Big_Ern

What's needed to get 150-200HP in a reliable daily driver?

I've done a lot of reading, but most of the stuff seems to be people going for more extreme HP numbers and turbos etc. I'm not looking for anything extreme, I just want a fun relible daily driver that isn't too bad on gas since my commute is about 100miles round trip.

What would you guys recommend for an '83 GSL 12A?

So far I've got a custom 2.25" exhaust from the stock manifold back (hi-flow cat & magnaflow straight through muffler).

I'm thinking a header would help a bit more.
maybe 2GCDFIS with the transistor trick.
Anything else fairly cheap that I should consider?


I've got a nasty dowel pin oil leak which seems to drip oil onto the exhaust cause it to smoke like crazy when I stop. So a rebuild to fix this may be in the near future. So at that time I might do a street port if thats something that I can do myself

rbf41182gt

a streetport, full exhaust, and a carb will get you 150- 200 hp

REVHED

How could a dowel pin leak be leaking onto your exhaust? It's on the other side of the engine. Must be a pretty big leak. lol It's more likely your metering pump.

Big_Ern

Doh, okay, well I got 2 oil leaks then. Guess I better look at the OMP pretty quick..

I can live with the dowel pin leak, but I though that's what was causing oil to get blown back onto the exhaust. Maybe I don't need to rebuild it anytime soon then. Damn, that was gonna be my excuse to tear it down port it at the same time...

rotarycrazy

iTrader: (8)

well if it is leaking oil onto your exhoust you are asking for trouble like FIRE for example. Get that **** fixed before you regret it later.

Dan_s_young

iTrader: (1)

yup like I said in the other thread your omp is leaking... And to get 150-200hp go for a streetport, lightwieght steel flywheel, weber 48dcoe, it will be like a whole new car...

Big_Ern

Ya, I'll take a look at it this weekend (I don't need it much this week).

Its been doing it for a while, so I made sure to get the optional fire coverage on my insurance




Back on topic tho, what kind of headers are there aside from RB?

Also, is it worth getting a new carb without porting it?

Dan_s_young

iTrader: (1)

for headers don't get anything except racing beat, well unless they are the custom ones but they are big bucks...

Yes its worth getting a different carb without porting it but if you have the engine out and appart why not, its the time to do it trust me...

Big_Ern

I will definitely port it when I tear it down to fix the dowel pin leak. But if fixing the OMP stops the oil leaking onto my exhaust I probably won't be doing a rebuild for quite a while.

what is needed to do a street port? Is that something that I could do myself? I'm pretty mechanically inclined, just short of funds.

Dan_s_young

iTrader: (1)

Well with the OMP, it could be several things, cracked lines or something... I just took out my OMP put a blockoff plate in its plate and now premix, but you probally dont want to do that...

To streetport you need a dremel and some carbide cutting tools and a porting template, oh yes and some practice will help you a ton... You can easily do it yourself as long as you take your time and read lots of threads and look at stock port-street port pictures...

Big_Ern

Depending on what the problem is with my OMP, I'm thinking I might start pre-mixing as well. Not really much difference than adding a quart of oil to the engine every tank of gas, just means I gotta get 2 stroke oil and add it to the gas tank instead.


Good to know about the street porting. Thanks.

Gregs

based on other setups that are idenical to mine down to the FPR have dynoed 165-175hp and mines a daily driver from hell sometimes 100 miles plus a day

rbf41182gt

I haven't done it, but what I've read about, you can do a streetport pretty easily by yourself. Just get a template and some good for your dremel or die grinder and you should be set.

clean85owner

My set-up was rated at 215 flywheel horsepower; which puts me right in the range of 180 wheel hp. My car was my father's daily driver for 10 years and 120,000 miles. It was also good enough to win 3 SCCA SoloII championships.

Power below 3,500 rpm is a little on the weak side, but when you really get on it, the car moves! I recently lost a coolant seal, however, and the car has been done for a couple of months. I am saving up to buy my own rebuild kit, but with only working ~25 hours a week at $5.15/hour, it takes a little while.

Anyways, I would definately reccomend a 150-200hp n/a rotary for a daily driver; they are great fun.

85rotarypower

Well, its pushing it to get a 12A to 150hp without porting. With porting about 170 is attainable. Its not gonna be cheap either. To get 150hp without porting, you need basically all the bolt ons. Weber 48 IDA, full custom exhaust with RB header, upgraded fuel pump and regulator, among other things. It would be at least $1500 I think.

As for my car, I picked up a used '88 13B 6 port that was supposedly streetported. The guy that sold it to me claimed it dyno'd at 150 rwhp in the 84 it came from, and thats with the stock FI system, and before the injectors were professionally cleaned. After the injectors were cleaned, he said the engine probably picked up another 10-15 hp at the flywheel. Figuring a 25% drop because of the drivetrain, the engine probably put out 180 at the flywheel before injectors were cleaned, and probably around 190 after.

After the engine swap, I drove the car on the partially working FI system, and the power was awsome. I figure once I get the engine converted to carb, it will put down somewhere around 180hp at the wheels. But even with the 6 puck racing clutch the engine came with, the car was very easy to drive.

1985_RX-7

Turbo from an FC i dont think it puts out too much hp, but im doing it nest summer .. Itl be fun.

stilettoman

iTrader: (1)

I have been a rotorhead since about 1979, made a few engine swaps, built some 12a and 13b engines, and have always ported them. Everyone who is knowledgeable, such as Racing Beat and others in the business will tell you that if you are only going to do one thing to improve performance, install an exhaust header. What this tells me is that the exhaust PORTS are not a major limitation on performance, and you should not get carried away with porting them. As others have said, there is no point in studying this issue- just get a header from Racing Beat.

I think you would be happy with the setup I have in my 84GSL - very mildly ported primaries, "street ported" secondary intakes and exhaust ports. That way the driveability is virtually unaffected in normal driving, but you get pretty good performance when the secondaries open. Take a look at the carb throat sizes and you can see that the main benefit is going to be in the secondaries.

If you have no experiece with air tools, get someone in the business to give you a junk end housing and do one port for practice. Get a template, such as the Racing Beat "Street Port" template ( someone on here might lend you one). Put some substantial plastic tape over the port area, as shown in my photo. Pin the template in place with the dowel pins and cut out the tape with a razor blade or sharp knife, and remove the template. Cutting the port out to the shape of the template gives you the TIMING that you want. The other aspect of this is the material you remove upstream of the port, which opens up the runner and improves the FLOW. You can buy a perfectly adequate air die grinder for about $15, maybe less, at Harbor Freight, and buy one or two good quality carbide bits (1/4 inch shanks.) Electric tools can do the job, but it will take longer. I spend one to two hours per port. Unless you are building an all-out race engine, don't waste your time with polishing - the carbide bit will give you the finish you want - a little roughness to provide some turbulence and prevent fuel puddling. Trust me on this - this was advice by a guy from Mazda's engine development program.

Everyone here will have their favorite carb and intake setup, but most aftermarket setups, Holley, Weber, or Dellorto, will have some undesirable cold start or other issues. I used an RX-4 carb (13b) on my 12a, and got 130HP to the wheels, which is probably about 155 to the flywheel. Mazda actually built a few RX-3s with this setup, but the manifolds are very rare - I built my own, using some phenolic insulator plates and lots of epoxy, and blended the larger bores into the 12a manifold. Been driving it for about 7-8 years, works great. Be aware that to go from 150 to 200 Hp, you will give up a lot of driveability (assuming normally aspirated).

PM me if you want more details on how to do this. Some details given here:

www.cardomain.com/ride/646433

Big_Ern

Wow, thanks for all the info stilettoman -- sweet lookin convertible you got too

Your setup sounds exactly like what I'm looking for

Rx7Kidd

whats the price for everything to do a streetport? i mean parts, ect.. to do it myself?

z-beater

Man at 5.15...that is practically slave labor...lol well at least you have a job and work for a living!

I totally agree with stilettoman. I have heard that the rx-4 carbs are great for a 12a. If I had a 12a this is the route that I would go. If you are going with a small port then I elieve that yes the exhaust ports are not such a huge issue. However naturally when more gas goes in...more gas needs to come out!

I know that mine is not a 12a but just ofr sake of comparrison I will give you an example. I have a SE with 180k on the engine. from the factory it puts 135 to the flywheel or about 94.5 to the ground(assuing a 30% drivetrain loss). With my RB header and no cat and stock muffler and stock ports I was putting down 124.5. This is a 30hp increase over stock. To date I have seen very few cars that can gain 30hp with only partial exhaust. If you go sp you could probably hit the 150 number and still stay extremely reliable. Just look at Stiletto!

Good luck...oh yeah it you port it you might want to change all the internals while you are in there. If you do all the work yourself I would leave 1000-1500 aside just in case something is out of spec or needs replacing.

FB II

T U R B O. cheaper than a rebuild and you get as much torque as you do HP. thxUplz

Big_Ern

How much are the parts for a rebuild & port vs turbo? I can do all the work myself.

besides, I think a rebuild would be a good thing to do on a 125k engine anyway -- especially if you're going to put the extra stress of a turbo on it.

DriveFast7

iTrader: (1)

http://pineappleracing.com/PricelistSvcs.html

clean85owner

You turbo'd your motor for under a grand, FB II?