I've got a 12A stripped of all emisions, header, no cats, free flow muffler, stock carb (minus lots of parts believe it or not there is a normal carb under all that junk). What is the likely HP output of this motor?

thanks,

Daniel

 

id say in the 115-120 range

what kinda millage on the motor

 

i pulled 107rwhp on a dynojet dyno

mods in my signature

 

your setup sounds almost IDENTICAL to mine. my motor has about 50,000 on the rebuild. same as you though, 12a, no cats, no emissions, rb header, 2 1/4" piping, high flow muffler, i also removed my a/c, air pump, and replaced the fan with a serperate electric one. my car dyno'd at 108 rwhp at 7,000rpms. 103lb/ft tq at 5,500. my hp was still climbing with my revs, but i let off. it was just for a base run, i'm bout to do alot of other stuff then go back and rev it out a bit more. but yea, you should be lookin at around 110 or so hp granted your motor, tranny, clutch are all in good condition. you may have more, my clutch is kinda crappy.

-zac

 

cool, those numbers look good.. i think the motor is around 20K it was pulled because the car was given to me to go into my 78 MG midget. Thsoe numbers sound encouraging. I think i'll eventualy look for more, but that should be enough to have fun for now. Thanks

 

mine has 143k miles on it and the rats nest is still there, a/c was hooked up, and 107 rwhp and 96.1 ftlbs of torque. thats not much lower than what yall pulled. im just surprise my motor did that

 

Different dyno's can account for the variation in the runs.

 

I have a question. I have a 12a, and i hear that 200 hp isnt that hard to get. Someone said they got more than that just from a streetported motor, but i dont believe it. Ide love to have smooth & drivable 200 hp. Noone really knows? I have stock carb, but full racing beat street port exhaust. Its hard for me to see adding a good carb/intake and street port giving me this much more power to get me to 200 or more. Am i wrong?

 

Average flywheel Hp for streetport, carb,intake, exhaust would probably be closer to 175.

 

215-225 flywheel HP 12 A streetport no turbo is attainable only with wide open exhaust and a big 2bbl carb with 38-40 chokes. This is what SCCA EP racers do.

RB streetport exhaust takes some power away. I think you'd be luck to get 185 hp at flywheel.

-bp-

 

Glad to see this has spawned an interesting discusion.. .. and i just realized i must look like a 4 year old idiot, as i put probably insteat of probable! HAHA.. Oh well.

I can't wait to get my car done and dyno it so we can see how close you guys where. sounds like 110 to 120 at the ground is probable as i am going to use a aftermarket carb and intake. We'll see how this goes. I'm trying to build the car for <$2004 for the next Grassroots motorsports challenge if it occurs.

Thanks for the help,

Daniel

 

Going back to the original question I predict 105rwhp with what you have got.

But of course it can vary 10% due to dyne inaccuracy, temperature, fuel etc. The critical test is how quick is the standing 1/4 mile. My prediction is about 16.3-16.5 seconds. A top gen 1 street legal car will get down to 10 seconds with over 500rwhp.

 

i can't wait to get a better carb and finally get my car on the track against some ricers there's a bunch of civic guys here that claim this and that and i've already whooped up on some hatches with swaps! AAHAHAHAHHAHAHAHAHAH I LOVE IT!

-zac

 

Thanks for answering my question. So open headers is what it takes to pretty much get up to 200 hp and over huh? Well, maybe i should just order up a TII i mean i look at them online everyday!

 

With a 12a and a desire to generate 200 hp you have 3 choices
- rebuild with a large strretport or bridgeport and
get a high performance carb, such as a Weber IDA
48 plus a good header/exhaust system.
- add a blow through gen 2 turbo with a side draft
carb such as a Weber DCOE 45 and front
mounted intercooler, use about 8 psi boost
- transplant a 13bt, a series 5 should get you there,
but there are numerous modifications to get it to fit
as listed on the sticky on the subject..

The decision is yours and the size of your budget.

 

One car im gonna go turbo so the 200+hp shouldnt be a problem. The other car im just leaving the 12a NA i guess. Its still fun.

 

How are paople only getting like 107 HP with Rb exhaust when on the website it say that a 25% HP gain is expected

 

The figure being quoted as 107hp is rwhp, the power at the rear wheels as measured on the dyno. The 100 hp frequently quoted for a stock 12a is flywheel hp, this is then subject to transmission powerloss to get rwhp.

Its more practical to measure rwhp as you dont have to take the engine out and measure power on a test bed.

A 25% gain in hp, however measured, is rather optimistic for just a header.