OPINION: the perfect amount of horsepower for first gen.
 

Forgoing the "unlimited powah!!!" What do you guys figure is the best balance of power for a SA/FB? I am taking into consideration suspension limits, brake capacities and tire options. I estimate that 200-250 FWHP would be pushing it on a street driven car. I feel that anymore would become a chore to keep on the road. Hell, a stock 12a can cause issues. I bring this up as yearly in my rx7 life I was planning on building a 7 that would crush anything on the road. Over 15 years later and new car performance has become insanely fast. Sub 3 second 0-60 and 11 second quarter mile times...ect. I just can't see chasing that brass ring anymore. So, for a non competitive car. what do you think the perfect hp is?

I have a stock port 12A pushing about 150-160 at the crank (est) ~ 134 to the wheels measured on a dyno. It would be nice to have a bit more power.

I would say 200-220 would be perfect. Anymore and you start to stress the stock tranny and rear end. A full bridge with the proper reinforcements and fuel intake would be more than enough to get you there I would think. Personally my next motor will be a large secondary street port with some hardened and pinned bits and a nikki tuned for the secondaries. That way I can spin it above 7 to get the power and wider power band and not have to worry about gross MPG if I stay out of the secondaries.

what you really want is a power band that feels ok in the low rpm range, and then ascends up to like 5-6k. this is fun. this is what you get with a modded nikki and a 74 style port, this is why everyone likes it.

no idea how much hp it is, its fun. nobody cares about the number

bridge is a slightly better powerband, with slightly worse street manners, so there is a little trade off

Yes, there is fun. Then there is terrifying. That will very based on skill and personality. This was not the reason for this thread, but I'm reminded now of classic car guys who would build a '49 Merc and put the most crazy supercharged V8 monstrosity in it. Only to realize no mere mortal has the chops to handle 700 hp in a Truman era lead sled.

I've often wondered about this. I have an old 74 13b in my 85. Its a wonderful engine for the street, but still a little bastard... IE(Dellorto48) Pulls strong to 7+k and idles ok.
Feels like 170 hp. 200-220 would be perfect!

100hp in an SA feels perfect.

Bear in mind that I do have about 3x that power in an FB. But it's not all that much fun. The POWER is nice but the compromises to live with that power are not. Power brakes are iffy, the heavy drivetrain components required sap the fun out of it.

I have another FB. I desperately tried to build a stockport 12A for it but failed so I gave up and put a stockport 13B in it. But it also still has nice light 13" tires, a nice light small-axle rearend (and I'd love to convert it back to the drum rear that the chassis is supposed to have), etc. Exhaust manifold not headers, nice quiet exhaust. Air conditioning. A fun car to LIVE with.

I also think the 1.6 Miata is best Miata for the same reasons... engine is fun and "enough" and the rest of the car is suitably lightweight. It even has the wussburger 6" rearend... but for a 1.6 in a 2200lb car it is plenty. By that measure, the drivetrain in an SA is overbuilt...

The question to me is what type of driving? Are you looking for stop light to stop light, scare your passengers with acceleration? Then I would say 300hp and as much torque as you can muster. Unfortunately I am not sure the stock drivetrain can put that to the ground or will the stock brakes stop that well. Now your upgrading brakes and suspension to fit more tire etc.

If your looking at the feel of driving down a curvy road and enjoying the feel a Rx7 can give you than 150-200 hp would still be plenty to make a nice spirited drive. Really now we are talking about handling and braking to really make the driving experience.

Mat

"Torque" sucks. When people say "OMG TEH TORQUE" what they mean is "My engine makes no horsepower but I need to talk it up in order to feel better about my bad life decisions"

See also: Diesel wonks who need 40psi boost to make almost as much power as a gas engine of the same displacement "BUT OMG TEH TORQUE" yeah too bad you have a redline of 2500rpm so you have to throw away all that torque by driving in a taller gear

Also, do not get me wrong. My daily driver is an all-turbo all-torque engine. I do see the appeal from a daily driving standpoint. But for a fun car, this is not fun. At only 5000rpm it sounds painful, which is completely sad. Also that torque requires a massive transmission and drivetrain and all of that is heavy and while okay it is nice to have something that makes 300hp at under 5500rpm you do find youself driving a car that weighs as much as a small truck and it ends up not actually being fun. For moving luxuriously from suburnan home to place of work, it is most decadent, but it's far down on the list of "what car do I want to have fun with today?" answers.

if you got a time machine, grabbed one of those, brought it to now and put it on a dyno, it would probably do about 350hp.

that being said, 350hp is a lot for a car with the a suspension so bad, it was bad when the car was new. i have some old road tests and those cars were bad then.

i've been using a 1.6 miata for a DD for about a year. its 2200lbs with a full tank of gas and no driver. 33mpg, and the top comes off, 90% of the time it is still more car than i need.

the down side is that its a piston engine, so the normal 120k mile service is to take half the car apart and replace it.

I like the 200 to 220WHP range. I'd have to guess that's where I'm at. It does require a hearty clutch, but the rest of the driveline seems ok. I do like the boosted method as it requires less exotic fuel management over the BP or PP.

I will say that I have to, after a year of hard driving, do something about my clutch setup. I think a turbo II transmission is the only way out. BUT I'm thinking that after that is said and done I won't have any more clutch or tranny issues.

200-220whp: "the rest of the driveline seems OK"

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I don't think pretzeling rearends (I know I went through about four S3 disk housings before I gave up on them) and wasting transmissions on a depressingly regular basis counts as "ok" in my book :)

Bear in mind that the large axle rears are actually weaker than the small axle ones. The axles themselves are stronger but the housing is less strong. And when the less-strong housing warps, you end up eating axles or at least the bearings. It looks to me like one could be able to get custom axles made to fit the large axle diff (or better yet, S2000 diff) in a small-bearing rear, for the best of both worlds.

The transmissions just suck :) The Turbo II trans is stronger but it shifts like a truck.

Since I can't edit posts:

The small axle rear has 24 spline by 25 (I think) mm diameter axles. The large axle rear is 26 spline by (I think) 27mm. Diameter measured at the splines, they get larger shortly afterward.

Honda S2000 rears look completely different but use the Mazda 7" internals, with a 28 spline by 29mm stub axle. Interestingly, the Kia Sportage rearend (not frontend!) also uses 28x29 axles, and its pumpkin is a "7.5" that allegedly drops in anywhere a 7" Mazda pumpkin will. At one point I was contemplating having 28 spline axles made so I could use an S2000 diff, but then I realized my weakpoint was not the ring and pinion, or the differential itself, but the housing. Thus, the 9" rear...

i just got a T2 up and running, and i was thrilled that 5th gear wasn't broken, but yeah it shifts like a truck.

but wait, its an FC. so it carries stuff like a truck, T2 engine is like a truck, maybe it IS a truck. with like a sport bed or something..

it does ride like a vintage caddy though, so its pretty sweet truck.

I liked my Turbo GSL-SE at 300 to 325 at the rear wheels. Street port, Stock ECU, Cartech kit from intake to turbo to exhaust. A/C was like ice cold,retained power steering, stock brakes, T2 trans, custom drive shaft. Felt pretty drivable like a stock GSL-SE but stiffer (It had 16" or 17" wheels which added to the stiffness) and obviously louder. Turbo kicked in like a rocket. I never felt too much power or out of control.

My Jaguar F-type V8 at 500 hp is much more squirrelly.

A 2100 lbs -/+ SA with GSL-SE / S4 13b EFI, stripped emissions, RB (or custom) exhaust is about perfect. I would guess it's somewhere around 165 hp at the flywheel (lightweight flywheel). I chirp 2nd sometimes 3rd gear on occasion. it shifts smooth like an automatic with the lighter flywheel, and I can bury the 85MPH speedo in what seems like 9 seconds :D. Maybe over estimated there, but it does feel quick. Best of all I beat on it a little bit every time I've driven it the past 5 years and never broke anything.

It feels on par, maybe even quicker when you shift or take a turn just right, than my 16 MX-5 Club with BBS/Brembo package which several automotive journalists recorded at about 6 seconds 0-60 and about 14.5 1/4 mile.

It certainly feels more lively than the GTUs (makes more power and has same flywheel, but weighs about 450-500 lbs more). GTUs will walk away from it above 100MPH I bet, and handles much better.

I'd say about 200HP feels pretty good. Maybe a tad more.

I have to agree with this. Right now my 12A is somewhere around 150-160 at the crank and its great but a little more juice would make it tremendous and I wouldn't want any more than that.

At 100HP+/- bone stock 80 SA, fast driving is a survival/art-form, particular in calculating passing another car (or, more often, not). Its an exercise in patience for sure. I love driving my SA but would be nice to at least keep up with most new Corollas, etc. running around these days! I have a new Sterling Nikki w/"smoothed/ported" (by Him) intake + RB exhaust awaiting install and pray for 150HP...tho my brain yearns for 200, that may be a bridge too far.

Stu Aull
80GS
AZ

Stu, that setup should get you in the ballpark for maximum 12A HP. Even though its a Sterling, read up on jeff20B dissertations on the permutations recommended for nikkis. You may find some things to fix or change even on the sterling nikki.

Thanks t_g_
Am a Nikki Neophyte, so will start with just actually dropping it (Sterling) in. jeff certainly has a great rep for Nikki-knowledge. Maybe he will offer some advice at the time.

Stu Aull
80GS
AZ

Maybe I will.

I'll let you know once I crack 600whp. :devil:

^ hehe, yeah I've been trying to show some restraint because its not a dick swinging contest, but they are a pretty good chassis. If your tyres and suspension (and driveline) are sorted, the sky's the limit.
Tyres are getting better every year. Circa 450 at the treads on mine, its pretty nice. Bit too aggro for the street probably. but low boost (12psi) is lovely, still an animal but still nice and linear.
Boost controller OFF is 7-8psi and about 250 rwhp, perfectly linear delivery, drives like a proper light weight sports car should. Can even drive aggressively in the wet without annoying traction loss halfway through every gear.