My buddy beat me in his hundia pos I have a 89 na vert and plenty of cash what little things could I start with ? I need the car to still be able to hit 80 but as fast as possible

 

 

get some 13 inch rims and low profile tires! is your vert an an auto? if so, swap it or sell it.

Exhaust/ fender mounted intake, and search these forums!!!

 

First converts are heavy about 600 LB more than a coupe,remove your spare tire and any other things you do not need(when racing)second rotary engines like headers, free flow exaust(noisy)also try replacing the stock air filter as well then you can try larger secondary Injectors,try a set of turbo11- 550,or 1985 SE 680s to start,as well remove your fuel sock in the gas tank,and replace it,and the pump too with a turbo pump or after market 255 liters per hour. other than that,besides a different(larger) intake,you will have to go inside the engine for some plate and rotor housing porting as well as oil pressure mods too

 

All of that sounds doable I want to know tho what do you mean by intake I've looked at filters and "cold air " seems like stock is pretty good on these fronts next I'm looking at throttle bodies any suggestions and how much gain can I expect from these Mods I do want to know the money is well spent and as soon as i start work I will upload pics and show my nice work

 

Basically everything 959595rotor said.

-Weight Reduction (especially rotational mass)
-Exhaust
-Improve airflow

 

Ok so I ordered a few things like lighter seats i will be taking the spares out and yes for some reason there were two in there looking at headers now any suggestion on good ones I don't want to halfa$$ it on a part like that I have the k&n drop in filter now and want to know if one of those single flap intake manifolds would help too has anybody tried one ? Tires and rims are next 13 inch right ? And light rubber would be good as well I imagine well keep the tips coming

 

You will not be able to install 13 inch tires on your car if you can afford it try a light set of Volk rims (very light) then reduce the overall height of the tire so as to get a slight gain in final drive ratio,smaller tires have to travel farther try some 40 or 45 series tires , for headers the best to buy a set of Racing beat headers they use a HD pipe and it will last for ever, I have installed lots but now (I have my own jig and I fabricate my own headers)for an intake check out the one I built for my friends race car see it on my profile page under engine builders,Iam not sure what it would cost but you could send in the stock one and have it Extrude Honed to increase the intake size and flow ...more later

 

Nos

 

Not ready for nos so you basically that a smaller tire would mean less travel per rotation wich makes it go faster around to gain a better final ratio do a little bit of rubber really affect it so much ? And if I bought one at e bay could you do a custom heading ? Or would cutting the old one before the catalytic converter and my old rx I think I went 2 1/2 on my exhaust with stock exhaust manifold is something like that sufficient ? And also I bought a electric fan and super light seats custom stitched steering wheel new stereo with dvd antenna k and n air filter and am really looking at 80 mm billit throttle bodies you know a single flap I just would like to know how big a diff it would it make I can't find any info but it says up to 30 % more air what exact rim and tires would be best there's so many choices !

 

I would recommend a light weight 17LB flywheel for better acceleration,do not use an alum flywheel they are too light for the street and will make your car bog off the line,because they lack the ability to hold large amounts of kinetic energy.the thing with big air intakes are,that they require the same amount of upgrading to the fuel supply,and injectors,as far as exhaust 2 1/2 is fine but...... loud...make sure you muffle it down so you can cruise around without the drone of the exhaust resonating inside the car at about 3000rpm............................. for rims and tires any rim over 16inches tall weighs more than the tires. for best accellrationI would stick with 15sand get as low a profile as possible, the only thing is that the low tires will reduce the cars top end ,but don't worry there are very few places you can drive 135 MPH anyway..

 

Just got back to Utah blew my radiator ordered a new solid aluminum one and electric fan put the k and n air in and lightweight seats front and maybe rear strut bars dumped a few pounds out from trunk lol carpet extra spare and other junk new slightly smaller steering wheel dvd deck fixed auto shifting linkage tightened belts to speck tuned throttle body doesn't surge anymore ! Looking at tires seems stock rims are r15 how low profile can I go ? 205/55 be low enuf for racing ? Still thinking of a 2 1/2 inch straight pipe that goes right to dumps no cat no muffler and heard that one of those ignition control units can give me big gains has anyone tried them I think they are msd brand oh and also will a billit 80mm throttle body that supposed gives 30 more flow then stock realistically help at all ? 350$ is a little steep for not any info on gains

 

I don't know if this is serious or not, LOL, but if it is, slow down a bit and think a little. The main issue with an NA RX7 is that it has no torque. Torque is what helps you accelerate, HP helps you go fast.

Unless you are going to crack open the keg, you need to do stuff that allows you to maximize what torque your car has. Everybody here is suggesting that you find ways to lighten your car, 'verts are heavy. Also reduce rotational mass, the things that rotate and transmit power and get the air in and exhaust out as fast as possible. A billet throttle body will do next to nothing unless your car's intake ports has been ported and you have an aftermarket ECU that allows you to rev higher than the stock computor allows you to go.

My suggestions are about the same as above and I have been racing RX7's for over 15 years. Go get some light (about 13 lb) 15x7 wheels. Put on a set of 225x45x15 r compound tires. Strip the interior of the car down to bare essentials, open up the exhaust by buying a proven complete system, like the Racing Beat header, mid-pipe and final muffler exhaust. There are other very good systems as well, but this system is streetable, sounds decent and won't drive you buggy on the highway.

On the intake side, take off the stock airbox and put on a cone filter. Build a cold air duct from outside the lower front of the car to the cone filter and enclose the area around the cone filter so that no hot air can get in. If you get more ambitious and can get someone to install it for you, get a 4:88 rear gear set. This will really allow your engine to be in the right rev range for massive acceleration when you need it. It will drop your top speed some, but you will get there very fast and your car will feel like somebody stuck a V8 in there.

All the rest of the stuff can potentially add value to your car and make it faster, but they are in the small gains area. I think you are looking for big chunks of gain as a starting point. Tons of performance can be gained from a stand alone setup, but at the cost of time to set it up, money to maximize the tune on a dyno and effort having to wire the whole thing in and do it right. Its not super easy to make a rotary RX7 go massively quicker, but sitting and thinking about what you really want and searching the forums will help out a ton.

Eric

 

That was the info I have been looking for rims and tires are do able air box sounds like it will gotta wait and thanks for the info on that throttle body saved me 300 bucks ! I think I will just dump the exhaust don't have emissions in the state its from ! And those gears where can I find some !

 

Ive pretty much done all of the above to my 91 vert except i have a AFC Neo/innovate wideband for tuning. My car is still full weight (speaker seats, ice cold a/c etc..), I have 4 new 225/50/15's waiting to go on with my coilovers.

Biggest issue i found with the stock fueling i saw was it was nearly 9.8:1 to 11.2:1 air fuel ratio. I tuned to low 13:1, high 12:1, and it made a drastic change in low and top end power. I can't wait to match it with my lower profile tires.

 

For your rear gears try Racing Beat ,or Mazda Trix,also a short tire(low profile) is like adding a lower gear in the diff ,your car should have a 4:10 rear gear,now, 4:88 might be a little deep for the street,you might try a 4:56 as they are a compromise,between the two.....,23racer ...is right about the gears making a BIG difference We run a 5:17 diff in our road Race car, and yet we can still hit 125 mph on our home track ..........good luck..............................

 

i went from 205/60/15's to 205/50/15's and it really woke the car up

 

Well i autocross so the extra width will be nice.

 

that too!

 

Lighten the load - leave your spare tire and jack at home; get a smaller/lighter battery; don't fill up your washer fluid tanks all the way.
Intake - cheap&easy = KN drop-in panel fliter OR elaborite = KN cone filter with air box surround
Gearing - undersized wheels will feel quicker and be lighter, but will throw off your speedometer and odometer.
FYI: stock rims for convertibles are already quite light, just get 205/50 performance tires. (Wider tires will increase rolling resistance...not what you want!)
Exhaust - Dump the stock cats and get a Racing Beat header+hi-flo cat+dual cat back (or a single muffler setup would be less weight)
Standalone - this can get complicated and expensive, but a good tune will maximize what you have to work with.

Remember: You're not going to make more power without rebuilding the motor.

 

sounds like you need money

Increase money, increases speed.

 

No, he doesn't need money...he says he has cash.

He is asking for advise how to spend it wisely. Not on a $300 thottle body, but on a free flowing exhaust system (but not too loud...it's a convertible after all), and lighter wheels and maybe a lighter flywheel. Consider a standalone ECU. And lastly, a radical rebuild.

 

Still needs more.

 

i just picked up an S5 vert and since its so heavy my back hurts now.....

really though after driving it around for a few days i think if i had money i'd do the following, and of course since its a nice quiet comfortable cruiser, this is aimed at keeping a comfortable street car

1. rear gears! it needs 4.8's. the top of second gear is about 60mph, it takes sooOOOOOO long to get there i had a chance to eat lunch and then go over my calendar, and then answer some emails.

2. exhaust with a cat. i kind of did this already, the engine is happier. you need the cat with the top down to avoid smelling....

3. tires! it needs either 205/50/15's on the stock wheels, or some LIGHT 15x7 with a 225/45/15 tire. mine has like 215/95/15's on it, not helping, the best thing i did with my last car was 205/50/15's, instead of 205/60/15....

 

wow just sell the car man if its not already blown lol. forget all of those mods. yank that motor out and go 13bt