M42 turbo fact thread

[MF DOOM]

So I decided against the S52 swap, and am going to keep the M42 and go turbo! Looking to get some advice/predictions on my build. I have read several build threads and am meeting with a local engine builder hopefully this week, because if I am really going to do this the Engineer in me has to do it as close to correct the first time as I can. Thoughts on the following setup for reliability/hp?

Compression goal: 8.5:1
Forged Pistons
Performance Valves and Springs
Polished and Balanced Stock Crank and Rods
Turbo Cam
Ported and Polished Head
ARP Hardware
MLS Gasket
Turbonetics Ball Bearing T3/T4 5 Bolt Turbine .63 a/r (High teens psi?)
SDS Stand Alone (Already Purchased)


Stay tuned for a build thread!

:)

Sounds like a promising build. You should give MM a call about a head. Might as well go with one of theirs and rev to 7700.

[elcoy]

So I decided against the S52 swap, and am going to keep the M42 and go turbo! Looking to get some advice/predictions on my build. I have read several build threads and am meeting with a local engine builder hopefully this week, because if I am really going to do this the Engineer in me has to do it as close to correct the first time as I can. Thoughts on the following setup for reliability/hp?

Compression goal: 8.5:1
Forged Pistons
Performance Valves and Springs
Polished and Balanced Stock Crank and Rods
Turbo Cam
Ported and Polished Head
ARP Hardware
MLS Gasket
Turbonetics Ball Bearing T3/T4 5 Bolt Turbine .63 a/r (High teens psi?)
SDS Stand Alone (Already Purchased)


Stay tuned for a build thread!

[ccsdo5]

^^ This is the same turbo I am trying to get from my friend. It's apparently pretty awesome on the sr20's. I know T25 with an hks wastegate (about 1 bar of boost) is somewhere around 200-250 I think for my friends 240sx. I think it'll be a good buy!

How/ where are you guys running coolant lines to the turbo? I am doing the mess under the intake stuff as well so can I get it from coolant pipe (the teal colored line in the picture below) and then return it to the cylinder head (also the teal line pictured below).

[jntar]

I suppose it depends what you want it for.
I'm trying to decide between GT2554 and GT2560.
My thinking is that I'm trying to supplement the powerband, not create it. So the 2560 seems like it should supplement the M42 powerband pretty well, and shouldn't run out of puff too much at the top end.
For me at least, the 2860 would be a little big I think.
Good part about those turbos is that flange size is the same for all T2s. So it's pretty easy to change between them.

What sort of power are you after?

I found an s15 240sx t28 locally I'm thinking about. It's pretty close to the 2560 spec. I'm fine with 200whp, but my current td04h-15g greddy turbo has a large drop on top end above 5k rpm. I'm looking to get something that spools similar, but pulls to redline.

[econti]

Contemplating a turbo upgrade in the very near future. I'm trying to decide between the gt2560r vs gt2560rs. Both spool pretty quick, the 2560 about 500 rpm quicker, but the 2860 has a better flow at the top end. I wont be running more than 12psi and still on stock motor (haven't even started on the new engine build).

Thoughts on these two?

I suppose it depends what you want it for.
I'm trying to decide between GT2554 and GT2560.
My thinking is that I'm trying to supplement the powerband, not create it. So the 2560 seems like it should supplement the M42 powerband pretty well, and shouldn't run out of puff too much at the top end.
For me at least, the 2860 would be a little big I think.
Good part about those turbos is that flange size is the same for all T2s. So it's pretty easy to change between them.

What sort of power are you after?

[jntar]

Contemplating a turbo upgrade in the very near future. I'm trying to decide between the gt2560r vs gt2860rs. Both spool pretty quick, the 2560 about 500 rpm quicker, but the 2860 has a better flow at the top end. I wont be running more than 12psi and still on stock motor (haven't even started on the new engine build).

Thoughts on these two?

[jntar]

What's everyone here torquing their ARP head studs to?

85ftlbs in 3 step intervals as arp recommends.

[varg]

What's everyone here torquing their ARP head studs to?

[wazzu70]

Yes, that image shows what pins on the AFM are for the IAT sensor.

[jntar]

Finally getting around to installing an intake temperature sensor. On the AFM harness pin 4 and pin 5 are for temp. Pin 77 on the DME is the IAT sensor input.

Does anyone know for sure if pin 4 or 5 on the AFM lead to 77 on the DME? I'm trying to not hack up my harness. I have a plug extension for the AFM I am going to cut and wire in. Ive been digging through the bentley manual and electric troubleshooting guide for the last hour. I'll keep going, but if someone already knows it would help :)

Think I figured it out: http://www.r3vlimited.com/board/show...7&postcount=98

[wazzu70]

For that power level stock rods and cams should be fine. Stock compression os 10:1...or does OZ have a different spec?

The turbos you mentioned should do the trick and be readily available on the used market there.

[econti]

I plan to into turbo sometime soon, and I have a couple questions.

I'm going to be shooting for 250hp with a focus on response. Someone I know who does turbo setups for a living recommended the GT2554, and if that doesn't quite do the job then I can step up to the GT2560R.

I'm reasonably keen on overboring, which means custom pistons, which means I'll probably change compression to around 10:1. Yeah I know that I could just fit a thicker head gasket but if I'm going to overbore then why not do it properly.

What are the rods like? Fine for 250hp with abuse, or for peace of mind should I go aftermarket forgies?

Where do you tap oil lines and such?

-edit-
And for cams, is the stock overlap alright? Or will a regrind/turbo specific cam be needed

[jntar]

You're probably going to have to call VAC.

[ccsdo5]

Does anyone happen to know what the installed valve spring height should be on vac springs? I need to start putting this head together and finish my engine. I thought they came with a sheet but I might have misplaced it..

[jntar]

I recall 16-17ish

Cool, I'm not going to worry about attempting to gain more.