S4 LIM gasket on S5 motor
08-01-09, 10:10 PM
#1
Full Member
Thread Starter
Join Date: Jun 2005
Location: calgary
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
S4 LIM gasket on S5 motor
well i went to the local rx7 shop and i asked for s5 lim gasket.. when i got home i found out that its an s4 gasket, noticed tehres a hole on the bottom right side. will this work on a s5 motor? i just wanna make sure cuz i really down wanna pull off my LIM agian
this is what i have^
what the farm animals!?
this is what i have^
what the farm animals!?
08-01-09, 10:38 PM
#2
That's not an OEM S5 gasket or an S4. Take a look here for what the S5 looks like: http://homepage.mac.com/carldavis/intake/mod.html. S5s have 2 ports on the sides where port air is directed to the exhaust ports for emissions. S4s instead use that center opening. What you have is a hybrid of the two, minus one of the side openings.
08-02-09, 11:56 AM
#4
Hah, but I should have noticed the 4 intake ports 
. I was too busy staring at the air openings.
Going from the pictures on the Mazdatrix and what you posted (probably the same ones), I'd say that opening on the S4 gasket may actually be for the EGR valve instead. The S4 & S5 turbo LIMs are nearly the same shape, but the S5 ditched the EGR, which is located on the backside of the LIM. So, your S5 LIM should just be blank in that spot, which means there'd be no problem having a hole in the gasket.
. I was too busy staring at the air openings. Going from the pictures on the Mazdatrix and what you posted (probably the same ones), I'd say that opening on the S4 gasket may actually be for the EGR valve instead. The S4 & S5 turbo LIMs are nearly the same shape, but the S5 ditched the EGR, which is located on the backside of the LIM. So, your S5 LIM should just be blank in that spot, which means there'd be no problem having a hole in the gasket.
08-02-09, 01:16 PM
#5
The real issue here gentlemen is that the s5 turbo irons actually have larger port runners than the s4's and this is reflected in the gasket shape. I have had both s4 and s5 turbo irons and both s4 and s5 gaskets as I was upgrading to the s5 parts on my recent motor build. That's why you really should match the LIM, LIM gasket, and irons all to the same series. Technically you could port match--but IMO this is a waste of time. If you compare the respective s4 and s5 turbo LIM's and irons you'll see what I mean. The manifold and port runners on the S5 are bigger throughout. Port matching would do nothing really, just introduce a step change into the air stream.
When I switched to s5 irons I sanded the inside of the port and manifold runners some to smooth them out in areas of laminar flow (I used a 40 grit wheel). Polishing manifold runners makes you really notice all the little details of the design: the holes in one of the primary runners for the anti afterburn valve, the passageways for the split air and port air passageways, the castings to support the ACV, the castings for the BAC valve. You learn a lot about intake manifolds and how the air pump emissions stuff works.
So anyway, use the OEM gasket for the appropriate series irons and manifolds and you won't have any problems. Just do it the way Mazda designed and it'll fit right the first time.
When I switched to s5 irons I sanded the inside of the port and manifold runners some to smooth them out in areas of laminar flow (I used a 40 grit wheel). Polishing manifold runners makes you really notice all the little details of the design: the holes in one of the primary runners for the anti afterburn valve, the passageways for the split air and port air passageways, the castings to support the ACV, the castings for the BAC valve. You learn a lot about intake manifolds and how the air pump emissions stuff works.
So anyway, use the OEM gasket for the appropriate series irons and manifolds and you won't have any problems. Just do it the way Mazda designed and it'll fit right the first time.
