Ap1 vs Ap2 for track use and eventually time trials
08-02-2019, 06:31 PM
#22
Partially yes. With the primary drive of the ap2 trans its like putting a 4.22 rear end on the ap1. But low/mid range improvement on the f22 depends on how good your tune is. On the primary cam only without the trans gearing advantage it may not be perceivable to you. The F22 does respond better overall to breathing mods, as any typical larger displacement motor would though.
08-02-2019, 06:45 PM
#23
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.
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.
As for your vtec cross over 4000rpm is what I said. 3500rpm is what I said you could tune to and pick up more. Note your vtec spike at 4k when it transitions, when it spikes that means the engine was still starving for more cam prior, but its well know these motors respond to 3500-3600rpm engagement. I was just further elaborating on where you could improve your tune along with your fueling, my only point. Id highly recommend it, if you can find a worthy tuner to make these improvements on your emanage. Your leaving 10- 20% power on the table in various places across most of your power curve. If you were local id make the adjustments for you without the dyno assuming you had a wideband to work from. If you dont, id highly recommend you run one to verify your actual afr. Always a good idea when running an aftermarket ecu or piggy back for safety and future troubleshooting. You will no doubt get a hiccup or a head scratcher in the future you will need to see how the engine is doing.
.
Yeah this tune/vtec was designed with no cat so if you put a cat on with this tune the power will fall on its face in the rpm you described. You need a tp or hfc to capitalize on lowering vtec bellow 5300rpm. The engine doesn't respond to lowering vtec under that rpm without it. A well designed header will just give you the cherry on top of your entire power curve, but the stock header is so good its a crap shoot to find and spend the money on something else. I never bothered. Once upon a time the J's knock off /PLM was $300 and actually seemed worth the trouble with some further mid range improvements.
Last edited by s2000Junky; 08-02-2019 at 06:58 PM.
08-02-2019, 08:51 PM
#24
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.
08-03-2019, 05:22 AM
#25
Partially yes. With the primary drive of the ap2 trans its like putting a 4.22 rear end on the ap1. But low/mid range improvement on the f22 depends on how good your tune is. On the primary cam only without the trans gearing advantage it may not be perceivable to you. The F22 does respond better overall to breathing mods, as any typical larger displacement motor would though.
If I had found a good condition F20 when my original motor went I kind of wish I went that route, but they were impossible to find.
08-03-2019, 03:07 PM
#26
You are running an F22 at 8800? Are you running an AP1 ECU or AP2 ECU and changed it? I'm just interested because I thought the Karcepts AP2 tune had an 8500 rev limit. I just sent my ECU to them. I had gotten a pro tune, but not knowing how to set it up initially, I didn't change VTEC or the rev limit. I found the STR setup thread after getting it tuned unfortunately. Emanage is less than ideal for setup and tuning... It's all we really have though for STR.
08-03-2019, 05:52 PM
#27
You are running an F22 at 8800? Are you running an AP1 ECU or AP2 ECU and changed it? I'm just interested because I thought the Karcepts AP2 tune had an 8500 rev limit. I just sent my ECU to them. I had gotten a pro tune, but not knowing how to set it up initially, I didn't change VTEC or the rev limit. I found the STR setup thread after getting it tuned unfortunately. Emanage is less than ideal for setup and tuning... It's all we really have though for STR.
I don't remember the e-manage software much from when I had my ap1 but you should be able to find it if you poke around. I wouldn't run it that high often.
08-05-2019, 03:28 AM
#28
You are running an F22 at 8800? Are you running an AP1 ECU or AP2 ECU and changed it? I'm just interested because I thought the Karcepts AP2 tune had an 8500 rev limit. I just sent my ECU to them. I had gotten a pro tune, but not knowing how to set it up initially, I didn't change VTEC or the rev limit. I found the STR setup thread after getting it tuned unfortunately. Emanage is less than ideal for setup and tuning... It's all we really have though for STR.
I only go up to 8800 when the track/gearing works out that way and I'm on a hot lap or trying to reel someone in. Usually I just shift at about 8200 to be safer.
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