Hey I was wondering if it would be worth it to switch to SLP 1.85 Rocker Arms
and how would that change my current lift and duration,


I have a mti r1 cam 232/236 .575/.578

thanks

 

It would make your lift too high (at least in my opinion). It would be (1.85/1.7)*.575 ~ .625. You'd have to get some monster springs to handle it, and you'd be changing those springs early and often.

Not worth it, I think. But if you just have to change rockers, I'd think about some full rollers in the same stock 1.7 ratio.

 

Thanks

I was thinking of going to a larger cam but thought the rockers might be easier.

I will pass on the rocker arms if I am gonna need new springs etc

 

How about running the setup u have now

 

LOL

Id love too, For some stupid reason while I have been waiting for my tranny I have been making changes. I guess Im bored. Hopefully soon I will have it back out. BTW I think I am going back to a closed loop tune also. I dont like the 9-10 mpg. I just drive the car way too much for that kind of mileage.

 

Check the CRANE "accel lift" rockers. 1.79.
They start at 1.79, at about .250>300 lift they go to 1.72 then proceed to go back to 1.79. They increase power and torque at low >midlifts without affecting peaks too much.
They are adjustables so you'll get proper lifter preload and makes your valvetrain quieter.
VINCI>>>> sponsor.

 

P-Z thanks for that explanation. I've been wondering what those were all about. Those sound kind of interesting but I think you'd need to take a good hard look at valve events of your cam to determine how much power you'd really gain from something like that. Which is something that is still over my head unfortunately

 

THey were designed mainly with VINCI/CRANE cams in mind, taking into account their lobe designs.
I personally think they would work well with XE or similar cams that have high durations and suffer from loss of trq down low. These would be a good way to increase power at midlifts under the curve by not going overboard on peak lifts and having negative effects on our valvetrain.
So in a nutshell they should work well with a cam that will not go over .600 lift at peak while using them.
When i have some $$ after the Holidays I plan to use a set of 1.7's on my 224/220 XE-R and see how it goes. This will allow me to have better lifter preload and a little quieter valvetrain, while getting a few more ponies from .250> .400 lifts.

 

FYI...Regarding the Crane Accelerated Lift Rockers...The 1.7's ratio start off at 1.79 ratio and at approx .300 lift, the drop back to 1.72 max lift ratio...The 1.8's start at 1.89 and drop back to 1.82...

Peace...Gman

 

Since I'm planning on running a much more sizable cam such as the FM14 those would really not serve much of a purpose for me, other than push me closer to valve float @ higher RPM's

 

I think valve float is more likely to be determined by your springs than the rockers.

 

Predator-Z is right...With the exception of comparing a really heavy rocker to a light weight rocker...But as far as rocker ratio's go...A higher ratio rocker also increases the effective spring pressure that the valve spring is exerting on the pushrod...

Example...Lets say your seat pressure is 100#...A 1.7 ratio rocker would take 170# of force to open the valve...

That same spring pressure of 100#, using a 1.8 ratio rocker, would take 180# of force to open...

The net effect is that your spring actually works better at controlling the valves with the higher ratio rockers...

Peace...Gman