Bazzard

Ok I cant find any decent info about this....
Ok I have a 88 rx7 with a 13b turbo2 it was a gxl origanly.
I over heated the motor and then lost compression, so i pulled the motor with the intention to rebuild it but i run out of money and stoped, but i have money now and i decided i would like to put it on a track in the scca but scca said i cant put a turbo charged car on a track so i decided to put a non turbo back in.
I found a good running 91 13b with racing beat headers and 5 speed trans for $600 so im going to buy it and put an intake and carb on i have an intake that im porting and pollishing and a carb and water meth injection and i might buy a small wet shot nos kit but thats a little later down the road my question is. im sure i need to change fuel pump and distributor is there any thing else?
what distributor should i use?

DaBrkddy

I would stick with fuel injection if I were you... But if you want to go with a carb and dizzy, that's your preference. If you want a good distributor, go with one from a first gen GSL-SE. It should drop right in. I have one I can sell you with the coils if you want it, but the distributor probably needs a new cap and rotor. PM me for pictures/info.

Do you know if SCCA allows Nitrous Oxide as a power adder? Chances are that if they don't allow a turbo, they won't allow Nitrous.

Evil Aviator

First of all, do not do anything to your car until you obtain a set of SCCA rules and have some time to talk to the racers in your class so that you have an understanding of the interpretation of the rules. You will need the General Competition Rules (GCR) here:
http://www.scca.com/contentpage.aspx?content=44

If they say you can't track a turbo, then that means you were probably looking at IT or EP class. Both classes are pretty restrictive about engines and intake systems. Keep in mind that a competitive car in these classes will cost about $20-50K, you will need a truck and trailer, and you are looking at about $5K per season in various expenses. If you are on a tight budget then you should probably just stick with autocrossing for a while, in which case a turbo motor is just fine.

Most SCCA classes do not allow nitrous, and in many events nitrous bottles are banned from even entering the premises.

Once you have competed in 2 events (including autocross), you are eligible to register for free at Mazdaspeed Motorsports Development. This will allow you to order parts at a discount, and the money goes toward the Mazda-sponsored racing teams. You can also sign up for the contingency plan if you like, although you probably will not win any major events for several years.
http://www.mazdamotorsports.com/

See our racing forum for SCCA car preparation. This 2Gen forum mostly just discusses street modifications.
https://www.rx7club.com/forum/forumdisplay.php?f=103

Bazzard

Your right about the nitrous. ii would like to get a decent amout of hp like 300hp-400 would be fine for that little car but keeping the cost under $1200
i thought a na with nice IDA 55 down draft weber carb port and pollished intake headers straight 3.5 exaust all the way a water meth injections to lower the air fuel temp and up the compression (water is non combustible(well it is by.5 a percent)and possible 50-75 shot of nitrous would be enoth? am i wrong?
i figured a turbo moter cost more then $1200 and a rebuild kit is almost $1200 with stock power
I will worry about the scca later.
thanks chris

Evil Aviator

No way in Hell are you going to get 300-400hp for $1200.

I think the best cheapie route is the following:
- Rebuild the current engine and street port it. Cost will be about $2,200 from a professional, or about $1,400 if you do it yourself. (Assumes no major parts replaced).
- Send your turbo to BNR for a Stage I rebuild and upgrade for $625.
- Install a Walbro 255LPH in-tank fuel pump for about $85.
- Install four 720cc fuel injectors for about $400.
- Install a Rtek Stage 1.8 upgraded ECU for $130
The above setup will be the cheapest route to 300hp, so you are looking at $2640-3440 for the engine unless you can source some used parts. If you need a good exhaust system, then that will add another $700-900 unless you can make it yourself. You will have additional costs for belts, hoses, coolant, oil, cleaners, filters, etc., which will add a couple hunderd dollars to that.

If that is too much money, then the NA drivetrain idea sounds like a good alternative. However, I recommend that you stick with a S4 engine because the S5 conversion is a major pain in the rear. In fact, converting your car back to NA trim will bump you back down to a lower class in SCCA autocross, so you will have a better chance of winning because you will not be competing against the rich guys in the higher classes.

Another option is to sell off your parts and buy a running TII when you have the money. One thing you may want to consider is spending your money on higher education, advanced technical training, or starting a new business so that you can make more money to support your auto racing costs.

Bazzard

I already have the turbo 2 brakes and diff and trans out of a 91
How much power do you think i would get out of the na with the upgrades i descibed
Thank you

Bazzard

i also have a microteck lt10 in the car i think the best bang for my money would be to use the na motor and run my turbo...
put my carb before the turbo out the other side of the turbo run pipe to a fabricated intake and run like 6psi of boost....

Evil Aviator

A stock 6-port NA engine makes about 180hp with a Holley 600 carb kit, fuel pump, and full performance exhaust.

It isn't such a great idea to run the LT10 and carb at the same time. The LT10 is far superior to a carb, especially for a turbocharged engine, so I would stick with that. The LT10 could run the NA engine either with or without an added turbo.

jtbshaw

iTrader: (33)

I doubt that you will be able to squeeze under the $1200 mark. With the carb'd/nitrous rotaries that I have built, I am usually over $1000 in the fuel system alone (meaning pump..usually Aeromotive A1000, -10 supply & -8 return lines, fuel cell, FPR, FPR guage, etc...). Then I usually go with the RB modded Holley 650 and a Nitrous Express Hitman plate system. The Hitman will give you 100-150-200 shot options.

The last 1st gen I had with this setup had a huge full bridge port and dyno'd at 409whp on the 100 shot. I never went over the 150 shot because the car was rediculous, I can't imagine what the 200 hit would have been.

Needless to say, I had well over $1200 in the system. Unless you score some crazy deals, $1200 or less isn't going to be an option.

Also, keep in mind, just because the carb is bigger, doesn't mean you will have more HP. If your porting is mild to moderate, a typical 48mm or even the RB 51mm IDA is more than sufficient. If you porting is stock a 45mm or 48mm DCOE could be a nice option. Otherwise, just stick with the RB Holley.

Bazzard

i wasnt going to se the lt10 with the carb... whats going to give me more power the na with turbo and carb or the fi carb stock?

Bazzard

The fuel lines i can just run 3/8 hard brake line thats worked for me befor and the fuel cell i will just use my stock gas tank. i have a holly 650 cfm at my shop so thats taken care of the car has gauges and i have the ability to make Nitrous kits (i have made them for v8 cars both fi and carb assuming its the same i can make it)
Basicly how do i get 300hp with out pulling the motor apart on either a fi or carb
i thought i could get more fuel with carb then i could with the bigger injectors.... and if i make a 3 inch pipe out of my turbo where you would normaly put a filter and make the small pipe with a mounting plate for a side draft carb... so carb before turbo then the fabricate a intake that gos from engine to the back side of turbo? and not run that much boost...(because its a na)
i would have no lag(the air only has to go 1.5 ft )
no intercooler the air fuel charge and water meth should be plenty cool
but i have no idea on the hp before i do all this work
of if some one else has a better idea

jtbshaw

iTrader: (33)

If it is a stock 6-port NA engine, nitrous is probably the only chance you have. Even then, she'll probably pop once you spray the juice because you will need a 100-150 shot to get even close to 300whp. I wouldn't suggest more than 5-7 psi of boost on a stock NA engine. Then is it really worth it?

You have the right idea that you can run the boost charge below the carb for a draw through carb (Corky Bell goes over this in his book Maximum Boost).

A stock NA, carb and a nice exhaust, e-fan, etc.. is typically flirting with 175-200hp. I don't see 5-7 psi boost getting you there, nor do I see your engine lasting long after spraying the amount of nitrous you need to get close to 300hp. Make sure your fuel system is sufficient and dumps the necessary additional fuel in there if you spray.

Either way, I don't see 300hp out of a NA without porting and a bunch of other items. 225-250 is more realistic.

Bazzard

So its going to be gut less basicly......
my only chance is rebuild my turbo2 motor street port it put nice big injectors and up the boost?

Evil Aviator

The only performance value of the carb is the intake manifold that it attaches to. The carb itself hurts power due to the venturi restriction and tuning limitations. If you want a good NA motor, then I recommend getting a Weber IDA intake manifold, but install a competition throttle body assembly and run the engine with your LT10. See here:
http://www.twminduction.com/ThrottleBody/carb_vs_fi.pdf
http://www.tweakit.net/shop/product_...fe1f0h5p398go4
http://www.twminduction.com/Throttle...leBody-FR.html

If you want to turbo the NA motor for cheap, then see Aaron Cake's write-up in the below link. The LT10 is capable of running the engine much better than the stock computer.
http://www.aaroncake.net/RX-7/naturbo.htm

A carb setup is horrible for turbocharged rotary engines.

An RX-7 with a stock NA engine will race evenly with a NA Porsche 944 of the same year, so I wouldn't exactly call that gutless. If you want to hit 300-400hp reliably, then yes, turbocharging is the way to go. See RETed's mod list and the BNR turbo options for performance ideas:
http://fc3spro.com/TECH/FM2W/power.htm
http://gonzaloherrero.com/bnr/index....d=67&Itemid=89

Bazzard

so what do you recomend i would prefer a turbo fi but i thought i could get more power cheaply with a na carb but i guess im wrong....
So i guess im rebuilding my turbo2 porting it buy bigger injectors and up the boost is my best bet and geting my lt10 tuned

Evil Aviator

Yes, since you have the LT10 you wouldn't need the Rtek chip that I listed earlier, nor would you have the hp limitation of the chip. You wouldn't need any nitrous, but meth/water injection would work well if you like that type of thing. The BNR turbo upgrades are not exactly optimal, but they do work great for those on a budget. You could have a 400rwhp daily driver for a moderate amount of time and money. The best NA street RX-7s have about half that horsepower.

Just don't forget to upgrade your fuel pump and clutch if you plan on targeting the higher hp numbers.

jtbshaw

iTrader: (33)

/\/\/\ This. You already have one of the most expensive components (LT10). Just finish it out.

However, I wouldn't say that a turbo rotary and a carb is such an aweful thing. I am actually building one now. 48 DCOE, BNR stage 3 S5 turbo, FMIC, big street port, DLIDFIS, etc... in a 2nd gen. Of course, I'm not shooting for 400hp though. My son just wanted something different so I'm building it for him. Sure, it's been a PITA, but it has been fun.

Bazzard

so everyone agrees bridge port my turbo 2 motor and rebuild it up the boost to 10-12psi bigger injectors better fuel pump and tune the lt10? and i should have anywere from 300-400hp

jtbshaw

iTrader: (33)

I'd say that is reasonable. With a bridge-port, your fuel mileage is going to be way down. I drove the above mentioned 1st gen everyday for over 2 years and I considered myself lucky if I got 150-200 miles out of a 15 gallon tank. BPs can be reliable, just just have to monitor them closely and keep your maintenance up. The LT10 is a great ECU to keep things under check.

I'm only expecting 300-325whp out of my current build for my son. But I am planning on running around 14-16 psi. You should be able to accomplish 300-400 with the bridge port and supporting items at 10-12psi.

Evil Aviator

Personally, I would go with a street port or extended port and more boost as opposed to a bridge port with less boost. A bridge ported engine will require high-rpm modifications, while a high-boost engine will require high-boost modifications. The high-boost modifications are cheaper, especially if you are just shooting for 300-400bhp. Also, bridge ported engines are louder, suck more gas, and have even less low end power.