AAN into Ur quattro, 400-450 Bhp Target

[macspring]

Duplicate post.

[macspring]

Also dying to see how you get on with the new turbo.




Just to record it on this thread while it is fresh in your mind. What rpm does the GT3071 start to make say 0.5 bar of boost ?

And what is the maximium boost pressure in bar and at what revs ?

Sorry for the questions, but had thought a GT3071 would have been suitable for me ?

My impression was that the Garretts were early enough boosting and just went on boosting, and that a a KKK 26/27, boosted a bit later, but with such a step that it felt powerful, but didn't boost quite as high as the Garret, which is more linear ?

Does this concur with what your found with your GT3071 ?

Thanks.

[DJones]

Be interesting to see how you get on...

So what do the numbers mean:

GT 30 71 R

GTX 28 67 R

If it was a GT5576r it would make sense i.e. 55 being inducer 76 being exducer..

I understand the .63 and .82 hot sides etc but not got my head around the cold side?

Thanks in advance..

Darren.

[URquattroGus]

I've ordered a GTX2867R with 0.63 AR Turbine Housing. Comes with anti-surge compressor housing as standard.

A very expensive christmas presnt to myself! It will be interesting to see how this compares to current turbo. I don't plan to change anything else at the moment so this should be a straight swap give or take a few mm here and there.

Excited but worried at the same time! Feel better now I have some kind of hare brained plan.

Once it arrives and I fit it the GT3071R with 0.63 housing will be for sale. It's only been run for about 2,500 miles from new.

[URquattroGus]

Darren, I'm Essex based, so not too far. Thanks for the offer, might have to take you up on that depending on how things go.

Ross, you've described pretty much exactly my problem, much better than I ever did too!

My only concern is that fitting the GTX2867R may give surge problems low down the rev range and not be easy to map.

I'm tempted to change the turbo as its quite bolt on, and I can sell the barely used GT3071R.

I reckon I can do this and then get head porting done if I'm still not happy or when funds allow.

The K26/K27 sounds good but that would mean changeing ex manifold and also oil and water lines so has some complications.

Funny really as with the 3071 I thought I'd got the spec just right looking at others experiences. Its not undrivable by any means, maybe just a bit too on off as ross says.

I could quite happily live with it as it is but I can't help but think I can do better.

[Ross]

The dyno graph looks pretty similar to my GT3071R coupe, in that torque is quite consistent but the peak isn't that high. Hence the power is quite progressive... my K26/7 is making similar peak power but a huge wedge of midrange torque puts the power lower down, and it then starts to let off >6500rpm. Where-as the Garrett just kept pulling hard to 7,000+.

Peak torque in 3rd at 3500rpm seems right to me, that's exactly what I was seeing, although due to surge it often wouldn't make peak until about 3800rpm. If you want power sooner on the 2.2 you need something newer... that GTX2876 does look rather promising to give you that extra 500rpm of spool and similar power.

I changed turbo because I was frustrated at the on/off switch at about 3,800rpm; I wanted better pick-up lower down. Getting the head port + polished makes a big difference, it is more responsive and alot better off-boost. The turbo still came in too agressively but the improvement driving round town is substantial. On-boost is more efficient, so 0.5bar at say 3,500rpm was producing more torque than before, hence on the road it's quicker even if spool is no earlier. As a one-off cost it's not cheap but IMO worth every penny.

I ended up moving to a newer K26/7 hybrid (wanted a direct replacement for stock so that was my only option for 400hp+), I still have the same 3800rpm in 3rd gear for max torque, however it's making low boost alot earlier and combined with headwork it pulls well from alot lower down than before. I guess the point I'm making is peak boost isn't everything - it's how it makes that boost and how efficient it is with boost too.

[DJones]

Angus

Not sure where you live but your more than welcome to drive mine to see what you think. I know how frustrating it can be...

As for the inter-cooler efficiency you can log the inlet temperature via VagCom to see what it peeks at and the difference from cruising to full boost.

Darren.

[URquattroGus]

Sorry I dont have a sensor for EGT.

Trying to plot rough points on a turbine map for GT3071R using "squirrel performance calculator" (Click the GT3071R/refresh to show map)

http://www.squirrelpf.com/turbocalc/index.php?version=4&target_peak_power=430&pr_ref=14.696&engine_disp=2.2&engine_disp_factor=0&target_af=12&bfsc=0.47&max_ic_loss=1.7&rpm_redline=7200&rpm_peak_power=5500&rpm_max_boost=3500&rpm_min_boost=3000&vol_1=89&vol_2=93&vol_3=90&vol_4=87&vol_1=89&vol_2=93&vol_3=90&vol_4=87&intake_temp_1=90&intake_temp_2=120&intake_temp_3=135&intake_temp_4=140&turbo_n=1&map_sel0=37

and the overlaying the same points on GTX2867R Map (a bit rough)

[A80Avant]

I dont think that downpipe is wrong. Its actually pretty identical to the original garrett hotsides with that funnel configuration. Dont do anything to it. No backpressure is created there IMO.

what kind of EGTs do you see (if you have a sensor) during cruising say at 3000rpm and 6th gear?

[URquattroGus]

Right.

A few areas where improvements could maybe be made;

1) I have a 3" system all the way except for a 2.5 " tapered bit directly after the turbine. Surely this is adding backpressure. I think there may have been a mistake when the turbo was ordered, correct me if I'm wrong but I have the T31/T3 2.5" turbine outlet and not the 3" 4 bolt outlet.

I think because I ordered the 034 downpipe at the same time, or some mistake/I did not make things clear, they shipped me 2.5 Outlet one.

Do you think a different housing with GT 3" v band outlet and a new/modified downpipe would be good?

See old photo below;




2) The drivers side front intercooler and pipework (one of two sidemount) has good airflow to it but the exhaust manifold is almsot directly above, and the engine block is also almost next to it. There may be quite a bit of heat radiation. Maybe I could make up a gaurd of some kind and lag/insulate the pipes. Both are thick bar and plate intercoolers. To clarify the intercooler infront of and below the turbo and manifold if that makes sense.

3) The boost pipe layout can't re reduced or improved drastically from what I can make out. There are some 90 degree bends from the intercooler end plates but I think this is the only option and less sharp bends may not fit/ may make a mess.

I am going to buy an infra red thermomemter to try and work out the efficiency of my intercoolers, unless someone can suggest a better way.

The GTX2867R is still tempting, the map makes it look like the dogs b*llocks. Having said that, I would have to have a 2.5" outlet for that turbo in any case.

[DJones]

off topic - darren, have you fitted the 6 speed yet?

Not yet, its in a million pieces in my garage currently being rebuilt...

[djh]

off topic - darren, have you fitted the 6 speed yet?

[DJones]

No offence taken, you and i have had this debate before and we both agreed as to why i use it.

I also agree that there are many systems within the Eboost 2 controller that can get you into trouble, the text box you highlighted being one of them without the correct monitoring equipment in place. Which is why i dont use it or can remember its name..

Every map in my car has been set up correctly and checked for safety with the most attention being paid to the 2.2bar boost pressure.

Consequently i can switch between six different boost maps with peace of mind. My car now runs a lower boost map in 1st and 5th. 1st because 2.2 bar in a 3.9 ratio light weight Ur is to much and fifth because a small amount of surge is introduced if the boost is to high..

As i say no offence and each to his own which is what the final part of my post was alluding to

All the best

Darren.

[prj]

A map that i have not used (cant remember the name....) but effectively because the system applies boost to the top and bottom of the wastegate, when your turbo runs out of puff at the top end it forces the wastegate shut to ensure you are getting every last puff.... Naturally this feature wont work if your turbo has nothing more to give.

This is a textbook example of why everyone should not "have a fiddle"...
Obviously it is your car and your property to do with as you wish, but I would strongly advise against doing everything described in these few sentences, if you care even a bit about the engine, turbo etc...
I don't want to offend you at all, just trying to say what not to do.

Btw, I mapped Tomas' car on the N75 with Motronic today. I have stable 2.2 bar in all gears without hunting and overshoot. Separate boost controllers are for people who don't know how to map the stock system, as is seen time after time.

Imo either keep the stock system functional in it's entirety or if you are unable or not willing to make it work as intended, run a standalone.

[DJones]

Hi David,

I think you are referring to boost control. The standard system (as we know) uses a 3 port N75 hence mapped boost map with signals from the TPS so it wouldn't apply full boost at half throttle as an example.

My system uses a 4 port N75 valve with mapped boost that is separate from the Motornic allowing me to adjust boost maps to a degree.. Naturally it doesn't communicate with the Motronic as well as the standard system but it is completely adjustable to suite your needs, which is the bit i like, i love fiddling but dont have the knowledge or equipment to map the original Motronic.

Quick summary of the Eboost 2 controller....

You can produce six boost maps and switch between them at any point i.e. different boost per gear selected.

You leave the standard spring in place, in fact i have wound my cap out as far as i can and without boost control it only produces .35 Bar.

You then set gate pressure i.e at what point the wastegate starts to open (creep) you can have this very high to produce a very aggressive map with an over boost facility. Or you can have no setting at all allowing for a very early open hence lethargic boost ramp (i use this configuration).

You then set the set point which is the highest boost limit you wish to achieve and then finally on the main maps you set sensitivity which ensure the boost stays steady.

Above are the main setting points to get it working but there are many many other settings as an example:

Over boost protection.
Water injection map (which i use)
A map that i have not used (cant remember the name....) but effectively because the system applies boost to the top and bottom of the wastegate, when your turbo runs out of puff at the top end it forces the wastegate shut to ensure you are getting every last puff.... Naturally this feature wont work if your turbo has nothing more to give.

There are numerous other features, but effectively that is the system i use which i hope answers your question...

Apologies for waffling and what sounds like a sales pitch.... its not and i know many of you wont use anything other than the standard system which i fully understand, as said i just like having a fiddle...

All the best

Darren.