dsmchip and tuning

[dsm1212]

alright so i just ordered my eprom ecu chipped with a stage 3 from dsmchips.com. I am running 650cc injectors with a 17psi actuator on a FPt28. My question is if i turn the boost up to 20psi will the ecu see the change in airflow and then give more fuel based on the amount of air it sees coming in so that i am not running lean?

 

[TurboAnything]

Yes even a stock chip will change the fuel for increase in airflow.

 

[dsm1212]

so i will be fine then? wont run out of fuel the chip just makes me be able to idle like stock and then at wot i wont run out of injector

 

[steve]

so i will be fine then? wont run out of fuel the chip just makes me be able to idle like stock and then at wot i wont run out of injector

If you provide the right information to Jeff then it will run fine. Running out of fuel at WOT isn't a chip issue. As long as your fuel pump, injectors and boost pressure are appropriate and functioning you should run out of fuel. But if you try and run too much boost for the pump or injectors the ECU will ask for fuel that you can't provide and you'll go lean. That's happening when the IDC > 100% and you should be designing your fuel system so you don't have IDC's > 85 to 90%.

Idle quality depends on how well matched your injectors are at small injector pulse widths. The larger the injector the more important this parameter is.

 

[JayRolla]

I dont know if its just me but I have never seen Jeff's chip run great at high boost levels. He even recommends an safc for wot tuning. He does the injector compensations which is never perfect at wot.

 

[steve]

I dont know if its just me but I have never seen Jeff's chip run great at high boost levels. He even recommends an safc for wot tuning. He does the injector compensations which is never perfect at wot.

I think you expect too much. Define great?

There is no possible way to be "perfect" for a couple of reasons, first is lack of resolution in the ECU calculations of injector size. As the injector global decreases (larger injectors) the range of flow rates for a global increases. Second is poor data on actual injector flow rates and injector matching done by the suppliers. Third is precision of airflow metering. It's not just the type of metering but the piping on either side that effect the output. Let not talk about hacking a MAF or how much GM hot wire MAF's vary unit to unit and with orientation.

What we can do with a chip is make the car run almost as well as it would if it came from the factory with a given setup (the factory has much tighter control of parameters) and we can make changes to the target AFR maps. To make it "perfect" you still need tweek the tuning just like you need to if you were running original parts and wanted it perfect.

 

[Black_Bullet]

If going the chip route and you want a fine tuned car with some adjustability your going to have to learn to burn the chips yourself, otherwise just settle for whatever you get when someone else burns your chip, or keep paying for reburn or get dsmlink.

 

[->PrOjEcTGS<-]

If going the chip route and you want a fine tuned car with some adjustability your going to have to learn to burn the chips yourself, otherwise just settle for whatever you get when someone else burns your chip, or keep paying for reburn or get dsmlink.

Exactly... I have some pretty basic mods that most people have FIC 650's, Walbro 190, NT FPR, 2G MAS. I plugged in the numbers into Tunerpro that should be correct for the injector's global and dead times and still had to tweak it from there. If I would have ordered a chip and not had a way to edit them I would still have to use a SAFC to get it 100% correct. And then I'd be compromising the MAS signal which should never be done. I'm proud to say that my fuel trims are all at 100% +/- 5. And can run 22-23 psi on my 16g with pump gas and have no knock.

 

[dsm1212]

well mostly i have just heard really good things about jeff and his chips so i decided to give it a try. my mod list is up to date, so i am planning on running around 20psi on the
t28. I do have a safc II for fine tuning but after reading a lot about it seems like that just messes up my timing curve.

 

[->PrOjEcTGS<-]

Shouldn't have to correct too much if he gets the tune close. So you won't gain too much timing. A good thing is that you own a 2g which has much more conservative timing anyway.

 

[dsm1212]

true well i guess i will just have to see what happens when the chip gets here. I'll be sure to post a few logs for you guys.

 

[JayRolla]

Yea you will be fine with the safc and the chip. You wont have to do much, most likely 5-10% fuel adjustment at most.

To steve Ive just noticed that the afr is either a little rich or lean for my liking at wot when doing just an injector compensation so its nice to have a safc to fine tune wot.

 

[kevbojunior]

wouldnt hurt to have a wideband guage either. im also deciding on getting one of his chips as well.

 

[steve]

Ive just noticed that the afr is either a little rich or lean for my liking at wot when doing just an injector compensation so its nice to have a safc to fine tune wot.

Exactly. Hopefully now you have a better understanding as to why the car might not exactly hit the target AFR we program into the open loop map.

 

[JayRolla]

Exactly. Hopefully now you have a better understanding as to why the car might not exactly hit the target AFR we program into the open loop map.

I do now have better understanding. I never thought of it in a way that the factory tune is flawed itself.

 

[dsm1212]

when he emailed me earlier he told me that he leans out the fuel maps because they are factory to rich but he still keeps them safe and that the timing curve is to conservative so he makes it a little more aggressive.

 

[dsm03]

DSM1212.

Which SAFC you running? My setup is pretty much like yours and I was going to go the Eprom chip route but Im leaning to just going with a SAFC since I will have to fine tune anyway

 

[dsm1212]

i am running the apexi safc II the blue one i was going to just run the safc but it screws with my timing way to much i can't turn the boost up so right now i am just driving around making sure to stay out of boost.

 

[matthewdesigns]

You are going to love the chip/safc combo. The other thing you need to have is a wbo2 sensor (as suggested above)...they are cheap insurance. Knowing what I do now, I would not tune without one.

I have one of Jeff's chips, and the pump gas tune is pretty much spot on. I can run 23-24psi on 91oct without any adjustment on the afc, and afr's go right where they are supposed to (10.5:1), with timing rising nice and steady. On my e85 tune at 28psi, I only have to use it for a little correction (up to 5% max) to keep my afr's in the high 11's, and timing is not affected...it rises and peaks as programmed. My car idles great on 950's, and drivability is like stock.

 

[dsm-onster]

Doesn't Jeff extend the maps for you?

The ecu can tweak timing for different g/rev (load) up to about 320ish hp (give or take your setup of course). After that and you're off the map; and the A/F and timing curve flatline, seeking the setting last shown on the last fuel and timing cell. There is zero resolution where there is no ability to create a curve for load levels after the stock maps' limits. A simple 16g setup can push you beyond. If you just have the safc, then you have to tune for the a/f ration and timing that will not knock at your peak flow. But for points under your g/rev. But points under that, you may be able to get away with leaner a/f and have a different ideal timing. However since all these flows will likely be beyond the last highest g/rev load cells on the maps, you're stuck with what works at peak flow; not with a curve that gives you the best tune for g/rev below your max.

The chip with the extended map allows you to tune the power levels over what the stock maps allow at differnt loads inbetween peak load and the stock maximum load cells. So this coupled with an safc is agreat way to fine tune your car and get the best curve for your setup instead of getting the best curve up to a certain level then having to accept a flat timing and a/f line for the rest of way up the rpm/flow range. I think this would be the greatest attribute to these chips. And if you can't do it yourself, it's a great alternative to get a MUCH better overall tune.

 

[JayRolla]

If your running pump gas I would have stayed with the stock 2g timing map. Unless he just added timing down low where it needs it.

 

[dsm1212]

This is the email i got from jeff, i think he knows what he is doing so we will see how it runs when i get it.
<br>
Matt,
<br>Our cars are not speed density, they are MAS-based, so the amount of airflow does not affect the AFR directly. The 2G factory maps are good to 25 psi or more, and they are actually too rich, ~9.5:1. I adjust the Global Fuel to remove 30% fuel for the 650's, and then I further lean the openloop AFR maps from 9.5:1 to 11.0:1, which is still very conservative for 92/93 octane. So, if you swap turbos or turn up the boost more, the MAS sees the extra airflow and the ECU automatically provides the correct amount of fuel to maintain an 11.0:1 AFR.I also give you slightly more aggressive timing maps, as the factory maps are way too conservative.<br>Take care,<br>Jeff O.dsmchips.com

 

[dsm1212]

and i will be running 92 octane pump gas, he asks about all that when you order

 

[dsm03]

Hmm.. So would it be ok for me to just run a chip, my car came Equipped with Eprom, do you guys think that I will need a SAFC or would I be ok to just run SAFC. Mods are in profile, I will be adding FMIC, 650's. Also, I wont be upgrading to a different turbo I dont want to push more than 380hp-400hp so that's why I decided to go with the setup that I currently have and have yet to complete the rest of it but have mentioned,

 

[steve]

Mods are in profile, I will be adding FMIC, 650's. Also, I wont be upgrading to a different turbo I dont want to push more than 380hp-400hp.

I think it's going to be a challenge to reach 380+ HP with that T28 turbo, 650s, and a 190 lph fuel pump.