I've read countless threads, some under the pretense that no one has ever cracked an exhaust retainer... Others of people posting their cracked exhaust retainers. My F20c has approximately 110k miles and the car has seen 2 owners before me, I really need to take care of this and want to replace them all. Have we come to the final conclusion that AP2 intake retainers are superior for a stock F20c? If I insist on changing all retainers should I buy AP1 retainers/keepers for exhaust or can those be AP2 as well? IDK if this is beating a dead horse or not I just need clarification as I read so many different things.

PS I'm aware the keepers are not interchangeable, I'll get the right ones as well as replace the stem seals while I'm in there. I'll do everything right

 

you don’t need to do the exhaust side but if you really want to you can replace them all with ap2 retainers and keepers. maybe just inspect the exhaust side while you change the intake side.

 

I thought I read how the exhaust springs are lighter and need a lighter retainer but I really don't know.

 

Change the exhaust side if it makes you happy. The AP1 items though are perfectly up to the task and are lighter.

 

tagging along, does changing to AP2 retainers lower the redline a little? what parts are needed if I want stronger/robust retainers and a even higher rpm than the ap1? (like above 9k)

 

From Billman and Woodard the intake retainers on the F20C are just fine until you over rev the engine.

If you do that then the intake retainers can crack. Changing to the AP2 retainers+keepers on the intake side increases your over rev threshold to about 10500rpm for over rev.
Past that you'll just slap a valve. If you change the exhaust retainers then the threshold drops even more. Changing the springs really doesn't do anything to help you either.

 

Isn't there a couple threads of cracked retainers on cars that never over-revved? Anyway sounds like ap2 retainers for intake and new ap1 on exhaust for me.

 

If so you cannot know for sure if someone over-revved it. Coming in hot in to a corner, downshifting and it over-revving a bit is not always noticed, especially on a track. And a lot of people will not admit their mistakes publicly so like to say "I drove this car perfect and it just broke for no reason!" lol. Seen way too much of that.

The previous owner of my car, since he was not the first owner, just opted to swap them out to AP2 retainers to be safe. They turned out fine when he looked at them, but at that point just did it. And since he, and now I, used this car primarily for autosports purposes, there is a chance it could happen in the future, so he went ahead and changed them out.

One thing to note just in case you ever do autocross the car, in Street or STR classes this is not a legal change per the SCCA rulebook. However, if anyone ever protested you about it, they a) would have to be a total weenie since that would be a weenie protest, b) would have to have some reason to know you did it since there is zero performance gain from doing it. I would be willing to bet a large number of AP1's at nats had swapped retainers. People will generally only protest if you are in a trophy spot (have fun with that in ANY s2k in STR anymore at a nationals level event with the field of ND's to compete with) and they were a raging wuss and willing to protest something like this. There are those people, however!

 

Hah yeah that makes sense, I hear people over rev constantly while heel/toeing in videos. I AutoXed it once with an audi club, if I ever go SCCA would it be wrong to just lie about the retainers? Anyway I'm still not clear on the reasoning for NOT using ap2 retainers for exhaust side and only intake side. I'm changing stem seals for good measure, I'm changing all 16 retainers one way or another.

 

agreed- those people need a wicked good smack in the mouth.
darcy