AAN into Ur quattro, 400-450 Bhp Target

[URquattroGus]

The car has a single mass alu flywheel of 12lbs from 034 Motorsport.

[Bram]

do you still run the dual mass FW?

[URquattroGus]

Darren

Interesting.... The more I think about this the more my head spins. Could be quite a lot of hassle to change things and then I could still not be happy.

The machined K24 Hotside of the MD357 explains quite a lot to me, smaller housing so potentially faster spool. Yet this turbo can supposedly do upto 32 PSI according to the word file you posted a while ago.

Darren- did you ever manage to get yours on the dyno with this turbo, what does the power curve look like?

[DJones]

That's more because you don't have TPS based boost control, rather than due to the turbo...
So you get full boost on part throttle all the time and the car is annoying to drive.

True, but it is still a very aggressive turbo, i think the hot side is .6 i.e. not even .63

My set up is with standard AAN spring with the least amount of boost ramp my eboost controller will allow, i.e. immediate waste gate creep. I could run a 3 port N75 but it currently runs a 4 port which I'm told are a bit more aggressive is use.

Still be interesting to see what the .82 hot side feels like..

[prj]

Interestingly enough my car with the MD357 spools to early making it to aggressive.

That's more because you don't have TPS based boost control, rather than due to the turbo...
So you get full boost on part throttle all the time and the car is annoying to drive.

[DJones]

Interestingly enough my car with the MD357 spools to early making it to aggressive.

I have ordered from CR turbos (Craig, who was very involved with the MD357 design, back in the day, as its quite an old turbo by today's standards) a Porsche derived .82 hot side.

It will be interesting to see how it works, can always swap it back if its not what I'm after...

Darren.

PS. the hot side on a standard MD357 is a K24 CNC'd to accept a larger wheel.

[prj]

The hotside is what is choking the setup, not the compressor.
The compressor can easily flow more, fitting a GTX comp wheel won't do anything for you with this hotside.

Fit meth on the car, run lots of of it. Easy 60-70hp boost for you and better transient response all around.

[DamoM]

Turbo dynamics have said they cannot supply the MD357 as they can't get the housings anymore, think it was the K26 exhaust one.

The turbo is also only K26 based (thought they could use another housing to make something similar) so it will not mate up to my t3 flange.

They have said that they cannot improve the response of my GT3071R 0.63 but could offer a different compressor wheel;

"We can however help with improvements to midrange and top end power with the addition of a Turbo Dynamics designed special forged billet compressor wheel offering improved strength, lighter weight and improved flow over standard cast item, however this may have negative affect in the spool time which you ultimately wanted to reduce"

I know this is not necesarily going to achieve what I was after, but hew, more midrange and top end power, who can resist that?

What do you guys think, is a billet wheel a worthwhile mod? I suppose this would almost turn my turbo into smilar turbo to a GTX series one. (incidentally I was told garret GtX turbines not available seperately)

Just gone back over my old paperwork and you're right. It was a k26 but the wagner I had was a T3 and so we had to weld a K26 flange on the manifold. Sorry for the confusion.

I do actually have a brand new turbo (I bought 3) that I was planning on putting in my RR quattro. If you offered me enough I might be persuaded to part with it....

It would however mean you getting your EM modded (not necessarily possible?) or a new EM.

[URquattroGus]

Turbo dynamics have said they cannot supply the MD357 as they can't get the housings anymore, think it was the K26 exhaust one.

The turbo is also only K26 based (thought they could use another housing to make something similar) so it will not mate up to my t3 flange.

They have said that they cannot improve the response of my GT3071R 0.63 but could offer a different compressor wheel;

"We can however help with improvements to midrange and top end power with the addition of a Turbo Dynamics designed special forged billet compressor wheel offering improved strength, lighter weight and improved flow over standard cast item, however this may have negative affect in the spool time which you ultimately wanted to reduce"

I know this is not necesarily going to achieve what I was after, but hew, more midrange and top end power, who can resist that?

What do you guys think, is a billet wheel a worthwhile mod? I suppose this would almost turn my turbo into smilar turbo to a GTX series one. (incidentally I was told garret GtX turbines not available seperately)

[DamoM]

and my compression ratio is 7.6:1

[A80Avant]

For once I am in total agreement

I'm not in agreement, but I haven't mapped any cars, just my experience on my car. Don't know if it is a good example, probably not but when my compression ratio was pretty low due to cylinder wear, my car ran like chap off boost and my spool went at least 300rpm later. I'm not talking about reaching proper boost just how long it takes for boost to build up. Increasing the timing didn't make any difference, but as I said this is probably not a good example.

With head work though I still run same timing as before and my CR is around 9:1 now. Some areas I run higher timing as well.

sent using Android

[DamoM]

3) Change to a MD357 Turbo Dynamics turbo. There may be a problem here as I have a T3 flanged wagner Evo exhasut manifold. I went for the Gt3071 at the time as it was £850 and proven and the MD357 was £1300 and had only been used by one person.

I think that single biggest gain wold be the turbo. It comes as standard with a T3 flange (we had to weld one on the wagner manifold to make it fit).

[Jamo]

For once I am in total agreement

[prj]

What?? Drop the compression ratio? Surely that would make worse off boost response!?

No, it won't, because you are knock limited on the stock engine pretty much any time you are at WOT/high load.
Does not matter if you have 0.3 bar or 2 bar, and the 0.3 bar you get instantly with these turbos when you dip the throttle.

The difference in timing between two cars tuned to knock free MBT at stock CR and 8.3 CR clearly show this, as does the general feel of the car.
Less CR on these cars means faster spoolup and better transient response, except for very light load cruise situations, so basically any time the throttle is over 30%.

I mean, if you ran it on LPG or E85, then you would benefit down low from higher/stock CR. But as long as you are running good old petrol, you are better off dropping 0.5-0.7 points off stock.

[URquattroGus]

What?? Drop the compression ratio? Surely that would make worse off boost response!?

I did spec an alu flywheel to try and lighten the bottom end a bit.

What other turbos can I consider? Did bram end up with comp turbo? I am looking into porting too.


I think some of the problem is that my everyday focus rs is 2.5 litre and boosts from just 2k rpm onwards, it pulls well low down and you get that lovely surgeing forwards feeling, particularly in the higher gears.