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My ViPEC V88 had some problem internally and i decided to swap for the recently released Link G4X Extreme. the ECU is a direct descendant of the V88 so it both plugs in and has a similar architecture. while my map, developed over the last 8 years, isn't a cut and paste into the Extreme it clearly is similar. sort of the same language.
and it is awesome in so many ways... so much to play with.
the second part of the story is Evans Performance Academy. i just bumped into it on YouTube. 'not sure if the guy sleeps as i bought his course specifically for the G4X Extreme which is just under 60 (!) tutorials generally around 30/40 minutes. some longer. all on the Extreme.
he also covers just about every other brand and model of ECU. i give him an "A" as to presentation and content.
i plan to add on to this thread to share my Extreme adventures so please stay tuned. while our community is pretty much Haltech Elite 2500, based on how awesome my V88 was (circa 2012) and my initial experience with the G4X Extreme (yes there is a plug-in) indicates it might be wise to take an in depth look at it.
This makes me happy as I just purchased Link's G4X PlugIn ECU along with their CAN Lambda Wideband. I look forward to reading your updates. Also going to check out Evans Academy.
Nothing sophisticated - I'll be deferring to Chris at Rotary Performance for my tuning and he has a slight preference for tuning with Link over Haltech. I'll still be learning, but primarily so that I can 'follow along' so to speak.
After reading through that other lengthy IAT thread, I'm curious what other Link G4X or G4+ users have been doing to tune their Charge Temperature Approximation table? Here's the table I'm referring to...
Basically what it does is compute charge temp that is used for the fuel equation (modeled or traditional method) as a ratio of measured IAT and CLT, to try to compensate for or approximate the heating of the air charge as it makes its way to the intake ports. So for this table, the 0% value means your charge temp = IAT, the 50% value means that the Charge Temp is 50% between the measured IAT and CLT values, so for example if IAT = 50*C and CLT = 100*C, Charge Temp = 75*C.
On my G4+ managed FD, I have a Cosmo 13B-RE LIM & UIM manifold, with a GM DBW throttle, so I'm measuring my IAT's with a fast reacting GM open element sensor in the IC piping just before it enters the silicone TB elbow, and I'm using a Bosch NTC sensor on the underside of the UIM with my spare temperature input. When the car is running, these sensors read nearly identical temperatures (+/- 2*F), but the one in the UIM is slower to respond to changes. When the car starts to heat soak (e.g., shut down after a hard drive and start up about 10 minutes later), I'll see a larger difference between the two sensors, the fast reacting IAT in the elbow typically 15~25*F cooler than the UIM sensor initially. After a short easy drive, both temp sensors will be back to close agreement as the temps drop and stabilize.
Short of drilling/tapping my LIM to accept thermo couples and getting a data logger to get some actual empirical data, does anyone have any ideas that would inform what to put in this table?
as you may recall i have had a ViPEC V88 since 2012. i have loved it. it malfunctioned (something in the otherboard) and i replaced it w the Link G4X Extreme. it is simply the latest iteration of the V88 so it uses the same harness and functions similarly. that said, it is amazingly faster and the V88 was fast. it has zillions of adjustment features and is user friendly. since you can't copy and paste the V88 map to the Extreme i spent about a month getting it done. during that period i bumped into a G4X Extreme You Tube Tutorial... of course i watched it.
awesome!
Evans Performance Academy. i subscribed to the G4X Extreme tutorials (46) and they have been a huge help in upping my game. i am really happy to now be in Georgia so i can road tune my car more than 6 months a year. a succession of small things has slowed things down. i am currently waiting for a new AI pump as last Friday as i was ready to do some runs i noticed a small puddle of methanol under my left rear tire. just another delay but the new pump should arrive today.
the Extreme allows you to set up pages that have parameters that relate to the page subject. for instance a page for open loop boost control, or a page for closed loop. you can load log charts with relevant items. you can load the vairous parameters, settings and tables. i have over 20 pages. so, if for instance, i want to know if any fuel trims are effecting my injector ontime i just go to a fuel trims page and get the answer. each of my pages has probably 50+ items as well as tables and charts so it is a process. thanks Evans! it sure is easy to get the answer to almost anything.
i will post a few of my pages so you can get a better look.
Last edited by Howard Coleman; 03-11-21 at 09:18 AM.
here's an example of one of the many pages i have constructed to zero in on an aspect, in this case fuel tuning, of the overall tuning process. while it takes time to construct each page it saves boatloads of time going forward. so easy... at one point i was getting a wastegate duty cycle less than i posted in my WG DC page. i simply went to my open loop boost control page and found an IAT boost trim was active. at that point i hadn't enabled IAT as a trim so it was going to default which was -90%. i don't use IAT trims so i turned it off and all was well. this took under 60 seconds. if you look at the top you will see some of my pages... Fuel, Ignition, Analog Inputs, Outputs, Fuel Trim, Accel/Decel, Spark Trim, Knock and a bunch more to the right using the green arrow.
thank you Link/Evans Performance Academy.
awesome.
Last edited by Howard Coleman; 03-11-21 at 09:19 AM.
there are a few ways to "auto-tune" with the Link ECU... one is to actually drive the motor into a cell and the program will change the ontime to meet your target. since you need to be in a cell for a period of time this is best done on a load dyno.
i use the "Mixture Map" feature and love it. after a drive, i just go to "Mixture Map", enable it and it posts all of my travels through the various cells. i can stipulate the area of the cells used, a minimum TPS reading etc etc...
i then get a reading for each cell that includes the number of samples, the actual logged AFR, the Target AFR and the amount of variance from Target. of course you can use Lambda or AFR. a right click on each cell and the selection of "Correct Fuel Table" adjusts the injector ontime to generate the Target AFR. pretty simple stuff. i am not familiar w other ECUs but assume they have something like this. i only know/care that my ECU does it. My 2012 V88 also had the feature.
i remember sitting in a wayside after a run in 2003 with my calculator and literally doing the math to adjust each cell. later someone created a calculating Excel spreadsheet so all you had to do was copy and paste into the spreadsheet and the entire base fuel was calculated.
for those not familiar w Link, here's a log and a Mixture Map from the log:
I like the # of samples in that mixture map to help throw out weird transient readings. are you using modeled fueling (VE) or millisecond mode? how do you like the transient fuel model and temp correction so far? I am considering moving away from the adaptronic and this Link is on the short list due to it plugging into the factory connectors.
in 2012 i decided it was time to capture more data as i was tuning to around 575 for the 2013 Texas Mile. i still loved (and still love) the Power FC but i needed more. i looked very carefully at the ECUs then available and it came down to the ViPEC V88 or some mix of Motec. i picked the ViPEC because it had everything in the box rather than having to do an ala cart deal. i ran it until last November and loved it but something in the motherboard failed. fortunately ViPEC was folded into it's twin, Link. and fortunately Link very recently came out w a whole new iteration... which is what i have. it is great for me because while my V88 was a wire in (which i did myself) the G4X Extreme has the same two plugs so i could just plug it in. it also is quite similar so it was sort of like a new friend that speaks the same language. while it is very similar it is crazy how much you can do with it. my ViPEC logged knock at 6 data points per second. the Extreme generates 16. it even has a math channel so you can write your own programs and load them.
i am currently tuning using the traditional rather than modeled mode. maybe down the road... the modeled mode is only as good as your assumptions so i will leave that for later. traditional is easy for me.
i am working through some items and optimising a few others and finally ventured into the Math Section. while the Link G4X Extreme is capable of allowing you to write formulas (o k formulae) up to 20 characters (!) i just wanted to log the Delta/difference between the temperature out of my turbo and the temp into my motor... that would be about my current speed as to equations. so GP Temp 1 minus GP Temp 2 =.
am comparing intercoolers and ducting. stay tuned.
This is good to see as I'm looking at Link PnP's for both my RX7 and my 300zx. Definitely going to check out the Evans channel once I get the ecu's up and running. Thanks for posting up!
01-11-21, 07:52 PM
