What kind of horsepower numbers can I expect from my stock port 12A and what kind of times have other people ran in the 8th mile. My mods are-

Modifed intake box
Racing beat header and presilencer
2GDFIS or what ever with 2nd gen plugs
rats nest removed
no AC
Rebulit carb (stock)
Mechanical Secondaries

I was just wondering what people have ran and if people had dyno there cars with around the same mods and what number they got. Also how much more is it capable of before I have to tear into the engine or go turbo.

Thanks,
Chris

 

125-130HP maybe.

The stock carb is your next bottleneck.It's low CFM rating (275-ish I believe)is keeping you from delivering more air to match the flow capabilities of your new exhaust.Mechanical secondaries will get the large runners open sooner,which might change your poweband a bit,but all the air still has to make it past the same size barrels and venturies.Plus youll tend to bog out at lower RPMs if you floor it.

Paul Yaw claimed(and I agree) that his 400+CFM nikki and manifold would make 150 crank HP on a stockport 12A with the same mods you have listed.I ran this setup for a few years and it felt right on.You cant get much more out of the stock 12A's small ports at that point.I imagine that Weber,Dell and Mikuni aftermarket carbs flow similar CFM's and thus probably make similar HP numbers on a stockport 12A.The Yaw provides stock-like driveability and tuning,however they are hard to find and not in production anymore.

Give Sterling and Carl a ring for a similarly modded Nikki....

 

ok thanks does anyone have any input on what they ran at the track. My friend ran a 10 flat in the 8th with simalar mods. I was just wondering what other people have ran with around the same mods.

 

yeah steve is right, it should dyno between 115-120rwhp

 

i dont believ that much power to the wheel can be acomplished with that setup stock is bout 80 hp on a 12 a somewaht like that and ive seen a 12a with headers precilencer racing beat muffler and a sidedraft dellorto do 115 horses to the wheel

 

he also has 8.5 msd wires with 2dgfis redline fuel pump 2 msd boxes

 

The stock fan sucks up quite a bit of power.

 

12A stock.... 0 to 60 in two weeks......

 

^

 

Stock carb flows around 315cfm or something like that. Suitable for stock use, but starts to choke the engine at around 6500rpm. A sterling carb is an excellent alternative to a higher priced weber or dellorto setup. I have not personally tried one of sterling's carbs, but I hear they are great, and with the research I have heard he put into them, I wouldn't doubt that they are great.

Without the carb, your probably putting out 130 HP at the flywheel. I would say that might be pushing it too. The only real power upgrades you have there are the exhaust and airbox mods. The rats nest removal doesn't increase hp, but decreases confusion, the AC removal doesn't do much other than decrease weight, 2GDFIS doesn't really increase power much, only increases throttle response and smooths out the powerband a little.

 

well, i dyno'd 110rwhp with very simliar mods back in the day. main difference is that my carb was running like poop and i had a massive exhaust.

don't expect to be much faster than 10 in the 1/8th or around high 15's in the 1/4

unless you gut the **** outta her

 

I knew it was a lot faster then it was stock but i havent had a chance to get her on the dyno (am waiting on carb, fuel pump and regulator). I knew it wasn't high HP, but just wondered what people thought it was around.

 

a higher flow, WELL TUNED is the key, carb will do wonders. Dont just throw anything on there without rejetting, etc. I tried that, a big old holley. It stunk.

 

Stock exhaust still? I'd also say no higher than 115hp... The reason why it feels much more "peppy" is because it is a HUGE difference compared to stock.... Stock you're talking around 85-90 whp.... That's over a 20% increase!!!

Dan

 

With a header/tuned exhaust and a modified carb setup a stock 12a should be @150 BHP. Factor in typical losses at 12.5% and you should be seeing ~130 RWHP.

Note that with a stock setup we are told by Mazda that the BHP is 105 for the 12a in an SA RX7 and we know that this same setup will yield ~90 RWHP as mneasured by some publish dyno runs. If you do the math, 105 reduced by 12.5% is 92, so the 12.5% loss figure seems to hold up. Yeah sure some folks are seeing less or more but that could also be chassis dyno affects. See this link for a good description.