hey fellas, got some questions.

okay i have a b16a, with pistons, rod.....and all the supporting goods, to support up to 20 or more, psi.

okay, so here's the questions:

while in third, my a/f is reading at mid 11's and pushing 17psi, and pulls really good. but in 4th and 5th the a/f drops to mid 10's pushing the same 17psi, but just feels so much slower. i have a jdm cable b16a tranny so gear ratio isnt the problem at all, i rev them gears out within seconds of another.

also, atm the ing. is set to -1 degree per 1psi. so at 17 psi at 8000rpm the ing is retarded to -15, is that too safe? combined with the rich fuel mixture, which in terms is making the car slower in the higher gears?

i know every setup is different and opinions on a/f will not be the same, but im just curious whats the ideal a/f when running this amount of boost.

thanks, for chimming in.

 

that was tune on crome, i just got my neptune rtp in today and will be missing with it this weekend. so any help will do. thanks

 

very generically, for regular pump gas you do want to be mid to high 11s like you have in 3rd gear.

the difference in afr you are seeing is due to gear correction and load differences. i would tune for my 11s afr in 4th gear, then use the gear based corrections to help level things out in other gears. you really shouldnt be boosting up for long periods of time in 5th, even with good afr the load can increase egt's and cause major issues. if for whatever reason you need to boost a lot in 5th get an egt gauge


what do you mean your ignition is -15? at 0" you probably run right about 30 degrees total, so if you are doing 1 degree retard per psi, then at 17 psi you would have about 13 degrees total. that is a bit low but not ridiculously low. a lot depends on the VE of the motor and fuel used. i usually start with the 1 degree per psi approach then add a bit back till either the plugs start to show slight detonation signs or until the color change on the ground strap really starts to get toward the base ring. on the dyno its done until the car stops making more tq. once you hit those points pull it back a degree or 2 and you are set

 

that timing is low, and AFR is rich, it is safe, but you are losing power for sure, you want to know the sure fire way to correct these problems?

A dyno, period.

 

Thanks for the input, -15 was a typo, but the ing is set to 15. And with the jdm b16a cable Tranny 5th gear only goes to 130 or less, and when pushing it in the hwy 4th only goes to about 110mph so that's the reason why I'm still pushing 17psi,only for 4 to 6 seconds if that because it revs up so fast.

Also when u say pull it back a degree or two, it that advance the ing or retard? Thanks again.

 

Yea a dyno is a must, but I'm not gonna put it in the dyno until I can hit 11s with this setup. Working on a new build lsv-t, so I don't want to spend that money just yet until my motor is done and new turbo gets here. Atm my b16a with 14psi runs 12.2 with small slicks. I just need some opinions and help figuring out what the best a/f ratio is for the mean time. Thanks for the input.

 

Since you didn't get it the first time, try using a dyno.

 

Like I stated earlier I know a dyno is a must and it sure will be done, but not now. I just need some opinions and not smart *** remarks. Thanks.

 

What fuel are you running?

Do you know how to make pulls and read plugs? Can you hear detonation (you have to have a keen ear for this)

If you can read plugs and hear detonation, you can tune it pretty well without a dyno.

start with .75 retard per psi, and try to dial the AFR in to high 11's in every gear except 5th, that should stay in the high 10's or low 11's

Then you need to listen for DET. and read the plugs to further tune the timing for power, I dont know how well your ability is for tuning, but the base adjustments of retarding the timing per psi will only take you so far, after that you need to manipulate timing in cell blocks manually to achieve the best tune possible.

Be careful with timing if your running 91 oct. as it will DET. much easier than if your running 93.

 

I'm running 93, thanks for the input boosted D

 

So at 17 psi, you are currently sitting at 13 deg. timing on the top end, switching to .75 per psi (vs 1.0) will net 17 deg. total timing adding 4 degrees of total timing

This will be a good increase in power, just listen carefully for DET. and if you hear any, you can start selecting cell blocks in chunks (on the high cam map) of like 6 cells, and pull like 2 degrees of timing from the highest rpm cells, then work your way down, slowly decreasing the amount you pull so that at lets say 5000 rpm you are only removing 1 extra deg.

Do you kinda get how that works?

Also neptune RTP has a fail safe for IAT temps. you can set values that the ecu will automatically pull more timing if the IAT's get too high, you should use this feature being that you are tuning in winter, come summer, that same tune will have higher IAT's and cause DET. if more timing isnt pulled.

 

Imma try it out later if the weather permits, I'm still pretty new to this so all the extra features that Neptune provide over Crome will be a slow learning process. Thanks again, I'll update as soon as I'm through messing with it, looking for the 11sec pass next sat if all goes well.

 

yea *** the dyno. the strip is better to tune and more realistic. i like to do my air fuel ratio on the freeway at night, and tune the ignition on the trak to see what gets better trap speeds with the same 60ft. dyno is cool for 10sec cars. you dont need a dyno for mid 11s if you know how to get down with your tuning, and i check my spark plugs after and the mornign after as well to make sure

 

so im guessing that if you are racing and your iats are dropping kinda quick as you are runing like for example 110 before a race and 98 after a race(datalogging), does that mean your most likely free of detonation?

 

If you know what you're doing then sure, if I had to make a thread asking about what to do...I would let a professional do it.

 

Not necessarily,

It is a good thing to see your Iats drop during a run, that means you are protected from additional detonation caused by high Iat temps. If they climb when you make pulls, detonation chances increase, but only if they climb too high.

You could still have detonation happening though even with good iats, if you have way too much timing or to lean of a tune.

Iats are simply one tool or reference in the grand scheme of tuning, I feel like I know a bit about it, and can make a decent tune, but by no means am I an expert at it, tuning is some complicated stuff, it's one thing to be able to make a decent tune, and another entirely to fully understand tuning and be able to make a pro quality tune, those guys have invested their lives into that kind of knowledge, and that's why they get paid good money to do it!

 

1

 

The engine experiences different loads depending on what gear you are in and there are tables in most EMS system to compensate via ignition timing or overall fueling values.

 

Hopefully I'm not thread jacking, but it seems the OP's question has been answered. I have a question in regards to my AFR's as well and dont want to start a whole new thread as my question is relevant to this thread. So here it goes.. I have a B18c 81.5 bore, stock sleeves and piston & rod. Currently I'm at 440 @ 17psi on 93 octane. I noticed that at WOT my AFR's drop to 10.0 flat. Would that be considered a bit on the rich side or is that AFR ok?? I'm not looking to make any more power as I know already that I'm pushing the limits of stock sleeves on 93 octane. I just want to know if hitting those AFR's (10.0) could possibly hurt my engine in the long run or am I safe?

 

10.0:1 will start to wash the cylinder walls with fuel.
Bump it to 11:1 at lest

 

Oh dang! I was not aware my current AFR readings could do that . Ha ha so is that AFR considered what people say is pig rich? Is there anything I could check on my end to what could possibly be causing it to run rich or is it all in the tune?

 

most people on pump gas shoot for 11.3-11.5 AFR, race gas and e85 generally 11.8-12.2 area
I myself like to do at least 1 deg per psi on pump gas to be on safe side, but if you have a dyno or can read plugs then going with a little more is ok

 

On my old tune my AFR's were exactly in that range 11.3 - 11.5. I was wondering what may of happend or what did my tuner encounter to run it on the richer side this time around. I thought he just did it to be on the safe side of things, but according to most people thats to rich. Well for sure I'll have a talk with him and see what he says. Thanks for advise so far..

 

in the 10's is rich, ive seen people take pump up to 11.5-11.7 on 93 and be ok, as long as its not detonating then should be fine

11.3-11.5 on pump is a safe range

 

not a problem, im still messing with my neptune rtp, and many more questions will be ask.