Arithmetic

iTrader: (9)

because, my knowledge on it right now is kinda bleek. Ive been doing some research on MIVEC and looking at other similar variable valve timings like, vTEC, i-vTEC, VVTL-I

Well, the reason why I ask is, I was on another forum and some dumb*ss kid said, "MIVEC is nothing but a marketing ploy done by mitsubishi to get in the VVT race, it's nothing like vTEC or i-VTEC, VVTI or VVTL". Also, it wasnt from a honda board either. Well, it's funny... ive been in other VVT cars and there switch over is cleary noticable, but it's not in our car. Sorta of like it's there, but not a change over note or the tach moving any quicker. The car picks up a bit after 3500... but maybe it's just "ME" thinking and really its not?!

I let my friend drive my car to see if he can "feel or notice it". He drives a 5thgen prelude vTEC. vTEC change over is @ 5800 rpms and it's def noticable. He got in my car and said "I notice it, not like vTEC... but it's there". Am I missing something? I don't notice it. Only time I really really notice it is if I leave it in 2nd @ 5-10mph and get 3/4 WOT I feel a slight histant change @ exactly 3500rpms... nothing "JAW DROPPING or OMG maD mIV3c pULl y0!" or again maybe im just trying to think something there. I was talking to a guy, who is the fastest N/A celica GT-S owner in the US. He ran a 13.7 @ 101. Im trying to remember, but he had I/E/Power FC and some slight weight reduction. We talked for about 2hours just on the celica and VVT and how it works with all cars. Anybody who knows the celica or driven a GT-S knows about LIFT and how nasty it is @ 6000rpms. When he drove my car, he didnt notice MIVEC or anything similar to VVTL-I. He said, "it's probably not a true lift, I didnt feel the high cam change, it's just a very torquey engine". I said "mitsu says it's a LIFT, I just don't know if it's a true lift like the GT-S"

So, is MIVEC not a true lift? I was reading some MIVEC info @ www.mivec.co.nz and they where saying the new MIVEC is nothing like the old one, it's more gas friendly with subtle power. Than I read on mitsu japanese website that the 4g69 MIVEC is about performance and gas friendly:

In the pursuit of pure driving enjoyment, potentially incompatible goals like fuel economy, environment-friendliness, and clean driving have all been achieved.

That's funny thou, because I got really really bad gas when I enter MIVEC, isnt the point to get BETTER fuel economy with MIVEC. Even in the lower cam of MIVEC, i still burn gas. I only get good gas on the highway, but on the streets, FORGET IT. I live 8.2miles away from my job, tell me how I burn 10-15% of my full tank just getting there, while staying out of MIVEC?

Here are some pics and details...



Well, I found some clips on the net of vids of vTEC and i-VTEC change overs on a ITR and TYPE-s and turned it into a lil vid... ill try to upload come celica GT-S vids later.
vTEC & iVTEC cam change over (VID)

Thing is, what can I do, to make the change over like there cars. I don't know much, but the fact the MIVEC change over is controlled by oil, while vTEC is controlled mechanical. Anybody whos delt with VVT or hondas or toyotas or even the guys @ RRM how dove into the ralliart engine/ecu (rock, jay, boe?), know what's the deal w/ MIVEC?

otter

iTrader: (14)

Having a very smooth and barely noticable change is a good thing, it means that the engineers did their job well. Remember, the guy who designed MIVEC (if I've heard right) is the same one who used to work for Honda and worked on the V-TEC setup.

Unlike Hondas, we have the benefit of a lot of low end torque, so our car pulls really well in the low RPMs. Because of this, and the point at which the valve profiles change and the timing starts to advance, it's a very smooth transition. It makes the engine more usable at all RPMs, instead of only above a certain RPM.

The point of MIVEC is to allow an engine to do two different tasks well. Have low end torque (pre-3400rpm, partially open valves, conservative timing), but still have a lot of high end power (post-3600, full open valves, very agressive timing, great for HP). Usually you can only have one or the other with small engines like ours. I don't think fuel economy was a big part of the equation, especially with how rich our car runs.

blk-majik

iTrader: (6)

i was kinda wondering the same. MIVEC is now M. I. Valve and life E. C. with the evoX's and such. Before, they excluded the 'lift' part out of the name (hence the acronym). I know OUR cams adjust timing on the intake ports, but i dont know about lift, honestly. i guess they surely do lift on the new evo, but i dunno about the sohc ralliarts. but it doesnt really matter.

our car was not designed to need a carzy cam profile switchover to kill efficiency to get power. it was made to produce good power throughout, but better power when applicable. want a crazy switchover like the vtec engines? then start with a 80hp base engine and throw some huge intake vales and high lift cams on it that get used once it builds momentium to try to push them as high as you can. just because you can feel he honda engines as they want to explode doesnt mean its a better design. i think smooth is better, but thats me.

and i doubt ur getting 4-5 miles/gallon on ur way to work. if so, they your car has worse problems than mine, and mine is wrecked =)

ooralliartoo

iTrader: (1)

I can tell MIVEC is there.

05 Silver RA

With this being my first VVT engine, i can certainly tell a difference when i pass 3500 rpm, it's definitely there

Jake

MitsuSkot

iTrader: (2)

I think the big thing with toyota and honda cars is the lack of torque. I agree with what was said earlier, that since our cars have good low end torque, the transition isn't as drastic.. where if you take a honda engine that has (for example) 160 hp and a 125 tq, the transition is more noticable because its adding something to basicly nothing. I wonder if those engines had more torque if the transition would smooth out..?

humanity

I know i feel it kick in. I remember seeing a dyno sheet somewhere in the forums and looking at it you could see right when it kicked in and it was pretty noticable. Atleast thats how it looked to me

Scarf Face

iTrader: (1)

If you're looking purely for the 'kick' of VVTi, then you can simply add mods that increase HP and lower torque. The kick comes from an increase in power; since our engines have a relatively smooth powerband, there is not too much kick. You can get a stronger, more noticeable change at the cost of low-end power. Whether or not it's worth it is up to you.

Just for the record, I can feel the switch anywhere beyond about 2/3 WOT. Obviously it's not as hard as the Honda/Toyota, but that's not necessarily a bad thing, as others mentioned.


Yes, it is, as opposed to running the engine in MIVEC mode all the time. You get the fuel economy (but not much performance) with low/medium lift, and the performance (with terrible fuel economy) with high lift. That's the plan for efficiency. It works more or less well for me and most other people; if you're wasting gas like crazy without going above 3500, go see a tech.


What exactly do you want to know about MIVEC? You'd probably get more responses if you formulate it in a more specific way.

otter

iTrader: (14)

The 4G69's MIVEC setup changes both timing and valve lift. From what I've heard about the new Evo head, they're getting the variable timing, but not the different valve profiles (I'm going to research this more to make sure my info is right). Being SOHC, the timing is adjusted on both intake and exhaust ports. It's the only downside to SOHC. A DOHC MIVEC setup could potentially adjust the intake and exhaust ports seperately. Finally, the varying valve adjustments (low/medium and full open) only take place on the intake ports.

MitsuRalliArt

The reson there is no KICK is due to the fuel curve. The mitsubishi engineers made the car burn real rich from 3500-4000 rpms. As you approach 4000, it gets back to normal. This is why you feel the surge at this point. Anyone with the RRM piggyback will tell you there is a definite KICK. It remedies this problem.

The only reason I have for this it ride comfort. I guess mitsu designed the engine with Galant-like intentions. These kinds of vehicles need to be smooth and civil. A giant kick in power would be unacceptable.

Racman709394

iTrader: (2)

just think of the new SI...that's not really a "vTEC". our MIVEC is simular to that.

AdamRA

iTrader: (2)

Just no..... The VTEC on the Si or SIR is a valve change thats all. It changes from 12 valve to 16 valve at I believe 2200RPM. It is designed for emissions.

Arithmetic

iTrader: (9)

I want the "kick" as people call it. Like the oldschool MIVEC, it was very nasty and much better than vTEC or VVTI. I know MIVEC switch profile is there, but it's not noticalbe, like otter said, mitsu engineers designed it to be seemless as possible.

Reason why I ask, is... I have some friends with ITR's, sI coupes, rsx-s and GT-s and im always making fun of them for having no torque, they make fun of my MIVEC saying it's not a real lift. Ill quote my friend, "torque mean's nothing if you can't launch"

I find that true, the GT-s owner can out launch me and than VVTL-I kicks in, the rsx-s owner I can out launch till 3rd, than vTEC kicks in. My thing is, If my MIVEC was as agressvie as there VVT, I could out launch them and still pull harder @ 3500rpms. That's why im trying to figure out how can I make MIVEC moooooore agressive. It can be done, I just need some help on doing. Im willing to throw the money at it, but I need some help along the way.

Have you guys seen some MIRAGE/FTO MIVEC vids? OMG... it's crazy! That's how MIVEC should have come, seems like only the Evo IX/4g Eclipse is getting the oldschool like MIVEC.

Some Intresting Parts:
Note - Im not for sure if they work on our MIVEC.

http://www.mitsubishi-fto.org/parts/...ics/index.html

reimundo

iTrader: (1)

arithmetic what mods do you have, and what mods do your friends have on their cars? i think the mivec doesn't kick in that hard because we have a three stage mivec.

MitsuRalliArt

Please read my post above. The reason it is not noticable can easily be fixed.