Stalling after full boost with bigger turbo.

[mike74]

Could it also be a slightly dicky/dirty engine speed sensor? they can do some weird things when not 100% right....

[jogi730]

Check wiring loom. This was the cause of my grief

http://www.s2forum.com/forum/showthread.php?t=34983&page=32

[Jimmaey]

okay got to work on the electrics. tested absoltely everything electrical. found the problem of the ****** idle and misfire. one of the wires on the 034 coil was not properly plugged in. you could onlt see it when the coim was off so no misfire no bad idle anymore ! now i had a word with the ex owner. he said tje stallikg after full boost was a problem he had since he put on the k26 turbo ( it was no k27) . he said the custom map was designed for a rs 2 turbo and not the slighly bigger k26. so that could be the source of the issue. as long as the car runs a couple of seconds after the stalls she starts just fine but as soon as full boost kicks in its over again untill the next restart. is there anything i can do without a new map or a custom ecu ?

[newsh]

Softer wastegate spring.

Or disconnect N75, fit boost controller and set up for less boost.

[UrS4boy]

he said the custom map was designed for a rs 2 turbo and not the slightly bigger k26. so that could be the source of the issue.

Sorry. I have to laugh. Why do people (in this case the previous owner) think that an older technology K26 turbo is better than a then new K24-7000 turbo that a team of Audi engineers spent time and energy selecting for the 3B, AAN and ABY back in the day over the already available to them K26? That 26 > 24 and therefore it MUST be better? Sorry. It makes me full on crazy.



The K26, in my opinion, is simply the wrong turbo for the 20VT engine. Either go back to a stock K24-7000 with a Stage 1+ (with 3 Bar MAP) off the shelf chip set, or go to a modified Volvo K24-7400 turbo with a chip set from prj or EFI Express. Or just rob the piggy bank and get a proper K24-7200 and use your existing RS2 custom chip set.

[Quattronaut]

he said the custom map was designed for a rs 2 turbo and not the slighly bigger k26....
is there anything i can do without a new map or a custom ecu ?

I am not an expert in mapping- but only another turbo, that in fact is similar to the one the map is written for, is no reason for a complete stalling. In my eyes. So maybe a remapping does not really make sense...

I would try to fit a RS2 turbo, then test the car again. If it runs good and without further issues- lucky you! Then you can go on. If there are still issues- what, to be honest, I´m afraid of- search on what is wrong.

The other way could be to read out what map it is, and try to figure out the specs it is written for and who wrote it, if that is possible.

Sorry. I have to laugh. Why do people (in this case the previous owner) think that an older technology K26 turbo is better than a then new K24-7000 turbo that a team of Audi engineers spent time and energy selecting for the 3B, AAN and ABY back in the day over the already available to them K26? That 26 > 24 and therefore it MUST be better? Sorry. It makes me full on crazy.



The K26, in my opinion, is simply the wrong turbo for the 20VT engine. Either go back to a stock K24-7000 with a Stage 1+ (with 3 Bar MAP) off the shelf chip set, or go to a modified Volvo K24-7400 turbo with a chip set from prj or EFI Express. Or just rob the piggy bank and get a proper K24-7200 and use your existing RS2 custom chip set.

The K26 maybe an upgrade for the S2 turbo, if you want more than 300 hp. That makes sense. But not for the RS2 turbo- at least the normal K26 hotside that are 99% of all K26 turbos built with. I think most people use the K26 because they are much cheaper than the RS2 turbo. And- they don´t know anything about ist

[UrS4boy]

S2 Turbo upgrade options

The K26 maybe an upgrade for the S2 turbo, if you want more than 300 hp. That makes sense.

Disagree. At least not with a straight KKK K26 from a 10V Audi turbo 100 or 200. Too much lag, not enough breathing up high.

K24-7200 is good for at least 380 hp with a good fuel pump and RS2 injectors

K24-7400 is good for 340-50 hp (I think)

K26-based hybrids from 034 Motorsport:

K26/GT28RS = 350 hp with very early spooling. https://store.034motorsport.com/k26-...bocharger.html

K26/GT3071 = 450 plus HP with rods, FP, etc. https://store.034motorsport.com/k26-...bocharger.html

[Quattronaut]

If you are speaking especially about the stock K26 fromt the Audis, you´re right. And in most cases, those simple ones are taken, I know. That´s the cheap thing.

But since K26s are a family, I spoke of them in general- and there in fact are many possibilities to upgrade K24/7000 an K24/7200 turbos with a K26, that make sense and work fine on a 20VT.

But- please: If we speak of K26, let´s stay on KKK. Not on garrett turbos with adapted housings

[UrS4boy]

But- please: If we speak of K26, let´s stay on KKK. Not on garrett turbos with adapted housings

What you don't like full boost by 2400 RPM?

[Jimmaey]

now that you mention the wastegate. he put a regulator on the wastegate which you can set manually. perhaps he set it to the wrong setting. i didny even know you could manually set the wastegate with an override. its a custom k26 hybrid with a modified inlet housing for faster spool he said.

[Quattronaut]

perhaps he set it to the wrong setting. i didny even know you could manually set the wastegate with an override.

Me, too. Normally you can´t. Throw it away, keep the WG stock, with stock spring.

[newsh]

now that you mention the wastegate. he put a regulator on the wastegate which you can set manually. perhaps he set it to the wrong setting. i didny even know you could manually set the wastegate with an override. its a custom k26 hybrid with a modified inlet housing for faster spool he said.

Well that's a good thing though, you can quite easily turn the boost down a bit and see if it cures your problem. Personally I suspect the software is bad.

[220bhp]

I am with newsh on this. Bad software BTDT

[Jimmaey]

i think so to tweaking the ignition and fuel pressure makes it run better if i put the clutch in fast enough after full spool. then she keeps running. its only after full boost and then clutch kick she stops. so i think im gong to buy maxxecu or vems. thanks for all the support everyone.