Sam or any others from Korea do you know of any , what i will term, 'badazz', monsterly built-up N/A Tibs in korea?
If so what are some of the common mods or tricks they use for their N/A cars?

 

<div class='quotetop'>QUOTE</div><div class='quotemain'>originally posted on Fxtreme by Cheuk in Seoul
The strongest NA Tiburons runs 2.2 L engine with ALL the NA modifications makes around 160-165 hp at the wheels (Around 190-195 at the crank). These cars have everything, ported heads, big big cams, intake, exhaust, headers, ECU.

I've been hearing about the Turbulence ECU's here on the board, but during dyno testing there really is no difference in power output. I'd say the Turbulence power output falls within the range of most stock 1gen Tibbies.</div>

 

The biggest limitation in these cars is the cylinder head, but it's a limiter in more than one way...

We've already discussed (over at FXTreme) how the combustion bowls and ports are not very good for N/A power generation. One thing we didn't discuss is the HLA system.

The HLA's (hydraulic lash adjusters) are there so you never have to adjust you valves like on any other solid-rocker design. Oil pressure builds up in the HLA's, and takes up the few thousandths of an inch between the cam lobe and the valve stem, which means it's always a perfect fit.

However, there's a severe disadvantage to these things: they're fragile.

Let's say the stock rev limiter in the Tiburon kicks in at 7K... No it really doesn't, but it makes math easier so deal with it smile.gif At 7K RPM's in a four-stroke motor, the valves will open 3500 times per second. That means each one of your intake valves is REALLY cookin! That leaves your valve about 0.1 millisecond (1 ten-thousandth of a second) to fully open, let air in, and fully close and seat against the head.

That's a LOT of motion.

This is the likely the "liveable" limit of hydralic lash adjusters. These HLA's work by oil pressure inflating a tough little membrane, and that membrane bloats up like a tire, and keeps the gap between camlobe and valve stem filled.

The problem is, that membrane is not that "tough". If you turn up the RPM limiter to 8K RPM's, you're opening and closing valves another 14% faster than you were at 7K RPM's, and those HLA's are going to hate you. High RPM's and hydraulic lash adjusters do NOT get along.

Another problem is cam height and ramp rate. If you get an "extra lumpy" cam, you typically increase the duration and lift, and the "speed" at which the cam transitions from fully-closed to fully-opened and then back to fully-closed gets much faster.

Even at stock RPM's (we'll say 7K RPM again), you're spinning those valves to open and close 3500 times per second. The only problem with a LUMPY cam is, the valves must open and close FASTER (same RPM, but different ramp rate) and must also open FURTHER (higher lift on the cam)... The results can be disasterous.

If you combine a funky lumpy cam with a high redline in one of these cylinder heads, you're going to rip all your HLA's a new one. And at $22 a piece, they aren't cheap.

-Red-

 

I know we've discussed this at Fxtreme.
What I am really trying to get at is ... since the Koreans originated this car and since they have the biggest aftermarket support for it (most likely .... at least to me that is what i see) what are the solutions they are coming up with for the beta's limitations. Even if those limitations have to be overcome by custom fabricated parts. What are they designing to do these things??

 

Red-

I hate to disagree with you...but I see a major flaw in your math.

<div class='quotetop'>QUOTE</div><div class='quotemain'>7K RPM's in a four-stroke motor, the valves will open 3500 times per second. That means each one of your intake valves is REALLY cookin! That leaves your valve about 0.1 millisecond (1 ten-thousandth of a second) to fully open, let air in, and fully close and seat against the head.</div>

7000 RPM = 116.7 RPS(econd)

We have 2 intake and 2 exhaust valves, but they both open and close only once per full cycle or revolution. As each cylinder only fires once per full revolution (cycle).

So at the most your intake/exhaust valves are opening 116.7 times per second and closing 116.7 times per second.

How did you reach the 3500 per second figure?

Am I missing something here?

(Btw...for the record, @ 116 RPS, your valves are traving 2.5 meters per second.)

 

It is less since in four stroke the intake and exhaust valves open every two revolutions each so they open around 60 times per second max.

[ May 22, 2001: Message edited by: Mario ]

 

Yeah, you guys got it -- I somehow got my head stuck in seconds and not minutes, hence a huge-ass math flaw.

Damn, after reading that, a valve opening and closing every 0.1 ms would make some NASTY noise.

Thanks for the catch!
-Red-

 

So does this correction remove the HLAs from the factors of limitation in the engine?

 

Nope. They're still an issue. Hydraulic lash adjusters are NEVER put on a car that has a high redline. Ever.

Soild rockers are needed to sustain the valvetrain at high RPM's, along with the necessary springs and titanium retainers if the valves are heavy or large.

Even if you found a "solid rocker conversion" for the BETA head, you'd still need to do something with the awful combustion bowls, casting errors in the ports, short-radius turns upstream of the valves, and somehow move or weld-shut the coolant veins that run down the sides of the exhaust ports.

It's readily apparent that these cars were never meant for high normally-aspirated power. They're turbo motors, albeit with weak pistons...

-Red-

 

HVE head has the same system? You can still go with a better cam than the one originally installed. HVE have them why dont you ask what they have?. I dont think they have a wild racing cam but I dont know if you want it anyway. My first mod was to install a cam from the Elantra 1.8 that has a bit more lift and corrected the timing a bit. The difference was nice but not enough. It makes me think that the intake up to the cam and head is where you can gain more for less. As we discussed somewhere before is good to plan your engine, the path is way different between the two and you might end up paying a lot of money moving from one plan to another.