I've been trying to tune out this lean crossover issue for weeks but cant figure it out.

I have skunk2 stage 2 cams in my car with about 9 psi on a JRSC. As soon as vtec crossover hits, it goes from 12.5 to 14.9 and then back to 12.5's. I've tried adding a bunch of fuel right at 5000 on the high cam table but it makes no difference.

I'm using Crome Dealer...with a P72 rom. I guess with crome there is no way of adding vtec tip-in adjustment like other EMS' right?

Anyone have any ideas???

 

My guess is that you have not put the vehicle on a dyno to even see if the x over point is correct to begin with ?

1. Look at your timing values between the low & high cam transition.
2. Try moving vtec up & down to see if these symptoms go away.
3. If you are datalogging, do a cell trace to make sure you are not having some kind of electrical issue with tps/map signals etc.

 

have you tried adding fuel just before vtec so transition period has more fuel?

is the timing similar at the low cam and high cam switch?

 

I am going to guess that crome still has this bug.

When using the P72 maps, it doesn't switch over like it should. I think it stays in the low cam map for longer.. for some un known reason.


Try adding fuel to the low cam table, right before vtec and like 2 cells below it. That should clean it up.

 

yea, OP...what version of crome are you using?

 

what i like to do is set vtec real high (7000+) and get the fuel tuned up to 7k on the low-cam map, then set vtec to 4000ish and get the high-cam map tuned from 4k to revlimit. I find this really helps with weird fuel issues around the vtec crossover.
I also find sometimes adjusting the RPM scalars helps fine tune, in crome the resolution is shitty around 5000rpms on the low-cam map, so if you adjust the scalars a little and can get it to go from 4000, 4500, 5000, 5500, 6000, 6500 or 4000, 4500, 4750, 5000, 5200, 6000, (it depends on where vtec engages) that'll help fine tune the fuel on the low-cam map just before vtec.

 

My timing is very close to being the same, like 18 and 16.
I tried to change it to be the same and no difference. I've tried adding fuel to the high cam switch but no change. I didnt try to add fuel to the low cam though. I will try that this weekend.

I have a dyno in my shop, and yes I did put it on the dyno to test. I tried alot of different things....no luck. I will try the low cam side to see if it works out. I'll post results soon