ridethecliche

iTrader: (2)

This is branching off JasonC SBBs thread from years ago here: https://www.miataturbo.net/dynos-timesheets-21/gt2560-261-ft-lbs-272-hp-60479/

Exchanging a few pms with him, he said that he had gains in the low midrange and high range. However, he used the nb1 vics(?) manifold instead of the nb2 vcts(?) manifold.

From reading a bunch of threads, it appears that the heads flow the same and the difference in peak hp is mostly due to this, however the vvt head can hold peak better, while the nb1 tends to fall off a bit more.

That said, I was hoping this thread would become a compendium of data for A/B tests of the heads if anyone had switched since I haven't really found any good pre and post data points. I've seen a few posts with vvt turned off, but thought that wasn't a great test because the cams are different.

Tldr: Has anyone swapped from an NB1 to NB2 head, all else equal, and dynoed or VD'ed? If so, can you quantify the difference?

18psi

iTrader: (76)

we have already done all of this before. yes there is a difference. vvt gets you more torque everywhere, not a lot, but measurable and repeatable. been discussed and documented in various threads

ridethecliche

iTrader: (2)

Fragmented info.

If this just becomes a compendium of those threads in one place, I'll be content. Im sure I'm not the only person that would like that info in one place!

And if I am... Womp.

18psi

iTrader: (76)

You know what would be better?
If you searched for said info, found it, put it together in this thread, and provided it to other people. Instead of not providing any of your own, or even making any effort at finding others, and simply making new threads where you want others to do everything for you. I do commend you on figuring out a way to constantly get spoonfed information, without coming off like an entitled/demanding n00b and therefore getting a lot less hazing for it.



PS: show us your scholar side

shuiend

iTrader: (24)

He would write it all, then send it into a peer reviewed journal to officially publish. Then it would cost $20 to actually see what he wrote.

18psi

iTrader: (76)

chicksdigmiatas

iTrader: (11)

Y8s had a good thread about it. He was one of the first to tune with it iirc.

https://forum.miata.net/vb/showthread.php?t=276072

Basically, with fixed cam timing, you are always compromising. You have to give up low end to get high end and vise versa. Dynamic cam control allows you to get the best of both worlds. To top it off, the vvt motor has the most aggressive cam profile to boot. I read somewhere, that there is less coreshift (terminology?) meaning the top and bottom of the head are lined up better, and the casting ridges were lower. I barely had anything to clean up. I notice it the most in off boost performance, and reduction in boost threshold.

Given the what people would spend on cam gears and dyno time compared to this (given in your case it takes 1 single wire ran to your ecu) it is your decision.

How much is the trade off worth to you? I would say the compromise would probably meet somewhere in the middle. I have no idea how much boost compounds or confounds this. Looks like in y8s case, quite a bit. It also isn't like your car will be a steaming pile of **** if you dont go vvt. You have to weigh the pros and cons yourself. Do you want the simplicity or the better set up. A 220whp miata is quick anyway.

It is one of those things I never planned on doing, but the right parts at the right time and the right price showed up making it cheaper that a nb1 head. Im a cheap lazy bastard. I run shitty turbos and drag race my car. Even I am glad i did it looking back on things.

y8s

iTrader: (8)

Just do what I'd do if I wasn't paying for it:

get a VVT head
get a square top manifold
do a whole lot of head work
shim under bucket conversion
modest cam grind with lots of lift
skinny stem valves
maybe oversize on the intake valves. not sure oversizing both will fit. i forget.
whatever valve spring setup the cool kids are running.
tune the VVT on a dyno by doing a few runs at various advances

type the whole process up and post it.

then get @emilio700 to tell you what he's done and see if his is better.

18psi

iTrader: (76)

the head you just described would cost more than his whole car

ridethecliche

iTrader: (2)

I ain't makin dat dokter monayyy 💰💰💰

This is why I need all yalls help!

Braineack

iTrader: (62)

the formula is posted all over m.net:

vvt
flattop
ms3
header/exhaust
150rwhp

ridethecliche

iTrader: (2)

****. I did it all wrong with a turbo. Ill never hit 150 now :(

Braineack

iTrader: (62)

dude.

use that brain of yours.


if you start with 150rwhp as a base instead of 120...

ridethecliche

iTrader: (2)

Haha, I completely misinterpreted what you were saying....

But again! What happens if you switch one thing around in there from the VVT head to the NB1 head? What's the drop off? How different do the dyno's look? This could be interesting to look at as well I suppose. I'll try to find those comparisons as well when I look again.

18psi

iTrader: (76)

y8s

iTrader: (8)

OK maybe forget the head work and cams.

Braineack

iTrader: (62)

off the bat, the NB1 and NB2 dynos look very similar.

put a better IM on a VVT (like a VICS IM off a NB1 ot a flattop) and things start to look much more in favor to the VVT motor.

chicksdigmiatas

iTrader: (11)

This, the VTCS (or whatever the VVT manifolds are called) suck giant *****. But, RTC, you already have a VICS manifold, so you're golden. There is a reason the 01-05 manifolds are half the prices as the 99-00.

18psi

iTrader: (76)

Here's why I'm always so skeptical when he makes these pointless threads: he's cheap. there aint even a remote chance he's gonna spend money on a vvt head, or any headwork, or any other stuff, because the gain-per-dollar ratio would be real bad for his setup. This is a theory thread. Dreamer thread. Aka waste of everyone's time. Aka he didn't even consider it worthwhile to do the basic searching and even cherry pick the low hanging fruit of information for this type of discussion.

Carry on

PS: no offense RTC, but you know it's true.

ridethecliche

iTrader: (2)

These are all very interesting statements to describe someone that has a full FM setup, racing beat sways, 949 endlinks, a brain built ms3x, diy billies with helper springs, a setrab oil cooler and coolant reroute... (last two waiting to go on). But yeah. Said foolish OP is a cheapass and doesn't spend money. A dreamer, one could say... I'm actually quite amused at how much disdain you have for me given that in a noob that didn't do things in a completely *** backwards fashion.

In any event, it appears that there really aren't any good A/B tests on this matter that quantify things. A lot of folks have data with the vvt on full retard but that's not an apt comparison. I recall Soviet having done this last comparison.

The intake manifold shouldn't really matter here. A head swap should still technically show a similar percent of gains in the regions of interest even with a worse flowing intake. VVT can account for that somewhat... Though obviously nothing beats breaking down the variables.

Tldr: You're wrong, but you can keep talking out of your *** because it seems to be one thing you're damn good at.
No offense 18PSI, you know it's true.