
Originally Posted by
350gtz
Hi, Im new here....
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The gearbox. When i take it out of 2nd to shift up, theres a bit of a thud feeling just before i chuck it in 3rd.. Its the same between 3rd and 4th... I read that these gearbox's arent the best, but is that consistant with the "normal" problem?? or is it something that i could be improved and i should get it checked out..?
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The engine mount. With so much torque, combined with talk about mounts breaking and recalls, im a bit worried. My question is, how much better does an after market mount feel? and has anyone heard of an engine mount breaking after the factory recall fix has been installed? Mine was changed by mazda. Am i safe?
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Lastly, turbo lag / blow off valve.. The turbo lag combined with above gearbox problem = slow shifting and passengers with sore necks.. will a aftermarket BOV improve the shifting?
Welcome!
Re: the 'box : 2nd to third does tend to be a bit noisier. After-market engine mount helps - the clunk, is - I think - engine and 'box slapping around under changing torque loads, which if you think about it, is happening as you pull it from gear...there are other noises that are not things slapping around, there is a bit of a bump noise sometimes, make sure you've got the clutch in properly, and that there's not a bit of extra throw that you could/should be using. I am aware that often if I get a clunk, I'm being a bit lazy with the clutch - this has bearing on how torque is loaded against the drivetrain and therefore how things slap around...
Short shift plate improved things for me as well. Engine mount, Solid shifter bushings, and short shift plate are what you might want to consider. I'm happy without solid bushings at the moment, so I don't know what I'm missing out on there...
You might want to try Penrite SIN75W90 gearbox oil - it's a GL5+/6 that meets the spec needs for the box. There's some debate about whether it erodes synchro's etc; I don't believe it does. It was in mine for 80,000K and there's no degradatiuon of anything that I've noticed - I'm back to GL4 now and am considering going back to the GL5+/6 Penrite for smoother gearbox operation. The Penrite is specifically specced as having good compatibility with brass alloys (synchro bits), and also meets LSD needs. Mazda put it in mine as warranty service in response to excessive cold start LSD chatter. This is again, one of the penrite oils advertised gains.
Re: mount - do it. CPE 60 or 75 duro seems to be the pick - there's others. I've a 75 and the vibes are noticable with the aircon on at idle, not so much with it off. Helps shift holding everything a bit tighter...
And last reason to do it is because it's a good precautionary mod. Here's what my OEM mount looked like coming out of mine when the CPE was installed.



Split and ****ed. From what I've read, that's pretty much what they tend to come out looking like.
Lastly bypass valve - OEM one holds pressure from testing I've read of. There doesn't really seem to be a good reason to replace it in terms of performance. Theres some feedback that certain aftermarket tunes perform better with the OEM valve.
Last edited by Nexus; 10-03-2011 at 01:21 PM.
"Blue Meanie" 2007 Aurora Blue MPS 3 - 18x8.5+44 SSR GTX01 - 235/40R18 Federal RS-RR - 3.5" ETS TMIC - CPE stg 2 mount - HKS/CPE BPV - 2XS inlet - 2XS short shift - 2XS turbo manifold - Hypertech tune - Leather/Aluminium handbrake - Momo shifty knob - 7" touchscreen - JDM Mazda Retractable dashtop screen assembly - PC based GPS and instrumentation - 36AH reserve battery and C-TEK isolator - TEIN Street Advanced coilovers 1" drop - Superpro bushings - 220Kw/410Nm.
"Lipstick" 2013 Velocity Red MPS 3 - 18x7.5+48 Enkei RPF1 -225/40R18 Federal RS-RR - CPE TMIC - COBB inlet - CPE stg 2 mount - COBB Stage 1 98 octane tune - COBB shifty knob - 2XS short shift.