207

iTrader: (1)

I have searched the forum and have lots of information to get my 850's to run.

However, I noticed that most of the post are two or three years old and I was wondering if there was any new updated way of tuning for 850's.

I have done the following and so far the car starts quickly and idles around 11.8 to 12.0 AFR.

1. Set Injector to Lag to -0.04 and 64.7%, set base fuel pressure to 38psi, pressure test fuel system, pressure test for boost leaks, etc.

2. Adjusted Accelerate INjector Values to:

5000 7.5 1
4000 7.5 1
3000 7.5 1.5
2000 8.0 1.8
1000 6.0 2.0

3. Set "Inj vs. TPS1 to

Input Setting
128 256
64 192
10 128

I'm hoping to keep a linear progression for the tip in.

Now here are my problems:

1 . It still leans out at tip in from a stop and idle, but not that much of a problem will driving.

2. Should I increase the negative lag further to get the idles down to 13.0 AFRs', or is -0.04, the recommended minimum. It seems the PFC minimum base fuel setting is 2.4-2.6 in the idle range so I have set them to 2.5 for now.

3. The car had 550/1600 and now has 850/1600. I want to try are maintain as much as possible of the 550/1600 maps because it took soon long to get right. Is there an agreed way to set the PFC so that the 850/1600 works similiar to the 550/1600 setup on off boost areas. I know I have to retune the boost areas and I'm ready to do that.


THanks

207

iTrader: (1)

No help from anyone !!!

arghx

iTrader: (3)

See my thread about tip-in tuning. https://www.rx7club.com/power-fc-forum-47/accel-vs-tps1-tuning-strategies-750370/

it presents some ideas to try that were helpful on my 720/1680 setup. The key is to try and figure out whether your basemap or your accel settings need to be changed. With the engine fully warmed up and consistent IAT conditions, datalog your InjFrPr and TPS V , and if the car is leaning out with steady throttle movements (and no pulsewidth spikes) then you likely need to focus more on your fuel map. If it's leaning out off-the-charts from throttle movements, you may want to try and adjust the "input" column further on your Accel vs TPS1, keeping in mind that any changes to that will require changes to the basemap so you aren't overcompensating. If pulsewidth is spiking far above what the fuel map cell calls for, and there is throttle movement, then your "input" column is probably ok (or close to ok) and you need to mess with Accel vs TPS 1 "setting" and Accelerate Injector.

I would use Accel vs. TPS 1 Input to make tip-in slightly too rich (or at least to eliminate any dead lean spots which are indicative of no Accel enrichments being applied at all), then dial out the fuel using the "setting" column, basemap, and Accelerate injector settings, in that order. Also, if I were you I'd expect to throw a lot of your map out the window with bigger primaries if you want really precise tip-in and low engine/vehicle speed driveability.

And chill out, don't expect a response to your thread in just a couple hours...

arghx

iTrader: (3)

This is an example of identifying when the PFC is applying accel enrichments. If you see the car lean and there is no throttle movement (throttlemovement being a spike in the curve, 2 volts steady is not throttle movement), then it's more likely not to be a problem with your accel settings. You can see in this case my Accel settings are ok for this level of throttle movement at this RPM, because pulsewidth is spiking but AFR is not shooting up or down drastically. But that doesn't mean my accel settings aren't off at a different RPM or at a more drastic amount of throttle movement (steeper curve). That subsequent dip in AFR is more from a rough fuel map than accel settings. It's really tricky to get the fuel map tuned in such a way that it isn't too rich in round-town driving but when you get on it it doesn't go too lean. I still struggle with it. Btw this is on a series 4 narrow range TPS so the throttle movements may seem a little more drastic than on a series 5 or 6, because the series 4 TPS reads WOT with the pedal about 1/4 - 1/3 depressed.

You can't see it on the right side, but in that graph I have RPM , InjFr , wideband , and TPS V all with their own scales. I am displaying the basemap as BASE X INJ, so that is the total fuel map pulsewidth in the map on the right.

subyfiles

what type of 850cc injectors are you refering? I'm running Denso 850cc on my car and they are really horrible to tune. I have tuned 1650cc Bosch and 1200cc RC injectors in some time ago and they were better than denso.

arghx

iTrader: (3)

I have Denso 720's. Denso injectors are actually underrated (at least the 720 top feed are, which is what I run on my FC)... they make their flow rate at a lower fuel pressure than 3 bar, which is where most fuel injectors are rated at for flow. So when tested at 3 bar like every other injector they flow more. The guy from KGparts was discussing this a while back...

207

iTrader: (1)

The 850's are the factory secondaries in a milled down rail.

207

iTrader: (1)

The car ran much better once it warmed up. I'm trying to chart the TPS v vs the AFR to upload. The hesitation at tip in gets less and less as the car warmed up. That is confusing because I would think the fuel maps are leaned out as the car warms up.

cewrx7r1

iTrader: (2)

You should not tune idle by AFR! You tune fuel for best lean smoothness.
Mine is between high 13s and low 12s.

Many times bad tip-in is not the ACCEL values, but lean fuel cells for acceleration off of idle. LOG IT.

207

iTrader: (1)

Okay I logged tonight and I need to do some clean of the map, but after 1 hour of logs and adjustments it seems the one cell for idle stays at AFR 12 and everything above or around it is getting too lean, 14's and 15's.

I decreased the injector lag to -.1 from -.04. I see some guys increase the primary injectors from 64.7% to 80%. Should I do this to help even out the difference?

SPICcnmGT

If you change the lag you will have to retune the whole fuel map, major PIA just to get a smooth idle IMO. The other is injector specific for what size you have, you might can tune some with it but you will have to do the whole map again, I wouldn't mess with it.

If you are idling at 11.8-12afrs with 850cc you are doing better than most, including me. I would just play with the idle rpm, timing, and throttle body screws before I tried changing the INJ settings just to get a smooth idle. The tip-in can be tuned out if you take the time without changing the INJ settings.

cewrx7r1

iTrader: (2)

One bad point about using INJ settings for tip in problems:
it will decrease your fuel mileage because every small throttle movement even while cruising will richen the mixture.

207

iTrader: (1)

Okay..It tune a long time to get a good map back, but it is done. The car seems to run so much better when the water temps are over 85deg. I think alot of the tip in problems and poor idle are do to temp adjustments.

I ran up to 10psi on pump gas, 11.5 Afr, 55 knock, timing 11 degs, split at 10 degs.

My car has a 3-inch exhaust and I want to get a lower knock, less than 40, do you think pulling timing will help. It seems as I raise he timing the knock reduces, but I don't rust that. It might be a sitting time bomb.

I need to raise the boost to 18psi on C16 for a friday night tune. I have raised each pressure rows of the map above P16 1 full point above each other.

The big turbo does not full boost in second, but once in third it pulls like crazy. I will need to get the boost going earlier for 1/8th track races. Any suggestions welcomed.

207

iTrader: (1)

Okay..here is my chart on the rolling pull. I wish I could get 10psi before 6000rpm. I'm going to post all of my screens for anyone who might be interested.

arghx

iTrader: (3)

If it were me I would just dive in there and be prepared to throw out everything you have to make it run better, or put it back near stock and live with it. I think your idea of a linear INJ vs TPS map isn't going to work any better than the map that came from Apex'i, which is clearly not linear. I don't know what kind of behind-the-scenes math goes on to calculate the actual accel correction (as in, how exactly these tables interact quanitatively) but what worked best for me was lowering almost all the numbers and fiddling with them, not trying to space them out evenly. But that results in you having to change everything else. It's all or nothing: commit yourself to building custom Accel settings from scratch the hard way or just go back to stock(ish).

My INJ vs TPS1 current settings are:

65 256
23 150
6 9

The more you play with this set of numbers, the more you may have to play with the Accelerate Injector numbers.

Accelerate Injector

7.4 1.0
7.4 1.0
8.0 1.5
8.0 1.8
6.1 2.0

And the more you play with these numbers, the more you have to mess with your fuel map, especially coming off idle. All the settings work together. It's a laborious process but it was worth it for me. Adding to Accelerate injector hadn't done a whole lot and increasing the lowest setting on Accel vs TPS 1 only did a little bit as well, so I just redid everything. But for Chuck and many other people, Tip-in is probably not as big of an issue, and many tip-in problems are simply fuel map problems as has been pointed out.

A fourth graph with primary (and possibly secondary) injector pulsewidth would've helped make that graph easier to understand. Now look at 40-45 . You have a sharp throttle movement, which makes it go a little lean (but not off the charts), which means your midddle or top Input number are probably not too bad, but then you have a gradual throttle movement that causes a bit of a lean spot. I would lower the lowest input number, then start lowering the other input numbers (and the setting numbers) and play with it from there.


I don't know how extensive you have played around with these Accel settings, but In my experience what your describing can be minimized (I also use cruise control but even off cruise you can keep it from straight dumping in fuel) when you reduce the "setting" part of Accel vs TPS 1 and reduce Accelerate injector to stock levels or lower. You pretty much have to redo everything to make it work just right as I said and it's time consuming and may not be worth it for everyone. If you have your accel settings right a sudden throttle movement will not change AFR much (or maybe got a little rich, but only under hard movements), or it will get a little bit leaner but not enough to physically feel the car stumble. Mine only goes rich (like drops into the 12's from an AFR of 15 in cruise) if I really stab the throttle hard like I'm about to go into boost. It's not perfect but it's better than an unpleasant hesitation.

cewrx7r1

iTrader: (2)

The map watch: your AFRs jump all over. You should be able to get them so when in one P row, they do not vary more than .2 AFR from 4000 - 8000 rpm. That is how I do it in about three runs in 4th gear.

The chart does not have RPM, but the values jump so friggin much. No smoothness to them which they should have except at injector transistion.

When I ran non-seq, I ran 11.2 AFR at 14-15psi. As boost dropped by 2 psi for lower P rows, I leaned them by .2 AFR.
Now with a single turbo, the values are now 11.0 AFR and .1 AFR leaner per 2psi drop.

arghx

iTrader: (3)

If you tune with the INJ map you have to be careful. You can end up getting fuel map cells that just jump all over, because the INJ map is a correction factor. I usually go through my base map (Base * INJ view if you aren't recalc'd) and check to make sure that the pulsewidth values generally increase as load increases (as you move down or to the right on the map). You may find weird cells that are just off for whatever reason (although injector transition and other factors sometimes affect fuel requirements). And those cells are the ones that are most likely making your AFR's jump around so much. It's hard to get it perfect, but you can certainly get it to fluctuate less than that. It's similar to the process of smoothing out your timing progression but harder.

207

iTrader: (1)

I understand. The dyno is not working so I have been driving around and logging then adjusting in small increments trying to get a stable AFR. It will take some time, but I'm sure I will get it stable.

My concern is doing all of this and then having to change a INJ, ACCEL, TPS setting for more power and having to do it all again. Thats why I'm asking for help in those settings then I can concentrate on the AFR's.

janrx7

great post

Xcessive

I do it a little different than others when tuning bigger injectors.
I set the 850s to approx 80% and lag time to -.4ms approx ,
and the 1600s to around +.4ms.approx and the size 1600 and 850.
Also make acc fuel stock setting for now. I always get primaries set
good for driving 1st. Then after that I go to secondaries and adjust the lag time up or down for rich lean closest to the base map.
Note: I came up with this from just tuning my own car to get the closest afr
and. throttle response. I cant tell you why but on all the cars I have built
and dynotuned in my shop The cars ran smoother and really responsive.
If you just keep the primary tuning @ boost level really low you have a hard time hurting any motor parts. note:::This information is for people that like to tinker
with stuff so this is only my opinion and do at your own risk.
Also I only used the factory high impedence primarys 850,s and no resister with 1600,s the tansistors can
handle the current onn the PFC.
Ralph Friend

blackredrx7

I learned alot from this post and need to log some more to see where I am at. Thanks for the info.