Hello, everybody. I’ve been reading posts here since November and trying to pick up knowledge, but I’m still just a newbie, and I appear to be somewhat automotively-declined. (As I said a long time ago, for me, changing a battery and getting the car to crank over is something to be proud of.) I’ve got a theoretical question to throw out, and any recommendations would be appreciated. (A long time in the research and pricing stage before buying and building, but still appreciated…)

The goal:
Complete customization of third-gen Firebird drivetrain, from engine to differential/rear axle, for peak fuel economy in the 60-75mph band, using only off-the-shelf (commercially available parts, aside from wiring/ducting. Assume that no part is too expensive, but it has to be off-the-shelf, cash-and-carry (i.e., no experimental ceramic blocks or prototype components). Fast acceleration is also desirable, but second priority to fuel economy.

The catch:
It all has to fit on a Firebird fitted with both Spohn AND Alston subframe connectors (unless somebody can recommend a set of SFC’s that has more structural strength than that combo). Auto transmission and DFI or other PC-controlled engine are requirements, also a heavy-duty, high-output alternator—there’s gonna be a lot of electrical/electronic accessories installed. It all has to fit under the stock ’82-’84 TA hood. And the entire setup’s gotta be emissions-legal (no gutted cats or anything like that).

Secondary question:
Is there any way to swap out fuel tanks? According to one source, the ’91-’92 Firehawks had either 18 or 24-gallon tanks, varying by vehicle and options. Is there any way to procure and install one of these tanks without tearing a rare, collectible, expensive third-gen Firehawk apart for its components? (Underlying thought: combining a high-fuel-economy engine/drivetrain with a huge fuel tank should dramatically extend the car’s range between fill-ups, and also allow some flexibility in when to buy gas, i.e. if I don’t like the price at Joe’s Arco in Wherever, USA, just go on to the next town and fill up there. Explanatory side comment: in my family, we’re extremely reluctant to let it get below a quarter-tank, and when traveling, some of us don’t let it get below half before filling up.)

As I said, I’m still way down at the bottom of the learning curve, so I’m deferring to the wisdom that only comes with experience. Anybody have any ideas?

 

Good thing I learned to read "theoretical" in a college foreign language class...

Pursuant to your specifications:

1. GM 10134371 aluminum engine;
2. GM 10134359 18º Aluminum Cylinder Heads, 2.00/1.55 valves;
3. 4.00" stroked gun-drilled crankshaft;
4. PM connecting rods;
5. 3.980" cast alloy pistons (298 CID);
6. 10.58:1 static compression ratio;
7. Balanced rotating assembly;
8. 8" FluiDamper;
9. Comp 09-410-8 camshaft;
10. Single row roller chain timing drive;
11. Balance shaft deleted;
12. Comp 1317 roller rockers;
13. Comp 730 retainers and 10° locks;
14. Comp 942 valve springs;
15. Titanium push rods;
16. Melling M55 oil pump w/30# relief;
17. Full dual 2"-2¼" exhaust and cats;
18. Hooker 2482 headers;
19. High flow mufflers;
20. MAF/CPI injection system and PCM, Herter programmed;
21. Saginaw 2.56 positraction axle with disc brakes; (NOT a typo)
22. Aluminum MMC driveshaft;
23. TH-4L60E transmission;
24. 1675 RPM stall lockup torque converter;
25. 17" x 7" wheels with BFGoodrich g-Force T/A 245/45-17 tires @ 44 PSIG;
26. ASCD glass reinforced plastic hood;
27. Spoiler and factory ground effects deleted;
28. 1.5" drop spindles front;
29. Jamex lowering springs rear;
30. 140A Delcotron alternator;
31. FouthGen UEC/power distribution block;
32. 87 octane (maximum) fuel;
33. 195°F thermostat;
34. Single poly V belt drive.

Those are all readily available parts and services. With the listed stroke, cam, and gearing, you should be right in the beginning/middle of the torque curve at 65-70 MPH on those tires. The long-tube headers and smaller exhaust tube diameter will maintain adequate exhaust velocity at the target RPM to accomplish good cylinder scavenging.

Then again, all this is theoretical, and I might be a little rusty.

 

Thanks much. I'm already getting started on the research to figure out how much cashflow I gotta generate before construction time.

Later.

nedry OUT

 

Damn Vader you just walk around with a notebook full of that stuff or what. :hail:

 

Just remembered having seen several places, including one of the tech articles here, say something about carbon-fiber driveshafts. One of those would cut the weight and rotational mass as compared to even an aluminum shaft, but do they have the structural strength to really be an improvement/refinement in this case?

Side question: I've heard a lot of people around here arguing that high compression and low octane are a bad mix because of detonation. Is this what the 18º cylinder heads and some timing advance are for, or is this another of the many things you guys know that I still have to learn?

Anyway, thanks much. (Wish that I wasn't such a slow learner... this would be such an embarassment if the folks at the college find out...)

Later.

nedry OUT

 

The stock base Firehawk 1LE tanks were 18.5 gallon units, and the optional Fuel cell was a 24 gallon unit.

Here is the info and the link to buy the fuel cell:

"Fuel Safe, Pro Cell", 24 U.S. Gallons, P/N SA114

http://secure.fuelsafe.net/cgi-bin/fuelsafe/SA114.html

The GM P/N for the factory 1LE 18.5 gallon tank is 10121026. You will need these as well:

Fuel sender unit (longer): 25094804
Fuel strainer (double screen): 25121120
Fuel Pump: 25116163