Ok so i blew up my turboII. got 166k miles out of it so i was pretty happy. I would rebuild it but it's a long story...figured the next turbo'ed rotary i get will be a FD

So i had this 88 Sport model and i bought a "master" rebuild kit from atkins and i'm going to rebuild it starting next week. i'm new the N/A world so i don't have the slightess idea how to make power. I'll have a racing beat header with exhuast and an intake. my friend and his dad know rotaries very well and said they would do a mild port on it aswell and do most of the rebuild work for me.

wondering what else i can do to make reliable driveable power out of this thing?

My friend the "sport" model came with the GTU motor so does it come with that 146hp?

 

A very powerful streetable NA will be about 200whp. You'll need a large streetport, exhaust, intake, and ECU and some luck. A webber style TB on a webber flanged manifold should help give more power, but you'll need to fabricate an air box for it or it'll be sucking in hot engine bay air. You could also just do a bridge port if you're willing to accept the bad idle, lack of low rpm power and not having a hope in hell of passing any emissions testing.

You'd be better off starting with an S5 engine, as it's more powerful to start with, and it's safer to run to higher rpm's which really helps to get more power out of it with large ports.

IMHO the best way to make an NA fast, is to mod the suspension and get some good wheels and tires.

 

lucky for me Oregon or well roseburg, oregon doesn't have to deal with emissions. we have old guys running there 900hp hotrods around on the streets for the fun of it.

Perhaps i should sell this one car after i get the paint touched up on it and start over. I have suspension parts for it. new kyb struts with tanabe springs and front and rear sway bars. wonder how much i can get out of it

 

You might as well say a very powerful streetable FD will be about 600whp. Show me a dyno sheet of someone who has gotten even close to 200whp besides Kahren (who made his own custom manifold). I'm not trying to call you out personally, but I think there is a big misconception on what N/A's are really capable of on the street.

I've pretty much reached the limits of what an s4 can do without insane amounts of time and money spent.

First, use s5 rotors (and manifold if you are willing to make it work on an s4. do a search on this). Do some kind of street port. Use a T2 intermediate housing. I personally have pineapple racing auxilary port sleeves. You can open your auxilary ports with a Racing Beat presilencer, or the factory smog (which is probably going to be the most reliable 2nd option), or an electronic pump. Port out your manifolds.

There is a debate over collected vs. true duals exhaust, but if you are doing a streetport you gain more from exhaust pulse scavenging by using a collected system. I would recommend the Racing Beat catback because of the header and the fact that the T2 intermediate housing has no exhaust diffuser in it and makes it louder.

Use an SAFC for fuel management. Don't waste your time with a standalone. You won't gain much on an n/a. For timing you could advance your CAS a little bit but in my experience if you go too far it will confuse the ECU and make it run a little lean up top, despite the SAFC.

All this should get you anywhere between 165 and 185whp if you're lucky, depending on how much S5 stuff you use. Realistically, you're looking at 170's max. That's what I pulled off with s4 rotors and manifold, and that's when I stopped modding the motor and started working on my T2.

Hell, just streetport it and spray a 50 shot.

 

I was just trying to give an upper limit, that's all. It would be about equivalent to saying a very powerful FD is 600whp. A few people have gotten there, but not many, so don't expect to get there yourself without a lot of effort. It also depends on what you'd call streetable. I've heard that some people consider PP streetable.

 

That's a very good point, and one that I used to point out in the past before I got tired of no one listening. Just assuming that you can easily get 200HP out of an NA is a flawed idea because it takes knowledge and experience to do so.

Just port the NA center iron. The castings are the same, it's just the port shapes on the surface that are different. There's no real advantage to going to the TII part.

I think you're confused. The intermediate iron has no exhaust passages. It is the rotor housings that have exhaust ports.

You just made your point for a standalone in that post. A full standalone is NEVER overkill. The benefits are easy to mention: new wiring harness, modern CPU, total programmability, no left over emissions legacy, flexibility to run ANY setup you want, and many more. A properly tuned standalone will run worlds better then the stock ECU could ever hope of. It will give better mileage, never flood, and make more power all around. Oh, and you can run your own timing curve without messing with the CAS.

 

wouldn't you be able to remove the MAF and a number of other things that complicate the rotary with a stand alone?

 

What I generally tell people is that with a a good, proffesional port job and a full exhaust/CAI, you are looking at maybe 160-170 to the wheels, and thats with fresh housings. With a standalone and a good tune, you can bump it up to 180-190, with 200 being about the theoretical max. Thats also with s5 rotors and an s5 intake.

 

A standalone will give more power than a piggyback when properly tuned, and allows you to do things like running ITB's, or turbocharge it later on.

One huge advantage is being able to remove the airflow meter (technically it's not an MAF) which is a flow restriction.

 

Search for "beefy N/A" in the archives.

 

Nothing really "complicates" the rotary as part of the stock system. But yes, you could run any AFM you want with a standalone, or none at all.

 

200whp, you are talking about making more power then most TII's at 8-10psi of boost. This is generally far fetched on side port intakes and barely conceivable on custom fabed intakes. This is nearly if not 100% increase in power output over stock.

 

yeah i went to my friends house and he showed me the street porting template and what the differences between street and bridge porting. don't think i'll be doing the latter.

things i ment by complicating was just a few things i've heard about making the AFM (get it right this time? haha) and a few other vacuum controlled devices obsolete by going with a standalone. althought this is just vague things i heard awhile back.

I'm not really expecting insane numbers like 200rwhp but just something to make it quick and the closest i can get to the power of my tII possible will still holding reliablility. althought i know the torque the tII had will never be achieved by gonig N/A

 

it really depends on what you are happy with. my philosophy is about balance. it's safe to say that a 200whp NA 13b rotary you will have to sacrifice some "driveability".
i've considered this, and to make a fun street driven NA car you pretty much have to factor power out of the equation. if you want power to be primary, you will most likely be better off starting with a TII.

this is what i have done what i have been trying to do with my own car. basically, as many bolt on mods as possible, some way to tune at least fuel delivery, drivetrain (light flywheel, clutch, LSD), suspension, and some minor weight reduction. the key here is to ensure everything is working perfect, so i've replaced brakes, etc. with new parts. it's not a fast car but it is a fun car to drive. (click sig for more details).
only thing missing is a streetported engine, and i would not go anything more radical that a streetport i don't think unless i plan on a lot more track days, etc.

and of course you get the advantage of generally better reliability and better gas mileage. when i drive my car i am not worried about taking it to redline time and time again. it has never broken down on the road and if i want i can get 25+ mpg.

i'm just saying don't set your goal as a power goal with an NA, you will just end up wasting money and not having as much fun.

 

yeah i mainly will be just driving this to work as a DD but on the weekends i drove my turboII in the morning on the local mountain passes as a hobby. I guess i should just do the street port and a few minor bolt-ons and then turn my attention to weight reduction and suspension. Wasn't like i need a huge amount of horsepower to enjoy my morning. just enjoy to get the adrinaline going

 

I disagree. If you can manage to get 200 whp from a large streetport, which is possibly with time, money and a little luck, then it will be very drivable on the street. If my car had s5 rotors and intake and a standalone, I am fairly confident it could at least get to 190 at the wheels and it was very driveable on the street.

 

If I had to make power on an N/A, I'd do just what everyone else mentioned, Streetport, Intake, Exhaust. However, what I'd also look into doing, is using RX8 rotors, as they are very high compression I believe. Waiting for Icemark/aaroncake to chime in on this one Lol.

 

RX8 CR = 10.0:1, S5 CR = 9.7:1.

There may be a couple horsepower there, but not much.

 

Mazdatrix has shown no improvments to be made power wise from the FE rotors in earlier 13b's.

 

i didn't say it wouldn't be very driveable. but you are sacrificing some of the driveability compared to stock. and the point i was trying to make is whatever you are happy with. some people don't mind sacrificing a lot of driveability if it makes power.
and yes, depending on certain things, streetported NA should be able to make the power you stated, and would be quite street driveable for most people.

as for the RX-8 rotors, i'm sure there are some SMALL gains to be had (the Mazdatrix comparison was a quite limited experiment, even they said so) and also they are better suited to high RPM operation since they are lighter and better balanced, but if you have any sort of reasonable budget why spend the money on that, especially if it doesn't work out then that is a big waste.

 

I haven't even see dynos of these mythical unstreetable 200whp n/a's, much less streetable ones...

 

Other than minor compression increases I don't even see the point in using S5 rotors. The castings are softer and unless you are using 2 peice apex seals, there is too much of a chance of a seal rolling out on used rotors.

 

Kahren's engine dynoed in the mid 190's with just a piggyback, so it definately possible. That was with a 4 port with a custom manifold, but I would think you could get even higher numbers with a properly done 6-port.
From the sounds of it Pengarafoo's car is probably over 200 to the wheels, but it has ITB's. Its still perfectly streetable, though.