4g13 piston.... maximum oversize

[waltertan]

Attach for my dyno result for proofs. Hope fully nothing goes wrong for further skim another 0.5mm, target 110 HP.

From the chart:
Red line (Lowest part) is when i install 4G12 pistons in my 4G13 engine. (Is like Shit)
Blue line (Middle part) is when i have skim engine head of 1 mm, before ECU tunning. (Powers Back YeH)
Green Line (Highest part) after ECU tunning. (Extra 4HP Gain)

 

[Izso]

bro, I hate to burst your bubble but that's not on wheel. Robins dyno measures on crank. But that's still a pretty respectable number for a 4G13.

 

[^pomen_GTR^]

with that amount of money i think u can spend on better camshaft instead of playing with piston size first? less hassle work...and more noticeable gain than major overhaul to fit bigger piston...

 

[Izso]

Incidentally - 4G13 block max size it can go is 1.5L size. Erm.. wait - that didn't come out right. 4G13 can be bored to 4G15 size max. Cheaper to buy a 4G15 block and bore it from there. With a stroker you can hit 1.7L long stroke. Torque galore!

 

[waltertan]

Hi Izso, I did my car dyno the wheel is still intact, how can you said is on crank?

---------- Post added at 06:46 PM ---------- 6 hour anti-bump limit - Previous post was at 06:39 PM ----------

Hi, poeman gtr, just my personal preference. I dont like upgrading camshaft, ekzo sound like shit. I prefer as normal as possible. I know that I spend a lot and the money I spend can purchase a greater than my 4g13 engine. But that is my hobby, unless my 4g13 has hit the limit in n/a setup. I will still continue to find room for improvement

 

[Izso]

Hi Izso, I did my car dyno the wheel is still intact, how can you said is on crank?

---------- Post added at 06:46 PM ---------- 6 hour anti-bump limit - Previous post was at 06:39 PM ----------

Hi, poeman gtr, just my personal preference. I dont like upgrading camshaft, ekzo sound like shit. I prefer as normal as possible. I know that I spend a lot and the money I spend can purchase a greater than my 4g13 engine. But that is my hobby, unless my 4g13 has hit the limit in n/a setup. I will still continue to find room for improvement

Don't feel offended dude. I have good respect for your dyno figures. You gotta understand how these dyno machines work - Robins one reads off the sensor, not off the wheel. There are some dynos that have load on the wheel portion and reads off the wheel which makes the figures very low. Anyway dyno is more of a guideline, not an ultimate figure. So don't worry about the numbers, as long as the car is nice to drive, it's a good car.

And I agree, I spent a shitload on my Wira 4G15, easily could have transplanted a GSR and a Mivec in with the money I spent on modding my 4G15. I modded it that way because I found satisfaction doing it that way rather than swapping engines. Besides, I wasn't gunning for big time power, just personal satisfaction.

:proud::top:

 

[waltertan]

Hi Izso, I just don't understand, like you said if they are dyno on crank, my friend NAZA Citra a 2.0 dohc has been dyno at the same place before. As his citra engine spec show that it has 139 HP, but after dyno result only shows 127 HP only. We presume that his car loss his HP due to the car tyres and rims is oversize. If that 127 HP is on crank, than on wheel is about 105 HP only. As i driven his car i don't like a 105 HP only.

Anyway, i also respect on your time and afford for hard core modding your 4G15. Swapping engine is easy, but by modding engine is more fun to explore. I learn something every time that i mod my 4G13, like you said just for personal satisfaction.

 

[Izso]

Hi Izso, I just don't understand, like you said if they are dyno on crank, my friend NAZA Citra a 2.0 dohc has been dyno at the same place before. As his citra engine spec show that it has 139 HP, but after dyno result only shows 127 HP only. We presume that his car loss his HP due to the car tyres and rims is oversize. If that 127 HP is on crank, than on wheel is about 105 HP only. As i driven his car i don't like a 105 HP only.

Anyway, i also respect on your time and afford for hard core modding your 4G15. Swapping engine is easy, but by modding engine is more fun to explore. I learn something every time that i mod my 4G13, like you said just for personal satisfaction.

Robins dyno unfortunately gives the highest figures amongst all dynos in Malaysia. If you went to Under5's dyno, you'd probably get something like 75bhp to 80bhp max. It's the different ways the dyno reads the data.

I did my dyno at GTAuto Sunway and the highest I got for my figures was 104bhp even with all my mods. Stroker, oversized pistons, cams, pnp, exhaust, everything NA possibly done except ITB.

If you think about it, the new Nissan Sylphy 1.8 is rated 96kw (130bhp) and that's assuming it's in ideal conditions. Give or take it's realistically probably 120bhp on the road. So with all your mods and all, you're still 0.5L less in capacity compared to the Sylphy so realistically you're probably getting 85-95bhp on wheel tops. And as for your friends Citra, I suspect you're talking about the torque of the car, not bhp. The Citra is a 2.0L mpv, it has quite a respectable amount of torque. Bhp on the other hand is probably 120+ to 130 give or take based on the manufacturers specs.

Anyway - don't get hung up on dyno figures, it's only a reference. Since you have reference using Robins dyno, stick with his dyno if you do any mods then you can see if you have any gains or losses.

And like I said - for a 1.3 that's still pretty respectable figures!

 

[^pomen_GTR^]

Hi Izso, I did my car dyno the wheel is still intact, how can you said is on crank?

---------- Post added at 06:46 PM ---------- 6 hour anti-bump limit - Previous post was at 06:39 PM ----------

Hi, poeman gtr, just my personal preference. I dont like upgrading camshaft, ekzo sound like shit. I prefer as normal as possible. I know that I spend a lot and the money I spend can purchase a greater than my 4g13 engine. But that is my hobby, unless my 4g13 has hit the limit in n/a setup. I will still continue to find room for improvement

well yes i respect for other people preference....and its good to find the power back....

why not next step u try 4throttle with closed airbox and see the next improvement

 

[waltertan]

Hi Izso, thank you for your deep explanations. I will accept your thoughts and verify your statements by trying others dyno shop. I not hung up with my dyno result, just want to find out why. As i only when to this single shop all this year and never try others shops before.

---------- Post added at 10:07 AM ---------- 6 hour anti-bump limit - Previous post was at 10:04 AM ----------

Hi Poeman_gtr, will consider your suggestion in future. currently i try to increase the engine compression ratio some more 1st.

 

[^pomen_GTR^]

Hi Izso, thank you for your deep explanations. I will accept your thoughts and verify your statements by trying others dyno shop. I not hung up with my dyno result, just want to find out why. As i only when to this single shop all this year and never try others shops before.

---------- Post added at 10:07 AM ---------- 6 hour anti-bump limit - Previous post was at 10:04 AM ----------

Hi Poeman_gtr, will consider your suggestion in future. currently i try to increase the engine compression ratio some more 1st.

increase more compression ratio need proper calculation first...or atleast a compression test..and see how much max pressure u can get with current setup.....

because probably u were pushing into knocking danger zone...and soon only have to fill up with ron97/vpower racing fuel.....

 

[Izso]

Hi Izso, thank you for your deep explanations. I will accept your thoughts and verify your statements by trying others dyno shop. I not hung up with my dyno result, just want to find out why. As i only when to this single shop all this year and never try others shops before.

Hi Poeman_gtr, will consider your suggestion in future. currently i try to increase the engine compression ratio some more 1st.

Dude - let me give you suggestions. If you want to try another dyno, try GTAuto Sunway. If you want a heart breaker dyno, go to Under5. Either one will give you lower figures than Robins one. Incidentally my dyno at Robins was 140bhp.

But why would you want to go anywhere else la? You got the base dyno done there, might as well go back there whenever you do any mods.

Btw, best way to increase compression ratio is to change to high compression pistons. Skimming the head can be a little risky, I would know, I killed my head because of it. I had completely max skimmed the head on my 4G15 and unfortunately I had an overheat and warped the head. Wasted all my PNP work since the head was no longer reusable.

 

[waltertan]

Dude - let me give you suggestions. If you want to try another dyno, try GTAuto Sunway. If you want a heart breaker dyno, go to Under5. Either one will give you lower figures than Robins one. Incidentally my dyno at Robins was 140bhp.

But why would you want to go anywhere else la? You got the base dyno done there, might as well go back there whenever you do any mods.

Btw, best way to increase compression ratio is to change to high compression pistons. Skimming the head can be a little risky, I would know, I killed my head because of it. I had completely max skimmed the head on my 4G15 and unfortunately I had an overheat and warped the head. Wasted all my PNP work since the head was no longer reusable.

Im not going elsewhere, just want to try so other dyno shop, up until now i still not figure out my dyno is no crank and not in wheel. I will still go back to my original place for dyno.

I have already purchased a head for skimming the 1st 1mm try. Must well try to skim further, if failed just sell besi buruk loh.

Btw, how much is your complete max skimmed done last time for your 4G15 head? 2 mm?

 

[waltertan]

Dude - let me give you suggestions. If you want to try another dyno, try GTAuto Sunway. If you want a heart breaker dyno, go to Under5. Either one will give you lower figures than Robins one. Incidentally my dyno at Robins was 140bhp.

But why would you want to go anywhere else la? You got the base dyno done there, might as well go back there whenever you do any mods.

Btw, best way to increase compression ratio is to change to high compression pistons. Skimming the head can be a little risky, I would know, I killed my head because of it. I had completely max skimmed the head on my 4G15 and unfortunately I had an overheat and warped the head. Wasted all my PNP work since the head was no longer reusable.

Before i skim my 4G13 head, i saw below the side got marking i think is the skim limit that your can go. That marking is about 1 mm, and i just skim is flat. Up until now my car does not face any overheat issues, even i rev to 6000 rpm and drive up to 180 km speed. Refer attach picture.

 

[waltertan]

increase more compression ratio need proper calculation first...or atleast a compression test..and see how much max pressure u can get with current setup.....

because probably u were pushing into knocking danger zone...and soon only have to fill up with ron97/vpower racing fuel.....

Like i said i have a spare head to play with, even if i keep it also no use. If is failed like you mention, just sell besi buruk loh.

---------- Post added at 03:50 PM ---------- 6 hour anti-bump limit - Previous post was at 03:47 PM ----------

I can still keep my original 4G13 unskim head for future turbo setup for my 4G12 low compression ration pistons. Currently, I'm try to consentrate on N/A first.

---------- Post added at 03:57 PM ---------- 6 hour anti-bump limit - Previous post was at 03:50 PM ----------

The 4G13 head if you buy from potong kereta, is cheap only RM 300 or ++. Price is even cheeper than buying high cam. I think the cheapest high cam for 4G13 is about 400 ++ if not mistaken is jasma brand. I don't like high cam, it is not truly gaining power, you take low end HP to added in the high end. As you gain something and you also loss something too. Plus Ekzo sound not smooth, peh...peh.....peh...