Boost Based Fuel Mapping / PCV pti (autotune too)

[Audiomaker]

Hi Guys,

I have an 02 non-intercooled turbo with a PCIII and I'm strongly considering a PCV pti (pressure/temp-input). I would also be installing an autotune unit with this.

I am really interested in hearing from anyone that has experience with this system and also those who would just like to offer theoretical input.

The first thing I'm curious about is the boost based fuel mapping. Is this a better way to do things over RPM/TP? Why?

What are the differences from this and a PCIII approach in the real world?

On the autotune, well I live pretty far from a dyno and I also plan on making some changes. I got myself stuck once already where I got the bike dyno'd and was 500mi away by the time I realized some adjustments needed to be made.

For this reason, I am interested in the autotune route even if it's just used to keep the bike "good" when changes are made until I can get a dyno/tuner to make it great.

Thoughts on this unit/combo?


Many Thanks
Sean

 

[The Big Red One]

I know a zx14 turbo owner who loves his auto-tune, he's been very happy with the results, but he's also invested TONS and TONS of time working with the auto-tune to map his 14......he loves the whole tuning process. I've heard from several tuners that an auto-tune set-up is not a good thing for a turbo bike, too easy to do engine damage. The guy I know who runs the auto-tune wants me to try it on my turbo 14, but I'm holding off for now. You can tune some issues out yourself by modifying your pc map with a little patience and research. You can also play with base fuel pressures. Just do small steps at a time and keep track of the changes. And some way to monitor your AFR is crucial. I have a good logger I picked up new for under $250 online I believe....all turbo owners should own something similiar. For major boost increases tho a good tuner is really the best option.
Turbo's are a tricky breed to own, you need to understand them to really enjoy the whole ownership thing....and the more you understand the easier it is to keep them running good.
You're on the right track Sean with your quest for knowledge

 

[Audiomaker]

Thanks for that answer BRO, and it's good to hear from ya

I watched some vid's on the autotune and I guess you can switch it on/off.

I must say that I like the idea of the bike being able to maintain a specified AFR based on an actual sensor. Knowing what that AFR should be at any particular RPM/Temp/Boost is quite another matter (I feel a future thread coming on).

There seem to be a lot of ways to know your AFR and I guess you can hook up the PC LCD to this system if you have the auto tune installed. Obviously no matter which way you go to get it, you're gonna need an O2 sensor, so this auto tune thing kind of kills two birds with one stone...even if you don't use the auto-tuning function of it.

The other half of this equation is boost based fuel mapping. That sounds smarter to me than TP/RPM based mapping, although I'm not sure what the real world result would be vs what I have now. The bike does feel like it's sorta "disconnected" from itself... or put another way... like it runs a bit differently at different temps and riding styles.
Even starting and idling, and even loading the engine by idling it in higher gears (to "coast" through 25mph zones) feels different all the time. For instance, I get a different feel between when it's just warm, at operating temp, or when heat soaked (at operating temp for awhile).

It feels like I'm riding a different tune all the time. Riding the bike "briskly" in the hills, then stopping for lunch for an hour....and I'm on a different tune when I get back on...etc. It's all rideable, but I've been riding long enough that I'm sensitive to slight changes in the way the bike responds. Being my first aftermarket turbo, I'm not used to this I guess, but I wish it would behave a little more like a factory turbo bike instead of an aftermarket turbo bike...if that makes any sense?

Being as ignorant as I am, it makes sense to me that adding a turbo to this bike has added a 3rd dimension to it's tune, and by that I mean "3D" where the possibility of having it in the right tune is exponentially harder. Of course then it makes sense that this "fishing" for tune feeling might be because I have a 2D map running a 3D equation.

It also makes sense to me that one could never simulate all conditions (boost/temp/TP/riding style...ie load) on the dyno, therefore something that reacts to O2/MAP/Temp input would be just the ticket. That of course, is theory.

Now, it also makes sense the what you say about the autotune being potentially dangerous to turbo bikes, except, were they speaking of the "pti" model where you can change the A/F based on manifold pressure, or just the basic PCV setup? The damage I can imagine would be from going lean under boost, but I guess you could dial that in if you could richen up based on real boost sensor input vs assumed boost@rpm/tp?

I dunno squat... just learning. The people that make the Powercommanders though made a special version for forced induction and I'm surprised more people aren't trying it?

(sigh)
Sean

 

[gulag]

I asked the guys at powercommander about this earlier this year,, (I have this setup, 2004 busa, stage 1 turbo, PC5 and Auto tune.. here is his answer)
-------------------------------------
The Auto-tune can help build your map and can even tune based off of boost vs. RPM as opposed to throttle position vs. RPM. You can turn up the allowable fuel trim for Auto-tune as high as 50%.

You are correct in that you would not want to rely solely on Auto-tune to build your map from scratch. You need to manually adjust the fuel curve so that the bike is at least driveable, before letting Auto-tune adjust the map as necessary. If the bike is so far out of tune that it runs horrible, Auto-tune is designed to assume there is another bigger problem, such as low fuel pressure, and it is programmed to do nothing. Basically the current air/fuel ratio needs to be within a window of 11.0 : 1 to 15.0 : 1 for Auto-tune to work.

 

[Boosted Cycle Perf]

I would not trust auto tune on a turbo bike. It just doesn't react fast enough to be safe. Part throttle tuning it be fine, but full throttle, you'll likely melt somthing.

 

[Audiomaker]

Ok, all good info'...

I'm curious about the idea that autotune isn't fast enough to fine tune a turbo bike. I've heard that the PCV can take PCIII maps and my map is already quite rich.

If you started with a rich map, would autotune be able to lean it out correctly without ever being over-lean since it is working off a map that already dumps extra fuel in for the boost?

The reason I'm asking is that in my imagination, the reason autotune could damage an engine is if it's running from a base map close to stock (-0+) and then has to figure out to dump all this extra fuel in there to get it to the right AFR at boost time, but what if your map is already darned close before applying the auto tune? Dunno.


Secondly, one thing that is still not being discussed is the advantage of boost/temp based fuel mapping vs TPS/RPM based. Could someone explain why that might be better? I mean cars have MAP sensors... there must be something to it or?

...and lastly....

Would you want your AFR to remain the same throughout the Boost/RPM range or would you want it to change? TPS signal no longer needed when doing boost based fueling?

What would be a good AFR at say 30% throttle, 5psi, 7krpm? Same for 80% throttle, 9psi, 9krpm? Do you still use all three (4 with temp)? Gets complicated fast. Really trying to wrap my head around this.



Sean

 

[gulag]

I would not be scared of using Auto tune, but starting with a decent map and making the auto tune fine tune it,,
if you think about it, what is happening on the dyno? basically the same thing, except there the bike is static.. minimum fluxtuations in heat, humidity etc.. why shouldnt the o2 sensor and auto tune not work when a long pipe stuck into the exhaust connected to a PC works?

drive the bike, take it home and open the auto tune map, take a look at it to see if there are any abnormal readings, fix it and send it to the PC5..
the car guys have been doing this for years with wideband controllers and data loggers..

 

[Moparict]

Take it to the dyno and tune it first. Then use autotune to put the final tweaks to your map. Just make sure you limit the amount of change it can make.

 

[Audiomaker]

Thanks guys. The bike has already been dyno tuned.

It was tunes on a 7 pound spring (no controller), and I requested the bike be extra safe for the 2700mi trip I was immediately taking with it afterwards (giving for bad fuel potential along the way).

It was also tuned with an expectation that I would be getting a controller that would be providing between 7 and 10lbs (two modes), so it's quite rich allowing for higher future boost.

In the meantime, I needed sprockets along the way and got the only one's available on my route, so I went from 18/39 to stock. I'm not sure if the sprocket change also affected my tune.

Bottom line, it's rich and fouling plugs regularly. My bike also has high fuel pressure and S2000 injectors, so it's all screwy. I've leaned it out about 10 points on the power commander and it's running better, but it still stumbles just as the boost comes on unless I roll on incredibly slow.

The nearest dyno tuner that I know of that I would trust (Goldenchild) is a 6 hour ride for me, and I really like the idea of having a map that is AFR target based vs RPM/Throttle based (Even though nobody seems to want to talk about the advantages vs disadvantages), so the PCV-pti fits this bill. $250 more gets me the autotune added to the setup, which is a step towards being able to log my AFR using Dynojet's LCD display/logger/thingy, so why not?

I think the route I'd like to try is getting the PCV-PTI and AutoTune, importing my current rich PCIII map and letting it have a go at it, then take it north to have the perfect target AFR's determined on the real dyno by Goldenchild.

What I am curious about is what my baseline AFR's should be on a turbo bike? Do they change with boost?
For instance, would you want a different AFR when the motor is getting 7lbs of boost vs 10lbs, or would the AFR target remain the same? Remember, I'm talking Target, not Delivery.

I've seen in my short time learning here that fuel can be used to cool the engine, so it's things like that where advice on proper AFR vs Boost vs Temp vs RPM matter.

Thoughts?

Sean

 

[BIG CC RACING]

Don't try do it yourself less you real confident & if your asking on here its questioning yourself. 6 hours is nowt to a burnt motor.

Take the bike to a dyno centre that has got proper accurate A/F Explain to them off boost 13.2 & on boost 11.8. When you pick it up & road test it before loading.

The PC3 USB just link to a Dynojet hub with map sensor plumbed into the 5v signal input.

I have tuned turbo busas to over 500hp & into the 7's with this simplicity. It's the equivalent of 4D mapping but easy peasy.

 

[GoldenChild]

Easy Answer, Call me to discuss goal & buy the right stuff the first time. When it arrives show up like you don't know a thing and learn how it all works. You get to watch it be done start to finish and learn along the way.. I try not to over think or over explain things, cause if you don't really know the basics it will all sound like chinese.. I don't try to reinvent the wheel, just remove the bumps from the road you on. If down the road you have an issue, call where you had work done, as that person will know what you have and how it's setup.. Good Luck..