DBW Rev Limiter
07-31-2018, 03:18 PM
#1
DBW Rev Limiter
I've been autocrossing the last few years in my AP1 and have done a few events in my new to me AP2. This past weekend, the course had me hitting the limiter pretty hard in 2nd a few times. The limiter on the AP2 felt really hard and like it fell on its face. I didn't have much time to try to ride the limiter but it felt like it wouldn't have let me ride it. It felt like it fell flat on its face, was going to let me drop a few hundred RPM's before giving me any power back. Is there a different type of limiter implemented in the DBW cars then the AP1 or anything that would cause this?
I can't tell if I'm being paranoid or if it felt really off. I've searched a bit and haven't found any difference in the 06+. I'm all caught up on maintenance but haven't changed the plugs yet. I just crossed 90k miles. I figure this is an unrelated note but the point is it is a strong running car.
I can't tell if I'm being paranoid or if it felt really off. I've searched a bit and haven't found any difference in the 06+. I'm all caught up on maintenance but haven't changed the plugs yet. I just crossed 90k miles. I figure this is an unrelated note but the point is it is a strong running car.
07-31-2018, 04:21 PM
#2
On my 2007, I hit the limiter in 2nd all the time at autocross events. Mainly when I run with the Porsche clubs who make really wide open tracks.
Sometimes on certain parts of the track it will just bounce (sometimes I need to ride the limiter until I let off for a turn or finish line) and sometimes (not as frequent) it will fall flat.
I have hit the different limiters during the same lap in different sections of the track.
I haven't had time to think about why it is different sometimes.
It almost seems like sometimes it is just electronically limiting it and sometimes it also cuts fuel, but I am not sure.
Sometimes on certain parts of the track it will just bounce (sometimes I need to ride the limiter until I let off for a turn or finish line) and sometimes (not as frequent) it will fall flat.
I have hit the different limiters during the same lap in different sections of the track.
I haven't had time to think about why it is different sometimes.
It almost seems like sometimes it is just electronically limiting it and sometimes it also cuts fuel, but I am not sure.
Last edited by exigex; 07-31-2018 at 04:33 PM.
07-31-2018, 05:13 PM
#3
On my 2007, I hit the limiter in 2nd all the time at autocross events. Mainly when I run with the Porsche clubs who make really wide open tracks.
Sometimes on certain parts of the track it will just bounce (sometimes I need to ride the limiter until I let off for a turn or finish line) and sometimes (not as frequent) it will fall flat.
I have hit the different limiters during the same lap in different sections of the track.
I haven't had time to think about why it is different sometimes.
It almost seems like sometimes it is just electronically limiting it and sometimes it also cuts fuel, but I am not sure.
Sometimes on certain parts of the track it will just bounce (sometimes I need to ride the limiter until I let off for a turn or finish line) and sometimes (not as frequent) it will fall flat.
I have hit the different limiters during the same lap in different sections of the track.
I haven't had time to think about why it is different sometimes.
It almost seems like sometimes it is just electronically limiting it and sometimes it also cuts fuel, but I am not sure.
08-01-2018, 04:49 AM
#5
I am wondering if it is typical to raise the rev limiter on the AP2 when doing a tune with Hondata, or is it better to leave it where it is unless the motor is built?
I plan on having mine dyno tuned and lower the vtec engagement, I am not sure if I should have the tuner touch the rev limiter though.
08-01-2018, 05:22 AM
#6
My FlashPro tuned 2006 has a 3600 rpm VTEC and 8400 rpm rev limiter. Gerby tune, same exhaust as exigen. I think the rev limiter cuts the injectors (not the spark).
My only experience in hitting the limiter is in "normal" driving and with the late gearbox hitting it in 1st and 2d is where I have to be alert as the revs climb fast with the lowered VTEC. I've never ridden the limiter, just shifted or lifted. I put a red line alarm on the car to get some warning when to shift and not bump the limiter. Your application running around parking lots will be different as you're unlikely to shift into 3d. I expect a different rear axle ratio could optimize some of this lower gear racing, it depends on how deep you want to go and what events you run. I've not seen quick change rear axles for our car but haven't spent any time looking for them either.
-- Chuck
My only experience in hitting the limiter is in "normal" driving and with the late gearbox hitting it in 1st and 2d is where I have to be alert as the revs climb fast with the lowered VTEC. I've never ridden the limiter, just shifted or lifted. I put a red line alarm on the car to get some warning when to shift and not bump the limiter. Your application running around parking lots will be different as you're unlikely to shift into 3d. I expect a different rear axle ratio could optimize some of this lower gear racing, it depends on how deep you want to go and what events you run. I've not seen quick change rear axles for our car but haven't spent any time looking for them either.
-- Chuck
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08-03-2018, 07:01 AM
#8
I am wondering what fuel system modifications can be done to avoid this on the AP2 DBW and still be street legal and legal for STR and similar classes.
I have heard that is is a bigger concern on road courses, which I would like to address before I start doing more track days and time trial events.
08-06-2018, 08:25 AM
#10
Former Moderator
It feels like the rev limiter "fell on its face" because acceleration stopped. That's normal and it's not a problem to ride the limiter. No other limiter can "give you more power" than the stock limiter.