AP1 or AP2 engine for racing
Community Organizer
Joined: Jun 2007
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I've run both in my race car now and there are pros and cons. The 2L requires less shifting on the two Summit Point tracks I usually drive--the engine is just plain more flexible. That extra 800 rpm in VTEC makes more difference than you would think.
The 2.2L is more reliable and has a little more torque but there are several places where I either bounce off the rev limiter or simply have to shift where I didn't need to with the 2L. Couple the 2.2L with 4.44 gears and my right arm is getting a workout compared to the stock geared 2L.
I ran a 1:40.5 on Summit Point's Shenandoah Circuit (tight technical 2 miles) with a 2L engine. I've never gone quicker than 142.0 with the 2.2L.
The 2.2L is more reliable and has a little more torque but there are several places where I either bounce off the rev limiter or simply have to shift where I didn't need to with the 2L. Couple the 2.2L with 4.44 gears and my right arm is getting a workout compared to the stock geared 2L.
I ran a 1:40.5 on Summit Point's Shenandoah Circuit (tight technical 2 miles) with a 2L engine. I've never gone quicker than 142.0 with the 2.2L.
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Joined: Jun 2007
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8500 is the equivalent piston speed of the factory limit on a F20. The F22 cylinder head is better equipped then the F20 however, so 9k+ as that’s concerned. I think valve float starts to ensue at 9700rpm per Billman, but don’t quote me on that one.
I put 80k boosted/SC miles with a 9k rpm rev limit on a Stock f22 with 8lb flywheel, and beat on that car daily, used every bit of the rev limit. The motor wants to rev. Obviously with a centrifugal SC, the higher you rev it the more power you make as well. The motor evidentially had some tuning woes and ran lean, scoring the cylinders. Crank and connecting rods never had an issue. First place of failure I would expect would be a con rod in this configuration, but no. Strong motors.
I put 80k boosted/SC miles with a 9k rpm rev limit on a Stock f22 with 8lb flywheel, and beat on that car daily, used every bit of the rev limit. The motor wants to rev. Obviously with a centrifugal SC, the higher you rev it the more power you make as well. The motor evidentially had some tuning woes and ran lean, scoring the cylinders. Crank and connecting rods never had an issue. First place of failure I would expect would be a con rod in this configuration, but no. Strong motors.
Former Moderator
Joined: Jul 2005
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From: West Virginia
That has nothing to do with the motor, that’s your rev limit and gearing choice. Both of which can be changed easily enough
Joined: Feb 2001
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From: Chicago
I've got fuzzy memory of plenty of guys running the 2.2 revving it up to a little over 9k with fine longevity. It likely has to do with how you do it; 9k on every straight is stupid, if for no other reason than you gain nothing. I ran my 2.2 in the way I described (shift at @ 8500, but comfortable running it to 9 into some corners) and did that for over 3 years w/no problem (I'd say and counting but I ran it out of water and warped the head/block so totally different issue).
Changing rev limit can be cheap and easy by just swapping in an AP1 ECU. Not the best route, but cheap and easy. You'll really though want to do something to tune the fuel or you get a rich running and poorly mapped 2.2 which lost you half your gains.
Changing rev limit can be cheap and easy by just swapping in an AP1 ECU. Not the best route, but cheap and easy. You'll really though want to do something to tune the fuel or you get a rich running and poorly mapped 2.2 which lost you half your gains.
Former Moderator
Joined: Jul 2005
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From: West Virginia
With a new ECU don't you have to have a key assigned to it by the dealer? How cheap is an AP1 ECU? How cheap is a fuel controller to supplement the ECU?
I do have my old AP1 ECU, an original key for it and a piggyback fuel controller so maybe I'll dig it out of the attic and give it a try. I can leave my shift light set for 8000 but have the extra headroom for those places where the gearing is just a tad short.
I do have my old AP1 ECU, an original key for it and a piggyback fuel controller so maybe I'll dig it out of the attic and give it a try. I can leave my shift light set for 8000 but have the extra headroom for those places where the gearing is just a tad short.
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