(ENGINE) Easiest way to make Hp on a stock 12a
 

Folks, if I wanted to get a 12A to the 150hp level, what's the best steps to take? I prefer to take a NA road vs forced induction.

My thoughts were to start with header/exhaust, dual webers, intake manifold, and fuel pump. Would that get me to 150? What else should I consider.

By the way, any thoughts on how quick of a 1/4 mile or 0-60 a GS of this level would be able to produce?

Thanks...

Carb & exhaust... you'll be good.

Porting + Carb + exhaust + fuel system upgrade.

Or

You can slap on a huge turbo.....hehehhehehe.

-Error402

Can you get there without porting?

Definitely fuel system upgrade + exhaust (in that order) for starters, then while you're having fun with that start looking in to the induction side of things.

You don't "need" porting to get 150 but it makes the goal a lot easier to attain.

You didn't say what year GS. My 2400lb (with driver) '80 GS ran consistent low 15's which is about 130hp. Setup was far from ideal, too. (Probably had 15-20hp locked away in the crappy intake manifold setup I had :) )

I was thinking about an 84 or 85.... are the later years heavier than the early models?

you can definitely get there without porting...i would start out with r/b exhaust, then fuel upgrade, maybe a holy 600 if not a weber 48 ida...that should get you in the 14's and about 160hp or somewhere around there...i was able to run 14.6 with a stock port 12a, holy 600, and exhaust on an '83 rx7

Generally speaking, the newer the car they heavier they are. It depends on how optioned-up your car is (does it have A/C or power anything?). All '84-85 cars have a rear axle assembly that weighs roughly 50lb more than the earlier ones (need a scale and some samples of each type to personally verify this) and this is about how much variance there is anyway.

Probably shed a good 50lb off of the car by putting a header on it anyway :)

Yeah sorry, guys I didn't mean my post to be that you "needed" to port the engine. Just as peejay said, it would easier if you do. :)

-Error402

In line with the original question, how much would the following run (installed)? I'm not really familiar with exhaust systems and induction so bare with me please.

• Carb (Weber 48 or Holley 600 - any pics of installed examples?)
• Exhuast System: Header, down pipe, presilencer, muffler ?? (can I get this emissions legal)?
• Fuel system (new fuel rail, lines and fuel pump?)

Will this still achieve sub 15 Qtr miles times on an stock port 84/85 GSL (12A) with A/C and no stripping of the interior. Could this all be done (parts and labor) for $1500?

Thanks!
-Mike

well if we are talkin eazy compaired to reliable id say throw a 50shot hell a 100 shot it about as cheep as porting with much better results..lol

so many things can be done to reach this goal but depending on time money and reliable power you want.So again in this world its all about money time and knowledge

Stepdaddy

i've got a 12a, el cheapo header and exhaust, and a dellorto dhla 48..... 117hp to the rear wheels, dyno verified. i'm POSITIVE there are several more ponies hiding in the exhaust.... the pacesetter one i've got is not very flow friendly. this is all on a stock port. my goal for the 12a is 200hp, then i'll be happy. time to save for a street port!

hrm, that reminds me... how much flywheel hp would 117 rwhp be?

There are more carb choices than that; it doesn't matter as much on a stockport engine which one you pick, the good ones tuned right are going to make similar top end power. Obviously a 48IDA is better than a 45DCOE, but not by a million years.

RB Dellorto setup with full RB exhaust and a good fuel system, along with timing advance and pulleys makes 154hp according to RB.

~150hp is approx. the limit for stockport motors.

As previously mentioned, it's all about the weight reduction; if you have a GS to start with that's a bonus.

With 150hp and a lightened 81-83 GS (no spare tire, jack tools, etc, no ac or anything like that, minimal stereo, superflous engine bay stuff removed, some sound deadening removed, etc) you can run approx. 15 flat in the quartermile.

Jeeze, installed? You gotta remember, these carbs are only available used (unless you get a brand new 45DCOE or RB Holley setup), and will need to be rebuilt, cleaned and tuned for it to work right. This takes a fair bit of time. I'd recommend doing it yourself if possible, if only because it's a hell of lot more fun.

Used Weber 48IDA's tend to run about $600-$900 as far as what I've seen. They're expensive because all the racer guys want them. I wasn't seriously looking for one though, I could be wrong. RB Dellorto 48DHLA setups are far more economical (and just as good for what you want). You can find them for about $300 with the intake manifold and other associated parts. A new Weber 45 setup from Mazdatrix or wherever runs about $750 I believe. The RB Holley setup is similar.


NONE of the systems are anywhere close to emissions legal, especially with an aftermarket carb. You'd have to figure out something custom with an aftermarket cat. BTW, RB exhaust is what you want for best power (racing beat). Don't even consider any of the cheap shitty stuff (ie. pacesetter, monza, whatever.)

Alll you need is a good fuel pump and pressure regulator. IMO forget about the guage, most of them are crap and you don't need one at all to tune fuel pressure. Look at a Carter 7psi fuel pump and Holley 4-9psi regulator, that's what most of us run.

No, probably not. You'll likely be somewhere in the low 15's.

You could definitely do it for that budget if you did the work yourself. It depends what carb you get, what parts you need for it, what exhaust, etc. If you're paying someone I would think that could come up a little short, I dunno. Personally I wouldn't pay someone to do all this stuff.

My 12A gives 124-rwhp, which equates o some 150hp at the flywheel. To achive this the modifications are:-

1. RB syle header and exhaust system
2. modified Nikki carb, and inlet manifold
3. K&N air filter
4. remove the air pump
5. good quality plugs

There was no need to change the fuel pump or go for a new carb. At that level of power the restricting factor is the ports. The total cost would be well under US$1500.

If you mean 150rear wheel power as checked on the dyno there is a sudden jump in cost.

1 upgradedfuel pump
2. possibly an upgraded carb and inlet system such as a Weber 48 IDA
3. porting is essential, the real cost as the engine will need rebuilding, unless
4. you go blow through turbo whichwill be cheaper than porting unless youdo your own engine rebuild, you may also get wat with using the Nikki.

if the engine is showing signs of wear it is better to go the porting route, as there is nothing worse than adding a turbo then finding the engine is too weak fo the increased power and requires rebuilding.

You may just get the turbo set-up inside a $1500 budget but have the engine rebuilt/ported wouldbe well over this budget limitation.

My 12A gives 124-rwhp, which equates to some 150hp at the flywheel.

I prefer to use rear wheel hp as the measure of performance as you can test the output against a dyno, and measure any furter improvements.Most hp quotes are speculation and estimate without evidence.

To achive this my modifications are:-

1. RB syle header and exhaust system
2. modified Nikki carb, and improved inlet manifold
3. K&N air filter
4. remove the air pump
5. good quality plugs
6. new fuel filter

There was no need to change the fuel pump or go for a new carb. At that level of power the restricting factor is the ports. The total cost would be well under US$1500.

If you mean 150rear wheel power as checked on the dyno there is a sudden jump in cost.

start with the above modifications and add:-
1. upgraded fuel pump
2. possibly an upgraded carb and inlet system such as
a Weber 48 IDA [Paul Yaw says he can modify a Nkki
for 150rwhp but it may be easier on a Weber or Holly]
3. porting is essential, this is a real cost as the engine
will need rebuilding, unless
4. you go blow through turbo whichwill be cheaper than
porting unless youdo your own engine rebuild, you
may also get wat with using the Nikki.

If the engine is showing signs of wear it is better to go the porting route, as there is nothing worse than adding a turbo then finding the engine is too weak fo the increased power and requires rebuilding.

You may just get the turbo set-up inside a $1500 budget but have the engine rebuilt/ported wouldbe well over this budget limitation. depending on the builder start looking at US$2,500.

Hey, awesome, this is exactly what I was looking for! Now that I have my car running reliably, I definitely would like to get a little more power from my stock '84 GS (who wouldn't?). The way I see it, at present, the most economical way to achieve 150bhp:

1) RB full exhaust (when you mean not emmissions legal, is that only for states that don't actively check emmissions at regstration?)

2) Modified, or upgraded carb (how can I mod my stock one?)

3) upgraded fuel system

Is this about right, or am i totally off? Also, does anybody know just how much power you gain from a K&N filter?

Paul: Sorry, I'm ignorant, what's the air pump?

Oh, and one more thing: how much does a streetport job run?

hrm.... that post didn't come out looking like i thought it would. i guess ya just gotta read between the lines! streetport prices vary.... a lot! if on a budget, you may want to hold off till it's time for a rebuild to do the porting. or be cheap and do it yourself!

On my 83 GS, with the weight reduction, removed sound-proofing, dellorto carb, RB exhaust system, no cats, stock fuel pump, RB intake... I should be around 150hp :)

so.. it's not very tough to have 150hp in a 12A

Max

About 130 if its 12% loss...I dont know if thats right...I just remember hearing 12% somewhere...

~T.J.

rotorhead: lol; it took me a bit to figure out what you meant, but now that i look at it; nice job :D

You kidding me?? You should have been there when I was tunning it...

LOL... yup, I as well wouldn't say the process has been "easy." It took a whole lot of work, time, research, soliciting help from kind and generous friends *cough*RXcetera*cough*, to get to the point I'm at. Of course, you can always go much further:)

Yeah guys, I just bought Ari's 650 hp FD drag car... so it's not too hard to have 650 hp in an FD:)

Sorry Max, just messin with cha!

how can you guys be running 15 flat with a stockport 12a without traction? No LSD on those cars...

I got even more mods than all those mentioned and I'm sure I'm on high 15s haven't tested it at the track but man it sure will not hit 15 flat.

You don't need an LSD to have traction.

My car wasn't a stockport but it didn't make all that much power, less power then a well set up stockport should do. I never dynoed the car but it only takes 130hp for a 2400lb car/driver to have a 90mph trap speed. Remember though this is REAL hoserpower, not "30hp from the exhaust + 10hp from the fuel system + 15hp from the air filter + 25hp from the stickers" type numbers yanked out of one's nether regions :)

Key to traction is decent tires and a stock clutch. By decent tires I mean tires that grab harder when heated, and no Z-rated short sidewall BS - you want a tall tire on the stock 13" rims and you want the sidewall to be nice and flexible. I used 185/70 Goodyear Clubs set to 50psi front, 20psi rear when at the track. The tires hook and the clutch slips down.

http://www.geocities.com/izzmus/about.html for the full skinny, some timeslips, and a video clip.

Look at this, ive gone crosseyed :ret:

i still ran 14.6 without lsd on a gs...i had m/t street tires, they worked pretty good for me

14.6? Impressive? What level of other mods were on the car?

all i had done was a holy 600, r/b exhuast, i did have a mild exhaust port, holy red fuel pump

again ported and we are talking about 12a...guys be realistic.


I got everything done so far but porting...no bull.

you can still get a lot out of a 12a...dont doubt the power of a 12a...if you know what you are doing and have the car tuned right you can run pretty good times...i have seen 12a's run mid 14's a lot without porting, its nothing impossible

jrios I don't doubt the power of a 12a but I find it hard to believe that without porting a 12a will hit 14s and have a regular size driver with all his clothes on driving the car:) Unless the car is seriously stripped and with good traction there is no way that a 150hp engine will push it to mid 14s. It becomes more of the weight factor than that of power.

Granted I haven't tested my car yet and I have yet to loose to anybody without a very built n/a engine including hondas... Last night I tested my car againts a light light ZC CRX with header, intake and mild cams...and I spanked him by a car lenght...I also tested my rx against a 1995 stock 170hp B16 Vtec JDM (right hand drive) civic hatchback and was dead even I having a slight edge. My car runs good but I don't think I'm in flat 15s, or I'm I, comparing it with those cars? I come from 13s or lower cars and I'm just again getting into 12a for the fun factor ....maybe it does run flat 15s but I just won't know until I take to a track.

Now this thread is very informative because I wanted to port from the begining and not even try to do all the mods I have made so far. But the fun is building a quick NON-ported engine first, I am impressed with performance of the 12a in stock port form, I'm a believer. But the porting will be done...nitrous will be done and turbo too...the whole point is to have fun :)

i know this guy around that has an '83 gs with a 140,000 miles with weber (dont know what size) and some exhaust and constantly runs 15.1...thats not bad for a 12a with that high of mileage...take your car to the track and find out the time, sounds like a good running car

how much more hp will a yaw tuned nikki give you over stock?

For real? You bought ari's stars and stripes FD? i was just taking pictures of that thing the other day...:cool:

mperformance:

1.you keep mentioning power:wieght but you also have to keep in mind the transmission and gearing..rx7s have wonderful gearing with plunging redlines that give us the edge...i know i ran the shiit out of my 85..to 10k rpm frequently

2.you havent taken your car to the track..do you just feel your time???

not trying to be an a$$ but your arguments arent very thought out;)

So I take it you had a peripheral port engine with carbon seals etc. to warrant that kind of abuse? ;)

no just a worn out motor i didnt care about....that damn overrev buzzer di d get annoying though;)

I'm with mperformance on this one. I can see 14's with no interior and drag slicks, but not with the setups we are talking about here. This whole thing started with a guy wanting to know what 150hp would get him with no big streetability compromise, and that's not 14's.

No, *YOUR* arguments aren't very though out! What do you think the point is of revving a stockport motor to 10k is?

I'll tell you what the point is: abso-fucking-lutely nothing. Not to mention that the u-shaped intake manifolds on the weber/dell carbs are too restrictive for this even with porting.

Reving to 10k isn't going to make a stockport faster through the 1/4, that should be blatantly obvious.

BTW, as REVHED said, there's no way you're going to be reving your motor to 10k all the time without massive problems. Are you aware of the things that happen when a stock motor is brought above 8.5k? Click the search button and learn about it. How do you know you were hitting 10k? I find your statement very questionable.

Bullshit, mperformance is being way more objective and realistic here.

RXcetera : facon de parler!

Wankel: I know, I know... Silver and me are just kidding around ;).

Lots of bold statements in this thread. One guy says he's seen "alot" of stockport 12A (RX-7's I assume) run mid 14's. Shit I would kill to see those... I bet sometimes I cant even do that in my 3rd gen. Another guy says he revs his stock motor to 10K rpm LOL! This I HAVE to see (as long as I'm not sitting in the car with him as he does it).

I think I would wear my ballistic blanket for that ride.....make a great set of pants

I have seen a lot of stock ported 12a's with upgraded fuel system, carb (holy or weber), and exhaust run mid 14's...I have seen a lot of guys in Puerto Rico run this time...its all about tuning and knowing what you're doing...just putting bolt on parts will not get you anywhere

I'm a human dyno/gtechpro I can "feel" acceleration/speed variations to the .10 scale. That's what I get from working on cars all my life....








BTW silverocket ....we finally agree on something...thanks :)

j/k:cool:

Guess the air is different in Puerto Rico, cause guys sure arent doing those kinds of times around here.

Maybe it's not in the air, but somewhere in the measuring tape.

make sure you are comparing apples with apples ... do Puerto Rican 12a's have the same sized ports as US cars ... European cars don't

the whole thread is about NON-ported 12a and how to get 150hp.

the subject comes up plenty of times in this forum. Like said the magic number is 150hp, I am sold on this theory which I did not come up with just what I have read here and elsewhere and I think is dead on accurate.
mid 14s with a non ported 12a n/a in a first gen (FA or FB) is not easy to achieve <---summarizing what is been described here, that includes any STOCK port being japanese, european, US, etc blocks.


My formula 150hp (I think ;) )if anybody cares:

engine:
45DCOE weber lake city intake
Carter 7 psi fuel pump
Holley FPR
Yaw advanced timing
Magnecore 10mm ignition cables/stock coils
header/ 2.5" no presilencer/dynomax superturbo muffler
electric fan
no pwr steering

non-horsepower acceleration/reliability/drivability improvers...
weight redux(no rear anything, including bins)
Peejay's cable engine brace
rear drums
no a/c (finally decided to get rid of it)
old style oil cooler
fuel and a/f meter gauges
dual alt pulley
stock clutch disc
modified pressure plate
215/50/13s all around

still NOwhere in low 15s (too many cars running flat 15s that can beat mine and I ain't a bad driver)...much less 14s, come porting should be well on low 14s with a large streetport :)