Little question from 1.8 mivec newbie

[HanZ85]

hi all zth members i juz finish my 1.8 mivec project near these days but somehow i still got something wondering cant get the answer c if can get some teaching from all the sifu's~

1.im using mivec extractor & 2.3 piping till end using 2.3 straight flow muffler,so does tis spec supports my present engine?

2.mivec 1.8 is suprisingly powerful when its on satria but when i flooring the paddle power comes very smooth on 1-3k rpm and start to roar after 5.5k rpm but when its 3-5k rpm it felts like some turbo lagging feeling like the power slightly dropping.but it will recover the power and start pushing the rev after 5.5k rpm...wat kind of condition is tis?should i apply the e manage to solve tis problem?or its the adj cam pulley setting making the powerband drop?how much digree sifu usually set for mivec 1.8?

3.my blok using 4g92p piston instead of mivec piston coz im afraid of knocking problem,in future if i wanna start new plan can i directly bot turbo on my 1.8 mivec?my blok edi done balancing job.any setting precaution from sifu's?


thanks for reading my thread ya everybody hope can get some answer from u all thank you!

 

[g4i8y0t]

As far as I know, the 4g92p piston has lesser compression than the mivec piston. This may be the main reason why you're not getting the power that the mivec is supposed to produce.
My suggestion is this:

1. Reset the ECU. Unplug the earth wire (-ve terminal) from the battery for >15mins. Then reconnect the earth. Try driving around for about a week and see wether the problem still exist.

2. Maybe the current setup for your exhaust is causing the 3-5k RPM power drop. Try asking other mivec 1.8 users for the correct setup.

3. If this still cannot work, retune the engine.

Just my 2 cents.

---------- Post added at 10:43 PM ---------- 6 hour anti-bump limit - Previous post was at 10:36 PM ----------

U can also read these thread about mivec 1.8:

http://www.zerotohundred.com/newforums/car-modification/2501-mivec-1-8-a.html

http://www.zerotohundred.com/newforums/car-modification/9771-mivec-1-8-a.html

 

[dreamsquall]

wah sui jai de satria come out liao
see ur car i let u pass 1st haha

 

[HanZ85]

Haha thanks bro but i duno who r u lar~

 

[Enslaved]

Always tune the engine after every mod to extract the optimum performance! Mine is using 2.5" straight through..

 

[pijulrs]

yes...mivec engine compression is at 11.1 but 4g92p sohc compression is lower at 10.1...you should opt the mivec piston inside the 1.8block.

 

[HanZ85]

Thanks for all ur idea ya i'll try dynotune my ride wif e manage 1st try if can change it to aeroplane anot haha~i heard vteckiller was good in tis do u think?

 

[mizi0604]

mine also using 2.5" straight flow,the power is superb...U might need to set ur campulley back,i also faced this problem while using 1.6 mivec,but the problem solved after set the campulley...just based from my experience...peace~

 

[Zeroed]

4G92 non-mivec piston in a 4G93 block will yield higher compression than in a 4G92, due to the extra 200cc. Not sure how much, but its likely enough for Mivec application. The compression with mivec pistons in a 4G93 might be too high for long term road use.

What intake manifold are you using? most older cars without cam-phasing will suffer from the mid-range torque drop, mivec and vtecs included. This can be aided with adjustable cam pulleys. In anycase, its best to go get a dynorun and ask for a professional mechanic's advise (would recommend Thomas from GT Auto, he's very helpful in explaining his customer's problems).

Its possible that your cam pulleys are set wrongly as well, since retarded cam timing will improve low and high range torque, while advanced timing will improve mid-range torque. Yours might be retarded a bit too much.

 

[dreamsquall]

i;m ur ex-rg mechanic's son haha

 

[DanzEterna]

use VAFC.

 

[Veloc]

4G92 non-mivec piston in a 4G93 block will yield higher compression than in a 4G92, due to the extra 200cc. Not sure how much, but its likely enough for Mivec application. The compression with mivec pistons in a 4G93 might be too high for long term road use.

What intake manifold are you using? most older cars without cam-phasing will suffer from the mid-range torque drop, mivec and vtecs included. This can be aided with adjustable cam pulleys. In anycase, its best to go get a dynorun and ask for a professional mechanic's advise (would recommend Thomas from GT Auto, he's very helpful in explaining his customer's problems).

Its possible that your cam pulleys are set wrongly as well, since retarded cam timing will improve low and high range torque, while advanced timing will improve mid-range torque. Yours might be retarded a bit too much.

Agree about the piston thing. Please don't use mivec pistons in a 1.8 mivec. Even with the 4g92p piston, I think the CR should be high enough and if you consider turbo in the future, you might still need to change to low-comp pistons.

mid range torque drop? Is there any possibility that it is caused by the overkilling 2.3" piping? Just wondering... No idea...

You have a beautiful project there bro... Keep it up!

 

[Newbienissan]

1.8 mivec you can maximum use 2.5" pipings. My friend sr16neoVVL engine is also using 2.5" pipings, I myself nonVVL sr20de also using 2.5" pipings. it works fine all the way up to redline.

unless you have mivec, just a normall 1800cc, then 2.0" piping will do the trick.

 

[mizi0604]

can use mivec piston in 4g93 block...dont worry,many have done it...no problem until nowdays...

 

[peterj]

mine done with gsr conrod and mivec piston, but need extra 1 afc neo for a/f adjustment since the compression reach 20bar standard mivec ecu cant supply enough fuel for that till make engine no power if not adjust properly

 

[HanZ85]

Could it be the maps sensor's prob?i've met tis condition before when still 1.6 mivec,when mivec engage power drop greatly like the max rpm was 5.5k oni...i tot my clutch was kong d,later my foreman checked and claimed tat the map sensor got problem and after a while of job(i duno wat he has done actually= =)everything goes normal again.

 

[Veloc]

1.8 mivec you can maximum use 2.5" pipings. My friend sr16neoVVL engine is also using 2.5" pipings, I myself nonVVL sr20de also using 2.5" pipings. it works fine all the way up to redline.

unless you have mivec, just a normall 1800cc, then 2.0" piping will do the trick.

Bro.. You seem quite experience in exhaust. In that case, I got something I would like to ask. Sorry to deviate from the topic a little...

I am using a stock 4AFE auto. I forgot what is the original piping. I think it is 1.75". When I bought the car as second hand, the user a straight flow muffler. The inlet of the muffler is 2.0" and the outlet is 2.5". So he modified the latter part of the piping from 1.75" to 2.0". I feel a bit overkill and noisy. Bottom end torque sucks but once past 4.8k rpm, it pulls great!

So I change the muffler back to the quite s-flow type. The problem is, The inlet of the muffler is 1.5" only. So they modified the latter part of the piping form 1.75" to 1.5". My bottom end form 1k rpm to 2k rpm is really nice but it gets weak once reach 3k. I find it ridiculous because we usually accelerate between 2-3k rpm.

So I just want to ask what is the ideal size for a stock 1.6 non-vvt engine. no mivec, vtec whatsoever. just a 1.6 economy engine. I feel the backpressrue too much form the 1.5" pipe. Stupid exhaust shop. I didn't know they did that. And if to change exhaust is expensive, is there any way to reduce backpressure? Can I puncture a small hole near the beginning of the 1.5" pipe to release some preassure?

Thank you.

 

[Sapeqlaa]

Could it be the maps sensor's prob?i've met tis condition before when still 1.6 mivec,when mivec engage power drop greatly like the max rpm was 5.5k oni...i tot my clutch was kong d,later my foreman checked and claimed tat the map sensor got problem and after a while of job(i duno wat he has done actually= =)everything goes normal again.

Sorry to interrupt, may i know whats ur injector's size?...

btw, for mivec 1.8, i have tried 2" , 2.3" and 2.5"...what i can say for each settings are:
a. for 2" : low to mid rpm very revvy but struggle a bit at peak rpm..
b. for 2.3" low to mid rpm not as revvy compared to 2" but best performance at peak rpm especially
when mivec's engaged. (u really can fell the air flows well in this diamater)..
c. for 2.5": sluggish at low and mid rpm...and sluggish at peak rpm compare to 2.3"...

so in d end i revert back to 2.3"...

 

[Newbienissan]

hmmm, but my friend's sr16neoVVL is using 2.5" not sluggish. its also only 1600cc.

mivec 1800cc kenot be sluggish if using 2.5".....maybe engine timing setting wrong ?

 

[Sapeqlaa]

hmmm, but my friend's sr16neoVVL is using 2.5" not sluggish. its also only 1600cc.

mivec 1800cc kenot be sluggish if using 2.5".....maybe engine timing setting wrong ?

not sure sir...

at first on the 2.3" diameter..when for dyno, manage to gain 162whp plus 16.++kg of torque..

but later changed the diameter to 2.5"..noticed as not responsive as 2.3" especially the duration taken to reach top speed around 180km (i did not removed my speed cut back then) ...went for dyno session for touchup...a drop of hp gain to 160whp but cant remember the torque..

later i will try to find back my dyno chart for you to evaluate sir...maybe u can detect something based on the graph curve...but honestly thats based on my experience using those diameters...