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the accent runs a 10:1 compression ratio.
what would happen if i was to up the compression to something like 11:1 12:1 like seen in honda's and stuff.
is there any NA gains to be made there ?
cheers
 

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Yeah, and prepare to have timming and fuel issues along with that. lol.

For a 'stock' engine i wouldnt touch the internals much at all. There is a reason Hyundai set the compression at that and not any higher.

You see it in Hondas and stuff cause they have much much more done to the engine then you do, and the parts are readliy avaible.
 

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... When he means on stock engine, he means the engine internals. You'll need to do a pretty intenstive engine overhaul in order to reliablily raise the compression of any engine. You'll need the typical items you'll find with a high boost turbo setup. High compression pistons, rods...

Howie~
 

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Medic_01 said:
okay so no for a "stock" car.
but then when you you be modified enough to consider this ?
I/H/E/BBTB/ Full Standalone ??
There now i fixed it. When you increase your compression you'll have to change your timming and fuel mixtures. And you cant really change the timming much at all. OH, and cam timming too wouldnt be too bad.

So just to bump it up you will need adjustable cam gears, and a full standalone system. And thats expensive. lol.

Honestly i wouldt worry about it, i mean if you are already going that route and are going to purchase those items anyways, why yes then do it. But if your only midly interested about going faster, dont worry.


Boost is always better anyways...:D
 

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wilburisthecoolest said:
1.8 pistons in a 2.0 will LOWER your compression. Somewhere around 8.5, somebody did the math somewhere. Thats like.. awesome for boost, not so nice for NA.
you mean 1.8 rods not 1.8 pistons.

The 1.8 pistons will raise compression and lowers displacement in the 2.0

the 1.8 rods will lower compression and increase displacement in the 2.0 ... unfortunatly it will increase the maximum acceleration of the piston

the 2.0 rods will raise compression in the 1.8 and decrease the displacement
which will lower the maximum acceleration of the piston (good for higher reving)

crank has a shorter stroke in the 1.8 than in the 2.0

The gains would be pretty good with raising compression. If I remeber correctly I calculated 9-12 hp with just raising the compression. Sounds low but the remember this raises your entire power curve.
 

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Coal_forge said:
The gains would be pretty good with raising compression. If I remeber correctly I calculated 9-12 hp with just raising the compression. Sounds low but the remember this raises your entire power curve.
It sounds really good. You was raising compression with 1.8 pistons or with lowering the head??(sorry I don´t know how can I say what I mean with the head. I hope that you uderstand....)
 

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Coal_forge said:
you mean 1.8 rods not 1.8 pistons.

The 1.8 pistons will raise compression and lowers displacement in the 2.0

the 1.8 rods will lower compression and increase displacement in the 2.0 ... unfortunatly it will increase the maximum acceleration of the piston

the 2.0 rods will raise compression in the 1.8 and decrease the displacement
which will lower the maximum acceleration of the piston (good for higher reving)

crank has a shorter stroke in the 1.8 than in the 2.0

The gains would be pretty good with raising compression. If I remeber correctly I calculated 9-12 hp with just raising the compression. Sounds low but the remember this raises your entire power curve.
Thats right.. so what about 1.8 pistons and rods on a 2.0 crank? would that in effect make a stroker 2.0? seeing as the 2.0 has a longer stroke, but the 1.8 pistons and rods would lower the compression but it would be a larger displacement engine? like.. good for turbo.. hmmm



Ok so i have a 2.0 AND a 1.8 both Beta I's... what parts should i put in the 2.0 or 1.8 to make a good NA engine? I wont be raising my rev limiter so 6750 will still be max rpm. Im looking for good power from 3k up. And yes i will be making my own intake manifold. Possibly making a kit so i can make more if it turns out good.
 

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Libor Czech rep. said:
It sounds really good. You was raising compression with 1.8 pistons or with lowering the head??(sorry I don´t know how can I say what I mean with the head. I hope that you uderstand....)

Yes raising compression can be done with 1.8 pistons or shaving/cutting down/trimming the head.



"The gains would be pretty good with raising compression. If I remeber correctly I calculated 9-12 hp with just raising the compression. Sounds low but the remember this raises your entire power curve."

let me reword it

gains would be good for 9-12 hp and the entire power curve would move up.


here wilbur
http://www.hyundaiperformance.com/f...-pistons-rods-sfr.html?highlight=rods+pistons

"Thats right.. so what about 1.8 pistons and rods on a 2.0 crank? would that in effect make a stroker 2.0? seeing as the 2.0 has a longer stroke, but the 1.8 pistons and rods would lower the compression but it would be a larger displacement engine? like.. good for turbo.. hmmm"

What have you been under a rock? ;)
1.8 rods and pistons on a 2.0 crank would lower compression hence increasing displacement. It would not be stroker though unless it was replaceing the 1.8 crank, then I would imagine it being called a 1.8 stoker. Changing pistons and rods will not affect the stroke of engine.

?Ok so i have a 2.0 AND a 1.8 both Beta I's... what parts should i put in the 2.0 or 1.8 to make a good NA engine? I wont be raising my rev limiter so 6750 will still be max rpm. Im looking for good power from 3k up. And yes i will be making my own intake manifold. Possibly making a kit so i can make more if it turns out good."

Using oem parts I would match it like this if I was concerned about reving
1.8crank
2.0rods
1.8 pistons
That will raise compression and lower max acceleration of the pistons.
 

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Medic_01 said:
the accent runs a 10:1 compression ratio.
what would happen if i was to up the compression to something like 11:1 12:1 like seen in honda's and stuff.
is there any NA gains to be made there ?
cheers
Can be done....me running 11:1 comp now on a 1.5L SOHC block and using 1.3L cam. All other parts are OEM. The head was PNP too. The power band is strong all the way to 6k redline. The top speed i tested...while playing with a RX300 was 190 at 5k rev at 5th gear. I know I can hit 6k rev...but i just wanted to play safe... But one thing to note, it just keeps going....it just rev happy. Speed from 120 to 180 is fast too.
Fueling issues...yes u will face that problem...use 1.6L injectors and for tuning, a SAFC1 will do just fine.
Igintion wise...i m using nology cables and brisks cold plugs...u need those cold plugs....and at least octane 98 fuel....using 92 is totally out....it juts pings....mixing 95 with 98 works too.
Next problem I faced was clutch...a brand new OEM cluch fails within 2 months.....maybe I was playing it too much :p. Running 3 plugs exedy unit. Able to wheel spin on 2nd gear too. 0 to 100 timing is 10.4sec....with wheel spins at first and second...I believe if i can find traction, should be able to hit below 10sec...
One point to note bro...better equip urself with bigger brakes...those OEM 1.3/1.5 ones cant stop this power....me running brembos max rotors used on a EK civic (same PCD) and a 1.6L single psiton calipers....sorry i dont know what ride they were from...:D they fit with little mod...
 

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Ok I understand almost everything here but why in god's name by using the 1.8 pistons on the 2.0 engine will lower the displacement? The compression will rise ok, but the displacement will remain the same! It's the same bore of 82mm. Please advice on this because I'm going to install those pistons on my 2.0
 
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