FRH intake manifold insall questions

[Ludachris]

Before I put the Magnus street manifold on the 1G I had a FRH manifold. I ran it on the road courses quite a bit. It performed well. I only changed manifolds because I felt I'd get more low end from the Magnus, it was going to be much lighter, and might as well move from a 2-piece design to a 1-piece to reduce the potential for leaks - not that the FRH ever leaked for me. Can't say it's a bad choice, but I'm happy with the Magnus street for my application.

 

[keltalon]

Before I put the Magnus street manifold on the 1G I had a FRH manifold. I ran it on the road courses quite a bit. It performed well. I only changed manifolds because I felt I'd get more low end from the Magnus, it was going to be much lighter, and might as well move from a 2-piece design to a 1-piece to reduce the potential for leaks - not that the FRH ever leaked for me. Can't say it's a bad choice, but I'm happy with the Magnus street for my application.

This is the same reason I chose the jmf street over the Forrester for the moment.

 

[spoolin ddub]

I did use two gaskets. When I took it off, the phenolic spacer was indented by the compression of manifold flange and head intake flange. This problem is similar to the plastic heat shield gasket that people use on their intake manifold. The phenolic spacer is not a good idea at all.

No one I know have had issues with the phenolic spacer. These are people who have been running the same forrester manifold since the mid 90's. All have been making 500- 1000whp. A few have been making 1100whp, and one is now knocking on 1200whp. The phenolic spacer not even a new idea. It's has been used way back in the day in most race cars on their carburetors. But no part is perfect so there is always a small margin for issues. This is honestly the first time I have heard of this issue.

 

[keltalon]

No one I know have had issues with the phenolic spacer. These are people who have been running the same forrester manifold since the mid 90's. All have been making 500- 1000whp. A few have been making 1100whp, and one is now knocking on 1200whp. The phenolic spacer not even a new idea. It's has been used way back in the day in most race cars on their carburetors. But no part is perfect so there is always a small margin for issues. This is honestly the first time I have heard of this issue.

There's a first time for everything unfortunately it had to happen on killa.

 

[killercolt]

I just don't like the phenolic spacer because it indented on me and started to leak. If you don't mine tightening the bolt every now and then to snug it down, you will be fine. I want to add that I never had a leak between the runner half and the plenum half. I did like the way it looked and how it makes good peak power. I had to get rid of it because it did not have a good average power band between 4500-8500rpm. I was running a km210 and later a 1g factory fwd tranny which dropped to 4500-5500rpm after a 8000-8500rpm shift. I went with the cyclone intake manifold for the manual setup because it made way more power in power band I was in. I am back to the JMF intake manifold now since I am automatic. The auto put me at 6800-7000rpm after a 8500rpm shift which is where the Forrester intake and JMf are more useful.


Regarding the installation, the ignitor can be mounted on one of the plenum Allen bolt. I like to remind anyone getting the Forrester intake manifold to not use a 1g n/a throttle body since the throttle body flange does of match up on the bottom and will leak without some major mod. The Jmf manifold has a throttle body flange is bigger and will accomdate an n/a 1g throttle body.