MX5 SP Bosch BOV replacement size

Postby **tomli123001** » Sun Oct 25, 2015 1:59 am

Just wondering if aftermarket BOV valves come in different sizes or they are have just a few standards?

I am trying to find a right valve to replace the stock SP Bosch unit. But not too sure the sizing. From reading threads here, somebody mentioned it was 25mm. I just like to double check and confirm.

If 25mm is correct, I found below 2 items. one is GFB and one is TurboSmart. Which one would be a better choice from your experience.
http://www.ebay.com.au/itm/150856270088 ... EBIDX%3AIT
http://www.ebay.com.au/itm/161516568241 ... EBIDX%3AIT

The engine is completely stock set as below.

bear2230 · Postby **bear2230** » Sun Oct 25, 2015 8:40 am

Both will be fine but why do you want to replace yours?

Postby **tomli123001** » Sun Oct 25, 2015 1:32 pm

bear2230 wrote:Both will be fine but why do you want to replace yours?

I just bought the SP with a good price, but high milage.
The throttle response and power felt less than I expected (maybe because I came off my modified SE before). So I am doing research to check things out one at a time.

From reading the posts, a lot of people commented on the stock BOV may leak air or crack cos of age. I think most of you guys changed it also and commented on the spring rate to change the throttle response.

That is why I am considering changing it.

bear2230 · Postby **bear2230** » Sun Oct 25, 2015 5:12 pm

tomli123001 wrote:
bear2230 wrote:Both will be fine but why do you want to replace yours?

I just bought the SP with a good price, but high milage.
The throttle response and power felt less than I expected (maybe because I came off my modified SE before). So I am doing research to check things out one at a time.

From reading the posts, a lot of people commented on the stock BOV may leak air or crack cos of age. I think most of you guys changed it also and commented on the spring rate to change the throttle response.

That is why I am considering changing it.

Ok then, Thats a good idea, probably wouldn't hurt if its the original as they are quite old now. I have the original one on my silver car and its still fine but there is only 40,000km on it and likes the garage.
I was also told that quite a lot of the Bosch units were installed the wrong way round from the factory. :oops:

I Have a turbosmart Vee-port on the white car and I like it a lot. You can drive it all day and no one would ever know but give it a little stick and its a lot of fun. Boys in blue don't like them that much but ND has hidden it quite well and I have never been pulled over yet.
https://www.youtube.com/watch?v=c0IXeNaePVM

If your SE had intake/exhaust/ECU you would have had 150+rwkw which is more than your stock SP. Mine was measured at 128rwkw before I started playing.
Look up "SP T-PIECE MOD" before you do anything else though. 145rwks after the $2.50 mod

Richard.