My 2000 Jimmy challenge

[wmjinman]

I figured that out back when I was doing my Bonneville Salt Flats landspeed racecar. I had another car of the same model & year (almost - 2 years newer, but with the same basic body style, at least) that I'd go out and test different air dams & stuff. It was too old to hook a ScanGauge up to, so I'd do coast-down testing.

But knowing the mods would have greater effect, and the results would be easier to see at higher speeds, rather than doing it on the freeway where the speed limit is 75 and lots of traffic and cops, I'd go way out - probably 80 miles from where I live - to a particular stretch of fairly flat road way off the beaten track with extremely light traffic & still a 70 mph speed limit. Of course, I was trying to exceed 200 mph in the "real car" too, so I wanted the tests to be a little closer to the speeds I'd actually be dealing with.

So I set up a 1-mile test section for my two-way tests & marked the ends with orange traffic cones. Then I'd go out more than a mile past the end, turn around & punch it up to 112-115 mph, then throw it into neutral, trying to guage it so I'd be down to going 110 at the "start" cone (or near it). When it hit 110, I'd start my stopwatch & then let it coast down to 60 & write down the time. Then I'd go a mile past that end, turn around, & repeat. And I'd try to do 3 sets of those.

To try to reduce the other variables, I had the tires pumped up to 70 psi, and would pour a couple gallons of gas in the tank after each set to try to keep the weight the same. Wind will slow down a lighter car faster than a heavier one, all things being equal, right? Of course, that big 455 Buick probably burned even more gas than that. I didn't do the easy to gauge "fill it all the way up" trick, because, trying to maximize the aerodynamic effect, I tried to run it as lightweight as possible, so with the tank less than half full. But with a couple of exceptions (which I think were probably due to intermittent wind gusts), I was pretty pleased with the consisancy of the data, and I was definitely able to tell which air dam (if any) cut drag the most.

Like I said earlier, I just love doing this type of testing. :-)

[wmjinman]

Attempting to post image...

[MetroMPG]

> Attempting to post image...

Looks like it worked. Neat old Riviera! What's the story?

[wmjinman]

Originally Posted by MetroMPG

> Attempting to post image...

Looks like it worked. Neat old Riviera! What's the story?

Wow - you asked for it!!! I could write a book about me & Buick Rivieras.

Part of the story is in the post before the picture - #31. Here's some more:

It started in '65 when I was a kid & my dad got a '64 Rivi "almost new" (repossessed from the bank & auctioned off). I loved that car & then when I got my driver's license, was the car I was allowed to drive. Of course, I promplty learned 2 things; first, that it was almost impossible to hit 15 mpg with it on the highway (I went to college in Reno, 92 miles from my hometown, so had many "highway driving" opportunities). And second, it's top speed was 130 mph+. YES!!!!!

Meanwhile, in '72, when pulling into a parking lot, I saw this WILD car that I thought was the most beautiful thing I'd ever seen. Low, long & sleek. A huge hood that musta had a HUGE engine under it, and a super-futuristic "pointed rear window" with a set of louvers on each side. Gawd, I'd never seen anything like that before!! (I was, at that time, unfamiliar with the boattail Covettes they had in the mid 60's). Well, I just had to go "check out" this gorgeous piece of art disguised as a car, and as I approached, imagine my shock and amazement as I started to recognize the "Riviera" logos and "styalized 'R's" on the thing!!! Holy crap - this is a Buick Riviera - a make and model I was already convinced was amongst the best cars on the road!!

Back to college & driving my dad's car. I guess he didn't like my "rebellious teenager act" and for punishment, removed my driving rights to the '64 Riv. OK, screw it - I'll get the car I really want anyway - the '71 Riv. Eventually I did, and that was in 1976 (or maybe '77). I've had that car ever since, driving it off & on as my "cruiser".

As the new century (2000) was rolling in, I was hearing things about racing. My sister married a guy who does drag racing (which never appealed to me - I liked to be able to "enjoy the speed" for awhile, not just take off as fast as you can & then slam on the brakes & stop - what fun is that?). And I'd read about the Bonneville speed record events once in awhile in magazines, too. One time at work, they had us in Wendover, which is only a dozen miles from the Salt Falts, so I went and checked it out. Wow! My reaction was much like Burt Monroe's in the movie "The World's Fastest Indian" when he first saw it. Also, a guy who's office was across the hall from mine at work was a drag racing guy AND and engine builder & we'd talk about stuff. I always wanted my '71 to go faster than it did. - guess 130 just wasn't enough for me!

Eventually, we decided to take my car out to Bonneville and run it for the "130 mph club", an event they had set up for licensed, street-legal cars to let "common folk" get a "taste of the salt". To get into the club, you had to make it to 130mph or more in one mile from a standing start - twice. And you had 5 tries. I knew my car could do 130, but I learned that it took more than a mile!!! So the challenge was on!! We started stripping weight, got headers, roller rockers, new manifold, several things like that. Then when I went up there, I ended up going 128.2 on my first run. On the second run, I blew the engine to smithereens (this was the second engine I'd blown in this car - the first, many years before).

When I got back home, which is a whole story in itself, since I DROVE up there ALONE in THAT car, we started talking. I wanted a new engine, built with some extra poop so I could go, maybe 150. Bob (my engine-building buddy) had other ideas. he said "screw the 130 club - let's built a REAL race car and go for an actual land speed record". And I wasn't too hard to persuade.

3 years and about $100,000 later, I'd blown 2 more Buick 455 engines, except this time, they were high-end race engines, and got up to an official 182.2 mph. - but NOT a record. Although, some of the guys in the Buick Riviera forums think I might well have the "World's Fastest Boattail Riviera".

But after the first RACE engine went away at 160 mph, we again needed a new engine. I happened to see the "green turd" (named after Robin Williams' rental motor home in the movie "RV") sitting in a vacant lot for sale. It was a '73 Riviera (the one year of the "boattail" models I liked the LEAST) & I thought, "Hey, that thing's got a 455 in it!!" So I bought it for $750 & drove it home. Now, from all outward appearances, it was a real P.O.S. It used to have a vinyl roof that was about 80% gone. Not 100% gone, mind you - that extra 20% of rags gave it a real "special" look! HAH!! Rust spots all over it, faded paint, missing door handle on the passenger's side, and it sounded horrible. The interior was all ripped up, the headliner was hanging down, holes in the carpet under your feet - full of dirt - you get the idea.

So I took it home and - bought ANOTHER engine for my '71, the race car - and so the "Green Turd" just sat there - for maybe a year. In the meantime, I was also wanting to try the "Silver State Challenge". This is a rally where they close off a 90 mile stretch of fairly straight highway in eastern Nevada and let sports cars scream through there (for a hefty price - entry fees cost you about $1000 by the time you're done). I think the record is 208mph average for that 90 miles. I was actually thinking of using the '71 for both Bonneville Salt Flats AND the Silver State Challenge. But, it was sitting there waiting for it's next high-dollar race engine and getting suspension & roll cage upgrades, and Bob said, "Well, how well does the 'Turd run?" Well, I didn't know... I drove it home that day I bought it, coughing and sputtering all the way, and never started it again.

So we checked compression and oil pressure & it actually looked good. I thought I remembered the guy I bought it from saying the engine had been rebuilt "30,000 miles ago", so if that was true, we might be in business. I put a new carburetor, distributor, coil, wires, & plugs on it, changed the oil, and it ran much better. Took it into a muffler shop & got the exhaust system fixed, and I'll be damned, it purred like a kitten!!! So I've maybe got the makings for the "ultimate sleeper" - a car that looks like ****, but runs like nobody's business.

We eventually took it to the "Silver State Challenge" and ran it in the 105 mph class (as "rookies", we had to enter a lower speed class the first time). But it performed like a champ - 90 miles down at 105, and then 90 miles back at 65-70 all on one tank. Adding in all the extra running around driving we did, by making it all on that single fill in the 20 gallon fuel cell, we had to have gotten at least 13.5 mpg. I was pretty impressed getting that kind of mpg with nearly half the trip at 105 mph & another several miles of it "city driving" - usually those big Rivieras don't get much better than that any time!!!

But the other half of the "Green Turd's" life - under my ownership - is as an aerodynamic research car for the salt flats project. After reading an article about sports car aerodynamics in "Hot Rod" magazine, I built a "snowplow" air dam for the salt flats car. This became a bit controversial with many people telling me it would ADD drag & slow me down. So off I went with the Green Turd to my testing area 80 miles away. First set of runs was with NO air dam - just the car's stock front end. Second set was with the little air dam I made for the Turd for "Silver State", the one in the picture. An improvement - GOOD!! Then came the "snowplow" air dam off the '71 Riv - the salt flats car. Guess what? That one WAS the best of the three configurations. I do have yet another air dam I'm making for the '71 that I think might be better yet, and when I get it done and recover a little bit from the financial devastation I've been in ever since the collapse of the economy, I'll go test that one head-to-head with the original "snowplow" air dam.....on the Green Turd, of course.

Oh, and one final post-script to the story; the 'Turd now has a Gear Vendors overdrive mounted behind the transmission, a new cam & new, ported heads, an improved oiling system (a famous weakness of those Buick 455s when you try to race them), a GPS speedometer, adjustable, lowered suspension, and about 130 horsepower more than it did when I first started playing around with it. It's nice having a sponsoring machine shop with both engine & chassis dynamometers available!!! ( I just hope they can stay in business through this "recession", too)

[wmjinman]

These two thumbnails show the "Green Turd" from the outside and then the engine compartment. As you can see, there's a bit of a difference. While the exterior was left "ratty", the mechanical parts were given quality treatment. "Work done" includes:

> Ported & flowed aluminum Edelbrock Buick "stage-1" heads
> Custom ground Erson cam designed around the "flow numbers" from these heads
> roller rockers - 1.67 lift ratio
> aluminum Edelbrock intake manifold - "port matched" to the heads
> rebuilt and recalibrated Quadrajet 820 CFM carburetor
> 1" phenolic spacer between carburetor & intake manifold
> TA Performance chrome headers, "X" crossover pipe, 2.5" dual exhaust
> Mallory "Unilite" electric ignition; distributor, coil, wires, "Hyfire-6" control module
> TA Performance timing cover/performance oil pump with adjustable regulator
> AM&P external oil filter and balance tube (feeding oil to the rear as well as the (stock) front of the main oil gallery)
> "Accu-Sump" oil accumulator (holds 3 quarts of oil in reserve under pressure & releases it to the main oil system if pressure drops)
> 20 gallon aluminum fuel cell with Mallory electric "pusher" fuel pump & regulator with return line
> battery relocated to the back - trunk area
> 17" aluminum wheels with Yokahama 55 series, "Z"-rated tires
> Home built fiberglass air dam, proven in coast-down testing to reduce drag in the 60 to 110 MPH speed range.
> "Moon-Eyes" aluminum "salt discs" on all 4 wheels
> Suspension lowered for 2" height reduction, new shocks
> All new steering & suspension neoprene bushings
> mechanical oil pressure & temp gauges, aftermarket tachometer and "Livorsi" marine GPS speedometer
> "Gear Vendors" overdrive on back of transmission (105 MPH = 1800 RPM)

[wmjinman]

A couple more views of the "Green Turd". Not too good for gas mileage, but really fun to drive otherwise.

The one with Bob & me was after our successful "Silver State Challenge" run, where we placed 6th in the "105 MPH class". In these classes, the goal is to come as close as possible to the target speed (105 MPH in this case). Due to a miscalculation by your truly, we missed it by almost 2 seconds (slow), putting us behind 5 others who came closer.

We were a little behind & Bob told me I'd better speed up & pick up some time in the last mile or so. I had it accelerating pretty good and saw the finish line coming up as he started counting down the seconds to our target time. For some reason, a few seconds before we crossed the line, I thought we were going to be too quick, so I took my foot off the gas. Well, that turned out to be not such a good decision. Oh well, for our first time ever trying that, I don't feel too bad. :-)

[wmjinman]

Since this is the 2000 Jimmy thread, maybe a picture of the Jimmy would help, eh?

For some reason, I can't get any confirmed MPG improvement out of those rear fender skirts. I don't get it....how can they NOT improve it? But after a couple different tests, I'm getting nothing.

[oil pan 4]

How fast are you driving?

[wmjinman]

Originally Posted by oil pan 4

How fast are you driving?

The first couple times I tested it, I was doing 50. First time showed a net loss of a fraction of a MPG. Second time showed a net gain of a fraction (and I mean a SMALL fraction - like 0.0-something.... in the hundredths of a MPG. Then I tried doing it at all speeds to see if it started showing an improvement at higher speeds. Nope.

- Well, maybe... at 40 and 45, the numbers were a little less, but at 50 they were the same. At 55, it was a little less, but then at 60 through 80, they virtually matched the tests without them. But it was a different day, different "calibration" on the ScanGauge (more recent fill-up), etc. I was looking for a trend, but didn't really see any.... except for maybe the fact it was worse at 40 and 45 (where the change shouldn't be as evident) shows that the whole new "calibration" moved my mileage lower, so if adjusted for that, maybe the fender skirts DO improve it at 60 and above. (in other words, without them, maybe the whole second test would have been lower MPG instead of just the 40 & 45 MPH part)???

I guess this is another example of the importance of doing MetroMPG's standard of "A-B-A" testing for this stuff .... same day, same session, then return to "A" for a "check".

[oil pan 4]

Originally Posted by wmjinman

I was looking for a trend, but didn't really see any.... except for maybe the fact it was worse at 40 and 45 (where the change shouldn't be as evident)

Me and my engineer talked about aerodynamic features changing how they act at different speeds in great depth, but never considered anything these low speeds and it was usually boundry layer stuff not whole structures.

This is kind of important to me since I would like to make real metal side skirts for the suburban that are removeable once I cut out and replace the bondo and fiber glass around the rear wheel wells.
I was planning on installing them for road trips since most of my usual driving was at or below 55mph.