1.8L Mivec Conversion

[ahmedshaikhani]

Hi everyone, I have been searching on this forum for a long time for the mivec conversions and upgrades rather then creating a new topic, but now I have questions piled up and I had to make a new topic. I request all the experts to share their view and experience. Finally after a long time wait is over I saved sufficient amount of money in order to to do the mivec conversion from 1.6L to 1.8L. I have few questions please I'll be needing your advice. Here is the list of stuff I already have with me.

1- 4G92 Mivec Complete with wiring, gearbox, ecu etc. 4G92 Mivec is from CJ4A chassis blacktop.
2- 4G93 SOHC Complete with wiring, gearbox, ecu etc.
3- Spare gearbox of 4G94
4- ACT Racing Clutch 6Puck.
5- Apexi Vafc and Apexi Safc.
6- LC 1 Innovate wide band

Now here is the list which I'm planning to do mods.
1- Planning to buy ITB's.
2- Jun type 2 cams, with complete valves, retainers and springs.
3- Adjustable cam gears.

Now here is the list of silly questions.
1- I'll be using 4G93 SOHC block, which pistons should I go for ? 4G93 SOHC pistons or 4G92 Mivec pistons ? I have been reading on this forum that if we use Mivec pistons we need thicker gasket in order to lower the compression a bit. Is that true ? Need experts opinion.
2- Which timing belt should I use, I'll be using adjustable cam gears.
3- Do I need to upgrade the bearings like to ACL or any other brand or stock Bearings will be able to handle 8200rev. I guess Mivec Gen 2 got 8200rpms ?
4- What should be the lbs torque for pistons and head ?
5- Can I get the ITB's for the Mivec or do I need to modify from the 4AGE 20V ?
6- Do I need to replace the injectors or injectors from Mivec will work out ?
7- I have been reading on many forums that mivec is faster in terms of paper in comparison with vtec. But in the real world it still lack behinds due to better gear ratios of vtec. If I swap with 4G93 gearbox with my mivec. Is it useful as 4G93 got bigger ratios ? I'm talking about the 400m drag scenario.
8- Is it necessary that I need a standalone ? Can I use Apexi Vafc for fueling ?

Aim is for 400m drag. Thank u all.

 

[^pomen_GTR^]

Hi everyone, I have been searching on this forum for a long time for the mivec conversions and upgrades rather then creating a new topic, but now I have questions piled up and I had to make a new topic. I request all the experts to share their view and experience. Finally after a long time wait is over I saved sufficient amount of money in order to to do the mivec conversion from 1.6L to 1.8L. I have few questions please I'll be needing your advice. Here is the list of stuff I already have with me.

1- 4G92 Mivec Complete with wiring, gearbox, ecu etc. 4G92 Mivec is from CJ4A chassis blacktop.
2- 4G93 SOHC Complete with wiring, gearbox, ecu etc.
3- Spare gearbox of 4G94
4- ACT Racing Clutch 6Puck.
5- Apexi Vafc and Apexi Safc.
6- LC 1 Innovate wide band

Now here is the list which I'm planning to do mods.
1- Planning to buy ITB's.
2- Jun type 2 cams, with complete valves, retainers and springs.
3- Adjustable cam gears.

Now here is the list of silly questions.
1- I'll be using 4G93 SOHC block, which pistons should I go for ? 4G93 SOHC pistons or 4G92 Mivec pistons ? I have been reading on this forum that if we use Mivec pistons we need thicker gasket in order to lower the compression a bit. Is that true ? Need experts opinion.
2- Which timing belt should I use, I'll be using adjustable cam gears.
3- Do I need to upgrade the bearings like to ACL or any other brand or stock Bearings will be able to handle 8200rev. I guess Mivec Gen 2 got 8200rpms ?
4- What should be the lbs torque for pistons and head ?
5- Can I get the ITB's for the Mivec or do I need to modify from the 4AGE 20V ?
6- Do I need to replace the injectors or injectors from Mivec will work out ?
7- I have been reading on many forums that mivec is faster in terms of paper in comparison with vtec. But in the real world it still lack behinds due to better gear ratios of vtec. If I swap with 4G93 gearbox with my mivec. Is it useful as 4G93 got bigger ratios ? I'm talking about the 400m drag scenario.
8- Is it necessary that I need a standalone ? Can I use Apexi Vafc for fueling ?

Aim is for 400m drag. Thank u all.

1)depends on your need...if u were looking for high power and torque as weekend car that only runs on ron97 fuel at least u better use mivec piston....but for daily with best torque but not much power up with some ease of mind filling with ron95 then better use 4g93 piston..

2)no idea which timing belt

3)u were using 93 bottom which not really high rev engine...so better send the clutch set+crankshaft+conrod and piston+new crank bearing to be balanced.....

4)no idea

5)no ITB for mivec..most ppl custom from 4ag.....just need custom the adaptor plate/manifold to fit...but if u were using this setup u need to use standalone ecu....

6)depends on the level of tuning and mods (especially if using mivec piston and racing cam)

7)yeap....if u use 4g13/4g15 gearbox would be better in term of acceleration..but suffer on highway journey....

8)standalone is a must if u proceed with no.5.....but if not then u can u e-manage..because of broader tuning level..

 

[MirageAsti]

Bro I am running a setup similiar to what you're looking for, mine is a 2nd gen Mivec RS

1- I am using the SOHC block with Mivec pistons, with the stock metal gasket (unknown thickness) from the 4G92 block. If you're looking for more power, go for oversized pistons - 82mm and so on. I am running on RON95 without any knock.

2- You need to calculate the teeth to match your setup. Using the Mivec oil pump you need longer count around 159, and if the SOHC oil pump you need around 157 if I'm not mistaken which is what I'm using.

3- For you engine's safety in the long run, use ACL crank and conrod bearings. I am using these too and have been running to redline almost everyday

4- Follow the stock value for torque settings (4G93)

5- You can custom make ITB's which will perform better for you, but keep in mind you need cams.

6- The stock 275cc injectors are quite enough but will be running near 90% duty cycle, better to go with 300cc+ injectors.

7- Search for the CJ4A RS gearbox. 2nd Gen Mivec gearboxes have better ratios than 1st gen Mivecs and are considered on par with VTEC.

8- VAFC is enough, it's all up to you. But I will advise you to install an adjustable fuel regulator.

cheers bro

 

[ahmedshaikhani]

@^pomen_GTR
Thank you for the input Sir. But, 4G13 and 4G15 will be a closed ratio gears, response would be very good in 1st 2 gears but after third acceleration on the top speed would decrease, won't so ? Just my 2 cents

@MirageAsti
Thank you for the input Sir. I'll be using Jun or Skunk type 2 cams with valve, valve retainers and springs. Which one is better in terms of output and lift Jun or Skunk ? The thing is I bought the engine and will buy the modification goodies from Malaysia, but the setup is conducted in my country Pakistan. I am a university student over here in Kuala Lumpur. Maximum fuel we can get their is 96Ron not more then that. Though I plan to use Mivec pistons, but still confused about the gaskit. I guess the OEM gaskit for the 4G92 Mivec is 0.8 or 0.5mm not sure. But using mivec pistons and 0.8mm gaskit won't result in detonation ? I'll be using an adjustable fuel pressure regulator and upgrading to 300cc and above injectors is not a issue. My mivec is from CJ4A chassis don't know whether it is RS or not. Here is the video of mivec in Halfcut when I bought the engine. I got spare 4G13, 4G93 and 4G94 gearbox lying with me in my house. *wink*

4G92 Mivec - YouTube

 

[kimster]

me too..i want to upgrade my mivec 1.6 to 2.0..ist possible...some say that i ve to get 4g94 block? how much it will cost me and any other that ive to replace? personally im not happy at all with mivec ck performance..huhuhu..

 

[ahmedshaikhani]

I guess 4G94 connecting rods won't support this much high rpm, you might end up in damaging them. If you are so crazy for 2.0L Mivec then why not go for 6A12 Mivec from FTO ?

 

[^pomen_GTR^]

@^pomen_GTR
Thank you for the input Sir. But, 4G13 and 4G15 will be a closed ratio gears, response would be very good in 1st 2 gears but after third acceleration on the top speed would decrease, won't so ? Just my 2 cents

nope..because 4th and 5th gear also closer than 1.6/1.8 gearbox....

one of my friend running mivec 1.8 with 4g15 gearbox if not mistaken cruising at 110km/h was already near to 4krpm...

of course reaching speed untill 190km/h was fast and easy..but beyond that depends on your rev limit...


sadly..his car was sold not long ago...due to family constrain

 

[ahmedshaikhani]

nope..because 4th and 5th gear also closer than 1.6/1.8 gearbox....

one of my friend running mivec 1.8 with 4g15 gearbox if not mistaken cruising at 110km/h was already near to 4krpm...

of course reaching speed untill 190km/h was fast and easy..but beyond that depends on your rev limit...


sadly..his car was sold not long ago...due to family constrain

Sir i'm still confused with two things one is gearbox, as my aim is to do drag. Second thing is about gasket, if I use Mivec pistons [Standard] what should be the thickness of head gasket ? Lastly like in Honda, if we make hybrid 2.0 vtec we need to provide oil line to the vtec solenoids, same goes for 1.8L Mivec hybrid ?

 

[^pomen_GTR^]

Sir i'm still confused with two things one is gearbox, as my aim is to do drag. Second thing is about gasket, if I use Mivec pistons [Standard] what should be the thickness of head gasket ? Lastly like in Honda, if we make hybrid 2.0 vtec we need to provide oil line to the vtec solenoids, same goes for 1.8L Mivec hybrid ?

u want purely for drag competition or some fun on the road?

for competition mainly 400m i personally think 4g13 gearbox suits better....

about the oil line no idea about that...

gasket thickness depends on your level of tuning and parts...what range of compression ratio u want etc etc etc....

 

[joe777]

this is comparison of gear ratio for 4g13/4g15 , 4g92, 4g93

4g13/4g15
1st 3.363
2nd 1.947
3rd 1.285
4th 0.939
5th 0.777
Reverse 3.083
Final 4.322

4g92
1st 3.083
2nd 1.947
3rd 1.285
4th 0.939
5th 0.777
Reverse 3.083
Final 4.021

4g93
1st 3.083
2nd 1.947
3rd 1.285
4th 0.939
5th 0.777
Reverse 3.083
Final 4.322

Im currently using 4g92 SOHC + 4g13Gearbox, but is it okay for me to stick with 4g13 GB or look for 1.6GB as i want a balance between acceleration and top speed.....?

 

[fastclubman]

you can get ITB setup for gen 1 mivec or 4g93 head, check out jenvey dynamics for their product. not cheap but works very well. but you will need a stand alone as mentioned.

 

[catan]

u want purely for drag competition or some fun on the road?

for competition mainly 400m i personally think 4g13 gearbox suits better....

about the oil line no idea about that...

gasket thickness depends on your level of tuning and parts...what range of compression ratio u want etc etc etc....

No.... 4G13 gb is long ratio suit for top speed only....

Mivec alway loose to Vtec becos gear ratio still longer than vtec.....

Vtec hav alot of advantage is 1~5 gear and final drive can get from aftermarket...... Just $$ only...

 

[ahmedshaikhani]

this is comparison of gear ratio for 4g13/4g15 , 4g92, 4g93

4g13/4g15
1st 3.363
2nd 1.947
3rd 1.285
4th 0.939
5th 0.777
Reverse 3.083
Final 4.322

4g92
1st 3.083
2nd 1.947
3rd 1.285
4th 0.939
5th 0.777
Reverse 3.083
Final 4.021

4g93
1st 3.083
2nd 1.947
3rd 1.285
4th 0.939
5th 0.777
Reverse 3.083
Final 4.322

Im currently using 4g92 SOHC + 4g13Gearbox, but is it okay for me to stick with 4g13 GB or look for 1.6GB as i want a balance between acceleration and top speed.....?

Thanks Sir for the info about gearbox ratios. Really helpful.

you can get ITB setup for gen 1 mivec or 4g93 head, check out jenvey dynamics for their product. not cheap but works very well. but you will need a stand alone as mentioned.

Sir I will look for this brand but its for Gen 1, so it means its for CA chassis not for CJ chassis right ?

No.... 4G13 gb is long ratio suit for top speed only....

Mivec alway loose to Vtec becos gear ratio still longer than vtec.....

Vtec hav alot of advantage is 1~5 gear and final drive can get from aftermarket...... Just $$ only...

So what is the solution for this ?

 

[catan]

Stay with mivec gb..... if want it better go find the ATS 5.1 final drive....
u will regret if use 93P gb.....

 

[ahmedshaikhani]

Stay with mivec gb..... if want it better go find the ATS 5.1 final drive....
u will regret if use 93P gb.....

Sir I was planning to switch 4G93 SOHC gearbox not of 4G93P. My mivec is of CJ4A chassis.