GTX 3071 .63 v KKK26/27 # 6

[macspring]

Hopefully this thread's discussion might be of use to others as all of the stuff releatively straight forward if a little expensive, engine rebuild and the rest of the stuff is bolt on, so will suit the people who cannot fabricate stuff or rebuild an engine, and don't have the free time due to other life commitments, work, partner, children etc..

My question is which turbo to buy is based on the use detailed at the bottom of the post.

(To make it easier to grasp the two specs, imagine the path of the air being taken in through the grille to when leaves the tailpipe).

First spec for the car could be;

HKS Cone air , std air filter, Wagner RS2 Evo intercooler, Wagner front inlet manifold, std throttle body, ABY cams, ported head, std valves and valve springs, forged pistons and rods, 7a flywheel and Southbend clutch, all balanced, Wagner cast RS2 T3 flange exhaust manifold, GTX 3071 .63, matching injectors, 3" down pipe, 3"inch exhaust, no cats, Motronic ECU, Off the shelf chip options, or a custom map from Prj?



Second spec for the car could be;

RS2 air box, std air filter, Wagner RS2 Evo intercooler, Wagner front inlet manifold, std throttle body, ABY cams, ported head, std valves and valve springs, forged pistons and rods, 7a flywheel and Southbend clutch, all balanced, Wagner cast RS2 KKK flange exhaust manifold, KKK26/27 #6, matching injectors, 3" down pipe, 3"inch exhaust, no cats, Motronic ECU, Off the shelf chip options, or a custom map from Prj?


Boost from 1500 rpm is not possible like a modern Audi, so say more or less 100% boost from 3000 rpm up to say 6500, but normally change gear at 5000. , as it's travelling quick enough compared to other traffic.

Car will never be tracked, used as daily, for short journeys around town, with the odd motorway include in some journeys, say 10 - 15 minutes worth as part of the journey. MPG will probably same with either spec. btw, what are people genuinely getting with either of the above specs and use ?

Just to confuse me further, what about Holset or any others, if suggesting them, please detail any fitting issues or anything else to be aware of as I need it to be more or less bolt on for both speed of completion, and secondly I can't do more than that, and I don't have any access to some of the amazing people on here.

All comments welcomed to allow the discussion to be fully fleshed out. Particularly keen to hear from people who have either turbo, and close to the car's proposed spec, thinking of Sonic and Ross, and a number of others.

Thanks very much in advance to all the people who take the time to make a comment.

[Rusty]

If you change gear at 5000 rpm then you're unlikely to get any benefit from a larger turbo, which is designed to produce more efficient boost to the red line and as a result requires more revs before full boost is available. Full boost from 3k isn't really available on the road with an RS2 turbo, so something larger will require more revs still. Also, you say it'll only be used in town and not on track, so you'll never get it up to the top of 3rd or 4th gear, where a larger turbo will make the real difference.

The .63 GT3071 was renowned for surge and so had to mapped accordingly, I'm not sure what the experiences are with the GTX though. For this reason, I have seen teh .82 GT recommended but that will produce boost later and hold boost longer, so doesn't really match your requirements.

Taking your description into account, an RS2 turbo would be a good option and with a rebuilt bottom end, you can get a lot of mid-range torque early on with minimal lag. There's also the bolt-on nature of the conversion, which is nice.

IMHO, you're better off minimising lag and maximising torque at 3k from the use you describe and spending the money eleswhere, on the suspension and looks perhaps?

[Rocco]

For your requirement ,just stock turbo with Prj chips.

Easy,cheap and very drivable to your rpm limiter(5000)

[tucalong]

A bit off-topic, but do prj sell maps based on spec or only real-time mapping on site?

[Error404]

I'm sure the turbo geek police will be along shortly to tell you there is already 25,000 other posts you need to read with sparse information that is hard to grasp unless you jerk off to compressor maps most nights

As this kind of question appears frequently and there isn't really a useful stickie on the subject, how about the forum creates a useful little table with say 50 hp power bands and what turbos fit into each band in terms of delivery on a 2.2, that might be easier for people who don't get too excited about trims and wheels to gather some basic information? So for example if someone wants to achieve say 450hp, they can reference the table and quickly see the handful of turbos or trim versions etc that might fit the bill and can be investigated further? Just an idea

[prj]

By the time you map out the surge on a 0.63 it will be almost like a 0.82 on a std. head.
On a ported head things will look better.
But for what you want the car to do, stick a K24-7400 on there and be done with it.
Don't even bother with fancy manifolds head port and what not.

Your mod list says silly money for very little gain. If you go all the way with head porting etc, drop the compression ratio as well to 8.3-8.5 and fit a GTX3071/0.82 or GT3076/0.82 on it.
If the MBT is dialed in properly on a dyno the result will be a car that will have more torque than stock until about 2200 RPM, then it will lag behind a little, and at 3400 and on you will be flying with torque levels far exceeding stock.

Paul (twenty_valve) on here has a similar setup, but stock head.

A bit off-topic, but do prj sell maps based on spec or only real-time mapping on site?

I prefer not to, but whatever you get off me is probably going to fit better than anything else generic. You must understand that no warranty of any kind can be given on such remote stuff though.

[Rusty]

I'm sure the turbo geek police will be along shortly to tell you there is already 25,000 other posts you need to read with sparse information that is hard to grasp unless you jerk off to compressor maps most nights

As this kind of question appears frequently and there isn't really a useful stickie on the subject, how about the forum creates a useful little table with say 50 hp power bands and what turbos fit into each band in terms of delivery on a 2.2, that might be easier for people who don't get too excited about trims and wheels to gather some basic information? So for example if someone wants to achieve say 450hp, they can reference the table and quickly see the handful of turbos or trim versions etc that might fit the bill and can be investigated further? Just an idea

Not a bad idea, would have to be very broad ranges though, as everyone has their opinions on this sort of thing

The OP mentioned the .63 housing which is why it's been referenced again.

[A80Avant]

@mcspring

noone can answer totally to your questions, because noone knows exaxctly what you want the car to do.

You will hear people talking about spool and boost and torque and numbers, but the bottom line is what your butt tells you, you like or not.
If i say that on turbo no1 you will have 5Nm more torque than turbo No2 or the first one spools by 2000rpm and really boosts by 3400 or 4000rpm, how do you know which gear im talking about? How do you know that the 5Nm will be something you will feel or not?

Best option is to get into a car that someone already has as a setup, see what the car feels like with lag and boost, see how much boost off a specific turbo will be 'enough' for YOU to make you happy, and then the choice will be clear.

If it were me, i wouldnt listen to anyone in here. Not even me!!! All of us have a different view of what is fast and what isnt. And that is a recipe of high expenditures of money before nailing the correct setup.

good luck!

[Jamo]

the car setup conflicts with what you want to use it for. The setup could easily handle 450-500 bhp however you want to use the car as a daily and short journey

Talking from a position of great experience you do not want more than 350-400 bhp for this kind of use and you want as smooth a torque curve to make the car relaxing to use in these situations.

a compturbo CT50 would be a good choice or maybe even better would be the Volvo K24

http://www.s2forum.com/forum/showthread.php?t=47576

Or if you wanted a bit more pub figures

http://www.s2forum.com/forum/showthread.php?t=57883

[macspring]

Hi, Mr. 404,

I'm sure the turbo geek police will be along shortly to tell you there is already 25,000 other posts you need to read with sparse information that is hard to grasp unless you jerk off to compressor maps most nights

I spontaneously laughed out loud when I read this first part of your reply, which startled my wife, and gave her further cause for concern about me being on S2forum.



Well observed.

[macspring]

As this kind of question appears frequently and there isn't really a useful stickie on the subject, how about the forum creates a useful little table with say 50 hp power bands and what turbos fit into each band in terms of delivery on a 2.2, that might be easier for people who don't get too excited about trims and wheels to gather some basic information? So for example if someone wants to achieve say 450hp, they can reference the table and quickly see the handful of turbos or trim versions etc that might fit the bill and can be investigated further? Just an idea

I think this is a great idea, which while obvious still hasn't been done on the forum. I'm just as much to blame as anyone for not doing it.

Also have to admit to starting a thread like this three times previously, and it is true the same people do reply. Having said that, each time I have learnt more about which turbo to pick, even if I seem to be taking forever to move forward.

Family, work, budget, and previous setbacks with the car, read :corey:, have / are conspiring against me.

So even though Mr. 404 was sarcastically cruel in his reply, it was both very funny, and contained an obvious, but very good idea. So all good.

In relation to the people that have replied each time to my "which turbo?" threads, thank you most sincerely, genuinely, as it is helping me, believe it or not, and presumalbly others who are surfing the threads.

The hall of fame is Jamo, Prj, A80Avant, Rusty, (and Error 404). Looking forward to having beer with you guys at the next MRC meet, whenever the next one might take place. Hopefully it does.

Remember, you guys only have to put up with me on this forum, pity the others on this forum who have to endure me in person.

Jeeez, I hope I not a marked man for this.

[macspring]

I'll try and kick this list of the stages for an I5. Once we have the information, it can be tidied up and placed in a sticky for all the newbies yet to discover an I5 engine's addiction, and all of us already here who want more poke.

1. Limp mode / no boost to 230bhp.

- Make sure it is running perfectly as the factory intended.
- Check the vacuum hoses, check the connection from the passenger side (rhd) top of the intercooler and the crossmember and install a Mark Halligan mod. i.e. a reducer pipe with jubilee clamps on the outside, rather than the factory set up which may have been suitable when the cars were new and on standard boost, but is now one of the first weakest links than should be eliminated.
- Check the condition of the spark plugs for any signs of trouble.
- Make sure your plugs are tight, on new plugs you should be able to feel the crush washer crushing as you tighten past the initial start of the tightness when screwing them in. Obviously do not over-tighten them, but is a known issue when people have damaged their engine's head through not checking their plugs. Or re-checking after a while when fitting new ones, No cost and easy to do.
- Buy a second hand POS as a spare. Easier than messing with the channels.
- Make friends with someone who knows how to work Vag-Com.
-
-
-



UrS4 Boy would be the perfect man and others, to step in with appropriate photos to further enhance the "brilliantness" of this I5 engine sticky.

2. 280bhp - Chip the ECU. For the money spent, it gives a great return. Prj or Homefry are the safe options.

3. 315bhp to 380bhp - Move to RS2 Spec.

4. 400bhp +

These stages above can be tidied up, improved upon, but they get us started. The same stickies could be individually done for the following areas. All of them could be "filed" under a new master section "Standard tried and tested upgrades for B4 I5 & C4 I5 cars" in the Home section of the Forum so that people, old and new, could easily find it to browse.


So, possible headings for the Master sub threads could be and in no absolute order;

1. Engine.
2. Brakes - Front and Rear.
3. Tyres.
4. Wheels.
5. Suspension.
6. Radio and Speakers.
7. Front Seats
8. Clutch.
9. Headlights.
10. Interior Trim - Carbon or Wood.
11.
12.

If people get through all that they should have garnered enough experience to attend to any other items that come up reasonably regularly, but may not have sub section.

This could be great or it'll fail and everyone will just move on, and we'll have people posting stuff like me, . Which turbo, which brakes, which wheels etc. etc.

http://forums.quattroworld.com/s4s6/msgs/15184.phtml

Let the games begin.

[newsh]

In the city you cannot have much fun with a GT3071 and keep your license for long I drive my coupe mostly on country roads and this is a great 40 - 100mph car, surfing the torque from 3 - 5k. I have the .63 because I wanted early spool but it needed mapping to get around the surge, it was mapped by Mihnea with RS2 EM and IM, ebay IC and custom pipework. I've since changed to full Wagner kit with evo EM and the general responsiveness has improved enormously, I'm sure it would benefit from another remap as it seems to pull harder now at 75% than at full throttle.

If you can get yourself to ADI you're welcome to a go in my Coupe

[macspring]

Thanks for the offer Newsh.

Have you still got the B5 RS4?

How does it compare with your Coupe with the GT3071 ? Just trying to get a feel for specs of the different cars via the forum as I can't get to drive them in person.

[A80Avant]

im towards the north east. i dont usually travel down south that far due to work and family commitments. Only when i go to Brian Tonks at mansfield is the southest i usually come.