RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   Race Car Tech (https://www.rx7club.com/race-car-tech-103/)
-   -   LS1 FC Dual Purpose Car? (https://www.rx7club.com/race-car-tech-103/ls1-fc-dual-purpose-car-719021/)

SuperSlow7 01-07-08 01:38 AM

LS1 FC Dual Purpose Car?
 
I had a 2006 WRX that was modified to run road course and that was a ton of fun, I enjoyed every minute of it. One day my WRX was taken from me in a head on accident that was not my fault and now I am picking up the pieces and moving on.

I really enjoy the road course, the people are great and it's such a great feeling driving like that legally. I am looking into FC's as they are cheap and often used as road course cars and drift cars too. I am looking into the LS1 swap from Hinson Supercars, which they say does not disturb the weight distribution that much and only adds roughly 100-200 lbs on the front end.

I know that if I build a high horsepower RWD car I will be incredibly tempted to drift it, legally of course. I would try my hand at a few drift events, as I know a few people that can help me out in this.

So my plan is to run a semi-built LS1 (fresh rebuild with some performance upgrades) a manual transmission, Kaaz LSD, good roll cage, Hoosier R6's for the road course and a set of street tires for drift, and some other stuff of course. Will a car set up like this work well on the road course first of all, that is my #1 priority, but can it be a dual purpose car with the switch of suspension settings and sway bar changes?

Thanks everyone, and please don't flame me too much for wanting an LS1 swap I have a few reasons for this and I really am not a hick or a redneck. I have never built a V8 or a Rotary for that matter. I just would also be street-driving this car a little (I know it's not going to be a proper street car, neither was my WRX but I still daily drove it) and would think the LS1 would be more reliable than a boosted Rotary motor.

Here's a few pics of my WRX for good measure. It was a sleeper.
http://i79.photobucket.com/albums/j1...rackday013.jpg
http://i79.photobucket.com/albums/j1...rackday018.jpg
http://i79.photobucket.com/albums/j1...rackday005.jpg

AmviciousRav 01-07-08 01:59 AM

flame alert or wrong fourm?

Black91n/a 01-07-08 11:13 AM

They're good cars for track work, but beware that they're old cars now and the one you get may have rust and it will require a fair bit of suspension work to deal with the loads of R's and an LS1. You should at least replace all the bushings (Energy Suspension maybe), install some DTSS eliminators (Racing Beat), coilovers and swaybars. Some bracing can't hurt either. These cars are limited to at most about a 245 in front with the exact right offset, coilovers and rolled fenders, some have run 275's in the back, but it'll be really tight. You'll need to get some alignment pieces for the rear, as it's only adjustable for toe in stock form. A camber adjustable subframe link is the minimum, but you can get some individual adjusters to even it out (AWR). Beware that the individual adjusters twist the rear control arm bushings and shouldn't be used with solid bushings, and should be used sparingly with stiff bushings. AWR sells some spherical bearings for the arms if you want to adjust a lot with them.

You'll want to get one with the 4 piston front calipers, and for the LS1 you'll want the diff from a turbo car as it's bigger and stronger, but it'll fit into an NA chassis too, so you don't necessarily need to buy a TII.

SuperSlow7 01-07-08 11:55 AM

Yes, I fully expect to be rebuilding this car from the ground up basically to replace all the 20-ish year old parts. Does anyone make a BBK for the FC?

Thanks for the serious reply.

slo 01-07-08 02:57 PM

Thats goint to make for a very tail happy car, that won't be anywhere near as easy to drive at the limit as a WRX.

It would aslo be quite easy to spend 12-15K on such a project, you should consider building an FD which in the end would be lighter, faster and has a far more advanced chassis.

Its very possible that the same project with an FD could be done for 3-5K more than with an FC, but in the end not only would it be a faster nicer car, if you had to sell it you could get back all or almost all of your money. Which would be unlikley to happen with an FC.

Black91n/a 01-07-08 03:13 PM

AutoRnD sells some BBK's, so does Corksport, but if it were me I'd piece one together myself from off the shelf Wilwood components and make an adapter.

An FD does have a better chassis and suspension than the FC, but the shell will be more expensive and there is less room in them for big seats if you're a big guy. The FC can handle quite well though and can match the FD for tire fittment with some cheap widebody fenders.

You can tune out the oversteer with a staggered tire fittment and/or suspension tuning, but it'll still want to kick the tail out on slow corners.

RockLobster 01-07-08 05:06 PM

I have your answer on brakes.

http://forum.teamfc3s.org/showthread...455#post585455

And yes the front brakes on FCs are great for street and autoX but lack when running higher HP (300+ crank) and r-comps for lapping days or racing.

SuperSlow7 01-08-08 12:39 AM

I know of a guy locally selling an FD shell for 7k but I don't have the money right now, I still need to get my check from the WRX, it was a pretty recent loss. I have contemplated going with an AWD platform but nothing other than the WRX/STi platform does it for me, and I don't want to build a GC.

I just think for the overall build it would be easier to build an FC, but 10x sexier to build an FD. We will just see what happens when I actually have the $$$.

Juan 01-08-08 03:54 AM

Just keep in mind that an FD will be more expensive everywhere. For example: Energy suspension bushings for the FC are less than $125 dollars for the master kit while a bushing kit for the FD will run you $500 plus whatever pillow ball bushings you need to replace (about $60 each). You're looking at $900 dollars in bushings alone.

Also like Black91n/a said, the FD's cabin is much smaller and only a hand full of seats fit properly inside. If you're a big/tall guy, youre going to have some problems fitting in the car. I'm 6' 4" and the only way I fit with a helmet is by slouching in my seat. My car has a sunroof so the headroom is less than an FD without one.

Your original idea of getting an FC is good. Many guys on the forum have FCs with LS1's who track the car and all of them are very happy with them. My brother has an n/a FC with a complete suspension setup and even with its low powered n/a engine, it's still competitive. You'll have fun with the FC. If your check is pretty big and can afford an FD, go for it. You cant go wrong with either of these platforms. :cool:

RockLobster 01-08-08 11:35 AM

The main drawback of the FC chassis vs the FD is the front suspension.

McPherson strut style supspensions are totaly inferior to double wishbone.

The FD suspension actually adds camber when traveling upwards. Thus on track days you can run between 2 and 3 deg neg camber and get everything out of the tires in corners.

With the FC i have found that anything under 3 deg neg camber just isnt enough to use tires properly. Because the camber is basically fixed in the front you have to run lots of neg camber static to achive good handling. I found my camber plates on my stance coilovers when cranked all the way inward still dont give me enough camber. I am going to try to run camber bolts in conjuction with the camber plates to achive 3.5-4 deg negative and hopefully my tire wear improves.

Bunchies 01-08-08 04:39 PM


Originally Posted by RockLobster (Post 7712959)
The main drawback of the FC chassis vs the FD is the front suspension.

McPherson strut style supspensions are totaly inferior to double wishbone.

The FD suspension actually adds camber when traveling upwards. Thus on track days you can run between 2 and 3 deg neg camber and get everything out of the tires in corners.

With the FC i have found that anything under 3 deg neg camber just isnt enough to use tires properly. Because the camber is basically fixed in the front you have to run lots of neg camber static to achive good handling. I found my camber plates on my stance coilovers when cranked all the way inward still dont give me enough camber. I am going to try to run camber bolts in conjuction with the camber plates to achive 3.5-4 deg negative and hopefully my tire wear improves.

Yeah, i've noticed very even tire wear with -3.3 deg in the front. That's the only way for me to maximize my front grip. And with -2.8 deg in the rear, the front grip is so much that it actually drags the rear end along for the ride. Oversteer in almost ALL situations!

SuperSlow7 01-09-08 02:09 AM

I slept on it and fc is the way to go. Is there any way to make the rear end plant a little better though? My wrx was very stable.

slo 01-09-08 03:03 AM

Stockish FC's set up for road racing are tail happy, you want one with 4x more torque and 3x more HP and a far less progressive torque band, its gonna be tail happy regardless.

Ideas to make it more controllable:

Choose a different engine (turbo 4 or 6, or modified T2 engine)

build the suspension and chassis first so you can get some experience with the much lower power more progressive powerband stock ish engine.

Use the 3rd member from a stock FD, its a torsen helical gear unit thats excellent for road racing, but won't stand up to drag racing with more than 350WHP (sometimes less than that), but since its a stock piece its available cheap (200$) and it bolts into the FC T2 rear end housing.


Originally Posted by SuperSlow7 (Post 7716559)
I slept on it and fc is the way to go. Is there any way to make the rear end plant a little better though? My wrx was very stable.


Black91n/a 01-09-08 11:23 AM

Wide rear tires, a good LSD and suspension tuning will help keep the rear end in check. You'll probably want to run no rear sway bar, a large front bar and springs in front that are a fair bit stiffer than the rear.

The S4 (86-88) TII LSD is a clutch type that'll work well, but it'd be a good idea to rebuild it, and you can get some Mazdaspeed parts for it to make it give more lock.

slo 01-09-08 11:57 AM

That would be just the thing for drag racing,

The Torsen would be far superior for road racing.



Originally Posted by Black91n/a (Post 7717606)
Wide rear tires, a good LSD and suspension tuning will help keep the rear end in check. You'll probably want to run no rear sway bar, a large front bar and springs in front that are a fair bit stiffer than the rear.

The S4 (86-88) TII LSD is a clutch type that'll work well, but it'd be a good idea to rebuild it, and you can get some Mazdaspeed parts for it to make it give more lock.


SuperSlow7 01-09-08 12:44 PM

If I build an FC it will be built from the ground up, upgrading whatever I can see gain from.

Roen 01-09-08 12:49 PM

it would probably pop with the LS1 powering the wheels as well.

An alternative is using the Kaaz LSD and setting it to 33% lockup.

Black91n/a 01-09-08 03:44 PM

My thoughts on the clutch type is that with the power and torque of the V8 in there it's probably a good idea to get a diff that's stronger with more lock than the Torsen, which is very good for road racing under many circumstances, but it's not the be-all and end-all of diffs.

SuperSlow7 01-09-08 04:37 PM

Pretty much I am thinking this is not going to be a super tight budget car, which is what I was looking for. On the WRX the clutch started to slip under large amounts of load (24psi uphill in 3rd) and it was going to be so damn expensive to replace because of how much the AWD transmission weighs I didn't want to do it at home.

So in my head here is my tentative plan...

LS1, probably around 350-400whp.
Coilover suspension with camber plates
Replace all suspension bushings
Weld in cage
Recaro SPG seats
Kaaz limted slip diff in a T2 housing
Big brake upgrade with proportioning valve for good f/r bias
All S5 T2 body work, possibly some aftermarket stuff for looks
Dual Apexi N1 exhaust or similar. Don't want this to look like the stereotypical LS1 swap.

Basically my mind is in jumbles but there are plans running through my head... going to get a re-spray to a clean white with black wheels and probably somewhere around 20% tint because all my cars have to be tinted, just personal taste.

And I will have the support and help from my loving girlfriend who will also be building a 240sx at nearly the same time.

BurlesonRX7 01-09-08 04:39 PM

Hinson sells a kit to convert a cobra rear end into the back of an FC. That will handle any amount of torque an LSx will put down.

I suggest buy thier book and memorize it form cover to cover. Also check craigs list for a car I know here in the Dallas/Ft Worth area there are 3 v8 conversion cars already up for sale ones a vert with the cobra rear end already in. and the Hinson v8 mounts already up front.

all three are being asked less than $1k.

SuperSlow7 01-09-08 04:41 PM

I might order up the Hinson book pretty soon..
I have been looking for my own project for a while, I have bought "someone else's" project before and regretted it thoroughly.

Black91n/a 01-09-08 07:33 PM

The cobra rear will also give more gear ratio choices and I believe that you can get a Torsen T2R for it, it's a type 2 torsen with a clutch type inside, best of both worlds.

I'd worry that with that much power and weight combined with R's that RockLobster's brake kit won't be sufficient. Some FD owners with around 400whp are finding wider 13" brakes to be just sufficient at the track when combined with 285 wide R's. I'd at very least want wider rotors for better cooling and you will want to get some brake ducts too. A widebody in order to fit big tires would be a good idea with that sort of thrust IMHO.

You should look up "owen is fat", he's got a widebody LS1 FC.

SuperSlow7 01-09-08 10:17 PM

I was looking into just wider fenders, since people were saying they can fit a 275 in the rear. In the GB section there is the front wide fenders, but those only make for a 245 safely up front. Can I pull the rear fenders a bit to run 285's in the rear?

My brain is still so jumbled at this point... so many possibilities!

And my girlfriend is picking up her S13 soon so it's like we're planning for two projects right now, it's a little crazy over here.

Black91n/a 01-10-08 12:27 AM

275's in the rear is tight. You should check out Tripoint Engineering, they make a nice widebody that should fit 275's in front. RaceonUSA makes some replicas, but they're apparently not as good quality and will take more work to get them to fit right. Some small overfenders like those from Corksport, or some small widebody rears will allow for a slightly wider rear with more room for larger tires, or just more clearance for 275's.

Other fronts are available from Corksport (~30mm), Mariah (~1.25") and a number of the Japanese companies (usually between 20-30mm, check out AutoRnD for some).

SuperSlow7 01-10-08 12:56 AM

Thanks so much Black91n/a you have been nothing but helpful!


All times are GMT -5. The time now is 07:05 AM.


© 2024 MH Sub I, LLC dba Internet Brands