ko4 wastegate chatter...

[Shy19s]

also reading through your posts, coming from the jap scene, and higher end turbo charged cars, over the years i have developed a high rev range driving style, low gears, engine braking etc and keeping it in high revs, maybe a hybrid is what i want, and like you said especially because its fwd. what do you think?

 

[Ess_Three]

very interesting read.. im currently working on suspension components, ive done shocks n springs (KW) im impressed with it so far, strutbrace bolted through the turrets.. just need to get the ARBs done as in finding the new limits, it does understeer, so once that is sorted i can think about power, but its all very useful for future reference.

thanks again.

I wouldn't worry too much about a front uprated ARB if you have some KWs on...but a rear should be high up the list.

As should working out how to get some additional negative camber on the front if you want to go round corners!

The A3s chassis is crap really...and you don't have the adjustment an S3 has to add more negative camber...but, as always, there are ways and means...

Anyway...we are heading off topic here...

 

[Essflee]

I agree this is a good read...shy are you planning on putting 300bhp through the front wheels ?

 

[Shy19s]

Yeah ive spoken to damian about a rear ARB, he recons 25mm, im not sure still, when i get back from NY my main focus will be sorting the car out..

leggy, i can always put a tranfer box in and make it quattro, its not an issue, will take a weekend at most.. but that can be delt with later.

but, as always, there are ways and means...

after the arbs, ill check the camber angles.. thanks again.

 

[Ess_Three]

also reading through your posts, coming from the jap scene, and higher end turbo charged cars, over the years i have developed a high rev range driving style, low gears, engine braking etc and keeping it in high revs, maybe a hybrid is what i want, and like you said especially because its fwd. what do you think?

It's not for me to say...

I don't think a K04 will dissapoint as long as you don't go chasing figures.

You can map a K04 to give a reasonably linear delivery that pulls towards the red line by pegging the low down torque back.
If you aimed for 270 BHP top end and pegged the torque back to 270 lb-ft ish it would feel perfectly linear and would give your front wheels a half chance of keeping grip.

With an S3 you can crank up the torque as you have so much more traction available.

My S3 felt flat as a fart at 6000, although it was still making around 270 BHP (peak power at 5500 ish) simply because the torque had dropped off from 330 lb-ft (3800 RPM ish) to 270 lb-ft (6000 RPM ish)
If it had been mapped with the torque pegged back, it would have given a more flat torque curve, and a more linear delivery...and would have felt like it had more top end.
It wouldn't of course...it would have had just the same top end, but less midrange.

Chasing headline figures is great if you can actually find the grip to use them...and like the way the power/torque is delivered...but sometimes the smoother power delivery and lower figures can make for a faster car point to point as you can use more of the power, more of the time, without fighting the car.

The question is:
What do you think a FWD A3 can actually use easily, every day?
270 lb-ft seems 'relatively' easy to control...
330 lb-ft coming in low down in a big dollop is just silly for FWD - ask any chipped diesel owner. I struggle like hell at 270 ish lb-ft in my Fabia...so 330 ( possible with a highly strung K04 or a 1.9 TDI) will spin up so quickly you'd go nowhere fast.

I'd suggest that a K04 mapped 1.8T FWD running 260-270 lb-ft and 260-270 BHP will be plenty quick enough....and even at that, would need either Racelogic Traction control or a decent LSD (or both) to use it easily.

 

[Essflee]

Was going to say if you are then fair play, think it would be great fun, I know it's not advised but it would be a hoot...a real handful

 

[Ess_Three]

I agree this is a good read...shy are you planning on putting 300bhp through the front wheels ?

300 BHP isn't the issue...it's anything over 250 lb-ft that causes the problems!

The A3s chassis just isn't the greatest at finding traction.

 

[Ess_Three]

Yeah ive spoken to damian about a rear ARB, he recons 25mm, im not sure still, when i get back from NY my main focus will be sorting the car out..

There are plenty of choices out there...
Eibachs have always worked for me in the past...
Neuspeed do some nice ARBs too.

leggy, i can always put a tranfer box in and make it quattro, its not an issue, will take a weekend at most.. but that can be delt with later.

Is your A3 a quattro, or not?
You can't just add the transfer box to an A3 and get the gains of the A3Q or S3...as they have a multi-link rear end that gives so much better control. (all relative, mind)

after the arbs, ill check the camber angles.. thanks again.

You can't pull the balljoints on an A3 like you can as S3 to gain a reasonable amount of negative camber...
There is no adjustment of the hub/strut joint...

So where do you go?
Adjustable top mounts?
TT/S3 bottom arms?

Interesting options...

 

[Essflee]

Was going to say if you are then fair play, think it would be great fun, I know it's not advised but it would be a hoot...a real handful

 

[Ess_Three]

Eye-up leggy...
You got Oldtimers disease? (double post?)

 

[Essflee]

Yeah, I'm on my ****** phone and it's messing me about...Lol

 

[Ess_Three]

Are you sure it's not operator error?
Drink related?

 

[Essflee]

Lol...I wish it was drink related but unfortunately not....

 

[Prawn]

very interesting discussion developed here!

I was running 290lbft through the front wheels from my ko3S at 1.65bar for a while, although it was only coupled with 230bhp, it made for a very interesting drive!

Once rolling, if you used the torque and short shifted, it would destroy a 'normal' mapped S3, although top end wasn't good with it being so peaky in delivery, it made a very quick car from A-B.

In the dry, it was OK (you had to be careful in 2nd, 1st was a no hope for WOT), once into 3rd gear it would pull like crazy with no hint of spinning up, although in the wet you had to be REALLY careful, as even a boot full in 3rd would spin the wheels!

All makes it more fun I reckon!

 

[Shy19s]

I just cant wait to get under the car again, start playing around with things. I like the idea of a progressive map, CC or JAbba me thinks, but not going to get in a "which remap" convo, far too long...

i need s3 hubs for my brakes and lower arms for the camber, but i think some decent tyres and rear ARB will sort it, glen i was thinking either H&R or Eibach.. i'll wait before i play around with cambers... its actually quite good in the corners, either way tho with 19s on its never going to be perfect.

after it handles better, FMIC, hard pipe kit and a remap should suffice until i look into hybrids, but thats a long way off as i want to do a bora conversion on the Golf too.

Thanks for all your help as always Guru's.

 

[Ess_Three]

i need s3 hubs for my brakes

Is yours a small engined A3?
You shouldn't need S3 hubs to run S3 brakes...they'll go straight onto 1.8T hubs.
Are the small engined A3s different?

 

[Shy19s]

yeah standard its a n/a 1.8 the carriers are part of the hubs, so for the 330s and calipers i need new hubs

edit... and i the new drive shafts didnt fit through so im running stock drive shafts, so i need to get them on asap.

 

[HTC]

Guys, I was watching some old WRC vids and came across this one. Listen to the turbo noises. I wonder what system they run?

http://www.youtube.com/watch?v=m5jZluytOOo&feature=related]

 

[Mr.G]

This is the noise my car makes. Although quieter. Happens exactly as the car is in the video, when coming off the accelerator/boost!

2:18 secs in sounds exactly like what mine does, it's more pronounced and louder first thing in the morning while pulling out of garage and up driveway.

 

[Prawn]

then your dump valve is most definately broken! No S3 should be making that noise.

 

[HTC]

Agreed on the S3 prob.................but the subaru certainly isn't broken. I have a login on NAISOC, so I'll see what's what later.

 

[Shy19s]

Sounds abit mad, first time i heard this, i was at a ford fair when i was about 12, my m8 had a cossie in the stands and one drove past us and made the most rediculous noise i ever heard.. something like a dolphin churp chatter.

After that when you see punto GTs racing about making that stupid tsssh noise, just doesnt sound at all impressive.. a friend has an evo 6 with a 9 turbo, the chatter sounds awesome.

But id rather hear the Tssh than the turbo internals being injested into my engine!

Kev, surely you can "set" your turbo to chatter..?

 

[Prawn]

oh the scooby clearly isn't broken!

Many high performance turbo cars run no DV or BOV system at all, I don't remember seeing any form of BOV when I had a good look over an Ex-richard burns WRC imprezza at a local body shop over xmas.

Incredibly interesting engines though, running massive turbo's with insane boost levels, and a 32mm (i think) restriction pipe on the inlet to the turbo, to ultimately limit power to 300bhp, yet with staggering torque.

 

[Prawn]

Kev, surely you can "set" your turbo to chatter..?

Of course you can, but only by either fitting a crazy strong spring into your DV, or simply running no DV at all.

I ran with no DV (just 25mm plugs on both holes and the vacuum line plugged) for a few months when I knew I was going to be fitting the ko3S.

I did it to see if the state of the already dying thrust bearing worsened dramatically as a result of the compressor stall. It didn't seem to get any worse in the 2k miles I did like that, but then it was already a near dead turbo.

 

[HTC]

NAISOC mention it's part to do with an anti-lag system. But on the whole Nick, sounds like you hit the nail on the head.

360° thrust bearings are a must or roller bearing for longevity. Also mentions that the WRC teams can afford to run no DV as they'll just replace the turbo every race....probably. Even so, they run flat out for a whole rally and they wouldn't want it to fail mid race.

 

[Ess_Three]

Let's not forget...in competition, 1/10 of a second matters at all costs - it can be the difference between a Championship, or a fail.

On a road car, when you are paying the bill...not so vital.

Competition cars also run Anyi-Lag...but injecting neat fuel into your red hot turbo manifold just upstream of the turbine, and wanting it to ignite to keep the turbine spinning, isn't the sort of thing you do if you want your fancy new turbo to see next week.

Just because it's used by WRC Teams or similar...doesn't mean it has any bearing on a road car.

As HTC says...Factory Teams can afford to replace the Turbo/Manifold after every event...or even the full engine.

 

[AxE]

Mine makes that noise when changing/lifting off the accel. It isnt mapped or anythin yet, am i best off gettin a Forge 007P?

Cheers.

 

[HTC]

Probably just a split OEM diaphragm DV. Swap it for a new one or upgrade.

 

[Prawn]

Competition cars also run Anyi-Lag...but injecting neat fuel into your red hot turbo manifold just upstream of the turbine, and wanting it to ignite to keep the turbine spinning, isn't the sort of thing you do if you want your fancy new turbo to see next week.

Interestingly, the VEMS standalone management system has a rather clever, but fairly primative form of antilag/launch control built in!

When you floor at with the clutch down, the revs rise to a pre determined limit, at which point it massively retarts the ignition advance to 0, stopping the revs increasing any further, and at the same time, it opens up all the injectors.

The result, on a car that's warmed up, is the fuel ignites as it leaves the head, and has an antilag effect spinning up the turbo and creating boost whilst the car remains stationary, with the RPM below that at which the turbo normally spools.

A friend of mine runs it on a 400bhp volvo S40 sleeper. it's incredibly comical when you get chavs in corsas next to you at the lights, and you flick the antilag/launch control switch and sit there popping flames, then disappear in a 400bhp old mans car!