The Project Pad

finally got to run it at the drag strip last night and i can say im happy but im not happy with the results. i am happy because it stayed together but im not happy because its exactly a second slower than a year and a half ago when i ran it on a stock ECU that was tuned. the car seems to be revving sooooooo slooooowwww compared to what it used to. i synced over all timing with the ignition lock in VEMS so the lock matched the light originally. when i lower the TDC after trigger it seems to advance timing and rev faster but i know its off the mapping at that point. i know this process at getting it tuned takes time but so far VEMS has just cost me a ton of money and made my car slower than what it ever was, im sort of disappointed in it at the moment. to add insult to injury when trying to log my 4th pass the USB to serial converter took a dump too, at that point it i packed it in and went home. i think some time on the dyno is in order to hopefully gain improvement over how it used to run on the OEM modified ECU.

You shouldn't be disapointed in the VEMS. Sure it has some quirks, but so do most systems, including stock ECUs.

I don't understand what you mean when you say "when i lower the TDC after trigger it seems to advance timing and rev faster but i know its off the mapping at that point." If it runs better with more timing advance, then add it in, just not by messing with the TDC reference.

Being a dyno guy, of course I will say that you need dyno time! I have yet to be presented with a better method of dialing in the timing map(s) than with the correct use of a loading dyno.

You tuned your stock AAN ecu, right? Are the timing maps similar?

Can't really blame vems for a bad tune. Sensitivity to noise, different firmware = changes and has trigger issues sure, but sounds like you got that sorted now. What are you using as tune/maps? Maybe post a good log, some guys here can help you out (i'm no tuner so don't count on me ).

Also not sure what you mean by revs faster? Quicker to free rev to redline or in gear? Maybe your accel enrichment is too lean?

Dyno's def a safer place to tune if you got the dollars and need the engine to be at it's ~100%, you won't encounter cops, cars, cyclists, distracting ladies or actual turkeys lol.

Just 1 thing I'd like to add if you decide to stay with VEMS...

SD Card Datalogger...

Or if you've had it with VEMS, sell it & live with Motronic... seems like you've always favored it anyhow...

On the flip side... even Dyno tuned cars can have a failure afterwards...

I say post some logs!

Wait, what? SD card data-logger? More info please.

85oceanic wrote:Wait, what? SD card data-logger? More info please.

Absolutely... HERE ... never miss a beat, unless of course you run out of memory...

for doing some of the tuning i have a big long concrete pad that used to be an old warehouse on my property at my shop so i just run cars back and fourth there, no sweating cops or anything like that. what i ended up finding out was that i had my TDC after trigger set too low and it was actually retarding the timing. i dug out the timing light and did a 20 degree lock and adjusted the TDC after trigger so it matched the timing light. strange thing is that it is spot on with my TDC after trigger at 57 degrees. not sure if thats good or bad but it runs best so far set at that. my other problem now is the severe richness under boost, i see roughly 10.0 AFR at full boost, my battery voltage drops down too and i know voltage is a factor for the injector constant or it alteast should be. lower the battery is the more it richens the car fuel mixture up. so i took all my spare 20V, V6 and 16V alternators to auto zone and had them tested. i chose the best alternator out of the bunch which was a 90amp from a 16V. i figured i dont need the big 120amp anymore because im not running the crap ton of electronics and such that the URS had in it. that helped a little with the voltage drop high RPM. next i got a brand new battery and installed that, it helped a little bit more but not cure it. the car would originally go as low as 20v at 7500RPM, now it goes down in into the high to mid 11 volt range which is better in my opinion but not right. i mean it is charging so i may just tune around the problem and go with it because i cannot think of for the life of me what else it could be. i have a super over engineered grounding system i built now, literally everything is damn near grounded to everything. i thought it might have been the 044 fuel pump causing a draw so i put it on a relay right off the battery and there was no change at all there. im trying to get dyno time setup in the near future because thats what it really needs. theres a schmuck running around my area with a 330i thats converted to single turbo and his PA plate says VAG SLAYR and i know he's not talking about pussy so i plan on teaching him a lesson to not fuck with volkswagen audi group cars. even though i dont want to i think i may have to remove my 016 and swap in my spare URS 01E because the 84 model year 016 is severely gear limited compared to the 01E. the one up point of having the close ratio 016 from 84 is the tranny and rear end both have 4.11 R&P which is what the URS tranny has so no need to even touch my rear end, sweat trying to track one down or worse case rob the rear end from my URQ.

oh and for my USB converter failure i came up with a pretty good solution for the situation. my brother gave me an old dell latitude D620 that has a serial port still. a fresh install of XP professional thats slimmed down a ton, installed 2 gig of ram in it and installed vemstune and the computer along with the connection to the car is faster and more accurate that ever it seems running straight serial.

i did buy one of those ebay bluetooth to serial modules just to toy around with because at 15.00 the price is right. i havnt had any success yet with making it talk to VEMS over bluetooth but im working on it. from what i read the baud rate of the module is set to 9600 by default and i need to figure out how to change it to 192000 to start and than i may have some luck communicating. its just a little side project to keep my brain exercised lol, like i need it hahaha!

You're locking the timing in VEMS too right? You can't lock it to 0, you have to go 1 or more degrees. So an adjustable light is best. But once you have the light and VEMS locked you can then adjust the TDC after trigger value. AND you'll have to reset the lock every time. Just a heads up.

chaloux wrote:You're locking the timing in VEMS too right? You can't lock it to 0, you have to go 1 or more degrees. So an adjustable light is best. But once you have the light and VEMS locked you can then adjust the TDC after trigger value. AND you'll have to reset the lock every time. Just a heads up.

i locked it with VEMS to 20 degrees in the ignition lock and than made a timing map that was all 20 degrees to double check it and i came up with the same result. i used an adjustable light too.

Not quite sure i understand that whole post, what are you loading at high rpm? Tps or rpm based kick in fans to cool stuff up? Surely not 90 amps worth. Voltage should be going up with rpm if anything, unless belt is slipping... Coils are probs not giving as much energy either at 20v...

Unless you're running without an alternator for the drag strip... In that case i'd get a better battery, like a 14v car audio competition battery. With no load on a good charged batt you should be getting 14+ volts at any rpm.

Def something wrong in your charging system.

Also, ignition lock panel should be kept up/open during the timing like chaloux said, otherwise it defaults back to ignition map that will dance around even if set to all the same timing across, unless you turned off ignition influences everywhere in your tune.

i posted my VEMS log in my other post by accident last night, whoops! it was late and i was tired. anyhow, here's the VEMS log from my very last pull on my test pad yestersday. this an easy first gear and than load it up in 2nd and pull to the rev limiter.

Voltage too low + Trigger errors.

carl wrote:Voltage too low + Trigger errors.

i dont see where your seeing trigger errors in the log. i have no idea what is up with the voltage, it has a brand new alternator and battery in it now.

Yea , my bad opened up wrong file lol (v3.3_u009465-2015.06.22-02.30.24) guess windows nudged the file at the end being a new file and having the folder open or something.

Checked out the new log, no trigger errors, seems ok, like you say voltage still weird.



If you have one, what do your standard car gauge say, same deal? Maybe strap is jumping off the pulley from a wobble or too loose or something.

Can't say much otherwise, spool up seems a tad slow depending on what turbo you're running, interesting use of the mat retard table.