Need solution: VR4 using 87MM piston

[reintel]

Need help, suggestion, solution here.

i have installed in 87mm piston to my vr4 block. currently its abt 6mm sitting low from the head. is there a way to compensate the loss and still able to run it normal using standard wiring, ecu? plans to get EMS end of the year.

 

[flushafteruse]

what piston u use???

 

[reintel]

semi forge piston. harrier. i was given 2 choice, potong the head to increas compression or leave it as it is. i opt for 2 option since i will b upgrading new turbo, injector and even using ems year end.

wondering wat will happen now? is car gonna perform slight better or much worse? bigger displacement, standard ecu = ??

 

[flushafteruse]

depends whats your setup planning into?? maybe try do your compression ratio test to get a better result

 

[reintel]

well, the setup plan is there for high boost application. however, budget is pulling me down. right now looking at the piston sitting. it is confirm gonna b very very low compression. imagine piston tdc is abt 6mm from the head, plus 2mm metal gasket, leaving space ard 7-8mm. it is yet to complete for engine start test.

when i was using 1jz piston, full boost is ard 3000rpm. i wonder how dis will react?

 

[pinkdotdesigns]

change to thinner metal gasket bro. I think it should help. or u can always skim the head a lil bit to raise the compression.

 

[reintel]

1 of the choice is skim the head to raise the compression. but wat if i use the current setting for future high boost application. wat will happen in short time? anyone has ever encounter this kind of mod?

 

[bertdeen30]

- .- "
87mm can be using sr20 piston , lagi is high compression piston .. lightnen your piston and dont ball the top part , lightnen your conrod , crankshaft to pull your torque and your boost to come even u can skim your flywheel..=D .. the torque respond faster than your block do ..~ keke~
compression u want to skim your head is not good enough, sooner or later if u want to go for high cam ..man~ u will sick of it..cause u have not place for high cam~ , anyway vr4 compression is not that high .. u dont worry man~..it build with not high compression also~ just boost to make it fast ..lightening crank , conrod , piston , flywheel , fuel regulator (make your fuel shoot more inner) explosion nicer ) , air injection to pump air into .. ori ecu is abit hard to stand ..but if u got for better gear ratio nor u have a better ecu .. slightly increase torque and horsepower at least 20-40..i think~but effect torque more..highcam in a same time .with cam spoket i think u change a standalone ecu with evo3 turbine also can go more than 300-350 hbps in between easily..im a vr4 user

 

[reintel]

at last some answer! but r u using same setup? is this base on theory assumption? i might be wrong but the piston im using may have same diameter but the height of the piston differs as it is much shorter compare the rest thus giving the low compression effect. flywheel, fuel regulator, AIC, crank lighten is done. im not sure if i lighten the conrod will give effect interms of strenghtness.

the engine still outside, but all have be installed and hopefully we could fire it up this saturday to c the effect. may take times to know as i've changed my intercooler and redo S/S piping.

 

[bertdeen30]

ok..how about ..
skim your top head ?
change air/fuel sensor into stand alone e.c.u by using richer and more air setup ?
if you have longer conrod higher compress , but doing work slow ?
high cam + cam pulley ?
what u meab by as i've changed my intercooler and redo S/S piping ??
intercooler and s/s doesn't effect much only if they are leaking..
exhaust piping ? too power ful till the air can't out from exhaust ? how many inches using ? alot of thing will cause as like what to do..
change to e3 wiring with e3 air/flow sensor ? but in this way i rather ask u to get a stand alone ecu..somehow they got anti lag system..~ ; D ..
good luck to u man~

 

[bertdeen30]

i mean change stand alone ecu is using by map sensor~ try to get haltech or other with 3 bar mapsensor..sharp ..for reading.

 

[reintel]

ok..how about ..
skim your top head ?
i decided to leave it as it is. thats why im wondering wat will happen? anyone try it before?

change air/fuel sensor into stand alone e.c.u by using richer and more air setup ?
i tot a/f sensor is (O2 sensor) wat relation wif stand alone ecu?

if you have longer conrod higher compress , but doing work slow ?
which conrod r u talking abt? is there any conrod that can replace VR4?

high cam + cam pulley ?
Cam pulley yes, camshaft standard.

what u meab by as i've changed my intercooler and redo S/S piping ??
intercooler and s/s doesn't effect much only if they are leaking..
exhaust piping ? too power ful till the air can't out from exhaust ? how many inches using ? alot of thing will cause as like what to do..
yes, that wat i mean lah. i've changed my intercooler and off courselah have to redo piping kan? unless u using rubber pipe, thats different story. exhaust piping 2.5inch 304 stainless steel.

change to e3 wiring with e3 air/flow sensor ? but in this way i rather ask u to get a stand alone ecu..somehow they got anti lag system..~ ; D ..
good luck to u man~

i rather get haltech or microtech to spend on evo3 wiring.

 

[keong_GSR]

in DSM forum, they suggest ROSS piston only that suitable for 4g63t...dunno why? y dun u go for fairlady bro?

 

[reintel]

Keong,

engine currently running. so far very good. im using the harrier piston. the top had ceramic coating. having problem on blow off as it din release completely. But, if i adjust too much. engine died off. found out, turbo need to replace as it is now to small for it. searching for a TD06 or bigger turbo.

 

[keong_GSR]

bro,

my piston still stock,my car is not yet ready but i already spare the fairlady piston liao... i'm using T04s but no lag at all...maybe due to d back housing that only 0.58 my car now around 0.9 bar but my rallyart clutch already slip! try d GT 30 from garrett,very cun for 400bhp category... i've sit on my fren Gt35 but too much lag...