cam change ?

Discussion regarding Turbocharged and supercharged MX-5s

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mhj
Fast Driver
Posts: 263
Joined: Fri Apr 25, 2008 8:23 am
Vehicle: NB8A - Supercharged
Location: bermagui ..south coast nsw

cam change ?

Postby mhj » Sat Apr 15, 2017 3:59 pm

im curious
how much money ( -)and power (+)might come from a change of cams ( stage 2 ?)
the car is supercharged nb 150rwkw. no engine changes but for sc exhaust and intake plus ecu and 380 injectors no race just country streets
mhj

93_Clubman
Speed Racer
Posts: 11854
Joined: Mon Aug 08, 2005 11:35 pm
Vehicle: Clubman
Location: Melbourne

Re: cam change ?

Postby 93_Clubman » Sun Apr 16, 2017 12:08 pm

NB with aftermarket cams not as common as NA because NB BP motor uses solid lifters & shims (not self adjusting) as opposed to NA BP (& B6) motor which uses hydraulic lifter assembly (basically self adjusting), hence changing to aftermarket cams is a bit more complex & time & money consuming. In very rough round figures: cams could cost from anywhere from $500 to $1k or more depending on what you get. At least you already have an aftermarket standalone ECU, but it will need to be retuned, so say another $1k. Then add another $500 or so for other parts (shims etc) & labour.

mhj
Fast Driver
Posts: 263
Joined: Fri Apr 25, 2008 8:23 am
Vehicle: NB8A - Supercharged
Location: bermagui ..south coast nsw

Re: cam change ?

Postby mhj » Sun Apr 16, 2017 1:43 pm

thanks for that
power improvement ?
mhj

manga_blue
Forum Guru
Posts: 4897
Joined: Mon Apr 24, 2006 7:27 pm
Vehicle: NA8
Location: Moruya, NSW

Re: cam change ?

Postby manga_blue » Sun Apr 16, 2017 3:05 pm

mhj wrote:thanks for that
power improvement ?
On a stockish sort of motor it's a "power change" of -5 rwkw to +15rwkw, depending on how well you blend all the elements of cam specs, compression, port shape, intake, exhaust and tune. I'm no turbo expert, but I'd guess the range is at least double that on a turbo, with a higher probability of going negative. :D .
’95 NA8

celicapain
Learner Driver
Posts: 18
Joined: Tue Dec 06, 2016 5:03 am
Vehicle: NB8A - Turbo

Re: cam change ?

Postby celicapain » Thu Jun 29, 2017 7:53 pm

For comparison the built bp4 in my nb makes about 190 rwkw with standard turbo cams, about 205rwkw with stage 2 turbo cams. I really need a bigger turbo to take advantage of the extra air flow the big cam allows, but as an example of what just changing the cam does that my experience.


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