strotter

Oh, Garrett, Garrett, Garrett: that sounds like a challenge! Though my 5.7 isn't wound up as tight as your L28, and for sure the car isn't as fast, with my T56 and "sensible" behavior my '72 is up in that range steady cruising. I did a series of freeway trips to Sacramento a couple of months ago, about 40 miles one way from my house, parts hunting. Topped it off before starting, at the end of the day the tripmeter indicated 267 miles; topped off again with 9.7 gallons, which calculates to 27.5 mpg. Note too that it was a warm day and there was a mile or so of stop-and-go at each end of the trip. To be fair, I was driving like an old woman, but nevertheless I was amazed. I'm convinced I can beat that number by re-enabling the "highway mode" in the ECU, and with a more refined tune.

We bought an early 260 in from a bank in '82 or so, with motor purposely blown at 78,000 miles; did a complete stock rebuild on the bottom end and buttoned it up. My girl drove it until '88 when it was stolen and rolled over a curb at 100+ (high speed chase, 2 15-year-olds). Ignoble end, but it went out with 177,000 miles. She took us to Oregon 6 or 7 times, daily driven in 105+ heat in the summer, always got us home. The only problems encountered were electrical in nature, along with chronic back pain from the truly miserable seats. The current Z now has a crate 350 with Holley Stealth-Ram, 7730 ecu, vortec l31 heads, Comp 268 Xtreme Energy cam (224/230 deg @ 0.050-inch 0.477-/0.480" w/ 110-deg l.s.a.), dual exhaust, T56 with stock R180 rear-end. I've been driving it on-and-off for 2 years now, the problems encountered involved trannys (used up 2 T-5's) and electrical (fuel pump failure at a gas station - embarrassing). Also, I grenaded the first motor (a 327 that was just wound too tight - it ran a 12.5 the only time I checked it). I've totaled up about 9,000 miles on the new (more conservatively built, high 12's low 13's kind of thing) crate motor, much of it in summer heat, and wouldn't hesitate to take the car a long distance - so long as I bring my tools. Also, I put some decent seats in it, so I think my old spine could take it.

Thank you. Lots.

Sparks, if it'll play in iTunes, it'll load onto the iPod.

This situation - I believe it's called "reversion" - has been discussed extensively at thirdgen.org in the /diy-prom/ section. Grumpyvette, who periodically checks in with Hybridz to share his extensive knowledge of applied mobile thermodynamics as well as his extensive collection of cool links, is very active over there, and has provided detailed explanations of the physics as well as a variety of solutions. There are some knowledgeable gearheads over there, as well as some accomplished programmers - some of those guys compile their ECM code from scratch!

Sorta-semi related question: what's kind of airdam/flair going on with the yellow and orange Zs? Pretty cool lookin'. I could see something like that on a street Z - the front on view is very often the least attractive for the first generation Zs, in my humble opinion, but the way that fender flair smoothly enters the airdam is attractive.

Confirmed - early Europa. One of the first modern-era mid-engined production cars (pre-Bora?). Fiberglass panels, one of the most interesting frames ever put into a street vehicle - large box-section running front-to-rear, forking fore and aft - Very cool, very fast car. One of Colin Chapman's best.

My girl and me are coming up on the 30th anniversary next April. Never got married - perhaps we have a problem with commitment?

Racer is absolutely right - having slapped many a car in my motorcycle days, I can tell you that racing one is often an exercise in frustration: all anybody at the starting line sees is the car jump out ahead, while the rider tries his best to keep the front-end near the ground. They cannot as easily make out the 1-2 shift, at which point the motorcycle humiliates the car.

I couldn't agree with this statement more.

I've been searching around for a TBI circuit diagram for your setup, but I haven't had any luck - regardless, to answer your original question (which I should have done yesterday, sorry, I'm easily distracted - Oh, look! A pretty penny!...) The VSS lines run in two different ways: 1. Directly from the VSS (at least for the 1227730) at pins BB9 (purple wire, VSS low) and BB10 (yellow wire, VSS high). This is an *unbuffered* input, directly from the VSS, no boxes in between. 2. From VSS to a buffer (a yellow box most years) and from there to the ECU at pin BC6. This is the system used in many of the TBI motors (it was in an '89 I swapped). You may be interested to note that there are two VSS output signals *from* the ECU, pins BB11 (4000 ppm output), BC1 (2000 ppm output), which you can use to drive an electronic speedo (such as the Autometer units) if you so desire. Automatic transmission operations come from pins BD14 (the 4th gear switch signal from the tranny) and GF6, the TCC control signal from the ECU to the tranny, via a 4-pin connector - this may be the thing you're looking at. Not to worry, just leave it undone, your new Memcal will ignore it. Hope this helps. I have .jpg's of the TPI setup, if you'd like them. Email me and I'll "attach" them back to you.

I'm wondering what "module" your missing? IIRC, in '91 the Corvette / Camaro motors used the '7730 ECU. The good news is you can go down to your local Chevy dealer (or GMPartsDirect) and order a "Memcal", (which is the chip, some "limp-home" and other circuitry on a carrier you just jam into your ECU). Looks like this: It'll cost around $75. You can go to http://www.usol.com/~okfoz/91/promcodes.htm to figure out which one you want. The bad new, as you may have noticed from the table at the above site, is that there was no T-5 equipped 350 that or any nearby year, so if you have a 350 and you're not happy with the "automatic tune" (which is a bit different that that for the manual, especially w/r/t timing), you'll need to burn your own chip. Not difficult, but not trivial either. If it comes to that I can give you some pointers. Also, JTR has a good book, "Chevrolet TPI & TBI V8 Engine Swapping", which talks about some of this stuff (though not in great detail - none of the custom tuning stuff).

Something I'm *amazed* I don't see more is rotary swaps. They seem like the perfect motor - unbelievably small, powerful, lots of potential for huge hp, and yet you seldom see them popped into other vehicles (other than here at HybridZ!). Stacking a couple of them either in series or in parallel might be an interesting engineering challenge. I was looking for "convertibles" on Ebay some time ago, and saw a Fiat 850 in my area (remember the teeny-weeny little guy with the rear engine?), and I thought "might be cool car - with a BIGGER MOTOR - perhaps a six? Maybe a D15b (of which I have one sitting around)? Or, ooh, a Wankel! Yes, a rotary! Now where would I put the turbo?"...

I'm just fairly impressed by the execution of putting a fwd clip under an rwd front-end. Impressive engineering, if somewhat - odd. On a more local note, some of these comments sound word-for-word like comments I've seen and heard regarding putting V8's into Zs. That guy put a *lot* of work into his engine swap, he deserves props for that, at least.

Aluminum heads - which both those motors feature - can take at least 1 point higher than iron. I'm sure somebody will pipe in here to clarify, but I understand heat dissipation, as well as heat distribution, make much of the difference for Al. Another point of importance, w/r/t detonation, is the dynamic compression ratio. There has been some talk about it on the forums here, but the gist is that the *actual, running* compression is always lower than the calculated number to the valves' being open during part of the compression stroke, and modified somewhat by inertia effects in the working fluid(s). So you can have a radical c/r calculated for static, but see a much, much lower actual number in operation. Grumpy is the one that clued me into this one. It's not hard to guesstimate, you just use the ratio of the volume at the valve closing point to volume at TDC, instead of from BDC to TDC.