S54 + FD RX-7?

In reply to sesto elemento :

2JZs go where they wanna go.

chaparral said:

FD with a Renesis. Does losing the turbo system leave you with a higher power-to-weight ratio?

Doubtful.  RX8s are rated at 238 and seem to dyno around 190, FDs are rated at 250 and dyno 210-220.  And that FD number goes up to close to 300 with very little work (exhaust, downpipe, computer), whereas the renesis is notorious for being hard to crank more power out of it.

Renesis is poopoo for anything other than stock power. 3 or 4 rotor N/A is the dream, but milage is terrible, as in severely limited range.

I'll be about 450whp with the single on pump and water injection. The cars are valuable enough now that a rebuild isn't a huge deal, at least it's no longer 1/4 of the cars value. Rotary will stay

mr2peak said:

Renesis is poopoo for anything other than stock power. 3 or 4 rotor N/A is the dream, but milage is terrible, as in severely limited range.

That and the engine will set you back $20-60k.

If I had that kind of money for an engine for which many components are either severely expensive if/when they come up for sale, or severely expensive and they have to be shipped from halfway around the world and hope the company that made them is still in business, I really wouldn't care about fuel economy.

3/4 rotor engines make R07 engine swaps sound like a logical and sane choice.

Another one to consider is a 4 cylinder Ecotec turbo engine. Yes, it weighs around 100 lbs more than the FD engine, but you can pretty much dial in whatever output you want up to 700 bhp or so.  400 bhp is easily attainable without changing out rods and pistons.  And the engine size would preclude the packaging issues of a large 6 cylinder engine.

Not sure I get the need to rev particularly high, though. Yes, an S2000 is a lot of fun, but if yu can attain the same power lower down, why not?  The S54 max rpm is 7900 and given the power curve there is a point to using that sometimes, but a turbo engine doesn't normally need to spin that fast (LNFs are fine to 7200 or so). In fact max rpm is normally determines by the envelope of the turbo efficiency - reach that and you are just churning and generating heat without any significant pay-off.  At which point you decide to lower your shift points or get a higher output turbo and put up with any increase in lag that entails.

RPM means you don't need to think about shifting.  It makes a car sooooo much easier to drive.

Pete. (l33t FS) said:

mr2peak said:

Renesis is poopoo for anything other than stock power. 3 or 4 rotor N/A is the dream, but milage is terrible, as in severely limited range.

That and the engine will set you back $20-60k.

If I had that kind of money for an engine for which many components are either severely expensive if/when they come up for sale, or severely expensive and they have to be shipped from halfway around the world and hope the company that made them is still in business, I really wouldn't care about fuel economy.

3/4 rotor engines make R07 engine swaps sound like a logical and sane choice.

The fuel consumption is an issue based on range. When you're getting less than 10mpg cruising, with dips to 4mpg for stop and go and serious use, a full tank doesn't get you far at all. No more weekend trips, no more canyon runs unless there's a gas station half way though and at both ends.

I'm no longer considering swapping this car, but I haven't chucked an apex seal thought the turbine yet so..

I've got an '85 RX-7 with a 9000rpm 355sbc, 4spd manual. Rev's pretty quick, gains rpm at a rate of 11,515rpm/second. Spins 3133rpm @ 70mph, but still pulls down 20.98mpg on the highway. Iron block with aluminum heads/intake, car weighs 2325lbs and is actually rear heavy. Not rotary, but still fun to drive :)

Grant

In reply to mr2peak :

While true, you could also swap in a 22+ gallon fuel cell to get range back.  My understanding of the multirotor engines is the 3 rotor gives you an option of cutting your firewall or ruining your front suspension geometry, and a 4 rotor, besides being crazy expensive, requires essentially hulling the car out and making a new firewall and floor.  At that point, a fuel cell is mundane!

Pete. (l33t FS) said:

In reply to mr2peak :

While true, you could also swap in a 22+ gallon fuel cell to get range back.  My understanding of the multirotor engines is the 3 rotor gives you an option of cutting your firewall or ruining your front suspension geometry, and a 4 rotor, besides being crazy expensive, requires essentially hulling the car out and making a new firewall and floor.  At that point, a fuel cell is mundane!

The firewall/floor mods may not be as difficult as you might think, here's a link that almost makes it look easy, my car has plenty of room for a 4 rotor... FB RX-7 floor/firewall modification

Grant