82mm Mahle Piston ??

[speed2horizon]

bro.... study more about cam.... your hi lobe cam have 55-98 degree of valve overlap... not suitable for turbo engine, medium size turbo still have hi ezos back pressure coz of restrictive turbine & ezos system... yr intake side only have 0.5bar pressure + big valve overlap... so the exhause will enter back cylinder & cause power drop.... maybe you need to low down 20 degree more ... but you will suffer low spool up coz less overlap low cam at low rpm.... you need a device to control the intake valve timing bro.... to suite yr turbo engine...

can settle this prob, you will have good spool up & good hi rpm power...

bro, may I correct u if u dun mind. Not abt the cams. But he should study more abt engine first. Then force inductions. Then cams... Cause cans involves more theorethical parameters.

Bro..thanks for your advice ! Actually I dont know about cam :( Hmm.. you mean I should get a low cam which is 277 or lower better ?? IF high cam only suitable for those vtec,mivec,vvtli right ?
Hope can call you and discuss with you the cam directly
Bro..So what should I do ?? now My LIFT mati at 6k coz of small turbo... hope T28 turbo bring my LIFT back...
How's your advice ?? thanks for help !

even at 272, it's consider damn 7 high duration jor. Will feel lag due to the overlapping. But once turbo spools into it's effective spooling speed, Mmmmm... It'll spins like there's no 2moro.

If u're spooling damn 7 high. Where lotsa exhaust is generated... Targetting 400-500whp, then just kill ur vvtli. Let it overlap. They'll work fine.

 

[nan83]

not cause yr small turbo you dun have power above 6k... the valve overlap is too big is the main prob... you change to bigger turbo maybe can help.... but if you can low the valve overlap degree, the hi rpm power will increase .... i give you some info :

valve overlap = both intake & exhaust valve open at same time..
cam duration = how long the valve will open in time
cam lift = how long the valve stam will travel...
valve overlap degree = (intake opens @ º BTDC) + (Exhaust closes @ º ATDC)

so you think... yr engine have big overlap.... mean intake & exhause valve open at same time at long time... yr exhaust pressure higher than intake pressure..... so some of exhaust gases will enter the combustion chamber before the exhaust valve fully close... that cause power loss....

huumm... hard for me to expain if you dunno much.... i need to draw it to make you easier to understand...

the prob is yr variable valve timing still act like N/A engine.... turbo engine want different setting ...

---------- Post added at 12:39 AM ---------- 6 hour anti-bump limit - Previous post was at 12:23 AM ----------

Here i copy article for you... hope you can understand... that below setup only have 10' valve overlap degree..... your car 55-98' valve overlap.... cannot like that looo...


Camshafts - Why 272 intake /264 exhaust?


It has been standard practice to make the exhaust duration longer than the intake duration on a normally aspirated engine. This has been done to promote scavenging and increase cylinder pressure at high RPM because overlap is longer and one can run narrower LSA's (Lobe Separation Angles).

Applying the same methods to a turbo charged engine, however, will not have the same desired effect because turbo charged engines do not make use of scavenging and reversion caused by larger overlaps, which can cause havoc.

In a turbo charged engine exhaust pressure is almost at all times (99.95%) higher than intake pressure. Reversion, when air flows the opposite direction than what it is suppose to flow, must at all times be prevented in a turbo charged engine. If not compressor surge will occur which can result in serious damage.

If we take a set of 264 degrees duration cams we will see that the inlet opens at 4 BTDC and closes at 43 ABDC for LS of 110 degrees. The exhaust opens at 36 BBDC and closes at 10 ATDC for a LS of 103. This gives us an overlap of 14 degrees and a total LSA of 7 degrees. Not good for a smooth idle and even worse when it comes to reversion

Now let's increase the exhaust cam to 272 degrees duration. Intake still opens at 4 BTDC and closes at 43 ABDC for a LS of 110 degrees, but exhaust now opens at 45 BBDC and closes at 9 ATDC for a LS of 108. This now gives us an overlap of 13 degrees and a LSA of 3 degrees.

Let's now go the opposite way, increase the inlet cam to 272 degrees duration but change the LS for the 264-exhaust cam to 112. Inlet opens at 8 BTDC and closes at 47 ABDC for LS of 110 degrees and the exhaust opens at 44 BBDC and closes at 0 ATDC for a LS of 112. This gives us an overlap of 10 degrees and a LSA of 4 degrees. Less change for reversion and great for cylinder pressures.

The following are achieved:

1) longer fill period for a more powerful combustion which in turn will lead to a higher volume of exhaust gases with a higher initial pressure.

2) smaller overlap which will prevent reversion.

3) longer effective exhaust duration which will help spool faster and stronger because of the higher cylinder pressures.

4) larger volume of exhaust gases present when the exhaust valve starts to open.

 

[veilsideboyz]

Thanks for your nice info !!!!!!
For example :
272 intake /264 exhaust is for N/A .. F/I then get a 272 intake/ 272 exhaust ????
BIG overlap good for N/a... but for Turbo should keep lesses over lap ??
correct me if I'm wrong

 

[speed2horizon]

Thanks for your nice info !!!!!!
For example :
272 intake /264 exhaust is for N/A .. F/I then get a 272 intake/ 272 exhaust ????
BIG overlap good for N/a... but for Turbo should keep lesses over lap ??
correct me if I'm wrong

Depends on ur wastegate diameter/downpipe diameter/boost pressure. Overlapping is not a problem for na car cuz there is not so much restriction on the exhaust. Turbocharged car, u have a turbine fin. There'll be pressure built before the turbine n the exhaust gas will flow back into the cylinder. If low boost, u'll even have pressure leakage on the cylinder due to the exhaust valve preclose n the intake valve early open.

Cam, Not necessary bigger duration is better. Neither smaller better. It all depends on what ur set up is for. For track purpose, if ur exhaust comes out directly from the side of the front tyre, boosting high 7 high, overlapping big 7 big also ok. But if the car bring to street drive, there'll be a problem when iddle n low rpm.

Teh Tarik at cheras. Remember. Kns....

 

[veilsideboyz]

Depends on ur wastegate diameter/downpipe diameter/boost pressure. Overlapping is not a problem for na car cuz there is not so much restriction on the exhaust. Turbocharged car, u have a turbine fin. There'll be pressure built before the turbine n the exhaust gas will flow back into the cylinder. If low boost, u'll even have pressure leakage on the cylinder due to the exhaust valve preclose n the intake valve early open.

Cam, Not necessary bigger duration is better. Neither smaller better. It all depends on what ur set up is for. For track purpose, if ur exhaust comes out directly from the side of the front tyre, boosting high 7 high, overlapping big 7 big also ok. But if the car bring to street drive, there'll be a problem when iddle n low rpm.

Teh Tarik at cheras. Remember. Kns....

Haha !! sure !!
I wanna discuss with you 3 day 2 night ..... for turbo and cam .....3-4cup teh tarik :D
CNY I go meet you la ~ collect ang pao ~~ Hehe....
AFter Cny.. Collect all ang pao..I will starting my project...hope wont kill my engine with 7psi T28

 

[speed2horizon]

Haha !! sure !!
I wanna discuss with you 3 day 2 night ..... for turbo and cam .....3-4cup teh tarik :D
CNY I go meet you la ~ collect ang pao ~~ Hehe....
AFter Cny.. Collect all ang pao..I will starting my project...hope wont kill my engine with 7psi T28

I belum kahwin. So no angpao from me... Lolz...

 

[veilsideboyz]

I belum kahwin. So no angpao from me... Lolz...

HEhe... okok~Teh tarik
Give me your h/p number la... we can meet up at night ~~ :wavey:
Taiko.. Thanks for helping me all the time.... Oh ya.. Taiko...
My auto gearbox drive daily ..
For example :
1st gear = 2-3k rpm =20-30km/h shift gear
2nd hear =2-3k rpm =30-40km/h shft gear
3nd gear and 4 gear =2-3k rpm50-60km/h drive for kampung road...
hard to above 3k for kampung road or daily...
--If using 8:8.1 with GT28RS.... will it hard to drive ??? since didnt above 3k rpm...turbo didnt spool... my car will move as slow as stock gt ?? :rolleyes:
Another question again

 

[kidRacer]

wannna my friend use piston forged wiseco, use that piston mmg berasap ke??its same happen if use others brand like cp or manley???

 

[speed2horizon]

HEhe... okok~Teh tarik
Give me your h/p number la... we can meet up at night ~~ :wavey:
Taiko.. Thanks for helping me all the time.... Oh ya.. Taiko...
My auto gearbox drive daily ..
For example :
1st gear = 2-3k rpm =20-30km/h shift gear
2nd hear =2-3k rpm =30-40km/h shft gear
3nd gear and 4 gear =2-3k rpm50-60km/h drive for kampung road...
hard to above 3k for kampung road or daily...
--If using 8:8.1 with GT28RS.... will it hard to drive ??? since didnt above 3k rpm...turbo didnt spool... my car will move as slow as stock gt ?? :rolleyes:
Another question again

Wei... That cannot be bro. If that is the case, ur gb is $&@€ing short ratio. And at cruising speed of 120km/h, engine already running 6000rpm... This can't be true.

Pls give me the the actual speed vs rpm on every gear.

wannna my friend use piston forged wiseco, use that piston mmg berasap ke??its same happen if use others brand like cp or manley???

does it happen only after changing to completely new pistons? If yes, I suspect the cylinder wall is no longer round. Normally ppl get oversized pistons to avoid this problem.

 

[nan83]

Thanks for your nice info !!!!!!
For example :
272 intake /264 exhaust is for N/A .. F/I then get a 272 intake/ 272 exhaust ????
BIG overlap good for N/a... but for Turbo should keep lesses over lap ??
correct me if I'm wrong

cam selection depend on power want to generate oso..... no need hi duration cam if just want power below 300hp....

yaa... big overlap at hi rpm good for N/A ... for scavenging effect ...

for turbo... need to set cam (overlap) on dyno, so we can see the optimum power for our setup... small turbo = less overlap need ....


--------------------------------------------

just like vtec, some say Bot cannot perform on vtec & mivec.... coz they not reduce the valve overlap..... just try retard intake cam & advance exhaust cam... so will get less overlap... but now no prob, tuner know already to tune BOT engine....

-----------------------------------------------

---------- Post added at 08:51 PM ---------- 6 hour anti-bump limit - Previous post was at 08:46 PM ----------

wannna my friend use piston forged wiseco, use that piston mmg berasap ke??its same happen if use others brand like cp or manley???

new rebuild engine?? humm, maybe cylinder clearance rebore too much... dunno lah, need to check...

maybe engine not proper break-in .....

 

[veilsideboyz]

Wei... That cannot be bro. If that is the case, ur gb is $&@€ing short ratio. And at cruising speed of 120km/h, engine already running 6000rpm... This can't be true.

Pls give me the the actual speed vs rpm on every gear.

My celica 4 speed automatic gts
This is a Gear Shift when racing ~~
1st gear 1 k-7.8k rpm = 60-70km/h
2nd gear 4k-7.8k rpm = 70-130km/h
3rd gear 5k-6krpm =130-180km/h MAX

Daily Drive to Kampung road
2nd gear 3rd and 4 th gear stick with 2k-3krpm for daily use ..(60km/h)

 

[speed2horizon]

My celica 4 speed automatic gts
This is a Gear Shift when racing ~~
1st gear 1 k-7.8k rpm = 60-70km/h
2nd gear 4k-7.8k rpm = 70-130km/h
3rd gear 5k-6krpm =130-180km/h MAX

Daily Drive to Kampung road
2nd gear 3rd and 4 th gear stick with 2k-3krpm for daily use ..(60km/h)

Racing or not... The gear ratio will remain the same. I need the data like this...

1st gear at ___ rpm = ___ km/h
2nd gear at ___ rpm = ___ km/h

and so on... no need to gimme the range. try 2moro and let me know...

 

[veilsideboyz]

cam selection depend on power want to generate oso..... no need hi duration cam if just want power below 300hp....

yaa... big overlap at hi rpm good for N/A ... for scavenging effect ...

for turbo... need to set cam (overlap) on dyno, so we can see the optimum power for our setup... small turbo = less overlap need ....


--------------------------------------------

just like vtec, some say Bot cannot perform on vtec & mivec.... coz they not reduce the valve overlap..... just try retard intake cam & advance exhaust cam... so will get less overlap... but now no prob, tuner know already to tune BOT engine....

Ok THanks ! Taiko !! I will change to F/I cam better...cos our cam are like type R ..damn high...
and.. after I install T28... wll get more overlap for my high rpm which can activate my LIFT...
Hehe...sorry for something I'm not understand about cam.... >
---------- Post added at 09:22 PM ---------- 6 hour anti-bump limit - Previous post was at 09:15 PM ----------

[/COLOR]

Racing or not... The gear ratio will remain the same. I need the data like this...

1st gear at ___ rpm = ___ km/h
2nd gear at ___ rpm = ___ km/h

and so on... no need to gimme the range. try 2moro and let me know...

??
1st gear at which rpm only km/h ??
1st gear at 7.8k rpm=70km/h
?
gv me example

 

[speed2horizon]

Ok THanks ! Taiko !! I will change to F/I cam better...cos our cam are like type R ..damn high...
and.. after I install T28... wll get more overlap for my high rpm which can activate my LIFT...
Hehe...sorry for something I'm not understand about cam.... >
---------- Post added at 09:22 PM ---------- 6 hour anti-bump limit - Previous post was at 09:15 PM ----------

[/COLOR]

??
1st gear at which rpm only km/h ??
1st gear at 7.8k rpm=70km/h
?
gv me example

Any RPM also can... just wanna know the ratio. Try all 3ooorpm.
U know how much does it cost to customized a Turbo cams for ur engine..? Lolz... Well, get a vvtli controller.

 

[veilsideboyz]

Any RPM also can... just wanna know the ratio. Try all 3ooorpm.
U know how much does it cost to customized a Turbo cams for ur engine..? Lolz... Well, get a vvtli controller.

Ok~let you know 2moro :)
BTW..power fc only for manual celica ... auto celica dont have any vvtli controller. :(
Taiko , my piston is 82mm... if change back to 82mm wiseco.. no need sleeve right ?
If within spec..only sleeve the block.. Hmm... i dont understand why people mean oversize piston ??
Mean now i buy a 84mm piston then oversize the block to make it fit ??:wavey::wavey::wavey:

 

[speed2horizon]

Ok~let you know 2moro :)
BTW..power fc only for manual celica ... auto celica dont have any vvtli controller. :(
Taiko , my piston is 82mm... if change back to 82mm wiseco.. no need sleeve right ?
If within spec..only sleeve the block.. Hmm... i dont understand why people mean oversize piston ??
Mean now i buy a 84mm piston then oversize the block to make it fit ??:wavey::wavey::wavey:

No need sleeve la. Sleeving if for those ppl damaged the cylinder too much or reaaly 7 high boost. Else not required.

Example. My case, my piston size is 81mm. But i'mafraid that my cylinder no longer 100% round n I'm planning to install new pistons. So, I buy oversized pistons of 0.5mm. Review my cylinder to 81.5mm. New cylinder bore + new pistons. Confirm 100% round.

2 reasons. To make sure my cylinders are like completely new, And to gain more cc.

Some ppl oversized purely to gain cc.

 

[veilsideboyz]

No need sleeve la. Sleeving if for those ppl damaged the cylinder too much or reaaly 7 high boost. Else not required.

Example. My case, my piston size is 81mm. But i'mafraid that my cylinder no longer 100% round n I'm planning to install new pistons. So, I buy oversized pistons of 0.5mm. Review my cylinder to 81.5mm. New cylinder bore + new pistons. Confirm 100% round.

2 reasons. To make sure my cylinders are like completely new, And to gain more cc.

Some ppl oversized purely to gain cc.

Oic !! :) Ok ~My piston is 82mm stock... So what I gonna do is...
1. I let my mechanic open the engine 1st...see my cylinder damage or not...
2. If is ok , just put a 82mm piston drop in right??
3. If cylinder is damage!! I just put a 82.5mm piston bore & sleeve to fit ??

Oh ya ! I just test my car justnow ~~
1st gear 3k rpm = 30km/h
2nd gear 3k rpm = 50km/h
hope this detail can help !

 

[speed2horizon]

Oic !! :) Ok ~My piston is 82mm stock... So what I gonna do is...
1. I let my mechanic open the engine 1st...see my cylinder damage or not...
2. If is ok , just put a 82mm piston drop in right??
3. If cylinder is damage!! I just put a 82.5mm piston bore & sleeve to fit ??

Oh ya ! I just test my car justnow ~~
1st gear 3k rpm = 30km/h
2nd gear 3k rpm = 50km/h
hope this detail can help !

No need sleeve la... If cylinder not nice, just buy oversize. Rebore n plunk in the pistons
=.="

 

[veilsideboyz]

No need sleeve la... If cylinder not nice, just buy oversize. Rebore n plunk in the pistons
=.="

Haha !! okok !! Just put 82.5mm..... and rebore !!
If put 84mm .. will increase cc

 

[speed2horizon]

Haha !! okok !! Just put 82.5mm..... and rebore !!
If put 84mm .. will increase cc

Suka suka oversize meh...? Must know the limit of oversizing ma... Everytime u rebore, it'll weaken the cylinder wall a little. So, when overzized over the designed limit for safety, the cylinder will fail...