A'ight, I am admittedly somewhat crazy, and only 14 to boot. I'm looking into building an RX-7 for my first car, but I may (make that WILL) need a few things answered.



Anyways, I've got a little bit of a grasp on how exactly the Rotary works, but not much. And therefore, my idea for a project is, ehh, on shaky ground, shall we say. I want to do an RX-7 as either a road race car or a street car, (big diff between the two, I know) but I currently have almost no clue what I'm getting into. I doubt that I'll even be able to find a good basis for my price range, but whatever.



The plan (IF, big IF, I can convince my old man to let me do it, he hates anything japanese with a vengance as a project car) is to find a decent car, probably an FC, for 1-2k. It needn't be a turbo car, and it doesn't really need to run perfect or be perfect on the outside. If there's absolutely no way that will happen, tell me. Anywho, I want to take it, strip it down, sandblast it, and piece it back together as either a D Production SCCA car or as a decent street car. I'd like to be able to keep it NA, and shoot for 225-250hp if I go road race, and for the street I'd want maybe about the same if it can be reliable. But here come the questions: How expensive would a port job be to hit the 200-250hp range? Also, would it still be streetable at this power level? And, if I go road race, how bad are suspension bits and pieces? If possible, could someone tell me some normal problems with these cars (FC's) and problems that could arise in the road race build?



That's about it for now, but I already know that there will be more.

Well, I stand corrected. Apparently, I am almost completely open on power mods in Prepared, but I am limited to being forced into a 32mm restrictor plate. So my only resort for power would be a compression bump as well as some port work to make it run right. Possibly running the aux port a little into the compression stroke to bleed a little pressure whilst running higher overall compression (static). Like I said, I'm a little crazy. But hey, from what I've seen out of a few reciprocal engines, it works. (Nobody except my dad and a few guys on the east coast do anything like it, but it sure as hell works) Whether it will transfer over to the rotary remains to be seen. All depends on how much $$ a new motor would cost. (As to if we'd try)



Now I'm wondering where the heck I saw 250hp at! https://www.nopistons.com/forums/pub...IR#>/wacko.gif Seriously, it's like I am living up to my claims of insanity! (Noooo! Not the funny farm!)

Start simple. Get an n/a, easily found for a grand. Do a tune up, throw on some exhaust (find a used header, get the rest fab'd by a shop). You can have springs, adjustable dampers, and polyurethane bushings for about $700 new. Get the 5-lug setup if the car doesn't already have it, for the better brakes. Strip the body down, eliminate any excess weight, and you've got a decent-handling, cheap, starter race car.



Then, once your level of skill surpasses the abilities of that car (which will take quite a while), you should have enough saved up for engine rebuild, port, and coilovers.



But that's just my opinion.

sounds like a solid plan to me.

ive been on this forum since i was 14 or 13 or whatever. jsut be a sponge, read everything, learn it, know it.

when you actually get a car itll come in handy.



my advice is just follow baldys, keep it simple. its your first car, youre not gonna build a road racer for your first car. just get one and keep it simple.

...which is what I've done with mine, except I kept the interior and sunroof, and daily drove it. Though not the fastest thing ever, it would still haul ass compared to most cars you'd encountered on the street. I autocrossed it, and I never came close to outgrowing my car. Engine died recently, though. Stripping it down.

btw, 250hp isn't out of the realm of possibility at all, you're just going to need to have a ported motor with full exhaust and a standalone ems. of course, you'll need the stuff to support the new goodies (prolly 550cc injectors to replace the 450's to be on the safe side, and that's just one thing), as this is an oversimplification, but those're the areas you concentrate on, i think.



and weight can be the cheapest mod as well https://www.nopistons.com/forums/pub...#>/biggrin.gif it's not always about raw power if you can strip a couple hundred pounds off the car (if you're racing it)

Thanks a lot guys!



I probably will keep it on the street. Just nabbing a decent set of rims, tires, suspension and brakes would help me out, I'm nearly positive.



Also, out of curiosity, (I KNOW it killed the cat, just lemme say it!) Is a turbo car with a bit of extra boost (thinking 15 or so PSI) as finicky as I've heard in a few mags?



And weight being the cheapest mod: Yes, it sure is! Helps everything to boot. 160-175hp car that doesn't weigh much more than 2700lbs... Ought to be quick enough, eh? Beats the ish outta my Vega.

i think that's a simple answer....if you have built up everything around the motor (and inside) to hold that kinda boost, there's no reason you couldn't do it ;D

mmm... 400 horses...

hey baldy i figured out my UIM and LIM issue....i forgot to set the TPS ....anyhow .....buy the bolt ons follow that up with a suspension set up ...i drift my car at actual events ..(.yes its hard to slide but so fun and respected )....and i will say the suspensions down fall is the oversteer ...other than that is holds up well so ...invest in some sway bars and bushings....as well as strut towers weight reduce to around 2400lbs...and then worry about springs ....i can get you a street ported motor for 1700$ *250hp core of 400$ so its 1300$ for a street ported motor.. * **w/ full exhaust ...intake...test pipe ...ported manifolds ...SAFC...and good ingnition..so around 200whp...

Ahh, I think I'll pass or do the porting on my own. Thinking "street" more and more.

just keep it na in the beginning.

turbo rotary is VERY picky.

na rotary runs forever.



not to mention, a turbo rotary would be wayyyy out of your league for a first car.

not hating on you or anything, but ive been there. i totalled my first fc which was my first car being an idiot.

you dont need a racecar to kill yourself in, na rotary is plent of power to get in plenty of trouble with.



and with a workin 6port setup and some decent suspension, you can drift the **** out of it.

thats how i roll.

I'm gonna run NA, but 400 horse sounds too dang good.



"I'll keep it stock, I promise!"- 10 minutes later you've got your car running a bigger turbo, a Ford 9", and slicks. (Happened with my dad's GN that he bought new in 86.)

Lee is exactly right in saying turbo's are picky. I have owned my 7 for nearly a year and a half now and have driven it like once. I bought it NA and immediately swapped to turbo. I have had it idle for about 15 seconds to date. Its just something with the wires and computers that I have had the most problems with. But the NA's are great for first time owners. I have just been around the power house scene for a while now with V8 circle track cars and am used to the difference.



Also, I owned a few nissan 240's (they are not all that hyped up to be, just as many problems if not more) I actually literally just bought suspension for mine and am still waiting on my springs to come in. But if when you decide what you want and get a car without the 5 lug hubs, hit me up. I have some sitting on my '91 parts car. Anyone else interested will have to wait for brakes as I am currently waiting on those too. But anyway, welcome to the board https://www.nopistons.com/forums/pub...#>/biggrin.gif and dont hesitate to ask!

if youre gonna go turbo, buy a tii from the beginning.



then you dont have to **** around with boosting it, and can work on matinience and upgrade.



i boosted a na motor in my car, dont get me wrong, it was a BLAST. but there were a lot of headaches figuring things out, when you could just buy a tii and enjoy boosted power without ******* with it.

lots of problems just stem from mistakes putting it all together, ask me how i know..

Like I said, I don't plan on turboing it.



And even if I did, I'd want to keep an NA hood on it. Front mount to the rescue! (I don't really love the offset scoop)



Aaand, my dad has practically shot this down. Could someone give him a few reasons? I'm running out thanks to the "Well, hell, if you want a daily driver, why not X car or Y car instead? What's the point? Race car? Hell, there's a million cars that would outperform it!" that I get from his end of the phone line.



And because there aren't many in michigan, it's japanese, and other than knowing the basic concepts of how it works, he/we know nothing.





AAAnd: How do you know, Lee?



BTW, willing to sell your Seven? I fugger Cincinnati ain't TOO far... Or, are there any in your area for sale (NA cars, thanks)?



Bet if I found one cheap enough, and learned enough about them to be a walking encyclopedia, he'd start listening.

Is your dad paying for it, or just offering advice? If he's paying for it, do whatever he wants.

Well, if I had the almighty dollar, I'd already have bought one. :P



But really, I've gotta convince him that I'm serious, and I've gotta somehow convince him why an RX is a good idea. Then I'll start listening to what he wants to do with it. https://www.nopistons.com/forums/pub...#>/BURNOUT.gif (But I'll have to be careful he doesn't drop a SBC in during the week... A Ford I'd be fine with... Nah, he wouldn't do that.)

ive got a shell sitting here. no motor, rust in the gas tank..



i put together a boosted setup basically with all stock parts and a front mount, wideband, 720s, safc, everything. took me a few months to track down the little mistakes i made putting it all together before it ran right. and i eventually blew it up, and am blaming the spotty battery relocation/shitty stock charging system... i then decided to just put a stock na motor in the car and enjoy it. i dont have the time or money to do the turbo set up right, so why half ass it jsut to blow it up again.



im turning 19 soon, ive been on here reading EVERYTHING since i was like 13. haha. i got my first fc at 17, and have had two more. i was in the same boat as you except i had the money i just had to put it in his name. after enough convincing he finally cracked and let me get it, and since then has been very impressed by what ive done with them. he is actually now a fan of the rotary idea, the 3 moving parts and the overall simplicity. i guess i talked his head off enough huh. haha.



although if hes a hardcore domestic guy, it might take a bit more pursuading.

for me, it's not just an "rx vs whatever else is out there" argument, it'd be an "why choose any motor with more than 3 moving parts" but, then again, i'm also a science/physics/electronics guy, and to me it just makes more sense to have less moving parts https://www.nopistons.com/forums/pub...#>/biggrin.gif and hellooooooo, a core that weighs ~200lbs and yet still pushes 140-160hp with 1.3l displacement??? and oh yea, what's that? your pistons take 2 full up/down motions to make a full cycle? lol, c'mon, ine one revolution, my motor has gone through combustion 3 times!!!

Yeah, and once you rotate you can never go back!

If you really want the power start with a TII. It will be a hell of a lot cheaper in the long run and less of a headache. From personal experience I would strongly urge you to get an N/A. Turbo rotaries can be much more complex and are less reliable. I own a turbo rotary and wouldn't trade for the wold but it can get real expensive to fix even now it is hard for me to afford the thing.



If you want to use it as a weekend autocrosser (I say this as a racer since the happy age of 15) Get a car with less power. The car I learned the most from a car that was no more than 100rwhp. An old MR2. You will figure out how to make up for the lack of power and thus become a better driver/racer.





My .02

Lee: How much for the shell? What's the worst a stock NA motor could cost me? 500 bucks?



Someone buy my Vega.

If your father has a problem with RX-7's/Rotary Powered Cars in general, pull up a video of Jesus Padilia in his 20b powered RX-7. That should answer any problems he has. https://www.nopistons.com/forums/pub...IR#>/smile.gif Or any RX-7 with 400hp running 10's in street trim. https://www.nopistons.com/forums/pub...IR#>/smile.gif



Honestly, your best bet is to get an S4 or S5 N/A, STOCK, and drive it for a while. Diagnose problems, figure out what makes it tick and go haywire, read EVERYTHING you can read on forums, and have fun. DO NOT buy a TII for your first car, as most are beaten to ****, or the other ones are pushing alot of power, and cost 5K+.



Or you could possibly go with an FB, but i nicely running non rusting FB/SA usually goes for more than an S4-5 N/A.

It's GONNA be a NA S4/S5.



I don't want a TII. I want to do a turbo NA motor if I DO go turbo. Just a re-port on it to bleed compression SLIGHTLY, and run an RPM switch on the aux ports.



I want to buy a exhaust flange and start piping it. Any idea how running both pipes separated all the way back would sound? (Might not make the best power, but the sound would be unique, even amongst rotaries!)



Huh. What think of that? I won't do it (the exhaust wackiness) until I'm used to the car's quirks, but it'd be another reason to turn heads.

you have the change out rotors to run lower compression.

wtf double post

Not if I port a little into the compression...



It's like tossing a cam meant for a 14:1 motor (in a reciprocal) into a 8:1 motor. Drops effective compression. And vice versa. The 14:1 motor NEEDS that cam. A mild job meant for an 8:1 will shoot the effective compression ratio up closer to the static 14:1. Detonation (and all the bad things known about high compression motors) ensues.



Methinks it would apply to rotaries as well.

never heard of it before, would think if it was that easy itd be a commonly known trick..

Ehh, we Mallenders are like that. We build turbo motors with more compression and less boost. More compression will spool the turbo quicker, makes better overall use of the air/fuel, etc.



The opposite is the usual. Low (like 8:1 low) compression with big boost.



10 or 12:1 rotors anyone? Of course, it'd need a little work on pressure bleeding, but it'd run good! (Pressure bleeding with higher compression uses less air/fuel to get the same or better reaction. Only real thing limiting us on reciprocals is the camshafts have a basic grind already on them, so we can't get it ground to where we need it for truly creepy compression ratios.)



However, I don't see rotaries having that sort of problem. How far up could we safely port into the compression? I'm getting crazier by the second. I now have reason. I will have a rotary. If for no other purpose than to occupy a back porch. (That's where the Vega is sitting)



Goddamn, man! Now I'm all bent out of shape.

Except for the fact that rotaries only have the 3 moving parts. No camshafts unless you are referring to the Eccentric Shaft as a sort of Cam, then I guess? There are several different port sizes you can grind to. A couple companies sell a template you can buy. I believe Atkinsrotary.com sells one but some people say they are weird about doing business. I have had no problems out of them, in fact I have actually received free corner seals and plugs from them before.



Have you considered flat out not using turbo and staying NA, but porting to Bridge Port or even P-Port and swapping to Carbs? I would imagine with all the talk of a Vega that you are familiar with the way a Carb. works and can set one up effortlessly. You may even consider saving money and finding a 20b to make the power you would get from a turbo. It might even be worth the time to mention something like this to your dad, IF he is as domestic as they come, "no jap sheeit in mah guhrahj" I have heard that for so long from friends it isnt even funny. No offense to you or your dad of course https://www.nopistons.com/forums/pub...DIR#>/wink.gif I am actually looking for a '70 roadrunner as a future prospect.



But ah well, just a thought.



-B.

i really dont think you can lower compression through porting.



sure you can port into the compression stroke, and that creates overlap, like a bridge or pport does.

but i dont think it lowers overall compression at all.



i boosted a stock na S4 block, and it worked great though. just gotta be careful and conservative with the tuning.

It's all in the working (aka. reaction/dynamic) compression. The static could be 15:1 for all I care, but as long as the effective compression is lowered enough, it'll run.



Oh, and I've got a few new questions for y'all. (I said there'd be more!)



How much power can the stock trans handle? The rearend? Because my dad has decided to go ballistic around corners with whatever the next project is (He wants to do a turbo quad-four Corvair). Apparently, he doesn't want to spend another 15 years figuring out another engine type, hence the reluctance. Damn DOHC motors... Eliminates the cam problem. Anyways, onward: How much compression do we get from filling in the dishes? (As in leveling them with the surface, or at least near it)



Curious. And how far up CAN we port into the compression stroke? I just got to know.

go read all of the engine building forum, you'll learn a lot.



rotaries are different animals. you dont just go filling in this and cutting up that. and applying piston motor techniques thinking that it should work..



just forget what you think will work, and read up on what will.

Paul Yaw articles. Read, learn.

You are thinking too much piston, and not enough rotary. Rotary is a baby engine compared to ANY piston engine, so your R&D is not as wide as pistons are.





Read anything by Paul Yaw, or the Engine Building section of this forum, there is alot of information.

A'ight, I need some of that research schtuff anyways to help throw my old man over the edge.



Thanks.