Bennoz spends more money - NOS!

[aza013]

nosssssssssss go for it Ben
and yes as jonowong said your going to get in big trouble this may happen BUT he is going to have a lot of FUN as well

[Bennoz]

I gotta lash out for 2 bottles thou, 1 as a dummy disconnected bottle to mount in plain view, the other to hide under the seat

[Delvance]

Aaahahaha.

Remind me not to sit in your passenger seat!

Dooooooooo eeeeeettttttt! No one would know, psh!

[SG]

Yeah mivec cams would require mivec heads... which would require mivec the oil system, the mivec computer, the mivec alternator & the mivec wiring. Too much hassle for not enough.

i meant just the billet cam shaft itself, and the valve springs, and i suppose whatever the oil system needs. not the heads.

theres 2 mivec cams isnt there in the motor? on the exhaust/inlet side i cant remember......... just swap them on the gr motor with the mivec versions. Plus the rest. I'm not talking about the motor being able to switch over to mivec. Its just a cam shaft upgrade........ i reckon its possible. Unless theres something I'm missing

[Bennoz]

Its a bit more complicated than that. I'll try & explain with some piccies

Both the mivec & non mivec motor has the same number of cams, the same number of lobes on the cam, the same number of valves. The big difference is the rocker assemblies, distance between lobes, cam profiling, and the heads themselve are very different.

This is a Mivec head:



This is a non mivec head:



Note distance between the lobes on the Mivec cams versus the GR cams? Also not that on the mivec cams, both lobes sit between the cam mounting towers. Where as on the non-mivec, there is a cam lobe on either side of the tower.

What actually makes the difference between mivec & non mivec is the lifters. Here is a Mivec assembly. Note that at any one time, only 1 out of the 2 lobes is controlling both valves. During low rpm, the smaller of the lobes is depressing both valves at a time. When in mivec, the oil pressure system flicks 2 valves on either side of each head & forces oil in to open small spring loaded pistons out from the centre of the rocker gear - thus forcing the second half of the rocker gear to engage on the Mivec lobes & effectively making the low rpm part of the rocker gear unable to reach the non-mivec lobe.




The mivec hydraulic pin here that locks the 2 parts of the rocker arm together:



-------------------------------------------------------------------------------------------------------------

Now here is the non-mivec assembly. As mentioned above, on the mivec rockers, only 1 lobe controls 2 valves at a time, here you see 1 lobe controlling 1 valve. meaning that on any cylinder both of either inlet or exhaust valves are being controlled independantly by 1 cam lobe.




This is what makes the head designs so totally different. Its a completely different style of cam design & profiling. 1 style to actually have 2 options of cams to choose from, the other having completely independant (yet fixed as in no second cam option) valve per lobe control. And in being so different, everything around them that makes them work is also completetly different.

Further down the track, what might be interesting, is if someone took the profile of the Mivec cam lobe & ground it onto a billet GR cam....(bags not paying the $2k for the billet cams thou )

[SG]

whoa ok.... didn't think it was that complicated. i knew the rocker/lifters were special but didnt know the cam was a 2 in one sort of thing.

yeah a mivec grind on a GR is what i wanna know how that goes.........

major torque loss down low though.

hats off bennoz for explaining it all hehe

[Bennoz]

Dont worry mate, its taken me 5 years to fully understand it

That aside, decision was made today. F*cking around with heads, porting & compression is gonna cost a bomb. We also investigated bigger valves which was gonna make a big difference, but at over $1000 for a set of 24, this was starting to really add up.

So, we are bolting on a 100hp NOS kit instead

[Bennoz]

Oh and dont worry, the whole porting & polishing concept is still going ahead, just at a slower pace on my spare engine

[Delvance]

*watches this thread closely*

[aza013]

I am never going to keep up with you now Ben

[manofwood]

sure you can, just buy a NOS individual runner setup for yours aza, think that makes it a wet shot. your engine's pretty much ready for it!

[aza013]

may be but I would rather just go with other mods chip,new ECU and so on.
as for the engine being ready for it I think I may have to do some more work on it to handel the nos I will just sit back and watch Ben have the fun with this

[Bennoz]

You mean, sit back & watch me spit a rod outta the block?

[jonowong]

i still havent found a place to refill...

[Bennoz]

My mechanic is about to be come a licenced nos refill station.

[Delvance]

160 kw atw. Not bad at all for the raw tune Bennoz and pretty close to what i guesstimated for the atw figure... i came up with ~172.5kw atw extra with the 100hp nos kit, seeing as you're getting 120 without nos.

So when you gonna take it down the strip ?

[manofwood]

dont the BOC gas stations do nitrous?

[RalliartBoy]

BOC will do nos for people who are licenced to buy it and even then the smallest bottle you can buy is a 6kg cylinder.

I worked in head office and dealt with the Gas and Gear stores Operations Centre (where the gas is produced) for three years and toyed with the idea of NOS as i could get it cheaply but 6kg cylinder was no good to me.

[aza013]

when you go to do a 1/4 run Ben let us know as I really want to see that run

[manofwood]

how the hell will you get 100hp extra to the ground in 400m without spinning?! you'll be mashing through the gears like there's no tomorrow!
do the mitsubishi L300 takeoff, in 2nd gear!