mx5 vvt head swap.

manga_blue · Postby **manga_blue** » Mon May 13, 2013 11:48 am

It's not just a case of turbo or ITBs. There are better ways to get usable power with reliability.

I've been doing track days in MX5s for years now across 4 states. 90% of the cars running do not have ITBs or turbos or superchargers. They just have OEM intakes system and they keep happily circulating month in month out.

About 90% of the cars that don't finish a track day have aftermarket turbos or superchargers. I'll exclude relatively stock SEs, which seem reasonably reliable.

For the turbos it's a constant stream of blown turbos, blown motors, mashed gearboxes and diffs, broken CV joints, boiling radiators and sick tuning - all to be a few seconds quicker down the straights.

For the ITBs it's just cars that won't start, won't run, backfire, won't make power or have broken linkages.

If you want to do track days and you want to join the sad parade of guys putting their cars back on the trailer by lunchtime then get ITBs or a turbo.

If you want to do track days and have fun then just start with a good wheel alignment, good pads, good rubber and good fluids and get faster by making the most of all the seat time.

carlmx5 · Postby **carlmx5** » Mon May 13, 2013 1:17 pm

In terms of vvt. would a car benefit from it if it is daily dríven and tracked? Or are the gains just not worth it. also are there other benefits of the vvt?

stb · Postby **stb** » Mon May 13, 2013 2:17 pm

I've made the switch to vvt in my NA8 (through engine swap). Increase in torque in 2500-4500 range with VVt enabled is very noticeable. Just what you want for a daily driver. But VVT is switched off above 4500rpm, and therefore has no real impact on track times except at a hairpin where I leave it in 2nd and revs drop to <4500.
I'm keen to try a more aggressive cam (eg 270-280°) and then use the VVT to widen the powerband to make it a more suitable daily driver. With regards to the naysayers about naturally aspirated performance, I agree on the evidence of turbo lack of reliability on the track and also want to stay in the same class (modified 1800cc here in SA).

manga_blue · Postby **manga_blue** » Mon May 13, 2013 2:30 pm

Fixed.

manga_blue wrote:About 90% of the cars that don't finish a track day have aftermarket turbos or superchargers or ITBs.

NB8B VVT engines have a better spread of power than the NB8A VICS engines but, as Dann said, VVTs take a fair bit work to swap in and they are harder to modify. For DD/occasional track I'd stay stock for a year while you learn your racecraft then think about other mods after that. Even then the first mods should be safety/handling related. So seat, harness, torsen and springs are probably the first priorities if you want to improve laptimes.

carlmx5 · Postby **carlmx5** » Mon May 13, 2013 4:43 pm

Sounds logical, thank you. Is there a link to the application and theory of vvt or similar?

manga_blue · Postby **manga_blue** » Mon May 13, 2013 5:15 pm

carlmx5 wrote:Sounds logical, thank you. Is there a link to the application and theory of vvt or similar?

I researched this years ago when I was thinking of doing it myself. You should get a fair bit from the old thread.
viewtopic.php?f=29&t=35757&p=464320&hilit=vvt#p464320

I just realised where you're coming from: you think all VVT is good. So maybe I should add that in scale of 1 to 10 in quality of VVT design Mazda's version ranks between shyte and fake. VVT probably went in because of pressure from the marketing department who said "Honda and Toyota have VVT and it's really good and helps them sell heaps of cars. Give us anything that lets us claim that we have VVT too without being sued for false advertising."