The 9k AP2...?
10-19-2007 | 02:58 PM
#1
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From: Santa Monica
The 9k AP2...?
I've finally found a way to be happy... (it really wasn't so hard)
I bought my AP1 in the summer of 2003 because the salesman told me that they weren't going to make the yellow any more, so I'd better buy now.
(He was telling a half truth... it was indeed the end for "Spa" yellow, but the beginning of the superior "Rio". Half truth is actually pretty good for a car salesman, so I won't complain.)
The AP2 motor is also better. More torque, better power (despite what they list... I've seen enough dynos to know) more durable, better suspension, no bump steer... the AP2 was better in every way except that it only revved to 8k.
For years, I've clung to my 9k redline as the only justification for purchasing an AP1 when I could have waited two months and bought an AP2 for the same price.
A few months ago I blew the AP1 motor. (good ol' cylinder #4)
The dilemma... Do I now go with the superior F22 and give up my beloved 9k redline (and all justification for my hasty purchase), or do I stick with the inferior F20c and go on deluding myself that the extra "bandwidth" was worth it.
The solution came in the form of a brilliant idea on the part of our good friend and S2000 mechanical guru Tony Fuchs:
Replace the stock valve springs and retainers in an AP2 motor with upgraded titanium ones, keep the AP1 ecu, and viola
I bought my AP1 in the summer of 2003 because the salesman told me that they weren't going to make the yellow any more, so I'd better buy now.
(He was telling a half truth... it was indeed the end for "Spa" yellow, but the beginning of the superior "Rio". Half truth is actually pretty good for a car salesman, so I won't complain.)
The AP2 motor is also better. More torque, better power (despite what they list... I've seen enough dynos to know) more durable, better suspension, no bump steer... the AP2 was better in every way except that it only revved to 8k.
For years, I've clung to my 9k redline as the only justification for purchasing an AP1 when I could have waited two months and bought an AP2 for the same price.
A few months ago I blew the AP1 motor. (good ol' cylinder #4)
The dilemma... Do I now go with the superior F22 and give up my beloved 9k redline (and all justification for my hasty purchase), or do I stick with the inferior F20c and go on deluding myself that the extra "bandwidth" was worth it.
The solution came in the form of a brilliant idea on the part of our good friend and S2000 mechanical guru Tony Fuchs:
Replace the stock valve springs and retainers in an AP2 motor with upgraded titanium ones, keep the AP1 ecu, and viola
10-19-2007 | 03:08 PM
#3
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From: Alamogordo, NM
The valve springs were not the reason the Honda engineers lowered the redline on the new engine. The extra displacement is the result of a longer stroke so they had to lower the redline to keep the piston speeds similar to the AP1 engines. The lower RPM is to help the long-term reliability of the AP2 engine.
10-19-2007 | 03:11 PM
#6
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From: Land of Cincinnati Chili
Well, drewchie. Good luck with her. Keep us posted long term. My only concerns:
I might have considered keeping the stock AP2 retainers instead of titanium as they are a proven commodity for 9K revving. Billman has been using them in AP1s for a long time and titanium will have wear issues that will have you regularly checking on and replacing your titanium valve train parts. Titanium is light but not durable.
The other thing I'd be concerned about is that with the stroke of the 2.2, the piston has to travel 20% further than it does in a 2.0 in the same time frame. I mean, Honda reduced the red line for a reason and that reason is that the increased piston speed at a given rpm causes the piston speed to get in to a less than optimum reliability zone. Your piston speed is now far beyond the piston speed of an F20C. You'll probably be OK if you keep it off the 9K line most of the time.
Happy motoring!
I might have considered keeping the stock AP2 retainers instead of titanium as they are a proven commodity for 9K revving. Billman has been using them in AP1s for a long time and titanium will have wear issues that will have you regularly checking on and replacing your titanium valve train parts. Titanium is light but not durable.
The other thing I'd be concerned about is that with the stroke of the 2.2, the piston has to travel 20% further than it does in a 2.0 in the same time frame. I mean, Honda reduced the red line for a reason and that reason is that the increased piston speed at a given rpm causes the piston speed to get in to a less than optimum reliability zone. Your piston speed is now far beyond the piston speed of an F20C. You'll probably be OK if you keep it off the 9K line most of the time.
Happy motoring!
10-19-2007 | 03:13 PM
#7
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From: Raleigh, NC
the valvetrain upgrade was unnecessary. It was already superior to the AP1 (the retainers at least, springs are the same).
The redline decrease is because of the increased stroke of the engine, it has absolutely nothing to do with the head.
Way to ineffectively address the issue
Plenty of people on s2ki are running F22Cs with an AP1 ecu and haven't touched the head....a little research goes a long way.
Now the "brilliant idea" is going to cause you to need to get the titanium retainers replaced in probably 10-15k miles if this is a daily driven car, where as the factory AP2 ones would have lasted almost forever.
The redline decrease is because of the increased stroke of the engine, it has absolutely nothing to do with the head.
Way to ineffectively address the issue
Plenty of people on s2ki are running F22Cs with an AP1 ecu and haven't touched the head....a little research goes a long way. Now the "brilliant idea" is going to cause you to need to get the titanium retainers replaced in probably 10-15k miles if this is a daily driven car, where as the factory AP2 ones would have lasted almost forever.
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10-19-2007 | 04:16 PM
#10
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From: Santa Monica
Originally Posted by dyhppy,Oct 19 2007, 04:45 PM
awesome to have you on board, Drew. most people get this scared look on their face when u mention 9k on a 2.2L.
that isnt to say the motor wont fail early, but no problems so far.
that isnt to say the motor wont fail early, but no problems so far.
)btw... You need to bring your GF back to the track!
Most female passengers freak out if I go more than 60-70% on track, whereas your lady actually wanted me to go faster than I feel comfortable taking a passenger. Still the only time my passenger had more nerve than me.
I
women with that kind of chutzpah! (does she have a 15-20 year older sister?)