SP ENGINE MISS AT 4-4,500 RPM

Engines, Transmissions & Final Drive questions and answers

Moderators: timk, Stu, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy, zombie, Andrew, The American, Lokiel

User avatar
bigdog
King of the kennel
Posts: 2233
Joined: Wed May 25, 2005 3:07 pm
Vehicle: NB SP
Location: Blue Mountains
Contact:

SP ENGINE MISS AT 4-4,500 RPM

Postby bigdog » Mon Jan 05, 2009 10:59 am

I'll put up my hand to run the GB Sean. PM me Steve's number and I'll post an expression of interest in the For Sale column and see how many we can get interested.
Image
Marvin - '02 Silver SP - BD, PSS9, Guru, Build #62 Cardomain

Fatty
Speed Racer
Posts: 3175
Joined: Fri Feb 03, 2006 10:39 am
Vehicle: NA6
Location: Melbourne

SP ENGINE MISS AT 4-4,500 RPM

Postby Fatty » Mon Jan 05, 2009 6:31 pm

i have a plastic Bosch BOV from an rx7 that i haven't got around to fitting yet. Apparently they are good to around 12psi. i was planning on using this but now I'm wondering whether it's likely to end up failing (assuming it hasn't already... it was bought from a wreckers) like many of you guys have reported with the other Bosch BOV's.

a bit of guidance from the experienced turbo guys would be appreciated here.... it will have a big influence on whether i go in on this turbosmart group buy or not.

cheers.

NMX516
Speed Racer
Posts: 2057
Joined: Mon Jun 19, 2006 12:05 pm
Vehicle: NB SP
Location: Brisbane

SP ENGINE MISS AT 4-4,500 RPM

Postby NMX516 » Mon Jan 05, 2009 7:03 pm

Fatty wrote:i have a plastic Bosch BOV from an rx7 that i haven't got around to fitting yet. Apparently they are good to around 12psi. i was planning on using this but now I'm wondering whether it's likely to end up failing (assuming it hasn't already... it was bought from a wreckers) like many of you guys have reported with the other Bosch BOV's.

a bit of guidance from the experienced turbo guys would be appreciated here.... it will have a big influence on whether i go in on this turbosmart group buy or not.

cheers.


Fatty expect the Bosch one to fail. While they give a 'rating' of how many psi they can handle, regular 'heavy' use can bugger them up anyway regardless of what psi you're using. They're plastic! You've only got to replace one or two Bosch ones and you've pretty much paid for one of these TurboSmart ones. I went through 2 of them on the ET years ago (in quick succession) before I woke up :oops: :lol: They were supposedly rated to 16psi - I was running between 10 and 14psi.
Pain is temporary, quitting lasts forever.

Fatty
Speed Racer
Posts: 3175
Joined: Fri Feb 03, 2006 10:39 am
Vehicle: NA6
Location: Melbourne

SP ENGINE MISS AT 4-4,500 RPM

Postby Fatty » Mon Jan 05, 2009 7:05 pm

yeah i was thinking the same thing... and it's a second hand one to start with so chances are it's already shagged :? :frown:

NMX516
Speed Racer
Posts: 2057
Joined: Mon Jun 19, 2006 12:05 pm
Vehicle: NB SP
Location: Brisbane

SP ENGINE MISS AT 4-4,500 RPM

Postby NMX516 » Sun Mar 29, 2009 2:03 pm

Just thought I'd follow up on this one again folks :D

I've had the SP for about 7 weeks now, and discovered something interesting last week. When I test drove mine, I ran through all the scenarios I've read about which seem to cause this bucking effect that everyone talks about, but could not replicate it on the test drive. I didn't notice in the first 1500kms of ownership either. Then I fitted one of the aforementioned TurboSmart Kompact BOV's. I played around with the settings on this for a while, and now have it set to full hard.

Now here's the interesting part.... I had noticed that the air box had seemed a bit loose, so decided to tighten the spring loaded bolt in the bottom of the airbox. In another thread on here in the last couple of weeks, Garry mentioned the airbox needing to be able to move about with the engine movement - makes sense. Since I tightened the bolt in the bottom of the air box, I had discovered some of this bucking effect, but didn't connect the two. I was thinking that the oxygen sensor might be playing up, as it also seemed to be running rich, and throttle response was quite poor. Long story short, while pulling my hair out over this, I decided that the symptoms were similar to what I had experienced in another car, where the wiring to the air flow meter had been damaged. I decided to check the connection to the afm, and while it didn't take much, it pushed onto the afm fitting by a small amount. Since then, the car has run like a dream!! :) I also backed the bolt in the bottom of the airbox off a bit, and made sure that the airbox has some movement to accommodate engine movement. My theory is that because the airbox was fairly tight, the engine movement pulled on the wiring loom to the afm (because the afm was not moving as it is attached to the airbox) and so compromised the connection of the plug to the afm. The afm is very sensitive to voltage change, so I think this may just be the cause of some of the SP "issues". It's certainly worked for me so far :D
Pain is temporary, quitting lasts forever.


Return to “MX5 Engines, Transmission & Final Drive”

Who is online

Users browsing this forum: No registered users and 10 guests