S1 Turbo?

[quattro]

Rite guys i have allready searched the forum and havent found exactly what i wanted, here is what i know so far

-RS2 turbo (k24 7200) will flow to around 360BHP safely max.

-S2 K24 has a smaller shaft than the RS2 k24.

-Audi 200/Porker 944 K26 will only flow to around 300bhp with a little more lag due to having a slightly larger hot side.

-A standard full K27.2 (from Merc 7.9L lorry) will be very lagy due to having a v.large hot side and wheel but will flow close to 480. . . . maby 500 bhp?

So here is my question. . . . . . if i get my hands on a k26 from a 944 or audi 200 and a parts for a k27.2 from a Merc lorry (comp wheel, cold side housing and seals) will i be able to build my self an audi S1 replica with a K26 Hot side & wheel /K26 Center section & shaft /K27 cold side & compressor wheel?

Or am i living on a different planet?

[dainys]

I think s1 has full k27, and you will have hybrid k26/27

[Jamo]

I'd buy a Garrett 2871 or 3071 to be honest. They are in a different league to a k26/k27

[quattro]

Yes but all i have been told and looked up on internet about garrett turbos is that they 'surge quite a lot' and 'they spool verry quickly and can hold up under higher temeratures BUT not ofr a long period of time' both come up quite common in searches and talking to my friends.

I push my S2 very hard, i would rather have a liittle less power, say 460 bhp with a 26/26/27, than having to worry about surge and life span of a garrett with 480bhp 2871, or 550bhp with a 3071.

I take it by the reply you run a 2871 or a 3071, how is ytours and how hard do you drive it?

Thanx

[Jamo]

They only surge if mapped incorrectly and it really only applied to the 2871 but as tuners have now got to grips with the turbo it's no longer an issue for somebody such as MRC.

Both the 2871 and 3071 will only make about 400-450 bhp.

No way will they make 550 bhp thats GT 35/40 territory

Check the thread project 400 by Ross

I don't run them I will be running a 3076

[quattro]

But the GT30R will hit around the +500bhp mark yes?

Who is running this turbo, if there is any one do you have any issues?

[Jamo]

But the GT30R will hit around the +500bhp mark yes?

Who is running this turbo, if there is any one do you have any issues?

3076 ak GT30R will hit 500 bhp, i'm hoping for around 550 with my stroker setup it maybe more time will tell.

Search for 3071 on the forum. It's the turbo of choice on the S2 by modders now days especially every day driving cars.

The GT30R is being run aronmatic2 he has details in his project thread. Myself and another member will be running this turbo.

The 2871 boosts quicker than a K24 and gives 400+ bhp depending on setup

3071 boost around 3.3k revs pulls to redline and 430-450bhp

[porkkis]

They surge if mapped incorrectly?? A-ha!
By mapping the boost can be limited so it would not surge but it really doesn't change the fact that they tend to surge. And why buy a BB turbo that costs a lot and then limit its output?
I have no personal experience of 3071 or 2871 with larger hot side but 2871 with smaller surges like hell. Or did before my mapping
Another cure is retiming the cams but that will lower top end power.

K27.2 is a series designation just like K26 or K24. There are lots of different K27 cold sides available.
For excess of 400hp I'd recommend you find a K26 with #8 hot side (porsche 944 turbo s 250hp) and then suitable K27 cold side for the power. Something with a bit over 50mm inducer diameter.

[A80Avant]

i believe that the 3071R garrett is quite balanced in size turbo and doesnt really surge.Turbos tend to surge when a really big cold side is mached to a really small hotside or thier internals are great size differences.It doesnt have to do with the fact that they are BB or 270 or 360 bearings.Those are only ways of oil distribution and cooling.

I on the other hand have heard the opposite about BB turbos,that they tend to last a lot longer and never need a service as long as they are run in their territory of power and pressure.KKK turbos always need servising after 150K kms.at least that is what audi says about the RS2 turbo

[porkkis]

You are very correct. 2871 has 54mm inducer and 48mm exducer. They are the other way around on RS2 KKK unit

Actually I think there are at least 2 different inducer sizes in 2871. This one is measured from an a/r .5

[quattro]

Ok then some good info here guys, @jamo let me know how you get on with yours when you get it set up, im leening towards the GT30R now since nobody has really slated it!

[Jamo]

Quattro have a read here http://www.motorgeek.com/phpBB2/viewtopic.php?t=9230

The lack of lag on the garretts more than make up for the surge possibility. Ross made what 428 bhp on a 3071 on small injectors and sees 2 bar on the road.

Also see aronmatics thread http://www.s2forum.com/forum/showthread.php?t=5399

He had a K26/K27 and ditched it for a GT30r with 0.63 hotside after testing the 0.82 hotside.

[S2central.net]

Agreed - the Garrett turbos make the old KKK devices seem like dinosaurs... BUT they do have to be mapped correctly - especially the 2871 with its tendency to surge if the boost profile is not properly observed by the ECU.

The Garrets are harder to fit on the S2 than a KKK hybrid of course, but the spool times are fantastic and the headroom and efficiency for silly boost (like 1.7 - 2.0bar) is just amazing.

[quattro]

Ok then my mind is made up its a GT30R with a .63ar hot side (A little les lag yes?), i will probably go for the 4" anti surge on the intake of the cold side too.

[|Maku|]

The 2871 boosts quicker than a K24 and gives 400+ bhp depending on setup

Is it realistic that it really does spools up quicker than stock K24 and gives 400+hp? So we can say that it spools up quicker than K24 and gives more power that RS2 turbo?