Chadmk3

Hi,
I just thought i should introduce myself and maybe get some questions answered about my possible endeavor into the rotary world.

Ive been into cars for some time, i had a jeep at first, got rid of that and got a supra, blew the headgasket and got a jetta because i was putting too many miles on the supra and spending way too much money on gas. Also the supra didnt have any room for anything.

The jetta is slow and now i have too much room. Plus the parts are really expensive.



theres my jetta



Supra

I didnt really have alot of money to mod the supra, it was NA but it was still a fun car for sure.


Now i am in the market for something sporty once again. I want an AWD turbo DSM, but i cant find one im comfortable buying, so i figured id look for an RX7. I would like a turbo one but thats harder than finding an AWD DSM.

Ive read that FC's were plagued with bad electronics, i can learn to solder and fix that. WHat im really concerned about is how many miles on the rotary is too many, and what kind of performance can i get out of an NA ?

Can i port it and do some other upgrades to it and get it to rev pretty high or at least make it threat to some of the faster cars on the road ?

I have a pretty good mechanical knowledge, how much of the work can i do myself ?


Thanks for your help


Chad

J-Rat

iTrader: (2)

Dude, welcome to the club. ALL those questions have been answered many times over. Just search. This forum is a WEALTH of knowledge. Start at the FAQ, top of the page.

Jarrett

vaughnc

It's not really that bad. The only glitch is the wipers don't work on high which is a sauder joint bug.

Everything else is just cleaning your chassis & ECU grounding contacts.

In their stock form these cars are bulletproof. High mileage engines (165K - 300K) need refreshing with new apex seals, oil seals, cooland seals, etc... and you can usually see early warning signs when this needs to happen. The turbo versions need new seals 140-160K miles normally.

If your buying a car, have the local Mazda dealership peform a ROTARY SPECIFIC compression test. You'll get 6 numbers back representing the "hot engine compression." If their all over 90+PSI the engine's in great shape internally. Besides that you'll want to look for any colored smoke & the color during warmup & at high RPM. If these 2 cirteria are met, any rough idel, 3800rpm hesitation, or other goofieness is minor and you can get a great discount that way.

All of this is covered in the FAQ and by searching for "buyers guide"

Chadmk3

yea i spent about 2 hours yesterday reading through a whole lot of posts on here.

How responsive to mods is an NA FC and how hard are they to work on ?

Also, how expensive are parts normally ?

Can i change the seals myself ?

Thanks for your replies

Chad

vaughnc

Lots of aftermarket, salvage, and OEM authorized replicas, so parts don't cost too much. The 2nd gens are about 2/3 cost of 3rd gen parts and 1/5 the cost of Porsche prices.

For a streetable setup the NAs top out ~220HP which will definitly be a good kick in the pants due to the great gearing, light weight, and high RPMs.

Atkins sells a supercharger bolt on that can run on the NA cars with an OEM ECU and 87 octane (4 PSI pully) or 93 octante (8PSI pully) that should get you into the 250+ ft-lbs of torque & HP range on a NA engine.

Yeah Atkins sells videos to guide you through a new seal kit. Just like any engine you measure tolerances & replace certain pieces. You can build an engine for higher RPMS, medium/low boost, high boost, supercharging, or larger a larger street ported engine.

If you've got time & some mechanical talent, you can build a 450+HP beast for fairly cheap.... that's one of the MANY reasons why we love our cars.

If you've got a little $$$, you can seriously extend your car into the "exotic" class with bodykits, massive power, and showcar looks.

BTW - both the Turbo & NA cars are great to own. The NAs to me is the best car to own, specifically the convertible. Most people would rather NOT have boost but have a 4 rotor engine instead... best of both worlds.

The rotary engine is more effecient with boost and has a wider RPM range, so it's got tons of torque and can apply it well with just a little boost. While you gain massive power as with most boosted cars you loose throttle responce (on/off). To me throttle responce is one of the major factors that makes a great purist sports car.

The Turbo's feel great on the track, but I like the NA convertible in the mountains & city myself.

Chadmk3

Thanks for the info, 4 rotors eh ?

I thought we could only get 2 in the US.

Thanks again

Anyone else have input ??

vaughnc

3 in the US. The australians are working on the parts needed to build your own 4 rotor. Soon, very soon

tannji

vaugnnc, great info! I managed to google and look at the old Atkins website, as the current one doesnt have any info on videos or super chargers. I would like to see some pics of the SC in an FC, if anyone knows where to look. Also, they seemed to specify carbs for the SC setup, is there any way to SC an EFI setup? has it been done, or would it be so involved that you should just go the turbo route? I am getting my first RX7 in a couple of weeks (90 with bad rotor, very cheap, and in very good overall condition) and I am liking the SC option, but want EFI. If this is not practical, I will just go with the street port by Rotary Resurrection, and headers, as long as some combo of silencer and muffler can prevent the "weed-wacker" sound effects, until I have every thing I need for a serious turbo setup. Can you read between the lines and fill in some of my obvious lack of knowledge on NA modding?
thanks!

tannji

vaughnc

tannji,

At sevenstock this year they were showing their latest version that retains the stock throttle body. Their fuel injected version replaces the carborator with an injector that sits atop the supercharger. As the air/fuel going into the engine is the correct ratio you'll make much more power without the OEM ECU realizing this. Of course an aftermarket ECU will let you tune to squeeze a bit for HP & better fuel economy as well.

Pictures here of their new vs old setup. Notice the airpump is replaced by the supercharger in the 1st picture.



I'm planning this setup on my convertible, except I'll be fabricating a horizontal mount intercooler & intake manifold to improve the supercharger's effeciency.

Here's the intercooler I'd like to do, but I'll have to work with atkins to get the proper piping & intercooler sizing correct for maximum effeciency. You may have noticed how easy it would be to turn the OEM throttle body around in the 1st picture using atkins new intake manifold. That would work perfectly with the hmic below:

tannji

LOL... too funny! I just bought 2fast,2Furious for the kid, just got done watching it, come down to the office and you post this.... = ) You left out some info tho, whether it be fact or specualtion..... $$ and HP.....? I am sure you can at the very least speculate... and when is this going to be available? I may surrender to the bug eventually and go with a radical turbo setup... but this setup with the EFI, and your HMIC appeals to me much more at this point. My datsun may have to get sold after all.... will need the money for some hardware, and the space for 2 FC's.... = )

tannji

vaughnc

Their fuel injected version's been available for a while, but their prototype intake manifold seen above isn't available yet. But don't let that stop you as their current setup works fine.

Supercharging's main benifit over a traditional turbocharger is much improved throttle responce, more lower RPM torque, and less overall cost for installation.

Most DIY type of people prefer turbocharging as they can aquire a Turbo II engine or just buy a junk Turbo II car and restore it . If your a convertible owner like me and prefer feel & substance over looks, you don't want to swap in a TII engine. You want to improve the stock setup to retain that "roadster" feel. To me that's keeping my high compression NA engie & rotors, adding boost with almost 0 latency, and not affecting the powerband & power delivery vs RPMS. Just improving the overall power curve by adding more lowend torque and bumping up the overall power range.

Some model prices based on condition and if your a DIY person how you can save money & gain the car of your dreams:

1989 - 1991 Turbo II RX-7 - $3500-$8500 depending on mods & condition
1989 - 1991 Convertible RX-7 - $3500-$6500 depending on condition & color.
1986-1988 Turbo II RX-7 - $3500-$5000 (cheaper due to ealier series motor with less HP)
1988 Convertible - $3000-$4500 (ealier series motor)
1989-1990 GTU-S - $3500-$6500 (stripped racing model - very collectible) -

1986-1988 SE, GXL, GTU, Sport - $500-$3500
1989-1991 GXL, GTU - $2500-$5000

Atkins supercharger + cheap NA coupe - $3500 + $1000 = $4500
Atkins supercharger + 1989-1991 convertible - $3500+$3500 = $7000

Atkins supercharger + blown engine convertible + DIY rebuilt engine - $1000 + $500 core engine + $900 rebuild kit + $3500 atkins supercharger = $6000

Hope that gives you some overall cost estimates.

tannji

hmm... so my 90 GLX $200, rebuild by Rotary Resurrection $1500, Atkins SC $3500 = Good package for for under $5500. Any idea what HP the SC brings to the RX7? I believe I read that the 90 GLX has about 160hp, and a good street port is what, 30 hp or so? would the SC get you any where in the neighborhood of 250hp? More? Has anyone taken an FC to the track with the SC? You are describing the things I would like to keep and improve on with the NA engine, for sure. Also, what does a rotary sound like with the SC? LOL, I cant even imagine it.

tannji

Chadmk3

Thank you for the info !

tannji

OK, I did some more Google cache searching to find Atkins info from inactive links.... this one is good: http://216.239.41.104/search?q=cache...ng_en&ie=UTF-8
They say that the SC is good for 30 to 50 percent increase in HP on top of any porting or such perf work you have in place.... so with good exhaust and porting, you could end up somewhere just shy of 300 hp in a 13b??!!! wow. I would dearly love to be able to drive an FC with the SC in it before I deposit the necessary scratch... but I suppose it cant be all that different from the stock feel... just beefier.
tannji