SP63 VVT/Timing Kit

D

DatsunZ

Greenie N00B Member
Greenie Member
What’s up Mazdaspeed Crew!

I have some questions about some performance oriented parts that are around that I can’t really find a review/info on pertaining to the Speed platform particularly. Hoping some people might be able to chime in with knowledge and experience. I know some people have strong opinions about the companies that make/supply the parts, but I would like to stick mostly to the theories surrounding the performance of the part.

SP63 Timing Kit:
Seems like your standard VVT/Timing kit composed of the upgraded OEM parts from later Ford Duratec engines, only with up to 50 degrees of VVT advance instead of the 30-35 on the original Mazda gear. It sounds like the ECU has room in the tables to control that additional timing, so it doesn’t seem like it would go to waste… but I can’t find info on anybody using this on a Speed3/6. Found some info about a DIY version for Miata’s with a 2.5 Duratec swap and they claimed that the additional advance was nearing a ~10% power increase almost across the board though it falls off up around 4,500RPM. Seems strange I can’t find any accounts of this used on the L3-VDT engines.

is anybody running this setup and getting any benefits from it? Or am I having a hard time finding info on it being used because it doesn’t offer any performance/efficiency/reliability on our platform?
 
Double posting to share some more info I found.

From some researching it seems like the Ford 2.5 Duratec VVT timing parts can be used on the 2.3 MZR due to its similarities, which is why I’ve heard of people using the Ford OEM parts to replace the weaker Mazda parts when it’s time for timing. This Duratec part uses the same 35 degree max advance as the Mazda parts.

But it turns out the 2.5 Duratec has been changed a bit since 2008 and the VVT cam gear from the 2021+ Maverick and Escape are the exact same gear as the early 2.5 Duratec VVT cam gear… except it has 55 degree max advance to help with the Atkinson Cycle now being used on it.

I assume this the gear SP63 is using for their kit. So it means the kit can still assembled with full OEM parts if my theory is correct.

New Ford Cam Gear Part # LX6Z6256A
https://parts.ford.com/shop/en/us/e...iming-camshaft-sprocket-25l-p-lx6z6256a?pdp=y
 
The VVT gear in the SP63 kit is just a FoST/FoRS cam gear. The L3-VDT can only use around 40 degrees of that advance before the valves collide with the pistons (I think 44* is the hard stop, but my memory may be off in that regard). Moreover, you may see some benefit across the power band, but with a good tuner who does some slight torque curve tuning you won't care for that slight bump, unless you use the VVT gear in conjuction with a big turbo setup and cams.

Everything else is a direct fit, but truthfully there's not too much benefit to the Ford system over the Mazda one. Everyone says it's more reliable, but truthfully most people won't keep their cars long enough to see the benefit in that. The only other benefit is that it's quieter, but when you hear the injection system firing away like a tractor, that's also moot.

If you get the timing sprocket for a more modern version of the Duratec (e.g. an EcoBoost timing sprocket), there's less room for failure there because it eliminates the need for an additional friction washer as the oil pump drive sprocket and timing sprocket are one unit.

I personally use the Ford system, but that's because of some complexities with my keyed crank; I see no actual benefit from my Ford timing system over the Mazda one. I would say that as a whole, the Ford system isn't a worthwhile venture, and especially when the SP63 kit costs a mortgage payment (you can put the kit together yourself for cheaper).

Hope this helps
 
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@dinnerplate

Thanks for sharing your knowledge and experience. With my goals ~400AWHP by staying medium turbo (CST4/BNR S3), CS Cams, and stock fueling (maybe WMI for charge cooling, not as extra fuel) I was hoping that additional timing might bring the gains reported on 2.5 Miata swaps in the low RPM before boost. I guess my goal is to rebuild the engine for as much area under the curve for street driving (biased towards the left of a dyno graph) without keeping the undersized K04.


You mention the piston/valve collision occurs around 40-44deg. Out of curiosity was that a measurement taken on a completely stock engine? I ask because it seems like most aftermarket 4032 pistons I have been looking at have extra relief for up to +1mm valves, so I was under the impression that should add some clearance for extra VVT advance if staying stock size valves that might allow full use of the timing if there was any interference in stock form.
 
Gen 2 has the valve reliefs in the pistons stock. That little relief isn't getting you anything meaningful for cam timing
 
Thanks for the great info!

I think I found the post discussing PtV clearance maxing around 40deg advanced timing from a discussion a while back after some searching. Interesting that the PtV isn’t an issue on the 2.5 Duratec. I guess the Miata subforum did seem to be a discussion surrounding track oriented build so maybe they were running an aggressive cam and pistons with extra relief.

Sounds like it’s not worth the hassle if all you get is 4-6deg of extra timing and run the risk of PtV collision.
 
The nice thing about a turbo car is that you don't have to chase every little bit of efficiency from everything thing you can just push a little more boost
 
I really appreciate the great info from members who seem like veterans of the site and platform. I come from the RX8 and 240Z, and Diesel and 2-stroke boat engines world so my knowledge on turbos and DI are good, but not excellent starting.
 
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