and time again. And they never work.

Another classic rip-off is the "ebay chip," which isn't a chip at all, but a resistor that you splice into the coolant sensor line. This forces the engine into warm-up mode, making it add more gas. This seldom improves matters as many engines are tuned cautiously from the factory and run fairly rich as it is under full throttle; some motors even gain power when you lean them out from stock. Amazingly, this device that dumps more fuel into the engine than it needs is now being rebranded as a fuel economy booster! They're really too numerous to count, but I've chosen a few standouts that offer extra laughs: This one, for its claims of MPG and power gains being higher than Jerry Garcia, and this one, for inexplicably wading into the abortion debate.

Let the bidder beware!

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Sunday, February 03, 2008


A Super Bowl post: Delusional football fan, or prank?

Found on CarJunkie Forums: an eBay auction that may be some sort of practical joke, or one of the most delusional asking prices of all time. You decide if someone seriously thinks a 1972 Ford F-100 can be worth $795,000. Apparently his basis for that claim is the odd paint color and some now-faded decals. That's right, the truck isn't even in show car condition - nicely kept for a '72 pickup, but pretty faded for a show car. It would probably be a 3 or 4 on the usual car value guide scale with 1 being pristine and 5 being barely functional but saveable. He even links to a thread where people are making fun of his own auction. I'm guessing this is a joke, but it's a very strange one indeed.


Saturday, February 02, 2008


More parts for the Dart

So today I ran down to Summit Racing Equipment and picked up a pair of Flex-A-Lite fans for the Dart. I decided to go with two of their pancake fans since there's so little clearance between the pulley and the radiator. These are some of their smaller ones, 2 5/8" thick. I also noticed from their catalog that Honda Civic fans are about that thin, which may be a solution for low buck projects that don't have enough engine compartment room. Too bad the Taurus fan I picked up earlier didn't fit; these are a pretty popular fan for people who want a lot of airflow and want it cheap. Flex-A-Lites aren't exactly cheap, although for the money you get American made parts and not something outsourced to the People's Republic of China.

I'll post the part numbers once I'm able to confirm they do, in fact, fit.



Wondering if there's any news on the Dart?

There is, this week. I talked to Thomas at AutoFab, and it seems they're taking the business in a new direction and need to get all the project cars out by the beginning of March. So it looks like I'll either have the Dart running again by then, or just pay him for the work done so far and then take it over to DIYAutotune's shop to finish the work after hours. Either way, you'll be seeing more of the Dart on this blog in a month. Stay tuned!


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