Real Fiero Tech

Maybe not a LS7, but a build like it. What I'm getting at is why have 5.5l and 7500rpm when you can have 7 liters and 7,000rpm? Not just that, but I've seen more than a few 7 liter LSX blocks rev well past 7.

You can build a 5.5 cheap, even with aftermarket rods and pistons. GM's crate LS7 is what? $13k? You can't put together a 7 litre for much less than that.

Aaron wrote:Maybe not a LS7, but a build like it. What I'm getting at is why have 5.5l and 7500rpm when you can have 7 liters and 7,000rpm? Not just that, but I've seen more than a few 7 liter LSX blocks rev well past 7.

You're going to need an LS7 block shortblock, or to sleeve out a non LS7 block. Haven taken part in the sleeving process, all I can say is that unless it's hack and slash, the machine shop labor to sleeve it will probably bend you over in and of itself. At my old work, they put together a 7L 7500 RPM drift engine that used a sleeved LS2 block... It cost more than a whole ZO6 when all said and done (though it was pure sex).

crzyone wrote:It is if you spin it fast enough.

Okay, let's look at this. RPM range is determined by parts, which are determined by money. The parts under consideration are the crank, the rods, the lifters, the valves, the valvesprings, the retainers, and the intake manifold. The crank is either the production 4.8L crank, proven safe for 7500 rpm in a 4.8L. But that's a N/A combo using TFS heads. There are no shelf 4340 cranks with this stroke, it would be custom-order, so that's $1500. Rods: no problem, except another $500. Springs: no problem. Lifters: stock can go 7000 rpm, beyond that, must spend money. And if spending, may as well gob solid roller. That'd be another $600. Valves: titanium is way expensive. Likewise for retainers, but those I would do. Intake manifold: The runner lengths in the FAST 102mm for LS7 heads are too long for power at really high rpm. Edelbrock should soon be releasing a Super Victor LS7, but until then...
So, I limit the rpm, add the stroke, and save at least $2600 in exotic parts, or I hope crzyone will send me a few thousand dollars, just to see the results.

The Dark Side of Will wrote:

retard wrote:Or just use an LS7, and have 7,000rpm and a lot more torque and horsepower.

For three times the cost of the other option...

glad to see Will is somewhat on the same page as me. But even so, this is still inferior power due to inferior heads. Plus too much stroke is more totque than this project can benefit from having.

Aaron wrote:Maybe not a LS7, but a build like it. What I'm getting at is why have 5.5l and 7500rpm when you can have 7 liters and 7,000rpm? Not just that, but I've seen more than a few 7 liter LSX blocks rev well past 7.

I don't want the torque that would bring. Which is why I'm liking the Mast heads better than twin turbos.

The Dark Side of Will wrote:You can build a 5.5 cheap, even with aftermarket rods and pistons. GM's crate LS7 is what? $13k? You can't put together a 7 litre for much less than that.

Actually, you can. The 6.2L block for $1500, a 4" crank for $1000, 4340 rods for $600, pistons for $800 with rings, then swap everything else over from a salvaged LM7 for $500. Add on the heads and head gaskets, and you're still well under half the $13k.

Blue Shift wrote:

retard wrote:Maybe not a LS7, but a build like it. What I'm getting at is why have 5.5l and 7500rpm when you can have 7 liters and 7,000rpm? Not just that, but I've seen more than a few 7 liter LSX blocks rev well past 7.

You're going to need an LS7 block shortblock, or to sleeve out a non LS7 block. Haven taken part in the sleeving process, all I can say is that unless it's hack and slash, the machine shop labor to sleeve it will probably bend you over in and of itself. At my old work, they put together a 7L 7500 RPM drift engine that used a sleeved LS2 block... It cost more than a whole ZO6 when all said and done (though it was pure sex).

The 6.2L block can take a 4.125" bore. just a bore and hone. No replacing the cast-in sleeves.

Atilla the Fun wrote:

The Dark Side of Will wrote:You can build a 5.5 cheap, even with aftermarket rods and pistons. GM's crate LS7 is what? $13k? You can't put together a 7 litre for much less than that.

Actually, you can. The 6.2L block for $1500, a 4" crank for $1000, 4340 rods for $600, pistons for $800 with rings, then swap everything else over from a salvaged LM7 for $500. Add on the heads and head gaskets, and you're still well under half the $13k.

Spoken like a true machinist... the rest of us pay to have blocks machined; gotta have a budget item for that, as well as all the ancillaries like MLS head gaskets to get the quench right, etc. If the 6.2 blocks can be had that cheaply, I'd do an aluminum 5.7 instead of an iron 5.5.

The Dark Side of Will wrote:

Atilla the Fun wrote:

The Dark Side of Will wrote:You can build a 5.5 cheap, even with aftermarket rods and pistons. GM's crate LS7 is what? $13k? You can't put together a 7 litre for much less than that.

Actually, you can. The 6.2L block for $1500, a 4" crank for $1000, 4340 rods for $600, pistons for $800 with rings, then swap everything else over from a salvaged LM7 for $500. Add on the heads and head gaskets, and you're still well under half the $13k.

Spoken like a true machinist... the rest of us pay to have blocks machined; gotta have a budget item for that, as well as all the ancillaries like MLS head gaskets to get the quench right, etc. If the 6.2 blocks can be had that cheaply, I'd do an aluminum 5.7 instead of an iron 5.5.

Fair enough. You got me, to the benefit of all non-machinists. They'll thank you. So, the price varies from shop to shop and region to region, but I'll figure high. Anyone in the 48 states should be able to get the machining done for under $400.

Atilla the Fun wrote: Anyone in the 48 states should be able to get the machining done for under $400.

I don't think that's accurate. Balancing alone is half of that budget. Boring and honing is ~$15 to $20 per cylinder ($120 to $160 total). Now you're left with $40 to $80 for block cleaning, surfacing, line boring (if necessary), regrinding and polishing the crank, servicing the rods, and installation of the cam bearings... those put it well over the budget, and we haven't even talked about head work yet.

I wasn't including crank balancing in that. $400 was just block machining.

until / unless this car is recovered, this project is on long-term hold. If this car is not recovered, I'll get another Fiero, besides the black '86, to continue this with. Right now I can't predict when.

IT'S HOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I was sitting in traffic, bored, no songs on the radio, only commercials. I got to thinking about venting the Fiero hood, when I saw a WRX STi backing across a parking lot. THAT'S IT! That big old hood scoop, turned around! Hasn't been done yet, either! Might look stupid, but should work well enough. Those scoops are at least 4" tall on certain years of STi's, like the one I saw. Now how to find one?

Don't vent the Fiero hood. Your A/C will stop working because the hot air from the radiator will get sucked in the cowl inlet for the HVAC. Your A/C will have to cool 150 degree air off the radiator instead of 90 degree ambient air.

I'll be looking at options to vent the radiator outflow to the fenders rather than hood when I get back.

the A/C was removed from the engine bay when I removed the 2.5L. This isn't going to be a summer driver. This might see street use in the spring and fall, but is being built to challenge an Enzo. Do Enzo's have A/C?

Yes.

http://www.caranddriver.com/reviews/car ... ive_review

Put that A/C comp back.

I think I'll just bolt it to the passenger's footwell, as low, forward and center as possible. Then carpet over it to hide it from the ladies.

Atilla the Fun wrote:I got to thinking about venting the Fiero hood, when I saw a WRX STi backing across a parking lot. THAT'S IT! That big old hood scoop, turned around! Hasn't been done yet, either! Might look stupid, but should work well enough. Those scoops are at least 4" tall on certain years of STi's, like the one I saw. Now how to find one?

This one was from a standard WRX: