^^^ Just a slight correction. No header needed to accomplish this, but Decat or HFC absolutely will be needed to see the results with the lowered vtec. At that point 3500-3600 engagement typical which that dyno doesn't reflect as noted by the vtec spike still at roughly 4000rpm. Also to note the natural airflow dip of this engine at that 5300rpm range is further exacerbated by the overly rich afr (10.9) so a better fuel tune in that area as the graph shows will help level this power dip out some as well. Overall that fuel tune is overly rich for NA too just fyi. But I imagine as with any blanket tune, its not going to be ideal for every car but set to the overly rich/safe side. If you want to see the best results you need to tune it to the car.

 

The ap1 makes less power but with TT5 I think you need to run a lot of weight so a lower power lighter ap1 might work better at some tracks. I'm not realy up on the TT rules but I used to run an AP1 in TTC and the long gearing and lighter weight helped vs ap2's at some tracks. I had a 9500redline and a 4.44 rear-end at one point that was a great setup at mid ohio. I think its definitely an advantage if you can run out 5th gear rather than using 6th.

I have any ap2 motor now it put down 237 tuned vs my old ap1 at about 210 turned. The ap1 is weak midrange unless tuned - The ap1 suspension geometry is fine.

 

This was also 180k motor vs 50k motor.

 

I'll put it this way, I love my Ap1, I really do. But when I popped the motor I swapped to the 2.2 out of an 07. I have put about 30+ hours of seat time at Sebring so I know it like the back of my hand. And the only change i made between the track days was JUST the motor. F20 had 86k miles and the new F22 has 54k miles.

I picked up 4.8 seconds from my fastest f20 time with the new motor. Same tires, alignment, weight and similar weather conditions. The mid range torque and power bump cant be beat by the f20.

Davo

 

F22 is a better motor no question. As long as you remove the boat anchor flywheel. 00-01 is the lightest car. Anything else is bolt ons between the years and make it what you want. So the correct answer is a Frankenstein.

 

Of course a Frankenstein is better. If I didn't use my '03 AP1 exclusively for SCCA stock class autocross it would have an AP2 motor with an AP1 flywheel/transmission and an AP2 diff. I've driven plenty of AP2's and they're more powerful and more settled on track, but the AP1 chassis is just "more fun"!

 

Save money with an ap1 with few ap2 upgrades and enjoy the higher rpm

Spend money on the ap2 for performance and lap times.

From my experience browsing the market last 2 years I notice ap2 cars are more likely to be modified heavily. Alot of people seem to think ap1 need the widebody kit. Overall I find ap1 to be better value myself.

The CR is the s2000 track car of all s2000 track cars.

 

My AP2CR made ~10 whp more than AP1; the AP2Cr would typically make 225-230 whp where the AP1 would typically make 215-220 whp. Both were setup for STR autocross with similar modifications; for tuning the AP2CR used flashpro and the AP1 used greddy emanage ultimate.

I never did any controlled testing, but I attribute some of the difference to rear alignment. The AP1 had 1/8" more (total) toe in than the CR, and with the CR it seemed to lose ~5whp increasing toe-in by ~1/8".

 

The accuracy of the sniffer used in those dyno runs has been called into question by a few that were also running their cars that day so I would like to double check with another pull to see (and preferably using a different AFR measurement method). That was a dyno day with a group of us there, so I did not get to stop and do anything in between. What little OBD data I have seen while actually driving the car hard has shown a bit leaner per the O2 readings. I will mention that there was another S2k with idential mods, with a slightly modified tune (his did show a tad leaner in some spots) but mine still put down 8 more hp than his did that day on the same dyno. But again, peak gains are not all that important for what this tune was trying to accomplish overall.

There is some room to play with that tune using the 2nd map, but to be honest, it has worked so well out of the box for so many for so many years I have left it alone. Brian mentioned that these engines are so consistent it was not super hard to make that "one size fits all" tune which is cool to hear. If I get some time to go spend at the shop I may play around with that tune more to see what improvements we can make.

True on the header/cat part, although I have heard mixed reviews from people with the tune and how much the header affected it. I can say from experience it runs like shit without a HFC/decat. Well, not totally like shit, but there is a very profound dip in power between about 3500 and 5000 rpm without that. Enough to mostly negate the gains elsewhere, especially when autocrossing.

One correction though is that VTEC engages at 4000 rpm, not 3500. I believe it is 4000rpm if throttle is at 70% or higher, and engaged no matter what at 6000 rpm. You certainly do not really "feel" the engagement as much as you do stock, but the pull is much more smooth and linear for sure.

 

I can agree there. If I were buying an S2000 just to own one, drive on the street and some track days here and there it would be a AP1 hands down.I find it much more fun, more lively, etc and love the motor. If I were looking for all out autocross perfomance or track performance then the AP2 makes more sense. That low/mid range improvement makes all the difference. I got used to the "snap" oversteer (not a fan of that term because it really just means the car is not being driven properly) tendancy within one event back when I ran the AP1 in b street. So that never bothered me that much.

Of course, when I mention all out autox performance, my real choice now would be an ND Miata (or the ND2 now that they will move into STR next year) since the S2k simply cannot compete with those anymore for autox usage. That makes me sad and I really hope there can be a class that they can become competitive in at a nats level again. I remember a few years ago there were 65 S2000's in grid for STR at nationals (and I think 2 older miatas). This year there will be zero with the ND taking over. Just too hard to make up for a 500 lb weight difference.!