Tdi Tuning.....

[davies1644]

im sorry to say this but some of you are right and some wrong i did motorsport engineering at uni and used my vento tdi as a uni project to see what pwoer gains come from certain mods.

For 1 you cant adjust the boost on a tdi mk3 as i have tried! manual boost controller, diode between pins 1 and 6 on the air mass to fool the car into thinking its creating less boost the works the only way is a remap as i did the diode and it hit 2 bar! and went into limp mode

As for mods fit a set of .216 nozzles like someone mentioned above as that gained me 23bhp just from that does give a bit of black smoke but still fine, i also tested a front mount intercooler only gained 1.4bhp but gained 10Ft-lb due to the denser air it was receiving

I also fitted a PD inlet manifold as thses are meant to be the 'boys' and their just not it was a 150bhp one and it actually caused the vehicle to loose power 3bhp over the full rev range even tho it has equal legth tracts and enlarged port

And no one in this country does a custom remap if youve got other mods on the vehicle so my suggestion is get on the tdiclub.com and get reading up and vw mickel is the guy you want send your ecu to america and itll be sorted

[Rixy]

i'll get a pic later, but this a proper old skool tuning box? looks like it was made years ago. Its basically a PCB in a metal box, with a screw on lid, and 2 x genuine vw plugs comin out of it. Plugs directly into the pump, and has wires comin from engine speed sensor, accelerator potentiometer, and 2 from ecu (i've checked these on wiring diagram - come from pins number 2,3,4 and 5 if i remember rightly??)

[davies1644]

yeah know them had 1 fitted to mine until i removed it, they do make a difference but all its doing it tricking the pump into intorducing more fuel, may as well just fit bigger nozzles far safer way of doing things

[Rixy]

for sure, nozzles will be comin my way as soon as i get some spare cash, or sell summit to pay for them :-) this is only gonna be a temp fix until they arrive :-)

What nozzle's are best though, .205's or .216's with a bigger front mount intercooler, and poss a stainless 2 1/4 downpipe and de cat??

Will prob get a remap too after a little while if i can run the nozzles on standard ecu for the time being that'd be ace :-)

[davies1644]

.216 nozzles off ebay 55 quid thats what i did and wouldnt bother with downpipe or intercooler unless your fitting a big turbo best thing is remap 300 quid would see injectors and remap so about 125 wheel horse power maybe more

[Rixy]

i see :-) might get round to gettin some of them then, though i'd heard bad things about the cheap nozzle's? i was advised to stay clear of them, nd go for genuine bosch ones??

[davies1644]

well iv been running mine for 6 motnhs with no problems ata ll so up to you

[Rixy]

on the tdi forum, under the faq's bit, it says that when setting up the car on new nozzles etc, you have to "install a bleed on the pressure sensing line that goes to the ECU so that the resistance upstream (to sensing line) and downstream (to atmosphere) of the ECU sensing port is about equal, and you install a mechanical boost controller in parallel with the standard N75 system calibrated to 17 psi maximum boost pressure which experience has been found is sufficient to adequately control exhaust smoke"

What does it mean by the bleed valve between upstream and downstream? is this the pipe from the inlet elbow to the ecu (upstream) and the one that goes to the wastegate? (downstream??)

im confused, i wanna fit my boost controller, and want to do it all as per the above......

[davies1644]

right starters mine wont boost to 17psi itll only do that when the vehicle has been remapped as the bleed valve cant changed this believe me iv tried, its only capable of 17psi cause thats whent the turbo reaches it heat soak point.

Tbh all i did was fit a bleed valve in between the n75 valve and that was it, just to prevent the car boost spiking too much, mines smokes but who cares??

[Rixy]

so does the bleed valve go between the n75 and the turbo then, on the red pipe, same as the boost guage?? my turbo spikes like a pig, and the guage flies round to 15 or 16psi, then drops of instantly to around 10.........