Turbo suggestions

[tommy gun 6]

Hi, I’m currently putting my 205 back together with the help of my eldest lads enthusiasm and motivation. 
Im trying to decide on a turbo to suit the spec of the build. 
it’s a standard (for now) Xu10j2te bottom end, all checked and good. 
head work so far, inlet ports opened up and casting imperfections removed, outlet also opened up plus mild port/polish. 
Skimed, valves lapped, head work to accommodate catcam turbo camshaft,and vernier. 
xu9 inlet manifold, ports matched to head and modified to take gti6 throttle. 
 tubular exhaust manifold and 3” down pipe. (Toying with the idea of external waste gate)

660 injectors intercooler etc.

dta s40 ecu, greddy electronic boost controller. 
vts, box and plated diff and plenty of other bits. 
now I need a turbo. I was looking at the gt2860rs but also seen the ihi vf series like vf30,vf24,vf34 or even tdo4?

 

I’ve been wondering, if I was to replace the pistons and rods should I go oversized and stroked? 
 

Thanks 

 

 

 

[Tom Fenton 1,542]

I don't think bigger is always better, the 8v cylinder head is going to limit the flow potential, I think a GT2560 is a better choice.

[wicked 103 3 Cars]

13 hours ago, tommy gun said:

head work so far, inlet ports opened up and casting imperfections removed, outlet also opened up plus mild port/polish. 
Skimed, valves lapped, head work to accommodate catcam turbo camshaft,and vernier. 
xu9 inlet manifold, ports matched to head and modified to take gti6 throttle. 
 tubular exhaust manifold and 3” down pipe. (Toying with the idea of external waste gate)

 

Given the tubular exhaust manifold, 1.9 inlet and turbo cam, I would pick the Gt2860r or Gt2860rs. 

Without those mods indeed GT2560 kind of turbo.

Edited September 21, 2022 by wicked

[SRDT 182]

18 hours ago, tommy gun said:

I’ve been wondering, if I was to replace the pistons and rods should I go oversized and stroked?

Stroked with a 88mm or 96mm crank?

[tommy gun 6]

I was going to change the crank

[SRDT 182]

A 88mm crank adds 46cc with a standard bore or 94cc with a 87mm bore .

A 96mm crank adds 232cc with a standard bore or 284cc with a 87mm bore.

 

So either a 2.1 or a 2.3 engine, I don't know if the 8v head is still enough for a 2.3.

[petert 588]

How much boost?

What CR?

What fuel?

How much seat pressure on the inlet valves?

 

I’d fit 86.50 forged pistons just so I could manage the boost and CR more effectively. The limiting factor is the VTS gearbox,

[wicked 103 3 Cars]

On 9/24/2022 at 2:21 PM, SRDT said:

A 88mm crank adds 46cc with a standard bore or 94cc with a 87mm bore .

A 96mm crank adds 232cc with a standard bore or 284cc with a 87mm bore.

 

So either a 2.1 or a 2.3 engine, I don't know if the 8v head is still enough for a 2.3.

Given that the 8v is not the most capable head, you probably will gain more torque on low revs, but not that much on high rpm.

I would not spend the effort on stroking this engine and end up with a kind of diesel engine that kills gearboxes. 

[petert 588]

5 hours ago, wicked said:

Given that the 8v is not the most capable head, you probably will gain more torque on low revs, but not that much on high rpm.

I would not spend the effort on stroking this engine and end up with a kind of diesel engine that kills gearboxes. 

I agree. Thus why I suggested just the 86.5mm forged pistons and control the boost effectively. With 15-17psi and 2026cc, the GT2860RS is a good match.

Edited September 26, 2022 by petert

[petert 588]

Here's the map - 2026cc, 6500 rpm and 15psi

[wicked 103 3 Cars]

With that setup you can run 1.2 bar as well, pushing it towards the 30lbs/min. 

 

Some turbo calculations

Edited September 27, 2022 by wicked

[Spesh 31 1 Cars]

I'd break the mold and use a HX27W with a 6 or 8.5cm housing.  sound way better

 

I had an original 2860rs on a S13 with a CA18, was a fantastic turbo that took an awful lot of abuse.

[Type-R 3]

I have a brand new hybrid HE221 in pieces ready to go back together. On the right engine it should make 400hp at 2 bar boost.

I feel like 8v turbo XUs tend to underperform (or we expect too much of them), and 16v is the way to go for easy power.

[Spesh 31 1 Cars]

On 9/28/2022 at 8:30 PM, Type-R said:

I have a brand new hybrid HE221 in pieces ready to go back together. On the right engine it should make 400hp at 2 bar boost.

I feel like 8v turbo XUs tend to underperform (or we expect too much of them), and 16v is the way to go for easy power.

 

Cracking turbo fair play, so underrated.