SETUP on 4age 20v head...

[Bo SEG]

hye there...here i have something to ask...

i want to top overhaul my engine BT 20v...should i skim the head to increase the compression?....i got 0.5mm metal head gasket...so it will improve the tork ryte?..

some of my source tell me that SVT head much better than BT based on its "kawah"...so is it good if i mix BT engine with SVT head?....any comment....can i use BT camshaft on SVT head?...how bout the compression?...do the ext hole need to bore coz the BT more big than SVT?....how bout the MAP sensor...??/....how bout the intake?...

which one better to made improvement on my BT w/o change camshaft....
i want to do mixing for performance which its low cost than put aftermarket performance part...

any idea on HEAD modification for performance?

 

[j_l200s]

well, usually ppl will use blacktop head because of the larger ITB and the ability to use MAP although some still using the SVT head with MAP and BT's ECU. wondering why u do the other way round... hmm... or maybe i'm the one who got it the other way round? Yes, u can use BT cams on SVT head.

if u want good torque, u might wanna consider TODA/CP forged 82mm high comp pistons. no use skimming the head... u are risking urself of over-heating if u skimmed too much.

well, to be honest... 20V BT/SVT u can't rojak much to gain extra HP/torque. they aren't like 4Gs or B series where u can rojak here n there. u should appreciate ur original blacktop IMHO.

but if u really insist on improving just the head, send it to a good machinery shop for a head job (those using CNC machines). get a good flow and balance the compression for all cylinders.

follow this link to get a better explanation :p
SQ Engineering - Articles - 20V differences


just my 2 cents... sifus, pls forgive and correct me if i shared any wrong info.

 

[nappx]

rojak also can for minimal budget..
incase u convert bt and intend to mod and want used svt part still can use.
bt block
svt head (port & polish) it depend want sent to engineering as mention by sifu j_l200s
bt itb
svt conrod
used svt piston with bt ring (ha ha ha...can arrr)

learning from experiance..using more than 81.5mm piston ring...better get spare set of piston ring..why..let think..
why svt not bt head to PnP...? ahaks..any1 want share..nubie here

 

[Bo SEG]

well, usually ppl will use blacktop head because of the larger ITB and the ability to use MAP although some still using the SVT head with MAP and BT's ECU. wondering why u do the other way round... hmm... or maybe i'm the one who got it the other way round? Yes, u can use BT cams on SVT head.

if u want good torque, u might wanna consider TODA/CP forged 82mm high comp pistons. no use skimming the head... u are risking urself of over-heating if u skimmed too much.

well, to be honest... 20V BT/SVT u can't rojak much to gain extra HP/torque. they aren't like 4Gs or B series where u can rojak here n there. u should appreciate ur original blacktop IMHO.

but if u really insist on improving just the head, send it to a good machinery shop for a head job (those using CNC machines). get a good flow and balance the compression for all cylinders.

follow this link to get a better explanation :p
SQ Engineering - Articles - 20V differences


just my 2 cents... sifus, pls forgive and correct me if i shared any wrong info.

so....the BT head also good ryte?....and if i'm not skim the BT head...and i only put 0.5mm gasket...is it ok and will it improve the performance?...some people say that more close your piston to the head.... more compression, tork and power you'll get....is it ryte?.....but im worried the top speed will decrease if i'm using 0.5mm gasket......

normally on head job...what they do and how much it will cost....about using 82mm piston.....i'm worried it will drain my pocket and budget..hehehe....

 

[levin818]

Hello Bo, GoodSpeed at Kepong is offering BT head swap at about RM1400 inclusive of labour.
You trade in yours and you will get a ported head.
I haven't have mine swap but according to Banzai the result is noticeable immediately.
For details on the work and price you may direct contact the mech Ah Choy at 019-2248 577.

 

[D7zul]

Hello Bo, GoodSpeed at Kepong is offering BT head swap at about RM1400 inclusive of labour.
You trade in yours and you will get a ported head.
I haven't have mine swap but according to Banzai the result is noticeable immediately.
For details on the work and price you may direct contact the mech Ah Choy at 019-2248 577.

can swap with SVT head?

 

[Bo SEG]

Hello Bo, GoodSpeed at Kepong is offering BT head swap at about RM1400 inclusive of labour.
You trade in yours and you will get a ported head.
I haven't have mine swap but according to Banzai the result is noticeable immediately.
For details on the work and price you may direct contact the mech Ah Choy at 019-2248 577.

Thanks bro!!!...i'll try contact them A.S.A.P.....to ask about the detail...

 

[j_l200s]

so....the BT head also good ryte?....and if i'm not skim the BT head...and i only put 0.5mm gasket...is it ok and will it improve the performance?...some people say that more close your piston to the head.... more compression, tork and power you'll get....is it ryte?.....but im worried the top speed will decrease if i'm using 0.5mm gasket......

normally on head job...what they do and how much it will cost....about using 82mm piston.....i'm worried it will drain my pocket and budget..hehehe....

the higher your compression is, the more engine knocks/pingings you are prone to.... it isn't just thin gasket, skim head and wa la! more power and torque. IF ONLY IT'S THAT EASY :)
In some sense, yes, it does raise a bitttt.... but still u gotta tune properly :)
the higher your compression is, the higher octane of fuel u'll need.

u can refer to sifu levin818's source for the performance head... or u can refer to the below link. i never done that before, maybe u might wana give them a call and ask for price. good luck

Nasty Portflow

 

[meg_omen]

- what's your budget?
- how far do you want to mod; for track & street or track totally?
- how much can you invest in ecu?

i think with the above, suggestion given will be better...

 

[pcmoddingmy]

I believe the TS is currently using BT engine and plans to overhaul it. So, he's asking if using SVT head on his BT block and BT ITB.
Well... I think it defeats the purpose of using SVT head as the cost involved to port match the SVT head to BT ITB and might end up with no significant power gains. Might as well send the current BT head for proper port polishing & matching (no need to enlarge the ports) and preferably do a flowbench as well.
Usually on a BT engine, some guys will opt for SVT pistons as it will increase the compression a bit.
Regarding 0.5mm head gasket, I think its quite risky because TRD & Toda only sells 0.8mm. Plus if you skim the head say 0.1mm or 0.2mm, then the compression is gonna be very high for street use especially if you plan to use RON95 fuel. Else, its gonna knock like crazy!

As I know, when increasing compression it helps to gain power with proper tuning via piggyback or standalone, but with stock ECU it will worsen the performance because the ECU is going to retard the timing the moment it detects knocking. Also, compression increase and be accommodated with aftermarket cams that usually higher duration & lift which will improve flow into the head and reduce knocking. So with hi-cams and hi-comp, the tuner can tune the engine with more aggressive ignition hence making more power.

Also, you can consider regrinding your stock camshafts at Matspeed Sunway. These guys are famous for regrinding camshafts but I never heard of anyone doing it for 20v though.

Just my 2cents...

 

[KHWONG]

Hello Bo, GoodSpeed at Kepong is offering BT head swap at about RM1400 inclusive of labour.
You trade in yours and you will get a ported head.
I haven't have mine swap but according to Banzai the result is noticeable immediately.
For details on the work and price you may direct contact the mech Ah Choy at 019-2248 577.

yeah... i did mine before at there.. today send in car, tomolo can take the car cus he already done the head port n polish standby with all the valve seal changed..

he normally will skimmed the head a bit just to confirm the head surface is in 100% flat condition for the metal gasket.

can swap with SVT head?

i think he can if little bit more top up or i believe he also did have the SVT head port n polish ready.. hahahhahahha



but for my opinion, above mentioned idea is for you to stick in standard BT camshaft..

if you wan try higher cam profile, i advised you " one time sakit" to go TODA.spend more time to save money for it.. it worths...

good luck bro..

 

[Bo SEG]

thanks to all...plizz help me on my new thread...
http://www.zerotohundred.com/newforums/toyota/429363-7a-ge-20v-problem.html#post1064271948