diabolical1

iTrader: (3)

Paul,
what you said is true and i would not try to argue with most of it. i can't speak for silverrocket, but i agreed with his response because i would have told rixseven the same thing. i assumed (from the tone of his question) that he was not planning on any engine builds or swaps, and therefore he just wanted to play with bolt ons.

now, like i said, i can't argue with you about the power limits of the stock ports and Nikki carb, but with an aftermarket carbie, you have a manifold that shifts the powerband a little, and depending on what style of driving he prefers, an aftermarket intake/carbie may give him what he wants. yeah, a Holley may not give him "more" horsepower than a modded Nikki, but to me, it sure feels like it gives you a bigger kick in the pants when you stomp it ... (and I'm not trying to push him towards a Holley, i'm just using it as the first example that came to me)

if my assumption was wrong, then i guess it's on me. because if keeping the 12A is not what he wanted, then i would have said go 13B or 13B turbo and leave it at that ...

PaulFitzwarryne

Your view is valid in that the Nikki has some flat spots compared with the Holley and therefore may give a smoother output in the low/midrange. One tuner in Australia is modifying the Nikki so that the Secondary opens at the same time as the Primary. Its on a link from Adsy01's website where its climed to operate along the lines of a Weber IDA48.

I agree the thread was relating to the 12a, the comment thrown in the 13bt as to have it as the final step in improving the SA/FB. I am at the bolt-on only stage, and have spent much time looking at the options, In my earlier post at 02.45, I listed my mods without going to a reuild, which gives just over 120rwHp. I have received numerous learned advices on the next mod,- new ignition, dual exhaust, Weber IDA48. light flywheel, cold air ducting etc. In cost terms they are not efficient because I have hit a limitation barrier- the size of the ports. With only 70k miles on the clock [ mostly long trips] I find it difficult to make a decision to rebuild/port and jump to the next potential performance plateau.

Sterling

With the perfect carb tuning (& carb), ported intake manifold, good ignition set-up, free flowing exhaust, yadda yadda, and the planets are all aligned, I still think that it's not that hard to break the 150HP barrier. However, I do think the limit is probably 160, and so on that knifes edge that different days will give you different readings.

I truely believe that the stock Nikki carb can be made to deliver the necessary breath to achieve over 150 HP, and furthermore that it can be tuned by changing its linkages, fuel jets and air bleeds to give either a really curved or a really linear power band; and that that band can be long and virtually seamless.

But my idea of a perfect carb, and SilverRockets idea (or yours) of a perfect carb could be so different, that there's no way for anyone to agree.
But the reason I always push the Nikki is because it's already on the car! It's right there for you to modify yourself for cheap! If you don't like doing that, then either get a Yaw, or just get what ever'll make you happy. But it's not lazyness or frugility - I really think the Nikki carb has alot of potential, that's all.
Move to a ported engine, and then you should probably shelf the Nikki.

Truth is, after you mod the exhaust and ignition and slap any modded or performance carb on there, anything more you do is just trying to wring out the HP cloth to get a few ponies out. You'll never notice the difference between 147 HP and 151 HP, for example.


About that cold air, though...
Paul Yaw and alot of the racers on the Mazspeed site claim there's nothing like a "good ole cold air box...".
Are they wrong? Or is it just that what they are noticing is in an application where they are seeing the difference in tenths of a second @ 7800 RPMs for a long duration?

But there's another possibility, I think- What if the engine compartment is really so aerodynamically inefficient that the engine can't take 100% of the breath it needs at really high RPMs? I mean, what if it's close, like 95%, but when you put on the cold air box, you get the missing 5% and it gives just enough increase that people think it's working because it's cold?

Paul, where did you get the figure of 12 degrees-to-1 HP gain?
I would like to know the coefficient of expansion for air- IE, what does a ten degree increase do to the volume of one kilogram of air?

I'm not disputing anyone, I'm curious. I've been driving around with an electric thermometer that has a sender unit on the end of 6 or 8 ft of wire. I've put the probe in different ares of the engine. The temp readings are really high when the car is sitting. But when moving, the airflow is such that the readings drop very very noticeably.
I have'nt charted any of this stuff into a notebook, which I really should, I guess. Maybe it could help someone here on the forum to develop the "perfect" air box?

Sorry- S'pose this shoulda been on another thread by itself!

813KR$

With my expirience in creating horse power on a stock rexy. First thing is what
you have already done, headers. I would suggest high output coils (msd blaster2),
then if you dont have the money for intake manifold and carb, make your air cleaner
look like swiss cheese, Mo' air, mo' air and some mo air! And obviously K&N air filter
Then to bring down the under the hood temps. Move the latch that locks the hood
down up so the bottom 2 holes on the latch bolt up to the top 2 holes on the body.
That will give you a couple inches of gap, that alone will give you cooler air into the
engine and with my car, it brought down my engine temp. When running my ac my
engine temp would get to 3/4, after the hood gap it will stay at the halfway mark.
Dont want to forget about a good elec fan either and a smaller main pulley(in diameter).
Also the less emmissions your engine has the better it will run.
Check out racingbeat.com for more ideas. There is plenty out there!