helmetface

Alrighty so apparently I've been living under a rock for my adult life because I never fully appreciated the power and capacity of the rx7's

So I've decided to build one! I'm still a ways away from being financially ready, but I've already done a lot of research. .which only revealed to me that I had a lot more reading to go.

Essentially, I'm sure of a few things but I've got loads of questions, I'd figure I'd start a thread to get a few basics out of the way:

Goals: track bitch/weekend warrior. I am unsure of exact hp goals, I would be completely satisfied with mid 400's And I intend to Auto X, time attack** and drift on occasion. So my setup will not be tailored to any specific event, I'm no competitor, just looking to have fun.

Initially I was all about the cheap power of an LS1, but I am now a rotary enthusiast(I know, I don't even own one yet! ) I will be seeking an FC (leaning to an s4 but would take an s5 as well) and I am hoping I can find one with a 13b in decent shape. I'd love a 20b..but the money just won't be there with all the other **** I intend on buying for the car. As a side note I will likely be running a water kit, what are popular mixes for 7's? I know that on speeds most people run 100% methanol.

I'm looking for single turbo suggestions, with the above hp goals in mind and my biggest concern is having as little lag as possible. I'm currently DD'ing a Mazda speed 3 (Mazda for life) that is making nearly 400 to the wrong wheels with a gtx3071- with this I'm able to reach 20 psi by 3800rpm when slamming on the gas at 3k...it's awesome!

I am also looking for suggestions for tuning solutions. I am no stranger to tuning and I am looking for very capable software, nothing that is too geared towards the track as I want to enjoy this car. (I read that some don't allow you to do CL tuning and that bugs me, I'd like to avoid things as such)

This was all much more long winded than I anticipated, but I figured my first post should be a good one

For those with a short attention span I'm mainly looking for suggestions for the following:

-Turbo size
-Street or bridge porting(unsure)
-Injectors (I'm least familiar here and I obviously don't want to run out of fueling)
-Anything that will help prolong the engine (besides the obvious not revving the **** out of it)
-Anything that will help spool and increasing that low end torque that the 13b lacks.

And whatever else people can suggest! I'm all ears.(especially links for future reading!)

Thanks

Skifledanabit

A couple of things. Bridgeporting reduces the active life of your engine, wears it out faster, you gain more hp but instead of a 60k mile rebuild (approx) you end up with a shorter lifespan between rebuilds, plis its only really worth it if you get all the supporting mods as well, i.e. ECU, intake, exhaust, injectors etc. Also not forgetting a rougher idle and increased fuel consumption. Street porting gives less hp than bridge, but your engine will last longer use less fuel and technically, you get the bang with pretty much standard, if not basic supporting mods.

Rotary engines love to be revved "the ****" out of, in fact, they kind of need it to get rid of any carbon build up, only when fully heated up though.

My opinion would be to find a rotary specialist near you, let them take a look and discuss your needs with them. They will be able to point you in the right direction with regards to your budget. I would also start slow, dont just buy a car and then slap massive power in it, thats a receipe for a crash and a write off. Get used to stock power, then add bit by bit the mods, you never know, you may prefer the more stock vehicle with some basic modifications.

diabolical1

iTrader: (3)

while i'll be blunt here, i'll try not to come off as mean. however, 90% of this is rubbish ... or at least, it should be prefaced with some qualifier or something.

1. if a bridge is built right, and cared for appropriately, it will last. if a bridge is turbocharged and TUNED right, and cared for appropriately, it will last.

2. to a certain extent, if your goal is to build a 400+ HP rotary, i think you've already made the decision to forfeit gas mileage regardless of porting. however, you are correct that a bridge will consume more, relative to streetports and stock ports.

3. careful tuning is required for horsepower and reliability regardless of porting. there will probably be nothing "basic" about 400+ HP streetport.

4. on the same turbo, the bridgeport, indeed, should yield a relatively better powerband and quicker spool. however, it will obviously also be somewhat more obnoxious.

5. as for revving, it's neither here nor there. once turbocharged, the NEED to rev higher to make power has been quashed.

this is sound advice.

Skifledanabit

1. On average, to a layman, who is not someone who meticulously services their car and follows all correct start and stop procedures, a bridgeport is more likely to have issues than a street or stock. I wasn't stating that was the case for all.

2 + 3, I wasn't taking into account 400+hp, I was thinking of initial work that will eventually lead to possibly 400+hp. I was stating that bridgeporting will require more supporting mods compared to street or stock in order to ensure a free and even flow of air/fuel. (bigger injectors, which aren't exactly required for street or stock ports, otherwise all you are doing is wasting fuel).

4. right, ok.

5. regardless of whether you have a turbo or not, there will still be carbon build up which will still need to be removed by a high rev or two, revving for the sake of power was never entered into it.


From a PM

I'm really only experienced with EGi's with UK setups, but I am versed with the TIIs. I'm sure if you search the forum, you will find all the info you require. Seeing as different people get different supporting mods which give different results, its hard to say how much power you can expect from each port.

Do not forget to take a read through this... https://www.rx7club.com/2nd-generati...faq-fc-494667/

as it gives a lot of information and link to helpful topics.

As I said, many people have tried many different things that have or have not worked, something that may have worked for one person may not work for another. So in order to please people who immediately call bull, just keep an open mind and decide which route you want to take. It is not a quick job and you should do all the research you can.

diabolical1

iTrader: (3)

at the risk of oversimplifying, my point was this: at the end of the day a bridgeport is still just a side intake rotary engine. there is no real magic to the engine itself. the magic lies in what you do with it. if you have a bridge that is built correctly, and then you go on to have it tuned correctly, you have very little to worry about when it comes to reliability. it is no more "difficult" to maintain, just slightly different. if you sidestep or ignore any of that, then the failure is not on the engine's part. it's on you. that was the main issue i had with the general statements you made. saying that the average person does this or doesn't do that merely feeds into what i'm saying. the focus is no longer on the engine itself. and i've had people imply (and even directly state) that since i've never built or owned one, then i have no business speaking about them, but enough people that have built and owned them have proved my stance to be true. i feel vindicated. so i'm still here - saying the same thing.

when i had my MR2 Turbo, i never had 272° cams, but i didn't need to own them to know that without making other changes in the head (springs, buckets, etc.) that it would be pointless for me to curse them as being unreliable if i installed them and proceeded to drive/race the car with no other changes. i hope i'm making more sense to you.

my only other point was the 400+ HP issues. i wasn't the one that brought that number into the thread, it was the OP. so in responding to him, you should have taken it into account.

finally, i'm not touching the whole "a redline a day ..."-philosophy any more than i already have. it's something that i hadn't heard until i joined this board and i bought into it for a little while. however, i've pulled apart enough engines now to conclude that that philosophy is baseless at best. i'm not knocking those who believe (and practice) it, but i have resigned myself to driving my cars as i see fit in the situation and just leave it at that.

diabolical1

iTrader: (3)

oh yeah ... to the OP (because somehow your questions got lost in my initial responses)

first of all, welcome to the board.

since you don't even have an Rx-7 yet, i think you should start with a running T2. try to resist the temptation to "build" one out of an N/A. do basic engine and reliability modifications, then start tuning the chassis (brakes, suspension, etc.) to your driving skills as you do whatever it is you're going to do (AutoX, drift, etc.).

unless you find yourself in a position where you NEED to build an engine for it, i would say just keep building on the stock ports until you have a better grasp on the nuances of what streetports and bridgeports each bring to the table. as i said, there is no "black magic" involved, but you may or may not be able to live with(out) certain things. you have A LOT of reading to do.

as for turbos, finding a compressor setup that will flow what you want is relatively simple, but your turbine setup will depend (to an extent) on porting. get started first and as you get to know the animal that is the Gen II Rx-7, you will be better equipped with questions and even a few answers.

Acroy

iTrader: (3)

Welcome to the board!
Buy this: https://www.rx7club.com/2nd-generati...-mods-1025535/
and be done. Built by an expert, and total cost will be waaayyy less than building it yourself

Black Knight RX7 FC3S

iTrader: (7)

you should try and get a "stockish" TII first just to see how you like driving the car.

For a goal of 400hp you dont really have to do any porting. A good old GT35r will get you there at 17psi, lag isnt much of an issue if you go with a .82 ar turbine housing but most people go with something larger like a 1.06 ar because rotary engines breathe lots of air in and out, a .82 is really good for response, but it will be restrictive at high rpm.

As for fuel delivery, get a good fuel pump like a 044, denso supra, or aeromotive stealth pump. 750cc primaries and 2000cc secondaries with a haltech ps1000 is a good start for 400+ hp

Theres lots of turbos that can get you to 400hp like a brand new EFR 8374, or even the old to4s, changing the turbine ar is the easiest way to change spool characteristic.

For reliability, it will only be as reliable as to how it is built and tuned. Basically, as long as the engine is built right, the apex seal is properly lubricated, and the tuning is top notch, I dont see it breaking down.

j9fd3s

iTrader: (3)

the stock FC ecu isn't flashable, so to tune it, you need to buy something else. popular is the power FC, and the newer Haltechs are pretty good.

injectors; people really like the newer EV14 bosches, i think 1000cc for the primaries and 2000cc secondaries would be tons of fuel.

for the pump a bosch 044 is a great option.

other stuff on the list are a GIANT radiator, and maybe some ducting to the stock oil cooler, or just two stock oil coolers


that's good advise!

Skifledanabit

basically, OP, this...

RotaryEvolution

iTrader: (30)

street port
simplify the engine and harness
3" exhaust turboback
GT35R T4 divided .96 A/R hotside
Microtech LT8(more beginner EMS) or Haltech PS1k (little more involved but more friendly to mods down the road)
stud or pin the engine
S4 turbo chassis car in good shape
a stout fuel system and good tune
FMIC or VMIC
upgraded radiator preferrably with stock fan clutch setup and decent ducting
upgrade the apex seals to a more durable seal in the event your tuning skills are lacking(ALS/Goopy/RA)

=
win

put you at about 450whp @ 15psi, full boost by 4k RPMs.


a 20B these days will set you back about $15k to get it up and running if you can even find one.

if you get a S5 turbo chassis car you may want to consider replacing the viscous LSD with a torsen or clutch type from S4 or S6(FD) because the viscous S5 LSD is the least dependable and worst for the type of driving you want to do.


i keep saying this so i guess i will say it again, a bridge is for the "BRAP" and not much else. it isn't going to wake up your power band, it will sound mean, it will help improve spool and peak power but it will not make a huge difference over a street port. it will also drink gas like a cammed big block V8 and buck like a bronco on the street at times.