7A-GE 20v PRoblem...

[Bo SEG]

hye there...
here i need some advice from all who know something about 7age 20v project...


i was built 7age 20v on blacktop.....

spec..

cp 82mm piston
7a-fe block bore 82mm
7a duratech con rod
king conrod bearing
stock 20v bt head + stock Cam + stock cam gears
4age 16v timing belt
0.8mm trd metal head gasket
7a 212mm flywheel
4age 20v 6 speed gearbox
clutch cover exedy racing with trinity clutch disc
tom's trumpet
e manage blue ecu
1 jz fuel pump
work fuel regulator
ngk r 09 plug cable
iridium tough vk 20 plug

but now after dyno...i only got 140ps..
the tuner said i must reduce the compression to get more hp..
he said my engine got to much of knocking...
he tell me to put around 2mm head gasket to reduce the compression..
too high compression will reduce the hp coz of too much of knocking...
so now he retard the firing(if not mistaken)...
and my engine dont have power that it deserve...

is that true???..
can this spec produce lot hp?
is there have another spec that suit for 7age setup????

i want to put 288 deg 9.2 lift for my engine...
but i want to settle this problem 1st to see the stock 7age 20v could make...

 

[Dayline668]

7A is never about power, its to make more torque. Except for race build 7A or turbo.

 

[Mr.Chaser]

iF NOT WRONG 7a BLOCK ONLY HELP U INCREASE MORE ON TORQUE & REALLY SLIGHT HP ONLY. U USE RON 95 OR 97 TO TUNE?

 

[Bo SEG]

now i use ron95....
before this i oredy try use ron97...direct from jb to kl.......kl to jb......jb to mersing.....fully ron97...
but there is no different....still got knock.......but i feel small amount of power increase......

now i have plan to put another head gasket on my engine...i find cometic metal gasket...1.5mm...and i also will put trd 0.8mm metal gasket...so total among 2.3mm before pressed...
is this thing can really help to reduce the knock and compression???...

 

[Dayline668]

Lowering compression will eliminate knocking, but how much compression u running now...? after installing new gasket...? u need to know how much compression your setup is. Stock is already 11, too high for current ron97.

 

[aHLengChai]

yup.. too high compression will make alot of knocking (need to use race fuel / jet fuel perhaps?)

reduce a lil bit your compression..

 

[j_l200s]

well, i think your CP pistons killed u. too high-comp. Should have used ST or BT pistons. wah... 2 different gaskets stick together? i wouldn't gamble that if i were u. try getting a piece of 2.0mm gasket instead of combining...
288 with 9.2 lift.... don't u think it's too high for an engine which can't rev that HIGH to squeeze 100% out from that aggresive TODA cams?

oh well, what would i know? i just read them over the net. just riding an EX5 now...

 

[Mr.Chaser]

I think u re-tuned better. Go find a reputable tuner as my fren compression around 13 also use 97:)

 

[Veloc]

Reduce compression la... Stock blacktop compression already high. Now you increase stroke but use back the same head. Compression sure super high. Use 1.5 or 2.0 mm gasket try la...

 

[Bo SEG]

last time...my pomen check....when he kira2....
he told me that my compression among 15....
i dont know its right or wrong....thats on my pomen calculation....
i already try finding metal head gasket 2.0mm...but never found....
now i only found 1.5 mm...the tuner said i must use at least 2mm...
now the 1.5mm cometic gasket still in shipping....

does anybody know where to find 2.0mm metal gasket for bt 20v??????????
help me....

---------- Post added at 08:41 PM ---------- 6 hour anti-bump limit - Previous post was at 08:36 PM ----------

well, i think your CP pistons killed u. too high-comp. Should have used ST or BT pistons. wah... 2 different gaskets stick together? i wouldn't gamble that if i were u. try getting a piece of 2.0mm gasket instead of combining...
288 with 9.2 lift.... don't u think it's too high for an engine which can't rev that HIGH to squeeze 100% out from that aggresive TODA cams?

oh well, what would i know? i just read them over the net. just riding an EX5 now...

boss...do u know where to find 2.00mm metal gasket for 20v?????????????

that's mean 7age cant drive 288 deg cam???...how bout 272 deg??....and how bout the lift???...
which one match for 7a-ge???

---------- Post added at 08:45 PM ---------- 6 hour anti-bump limit - Previous post was at 08:41 PM ----------

yup.. too high compression will make alot of knocking (need to use race fuel / jet fuel perhaps?)

reduce a lil bit your compression..

so the problem is compression........what is the best compression for my engine....the maximum before knocking....

 

[Veloc]

Bro, try kegani autotech

---------- Post added at 09:52 PM ---------- 6 hour anti-bump limit - Previous post was at 09:48 PM ----------

Try Kegani la... They are known to be 4AGE specialist and famous among 4AGE players. But I've also heard of their not so good services. Not sure if that is the norm or just an isolated case. I mean, no matter how good a product or service is, sometimes a defect will popup anyways. Try ask them for the gasket. If you want back your mechanic, see if you can source the gasket from them for your mech to work on.

If none, maybe you got to try look overseas already like Tomei, HKS, Toda, etc...

If still don't have, custom make one.

---------- Post added at 09:55 PM ---------- 6 hour anti-bump limit - Previous post was at 09:52 PM ----------

Or else, you can try to plonk in 4AGZE pistons or shave off a bit of material at the head. Sorry so send so many separate replies. Ideas just keep coming. That is the beauty of 4A family engines bro. Can mix and match plenty parts!

 

[Bo SEG]

Bro, try kegani autotech

---------- Post added at 09:52 PM ---------- 6 hour anti-bump limit - Previous post was at 09:48 PM ----------

Try Kegani la... They are known to be 4AGE specialist and famous among 4AGE players. But I've also heard of their not so good services. Not sure if that is the norm or just an isolated case. I mean, no matter how good a product or service is, sometimes a defect will popup anyways. Try ask them for the gasket. If you want back your mechanic, see if you can source the gasket from them for your mech to work on.

If none, maybe you got to try look overseas already like Tomei, HKS, Toda, etc...

If still don't have, custom make one.

---------- Post added at 09:55 PM ---------- 6 hour anti-bump limit - Previous post was at 09:52 PM ----------

Or else, you can try to plonk in 4AGZE pistons or shave off a bit of material at the head. Sorry so send so many separate replies. Ideas just keep coming. That is the beauty of 4A family engines bro. Can mix and match plenty parts!

Kegani???....where it's located?.....how can i contact them???....


what's diameter of 4agze pistons???......is shave material on head same like port n polish??

 

[Dayline668]

U can lower the compression by shaving the piston crown, but that gonna cost more n is the best way for reliability.

Kegani is at puchong selangor, they build 4ag race engine.

High cam perform at high rpm, 7A cannot rev high, so high cam also wasted.

 

[Veloc]

Kegani???....where it's located?.....how can i contact them???....


what's diameter of 4agze pistons???......is shave material on head same like port n polish??

All 4A family engine piston have same bore and stroke. That is the beauty of it. Need to change conrod and main bearing. Easy to mix and match. 81 mm bore x 77 mm stroke. Oversize is 81.5 mm bore.

You want to lower compression, shave off some material in the combustion chamber, use 4AGZE pistons, use thicker gasket or use engine head spacer. If not enough, use a combination of these. DO NOT shave off the piston. That will lower reliability. Pistons receive the direct impact of ignition and expansion of gases. There are made to a certain thickness for a reason. All have been R&D before.

 

[Dayline668]

There nothing to shave off in combustion chamber only will weaken more already thin 20v head. 4agze piston yes, but he already bore to 82mm. Thicker gasket n spacer not reliable (except add weld to the head like thishttp://www.zerotohundred.com/newforums/car-modification/421995-swift-bot-low-comp-head-build.html ). Forged piston can be shave off to a minimal tolerance, contact CP for the number, n get it pro machined, tuning is very important, lean tune will melt any piston.

 

[j_l200s]

HKS Head Gasket AE86 Corolla 4AGE 4AGZE 82 0mm 2 0mm | eBay

:)

 

[D7zul]

your exhaust cam gear need to change to an adjustable 1..

coz timing a bit 'lari'..

try that 1st..

 

[meg_omen]

it's easier to change to another piston...
cp has the lower compression type...:hmmmm:

 

[lkeong88]

Kegani has no experience with 7a what makes you think it will work by going there.

Its better to go to Trial Tuning, they had a 7a

 

[mh wong]