weird issue at high speeds after OFT tune
 

Before i start, i don't think this is a problem... and im 100% happy with OFT... but its something.
Lets get to the issue. I live in Argentina, some highways here don't really have a speed limit... and they are freaking deserted in some places. So i was traveling, and decided to do a top speed test, since ive never done one after i did my OFT flash.

I was in 6th gear, and just started to go, as easy as possible... when i hit 180km/h at around 4ishk rpm, the car kinda stopped accelerating... like for an entire second. This didnt happened before the tune... (i did a top speed test before the tune, some months ago).

Tried to reproduce this a couple of times... all the times it happened. Tried it in 5th gear, nothing happend.

Any opinions on what could be the source of this?

Before anyone gets mad at me for the speed... its a veryyyyyy long straight, with lots of space, and not a freaking soul... otherwise i don't go this fast... =)

Could you have lost traction? This has happened to me before.

Try logging what is happening when you experience this, especially since it's repeatable.

+1, also are there any codes associated with this issue? you can send your logs to sales@vishnutuning for feedback.

Since not many people take their cars up to top speed the experiences are far and between. Here is what I have experienced in top speed runs.

1. In some cases when I was running pump gas (I didn't have the logger on during the times it happened) the car while accelerating from anywhere between 150km/h and 240km/h would like you mentioned hit a wall but in my case it is brief (1-2 seconds) and then the car continues to accelerate. Having said this, I have not had this issue occur again since moving to 100octane fuel.

2. The stock mapping has a top speed limiter that kicks in at 221 km/h and I had posted about this before (see link below)
http://www.ft86club.com/forums/showthread.php?t=58835

3. Friends of mine with ECUtek have had issues with top speed that are a bit different. In their case the car hits a wall at 210 km/h every time without fail.

mmmm thanks all for the answers... Ill try to take a log of the issue and post it here as soon as possible.

Dont mean to bump an old thread, but I just ran into this issue as well on my stage 1 flash. was at 6th Gear 99mph and then just hit a wall like fuel cut? Odd. Would not happen in 5th or 4th gear like the OP.

Automatic or manual transmission?

Plug in your OFT and log the issue

AFR
IAM
LOAD
THROTTLE position
SPEED
LTFT
MAF V

etc

Check for any stored DTC/CEL codes

MT

Will do when I get the chance!

interesting.. I'm running stg1 on B01c, I haven't had many opportunities to drive over 100mph, however my car sails right past to about 110 with ease, 110 seems to be its comfortable speed right around 4k rpm in 6th. tbh I have never tried to go above 110.

it's pulling timing out in that little spot for some reason, i've seen it drop like 20* of timing in that spot.

i would check all the speed limit tables in the tune in rom raider, just to be sure.

what elevation are you at when doing this?

Sea level

FWIW, we don't make any changes to speed limits in our OTS maps. But I don't see why anything should be intervening at 110mph.

exact same happened to me. Pulled back on the throttle, and tried again and it didn't do it the second time. weird.

i will see if i can get a log of it tonight

same thing happened to me last night got up to 120 but it felt like a fuel cut. before i could go past 120 with ease. anymore info on this? im on stg2 el e85 tune if that helps.

If you guys could log the problem it might help to work out what the issue is suggest

throttle
load
ignition advance
speed
fuel pressure
injection volume ml
AFR
FLKC
IAM
knock correction

Just want to chime in too. I had the same issue as above at 100mph around 4k. yesterday. running Stg 1 93 2.0 tune. Sorry no logging done yet.

I'm going to take a wild guess and say this happens between 3500 RPMs and 4000 RPMs?

EDIT: from at least two reports on here, 4000 RPMs is indeed the magic spot.

Over and above the SI mode throttle speed cut tables, there are two tables that are RPM based - hysteresis between 3500 and 4000. I don't think I've heard of anybody hitting these limit before (at least on the Subarus), but then again, not many people cruising at those speeds.

If you want, I can add these to the definitions, and you can test the theory out.

I'm on the 91 oct. Stage 2 maps...got up to 106mph with no hesitation today..think I was in 5th gear though.

Not sure I'd personally call this an issue as much as observed behavior. personally at least.