O2 Sensor

[VRmonster 1]

With me researching fitting a turbo myself! i was advised by some VR6T owners to buy a wideband O2 sensor and meter to tune the car with. just wondering what experience ppl have with them, and what should i look for. also, would the vag-com work. ie, could i tune the air/fuel mixture with one?

[ingham 5]

had a honda ,fitted mixture dial to tune with a box that allowed mixture and vtec to be tuned ,dial connected to lamda probe (o2 sensor) worked well ,just kept messin till mix fell in middle (14to1(air to fuel))dont know if vw can do same

box came from a mate in japan

instrutions were in japanize !

gave alot of power thou & still going strong

[VRmonster 1]

thanks for that. i understand that the air/fuel ratio can be altered, but im unsure of how. i thought it was an ecu only kind of thing, but surely when a car is tuned by a local garage they cant have the facility to modify the ecu all the time. so expecting vag-com to be able to do it.

[FishWick 21]

Widebands give you a bigger spectrum of 02 readings, i.e. proper air/fuel ratio readings instead of a grid of moving LEDs. WB is highly recommended for forced induction. Get a second Bosch WB lambda installed in the front pipe which lets the OE lambda do it's job of reporting data to the ECU without the additional load of an AF meter, the second lambda concentrates solely on O2 readings, again, without interference from the original lambda.

You can't actually modify the fuelling using a WB lambda kit. The ECU just alters the fuelling according to what it's told by the probe, but I suppose you could trick the ECU by artificial loads on the Lambda by means of a variable resistor. The Lambda is not consulted at wide open throttle anyway, the ECU just fires in a set amount of fuel determined by the hard coded chip. The lambda is there purely for part throttle running and emission control.

[VRmonster 1]

your just out to solve all my problems tonight arent you kev. you have just explained that in a way i can understand, some guy on a vr6T forum explained it and i was like wtf?

so if i did FI my vr, how would i get it to fuel correctly at part throttle, or would i just have to use the wb sensor to make sure it wasnt knocking, or pinking and have the chip mapped to suit the turbo. the kit has a chip already but as to weather it runs on my ecu is another matter. also, would an apexi safc II be any good for metering/adjusting the air/fuel ratio?

http://www.apexi-usa.com/electronics_safc.asp

this modifies the maf signal to tune the fuel input, so this would need setting up on a rr wouldnt it. cheers again kev.

matthew.

[FishWick 21]

LOL, I try not to be too techie. That Apexi gadget looks funky! It appears to be a kind of piggy back chip system, much like the one Stealth use, less all the fancy tricks of that Apexi.

Vince is your man really, he's built a VR6 turbo before but basically you just optimise the fuelling via the chip. You'll need some bigger injectors too, depending on how far you're taking this. If you're going for big power, you might also need a beefier fuel pump. I don't know enough about it to be honest.

[VRmonster 1]

well i have a fse pressure regulator at the mo, and injectors are supplied with the kit (unsure what size, i didnt ask as i have only just realised. lol.) so fuelling shouldnt be a problem, just setting it up. there is a chip supplied with the kit, but unsure if it will work on a uk car. so i was planning on just getting stealth to fit a dastek piggyback, to have it tuned correctly. just wondered if i can make it driveable before getting the chip.

[FishWick 21]

Yeah you can install it yourself and just drive it gently to stealth for a rolling road setup. What psi is the blower giving? Do you need to lower the comp ratio? I would imagine you do if it's around 1 bar!

[ingham 5]

are you going to use an intercooler ?

[VRmonster 1]

the non intercooled kit can hit around 7psi, but i am intercooling it with a custom designed kit, so hiping for over 10psi. i think i am going to go for a lower compression ratio to be safe. and if i do drive it, i will just set the wastegate as low as poss, to try and hit as little boost as poss till its chipped n tuned. its just to get it to stealth, want to avoid trailering it.

[FishWick 21]

Please don't use bodgey copper gaskets! Use the proper JE 9:1 pistons and you'll have a much more reliable, tougher motor. You can go higher than 10psi with those too and you'll get an easy 350 brake.

As you know, the VR is one hot running motor, especially the rear bank, so Aquamist water/methanol injection is a wise addition to the itenary too. It will relax the knock sensors and knock those inlet temps right down.

[VRmonster 1]

so if i fit 9:1 pistons does that require any additional work, porting etc? or can i just fit them? and could i just fit these to go to say 3.0L? or does this definately require work?

[FishWick 21]

Depends what your overall goal is mate. The 9:1s wil give you a nice 3.0 and if you're planning on big boost, you may aswell stress relieve and shot peen the conrods whilst the block is out. Raceware rod and head bolts are a must too. They're high tensile and reusable, so a good investment.

Flowing is a consideration but not essential. Adds to the bill quite considerably. Looking at £1200 easily for a Schrick flowed and big valve head..... makes a massive difference tho, even on normally aspirated.

I'm no expert on VR turbos but if you want a solid motor that will be daily usable, tough and reliable, use the best parts and over-engineer the fecker in true British style. As they say "Built in Germany, refined in Britain".

Some wills total seal piston rings are a worthy investment too.

I tell you what, I am seriously interested in this little project of yours. I am considering a similar route myself.

But as a I say, if you want the best advice about this, speak to Vince.

K

[ Edited Sat Jun 19 2004, 07:53PM ]

[VRmonster 1]

cheers kev. i have been searching for a turbo for about 6 months now, and didnt want to have one fitted by any companies cos i want to pick and chose parts myself, so labour costs would kill me. so now its a self build kinda thing.

i was planning on some headbolts, poss apr, but where can i find raceware gear? i like the sound of reusable. lol. and was thinking about uprated conrods too, cant rememver where i seen them but theyre about somewhere.

so to fit the 3.0l je pistons i would have to bore the 2.8 out to an 83mm wouldnt i. where would i go to get this done? i suppose all of this rides on the turbo fitting or not. altho i mite go 3.0l as an alternative if it doesnt.

[FishWick 21]

Stealth can get the Raceware bolts for you. They're the best in the industry and they'll keep that engine together when you apply the big boost :-)

Yeah the bores will need taking out if you fit the JE pistons. Yep I think it's 83mm too.

I am also considering a 3.1 High compression NA lump using the 11:1 JE pistons. And also, Vince has somewhere a special ABT crank kicking about than can in theory give you a 3.4 swept volume.

I dunno, choices choices, eh? I'd be happy with a 3.1 High compresion engine with a Schrick big valve head, the VGI and the 268s.... looking at an easy 250 with that lot. But then it's no turbo motor!

I would entrust block builds to Stealth or Grant Motorsport personally if you don't fancy doing it yourself.

[VRmonster 1]

yeah, before undertaking the whole turbo project i might go for a rebuild and have a few things uprated. i noticed that je do some 2.9 9:1's i would obviously have to have that bored out still wouldnt i. hmmm. your right about the descisions. i cant decide. lol

oh, and the high compression would be great, imagine the torque...

[FishWick 21]

Yeah Vince built a high compression 3.0 and it kicked butt. But the owner decided he wanted more, so sold it, nutter!

Trouble is these days, where the hell can you use this power freely? I don't know about you but my daily commute consists of 30 minutes crawling in traffic and about enough room for 90 tops on the dual-carriageway! This is why I cannot stress enough the importance of making the turbo conversion factory reliable. Not trying to put you off or anything, LOL!

I would still go the turbo route mate. You will have so much power and torque on tap, which = big smiles per miles :-)

I would say, yep, definitely the block needs to come out for a compression ratio reduction, so you may aswell go 3.0, rude not to really :-)

And once that's out, you'll probably look at the head and think, hmmm, that could do with a build too. Thing is, even in NA form, the rear bank of 3 cylinder's exhaust valves glow red hot when really pushing it and the turbo housing will almost certainly be a cherry red when on boost, so it's a good idea to build the head with some sodium filled exhaust valves.

Am I making this project a lot more expensive for you?

[ Edited Wed Jun 23 2004, 07:19PM ]

[VRmonster 1]

yes indeed you are. but i know of people in canada running reliable cars with a standard block. so i might just go for the turbo kit first and limit the boost to say 7 psi, which should see me a nice 300bhp.may use a plate to reduce compression for now, just for safety. then uprate things as i go. ie: save up for a rebuild, porting, 3.0L low comp pistons and stronger rods, and the 'then essential' traction control, and CO2 cooling/water injection. lol.

luckily i dont use the car for work at all. i use a van. he he. so my care is for pure pleasure. still want it reliable tho. altho it isnt exactly factory reliable now never mind with FI. ha ha. this project is probably about 3-4 months away due to cash flow, but realy do want it finished before the end of the year.

cheers again kev.

[ Edited Thu Jun 24 2004, 04:01PM ]