Turbo still not finalised ?

[macspring]

Demetri

What does a "if there is no fuel pressure taper" mean.

Embarrssed, forgot to include that macanmar fitted a 044 pump to the car a while ago while the block was with JP. I've gone back and added it to the spec list post.

Can I use the std S2 ABY fuel presurre regualtor or does it need to be changed and to which one / part number ?

Clutch is a South Bend Stage three one with a metal face on one side and an organic side on the other, Marc in EFI Express would be able to confirm the exact one if he reads this thread ?

Note what you say about the K26 / 3071 hybrid, but interested to know why you don't recommend them ?

You're right about the Wagner Exhaust manifold, the one I have is for a kkk, so would have to swop it for a T3 one.

Presumably even though 034 are dearer, they would be able to supply the correct new lines kit for the 3071 ? Or is there someone in the UK to contact ?

Would probably cut up an S2 air box to work with the 3071, couldn't cut up an RS2 airbox. Or use a non oiled cone filter and some ducting to "fence off" the cone filter from the rest of the engine bay.

"you will need a maf-turbo hose with bigger opening for turbo", where would I get one of these ?

[prj]

Because the 3071/K26's I have mapped tended to be very knock prone for some reason...

If you have a KKK manifold, stick a K26/K27 on it and save yourself the ball ache.
The existing oil and water lines will bolt right on, it will work with the airbox etc.

The MAF-turbo hose you can get from 034 I guess.


Your clutch should be fine then, thought you had a std. one.
Same goes for fuel pump.

[A80Avant]

I don't understand why a 3071 would have anything to so with knock. If a 3071 is similar power turbo than the k26/27 you shouldn't have any problems. I eliminated any knock on mine with about 14deg timing around the full boost area, then gradually increased it.

K26/27 is easier to fit, but I wouldn't use the k26 hotside of the 034 unit on the garrett hybrid because after seeing the quality of the original garrett part, it is much better. I think you can modify the k26 to fit a T3, but I may be wrong.

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[mcandmar]

Knock will be an issue for us when mapping as we cant get proper 98 fuel over here, we both use E5 as a substitute. As this will be Davids daily driver using any additives or octane booster isnt really an option. Weather this influences turbo choice i dont know?

[prj]

I don't understand why a 3071 would have anything to so with knock. If a 3071 is similar power turbo than the k26/27 you shouldn't have any problems. I eliminated any knock on mine with about 14deg timing around the full boost area, then gradually increased it.

I am guessing it might be because it is not such a good match.
This is just my observation from tuning two of these. YMMV.

[macspring]

Does the knocking happen with the K26 / 2871 also ?

What does a "if there is no fuel pressure taper" mean.

When you're were mapping a 26/27, what point does full boost occur ? And how much boost is there at say 2k rpm and 3K rpm ?

Low down the rev range will it drive as well as say a standard but chipped ABY Avant, or is there more lag and flatness with the 26/27, but much more poke when it does come on boost at x(?) rpm ?

Notwithstanding the above, my choice is either a 26/27 or a GT3071.

( The RS2 and 2871 should be left out of the turbos to choose from, because they don't suit what I want ? Is this right ? )

And so if I go for a 3071, I need to do the following;

I should swop my Wagner exhaust manifold for a T3 one and buy a 3071 .63, get the custom lines and the maf hose.

I know the K26 (#6)/27 will fit easier and be cheaper to buy and not necessate the purchase of custom lines, maf hose and manifold, but the 3071 should spool quicker and give as much bhp ?

You might confirm if I'm right or wrong ?

(I know you will anyway).

Thanks.

[A80Avant]

Knock will be an issue for us when mapping as we cant get proper 98 fuel over here, we both use E5 as a substitute. As this will be Davids daily driver using any additives or octane booster isnt really an option. Weather this influences turbo choice i dont know?

Is say you will have a problem with any turbo I'm afraid. Consider water/meth injection as well to be safe.

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[prj]

I never mapped any K26/2871 hybrids or any 2871 for that matter at all.
Just hasn't happened.

And it might have been a coincidence, my guess is that the hotside of a 3071/K26 does not flow as well as 3071/0.63 with Garrett housing, that's all I can say.

[prj]

P.S.
What I meant to say before, is that 3071/K26 started knocking earlier than 3071/0.63 for me on very similar setups. Twice.
Why? I don't know... can only hazard a guess. Might be a coincidence as I said.

[JP]

The casting configuration on a k26/3071 hybrid is a T31 housing or similar with a round cutout to match the k26 flange. A T3 flange has a much larger opening allowing for improved airflow resulting in better scavenging from the combustion chamber. This in turn means more fresh air to burn the fuel creating a more complete burn less prone to knock.

[A80Avant]

so really, when you ported the K26 housing on yours you made it slightly closer to the original T3 garrett one then ?

[prj]

Great info as always, thank you JP!

[Ross]

I am sold on the KKK hybrid solution. I think, conbined with head work and good mapping, you can have good round-town driveability and off boost performance. That said - if the car had been more of a project and I wasn't so keen to keep it close to stock I would have probably experimented with one of the new Borg Warner range.

But it does sound like you're looking for a car with K24 like driveability - 2-5k torque range. I'd definitely take Diesel Des' offer up and see how you find that, because that is the only turbo i know of that (as far as I know) will give you the response you're looking for AND 400hp.

You'll find the K26/27 is laggier than you're used to low down, and even the RS2 hybrid (although not to the same extent but only good for 390-400hp) But the GT3071 needs to be driven above 3000rpm as well really - though with that BB centre it is quick to respond, and the headwork may improve it some.

What I'm saying is I do think you'd find that a nice, driveable car round town that isn't quite as fast as you're used to below 3,000rpm isn't such a bad thing. Especially with a nice smooth engine, you'll want the desire to rev it higher trust me

[Billman]

I am sold on the KKK hybrid solution. I think, conbined with head work and good mapping, you can have good round-town driveability and off boost performance. That said - if the car had been more of a project and I wasn't so keen to keep it close to stock I would have probably experimented with one of the new Borg Warner range.

Isn't off boost response better with a very big turbo helping the engine breathe? Plain thinking says that a small exhaust housing would restrict the airflow thus reducing the efficiency of the engine. (Not very relevant to the subject but i made me think about it).

When i drove A80Avant RS2 with the 3071/K26 hybrid it was when i had the RS2 turbo on my car and i have to say that i liked it a lot. It didn't felt laggier than the chipped RS2 I had a the time.

Of course i would also prefer the T3 version because of the flow, simplicity and many upgrade option.

Right now you want a good daily driver but you maybe see soon that a GT30 or 35 turbo drives very well also

[A80Avant]

and at the time there was no cyl.head porting. Only a service was done.