Feds

O.K, as time goes on, I get more info on this project, and I start to flesh it out in my head.

Starting with a GSL-SE, 10k, and 4 days build time:

2nd gen turbo front clip: Nets me aluminuim control arms, better brakes, more options for wheels, a turbo motor.

Smaller turbo on the motor (for faster spool/flatter torque curve)

Light flywheel

4.30 rear end (to keep a little load on the motor)

Possibly keep -SE gearbox (for lower gearing vs. 2nd gen)

g-force tri-link rear end, or possibly miata swap...

Tire the crap out of it, and spring the crap out of it.

Thoughts/modifications/criticisms?

Cheers!

this ultimate autox'r what class will it be competing in? No point building a ultra custom car when you are outclassed. Might as well get some ex FSAE cars from the states. Several schools are trying to sell their old ones.

FSAE cars are built for around 15k USD. That is how much the 04 Queen's FSAE car costs us if we had to purchase every single part with the machining time factored in.

Feds

The class is me vs. another RX-7 with the same constraints. I just want to do it better.

jgrewe

iTrader: (1)

Maybe a 4.87 rear gear, easier to downshift to 2nd at speed for a slow turn. It would all depend on the courses you normally get. Other than that, it all looks like a nice combo. Practice left foot breaking to keep that turbo spooled up!

RoadRaceJosh

Do you mean to graft the entire 2nd gen front clip to the GSL-SE? How does that help with wheels? Don't you have plenty of 4x100mm wheels available? How do you plan on doing this in 4 days? The turbo gearbox is quite a bit stronger and you'll want that strength if you turn up the boost. Why are you starting with an FB anyway? I'm confused!

jgrewe

iTrader: (1)

I think he's just going to mount the x-member from the FC under the FB. That will give him all the moving parts of the suspension.

RoadRaceJosh

Really? Are there any other threads on doing this? I have a GSL-SE and wouldn't mind ditching the recirculating ball steering.

JEC-31

My thought is that there's absolutely no way you'll succesfully complete a project of that scale in 4 days, even juicing up and going 24 hours per.

1) The amount of fabrication and design required to make major suspension swaps work takes time to sort out.
2) Playing around with custom turbo setups means lots of careful tuning, not plug-n-play.
3) I seem to recall that the13B-T motor doesn't exactly drop right in to a RHD FB, there's a steering rack where the turbo belongs. There's an Australian write-up on how to get around it somewhere on this Internet thingy but I can't find it.
4) "Tire and spring the crap out of it" takes tuning too, or you wind up with a stiff ride lacking useable grip under auto-x conditions. And if you have the suspension swap you'll be forging ahead into new territory.

I think a realistic time budget assuming no job and no significant other is 4 weeks. If you have an actual life then we're looking at months if not a year plus, man.


OK I'm done being Mr. Negative-*** Devil's Advocate. All I'm sayin' is don't rush it, it's an awesome Ultimate Trackday Car concept, and one I've nearly committed to myself (this was before my avatar LOL). Take your time and do it right, and it'll be one hell of an RX-7!

Feds

O.K. Pretend like this is monster garage. Pretend I have 3 other guys, unlimited tools, and all the hoists/etc. I can get y hands on.

If this plan is NFG, what do you suggest? Any other ideas?

JEC-31

OK I'll play along with Fantasy Rotary project.

The plan is good, starting with the GSL-SE is correct.

Which path you choose for underpinnings must be cohesive. Don't mix the FC front suspension with FB rear tri-link setup, it'll be odd to have different bolt patterns on each end.

Option 1: keep FB hubs and solid axle with CP Racing (or build yor own VW-based rack-n-pinion steering rack) steering up front and G-force full-race tri-link out back.

Option 2: Strip unibody of all FB components and weld in complete FC front and rear suspensions. This will require obviously major cutting and fabbing of sheetmetal, you may even have to weld in chunks of the FC unibody that contain the mounting points. The striking advantages to this are: One donor car, end up with same bolt pattern all around, as well as same track width front-rear, and lots of trick parts available for tuning FC suspension.

Option 3: Fab in the FC hubs up front and weld in a Miata rear. Many of the same difficulties as #2. What's the bolt pattern of Miatas anyway?

Don't forget to make an appointment with the Magic Horsepower Fairy to come visit you as well.

grantmac

Option 3: Use a GX front suframe to have 4x114.3 on all three corners. Do the rear as per usual. With this suframe you pretty much have to go with a FC engine, may I suggest standalone and PPort? Or with standalone go high-comp/low-boost.
www.bcrx7.com/swap.pdf

Grant

Brent_F

The gearing is extremely important in auto-x. The stock SE set-up (tranny and 4.10 rear end) I use is not bad where I run. I frequently wish the gearing (esp second gear) was longer as in a second gen tranny. I recently ran a friends car equiped with a second gen tranny in an SE and mild port job 160ish hp. This combination worked quite well in what was the fastest auto-x I've ever experienced (65+ mph).

My point is think realistically about your power and your course before choosing a final drive set-up. remember you can vary your tire diameter to change final drive also. Do some calculations and try to observe some similar set-ups and where they do and don't work. your gonna put alot of time and money into this from the sound of it. So do your homework and make sure its something worth having when your finished.

Feds

Cool, useful information... Thanks guys.

The 4-bolt 2nd gen is a good idea. Matching bolt patters are nice. I had thought about the Miata rear end, though complexity and bolt patterns took me off again.

I wonder if I should set up 2 trans (-se and 2nd gen) and maybe 2 rear ends (different gear sets) for day-of-comp-swapping....

Keep 'em coming, this is great stuff!

Lt. Dan

Screw it... no rules? V8 swap.

Dan

Feds

Yeah, I'd love to do a V-8 swap, but I will have to clear it with the other members of my team. A V-8/Auto combination would rule old skool!