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1.3 Vs 1.5 Roller Rockers?


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#1 Bobbins

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Posted 10 July 2019 - 04:04 PM

There's plenty of info about the advantages and gains of fitting 1.5 ratio roller rockers, but what are the disadvantages, or rather when would a 1.3 roller rocker set be preferred over the higher lift 1.5 set?

 

I'm in the process of assembling all the bits to fit a big valve head (36/30) to my '98 JDM (MPi/SPi) and currently thinking lightweight flywheel, LCB and RC40 system but retaining the MPi cam. I'm looking for good mid-range torque rather than ultimate high-revving power because it's a road car, not planning to track it. Would the 1.3 offer any benefit in torque?



#2 phillrulz

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Posted 10 July 2019 - 05:22 PM

Also interested since swift tune say over 1.4 is pointless 



#3 Magneto

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Posted 10 July 2019 - 05:36 PM

Doesn't it depend on the cam? I think if you run a stock cam running the 1.5's works, with big cams either the 1.3 or Calvert's 1.4 forged rockers work well. I built one with Calvert's big valve head, a 266 Kent cam and Calvert's 1.4 rockers. Running 10:1 compression it made 80 hp at the wheels, is completely drivable and made a ton of torque from 2-5K, perfect for city driving and B roads.


Edited by Magneto, 10 July 2019 - 05:37 PM.


#4 Steve220

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Posted 10 July 2019 - 05:51 PM

Sw5 cam and 1.5 rockers make a massive difference pm the MPi. Swiftune are a great bunch to chat to on the phone about this sort of thing 😎

#5 ACDodd

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Posted 10 July 2019 - 06:05 PM

These ratio corrected bushed A+ rockers are now available from me, another alternative if you are looking for a 1.3:1 rocker setup.

Ac

Attached Files



#6 Moke Spider

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Posted 10 July 2019 - 07:10 PM

The Rocker Ratio on it's own is a mute question.

 

It comes down to much more than that on it's own. Magneto touched on these and it also comes down to how you drive and how you want the engine to behave.



#7 cooperd70

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Posted 10 July 2019 - 07:23 PM

These ratio corrected bushed A+ rockers are now available from me, another alternative if you are looking for a 1.3:1 rocker setup.

Ac

 

Ac,

 

Are you offering ratio corrected A+ for 998cc as well? If so would be very interested as I know the standard rockers are way off.  If so this will go onto my purchase from you with a billet RS cam as well....and maybe some other bits  ;D



#8 ACDodd

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Posted 10 July 2019 - 08:14 PM

These sets fit both 998 and 1275 based engines being based on the universal A+ rocker. Ideal for use with my RS cam when using the AEA 525 valve springs.

Ac

#9 bogstandard

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Posted 10 July 2019 - 08:14 PM

I can only add to the knowledge bank of experience and not an expert but adding the SW5 CAM with the 1.5 rockers made a lot of difference. Logical to me that the two work best together.

Seems to me the lost item from many claims of 90bhp gains from MPi Stage 3 kits widely available which from my experience do not deliver anything near that. Saying that any power gains could also be lost from the locked MPi MEMS.

I have ditched MEMS and the difference is amazing with a Stage 3 head and SW5 CAM. 92bhp 100lb Torque.

Edited by bogstandard, 11 July 2019 - 12:25 AM.


#10 Orange-Phantom

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Posted 10 July 2019 - 08:42 PM

Also interested since swift tune say over 1.4 is pointless 

Can you show me the documentation where Swiftune state over 1.4 is pointless?  Probably not as...

 

Swiftune recommend 1.5 ratio rockers for a lot of their cams for instance the SW10 which I run with 1.5 rockers and that is after I spoke with Nick Swift himself!

 

If you click on the link below and on the SW5, SW8, SW10 cams they all state that the example engines with the corresponding dyno graphs are using 1.5 ratio rockers!

 

https://swiftune.com.../camshafts.html



#11 Moke Spider

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Posted 10 July 2019 - 08:44 PM

 

Also interested since swift tune say over 1.4 is pointless 

Can you show me the documentation where Swiftune state over 1.4 is pointless?  Probably not as...

 

Swiftune recommend 1.5 ratio rockers for a lot of their cams for instance the SW10 which I run with 1.5 rockers and that is after I spoke with Nick Swift himself!

 

If you click on the link below and on the SW5, SW8, SW10 cams they all state that the example engines with the corresponding dyno graphs are using 1.5 ratio rockers!

 

https://swiftune.com.../camshafts.html

 

 

There's little point opening the Valve beyond what the Port will flow.



#12 phillrulz

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Posted 10 July 2019 - 08:44 PM

 

Also interested since swift tune say over 1.4 is pointless 

Can you show me the documentation where Swiftune state over 1.4 is pointless?  Probably not as...

 

Swiftune recommend 1.5 ratio rockers for a lot of their cams for instance the SW10 which I run with 1.5 rockers and that is after I spoke with Nick Swift himself!

 

If you click on the link below and on the SW5, SW8, SW10 cams they all state that the example engines with the corresponding dyno graphs are using 1.5 ratio rockers!

 

https://swiftune.com.../camshafts.html

 

 

https://swiftune.com...r-assembly.html

 

 

"Years of dyno and track research, testing and development have established that for current camshaft profiles and cylinder head designs, there is no need to increase the rocker ratio beyond 1.4.

"

 

If you look, they also only see 1.4 ratio rockers. 


Edited by phillrulz, 10 July 2019 - 09:05 PM.


#13 Orange-Phantom

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Posted 10 July 2019 - 09:55 PM

 

 

Also interested since swift tune say over 1.4 is pointless 

Can you show me the documentation where Swiftune state over 1.4 is pointless?  Probably not as...

 

Swiftune recommend 1.5 ratio rockers for a lot of their cams for instance the SW10 which I run with 1.5 rockers and that is after I spoke with Nick Swift himself!

 

If you click on the link below and on the SW5, SW8, SW10 cams they all state that the example engines with the corresponding dyno graphs are using 1.5 ratio rockers!

 

https://swiftune.com.../camshafts.html

 

 

https://swiftune.com...r-assembly.html

 

 

"Years of dyno and track research, testing and development have established that for current camshaft profiles and cylinder head designs, there is no need to increase the rocker ratio beyond 1.4.

"

 

If you look, they also only see 1.4 ratio rockers. 

 

Fair enough.  I'm just going on what Nick Swift told me to run which was 1.5 ratio rockers with the SW10 Cam.  They also only sell non roller rockers, due to the historic racing regs.

Still curious as to why they would then use 1.5 rockers for their test engines that produced the cam graphs for their SW5, SW8 & SW10 cams and as documented on their website?



#14 phillrulz

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Posted 10 July 2019 - 09:58 PM

 

 

 

Also interested since swift tune say over 1.4 is pointless 

Can you show me the documentation where Swiftune state over 1.4 is pointless?  Probably not as...

 

Swiftune recommend 1.5 ratio rockers for a lot of their cams for instance the SW10 which I run with 1.5 rockers and that is after I spoke with Nick Swift himself!

 

If you click on the link below and on the SW5, SW8, SW10 cams they all state that the example engines with the corresponding dyno graphs are using 1.5 ratio rockers!

 

https://swiftune.com.../camshafts.html

 

 

https://swiftune.com...r-assembly.html

 

 

"Years of dyno and track research, testing and development have established that for current camshaft profiles and cylinder head designs, there is no need to increase the rocker ratio beyond 1.4.

"

 

If you look, they also only see 1.4 ratio rockers. 

 

Fair enough.  I'm just going on what Nick Swift told me to run which was 1.5 ratio rockers with the SW10 Cam.  They also only sell non roller rockers, due to the historic racing regs.

Still curious as to why they would then use 1.5 rockers for their test engines that produced the cam graphs for their SW5, SW8 & SW10 cams and as documented on their website?

 

 

I did chuckle inside when you said i couldnt prove it, I was suprised when i read it too ( 1.4 being best). I noticed since im buying a SW5 and wanted to see recommended setups. 



#15 Orange-Phantom

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Posted 10 July 2019 - 10:00 PM

 

 

Also interested since swift tune say over 1.4 is pointless 

Can you show me the documentation where Swiftune state over 1.4 is pointless?  Probably not as...

 

Swiftune recommend 1.5 ratio rockers for a lot of their cams for instance the SW10 which I run with 1.5 rockers and that is after I spoke with Nick Swift himself!

 

If you click on the link below and on the SW5, SW8, SW10 cams they all state that the example engines with the corresponding dyno graphs are using 1.5 ratio rockers!

 

https://swiftune.com.../camshafts.html

 

 

There's little point opening the Valve beyond what the Port will flow.

 

 

Very true!  I probably could go wilder and higher lift with my cam than the SW10 with the AKM 7 port head.  I find the SW10 really easy to drive on the road and not that wild a cam. 






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