4g93T gsr engine rebuild, need advice

[speed2horizon]

any articles to read?

Before u go deeper, Read this to understand more about ur engine characteristic.

Our beloved Wikipedia has everything...
Stroke ratio - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Ambox_globe_content.svg" class="image"><img alt="Globe icon." src="http://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_globe_content.svg/48px-Ambox_globe_content.svg.png"@@AMEPARAM@@commons/thumb/b/bd/Ambox_globe_content.svg/48px-Ambox_globe_content.svg.png
Though not in deep, but u'll understand the fundamental

 

[mojoloon]

hehehe.. i think this one more clearer to me

http://www.pumaracing.co.uk/CAPACITY.htm

 

[speed2horizon]

hehehe.. i think this one more clearer to me

http://www.pumaracing.co.uk/CAPACITY.htm

Err... they are 2 different topic. One is about capacity and compression ratio which u posted. The one that I posted was abt engine configuration on bore/stroke ratio which categorize engine into 3 different configuration.

Square engine
oversquare aka short stroke
undersquare aka long stroke

with their advantages n disadvantages.

4g92 is considered oversquare n 4g93 is considered undersquare.

 

[amel666]

Stick to standard displacement and slap the biggest turbo your stomach can take then upgrade the oil pump, internal and head with aftermarket performance part. Your engine are stronger enough to rev up to 10k....

I 200% agree with u!!
In fact That's the wises way to enjoy our turbo engine. Instead of trying to take a harder path of stroking a good 1.8liter engine why not strengthen its weakness.
No Kaboom... No skirt patah.. etc..

good old, Reliable, hi-way boosting, wastegate farting.. machine.
That can rev till 10k, higher than some v-tecs. Hi-boost with hi-revving madness -- participate in time attack

BTW, Jo1
Do u know how high or the safest limit can we gsr's rev - with stock cams/lifters/valve springs? 7.5k..8..or even 9000rpm's?
Too scared to experiment ownself la bro. :hmmmm:

 

[speed2horizon]

I 200% agree with u!!
In fact That's the wises way to enjoy our turbo engine. Instead of trying to take a harder path of stroking a good 1.8liter engine why not strengthen its weakness.
No Kaboom... No skirt patah.. etc..

good old, Reliable, hi-way boosting, wastegate farting.. machine.
That can rev till 10k, higher than some v-tecs. Hi-boost with hi-revving madness -- participate in time attack

BTW, Jo1
Do u know how high or the safest limit can we gsr's rev - with stock cams/lifters/valve springs? 7.5k..8..or even 9000rpm's?
Too scared to experiment ownself la bro. :hmmmm:

it's not the danger to the cams. It's the valve float phenomena after 7.5krpm. The cams turn too fast but the spring does not react fast enough... So, valve don't seems to close properly before the next exhaust stroke comes in...

Just change the spring and u're ready to go. Valves are strong, the valve seats and valve guide material are harder than the head. So, nothing much to worry.

 

[goo_61t]

any articles to read?

u can search in zero not long ago i posted something related to stroker engine full documentation with some scientific explanation.

amel666, why u want to rev 9K haha giler laaahhhhh :p

is ur turbo that large that u need to rev to 9K?is ur cam that aggressive?is ur valve terrain that strong? hehe.. with standard valve terrain,cams i dun think u can rev past the rev limit.. the limit is there for a reason :) why not stick to the rev limit n push ur turbo to the max..run it n maxxed it out rather then revving ur car up high where ur turbo does not support the power band

 

[contreasjun27]

Hi Guys few weeks didnt enter forum already!
this thread is getting very active keke

 

[jo1]

standard valve train had been rev up to 8500 with tdo5 without any problem, with jun copy cam and valve train for now up to 9500 using gt30. The motor been rev up to utilize the gearbox ratio/shift point and power band of the engine not just for fun of revving it to the moon.

 

[goo_61t]

standard valve train had been rev up to 8500 with tdo5 without any problem, with jun copy cam and valve train for now up to 9500 using gt30. The motor been rev up to utilize the gearbox ratio/shift point and power band of the engine not just for fun of revving it to the moon.

i think i knw which GSR ur talking about ngehehe..but the gear ratio has been modified :)
as for amel666 i think he is still using standard gsr gearbox :) so would be a waste to rev the engine past the rev limit :) just my 2 cent.. i'm not runnning gsr anyways ngehehe just from personal experience and observations

 

[amel666]

u can search in zero not long ago i posted something related to stroker engine full documentation with some scientific explanation.

amel666, why u want to rev 9K haha giler laaahhhhh :p

is ur turbo that large that u need to rev to 9K?is ur cam that aggressive?is ur valve terrain that strong? hehe.. with standard valve terrain,cams i dun think u can rev past the rev limit.. the limit is there for a reason :) why not stick to the rev limit n push ur turbo to the max..run it n maxxed it out rather then revving ur car up high where ur turbo does not support the power band

I'm not asking u whether d stock setup can/would rev to 9k rpm brader..
And what do u care if its waste to rev the engine past the rev limit brader.. it's not like i'm borrowing/using ur dogbox rite? hehe

Thanks jo1,
My powerband is a bit later in the rpm. So was thinking if can raise the rev limit a bit to have longer powerband before having to shift. As for my tranny is still stock ratio evo lsd box.
If it's safe to raise my rev limit just a bit from 7.5k to 8k/8.5k rpm, is good enuf.

 

[slow_gsr]

Sometime i do a stupid tuning but a good result come out hehehehe.U can use B18 Wiseco Turbo Pistons and Rod combo.The price very cheap out there.Around 3K+.

sorry to disturb, if i want to use wiseco 82mm what piston compression ratio is better for gsr bro? cr8.6.1 or cr9.0.1. and what saiz of metal gasket is better, 1mm, 1.2mm,1.5mm,1.8mm or 2mm if i want to boosting 2bar. Tq...........

 

[speed2horizon]

sorry to disturb, if i want to use wiseco 82mm what piston compression ratio is better for gsr bro? cr8.6.1 or cr9.0.1. and what saiz of metal gasket is better, 1mm, 1.2mm,1.5mm,1.8mm or 2mm if i want to boosting 2bar. Tq...........

The reasons I see to use thicker metal gasket are:
- u wanna reduce ur compression ratio in order to boost higher.
- to overcome the problem of protuding pistons fron the block when u use a non standard pistons.
- to replace the lost material of the cylinder head due to skimming.

So, u're using a customize pistons that suits ur desired compression ratio, then u may not need to bother abt a thick metal gasket.

But if 9:1 or 8.6:1 are the only pistons u find, and u still wanna further reduce ur CR, then u opt for a thicker metal gasket. The selection of the gasket depends on how much u want to reduce ur cr. And ur cr reflects directly to the maximum boost level before pre-mature detonation occurs on the selected type of fuel u'll be using.

 

[slow_gsr]

The reasons I see to use thicker metal gasket are:
- u wanna reduce ur compression ratio in order to boost higher.
- to overcome the problem of protuding pistons fron the block when u use a non standard pistons.
- to replace the lost material of the cylinder head due to skimming.

So, u're using a customize pistons that suits ur desired compression ratio, then u may not need to bother abt a thick metal gasket.

But if 9:1 or 8.6:1 are the only pistons u find, and u still wanna further reduce ur CR, then u opt for a thicker metal gasket. The selection of the gasket depends on how much u want to reduce ur cr. And ur cr reflects directly to the maximum boost level before pre-mature detonation occurs on the selected type of fuel u'll be using.

ty for that info. is u in my position what piston cr and what metal gasket saiz u use?......he3

 

[amel666]

IMO,
9.0:1 cr wiseco pistons is the better choice. As it is forged from 2618 aluminium that can withstand > 2bar of boost. Even if its made from the higher silicone 4032 aluminum still its far superior than any factory/oem.. (out of topic abit)..

Using 9.0cr means u can achieve higher HP/torq figures compared to using 8.6/8.0cr without having to boost as high. .
As for the MLS gasket if it's up to u. But remember, the more thicker the gasket the higher the risk of detonation can occur from the increased "squish" volume.
The head gasket will lower the compression more depending on it's thickness.
But Normally i think it's easier to find or gsr the 1.5mm compared to 1.2/1.6/etc in the market. so just proceed with the 1.5mm gasket. I myself are using 1.5mm.

U don't have to worry about the piston hitting the valves, wiseco's 4g93/b18c pistons have generous valve relief pockets. Even if u use hi duration cams, ur valves would still clear the piston dome.
But i u want to use Nitrous Oxide/NOS better use lower (8.6cr) and thicker gaskets.

Only my opinion from experience.. But the piston can still ht the valves if not installed properly :hmmmm:

 

[speed2horizon]

IMO,
9.0:1 cr wiseco pistons is the better choice. As it is forged from 2618 aluminium that can withstand > 2bar of boost. Even if its made from the higher silicone 4032 aluminum still its far superior than any factory/oem.. (out of topic abit)..

Using 9.0cr means u can achieve higher HP/torq figures compared to using 8.6/8.0cr without having to boost as high. .
As for the MLS gasket if it's up to u. But remember, the more thicker the gasket the higher the risk of detonation can occur from the increased "squish" volume.
The head gasket will lower the compression more depending on it's thickness.
But Normally i think it's easier to find or gsr the 1.5mm compared to 1.2/1.6/etc in the market. so just proceed with the 1.5mm gasket. I myself are using 1.5mm.

U don't have to worry about the piston hitting the valves, wiseco's 4g93/b18c pistons have generous valve relief pockets. Even if u use hi duration cams, ur valves would still clear the piston dome.
But i u want to use Nitrous Oxide/NOS better use lower (8.6cr) and thicker gaskets.

Only my opinion from experience.. But the piston can still ht the valves if not installed properly :hmmmm:

True enough abt the torque. But sad to say the pistons melts on my friend's gsr due to detonation occured at 1.9bars 5krpm. Reason was ecu up to 9krpm but e-manage 8krpm. So, it's time to determine muscles toughness or brain is more important.

I'd say chances of valve hitting pistons are more prone to happen due to the lift n less effect on the duration.

Btw mel, is it the silverstone's that causes the dmage to ur engines??? Cause I saw their foreman drives like cock..