Building Turbo engine

[Starch]

Hi I am currently stripping my turbo down and I will be building/rebuilding it now so that I can put it in the drift project.

As I will be aiming for 300+ BHP I want to know what I should be aiming to do and what are the best parts to fit.

I already have all the parts for the Promax stage 2 mods (dual port wastegate, bailey DV, manual boost contoller, ECU chip and 3 bar fuel pressure regulator).

I will be running with an Augment automotive ECU, which negates the standard chip, but I still have a standard head gasket, what should I replace that with? Whats the best brand?

What mods should I make if any to the engine whilst it is out?

I have been told I should have a 3 inch exhaust system?

Do I need to modify the intercooler?

Can anyone give me any idea of other bits I should be doing?

 

[JamesO]

I would replace the standard headgasket with another standard headgasket.
Somebody did a list somewhere of restrictions, K26/6 turbo tops out @ 290 bhp and IIRC the Intercooler quite a bit higher than that

 

[Starch]

Should have said that I have a K26/6 I think, its a 220 car, and as far as I know the original turbo. Although I am considering upgrading to a HX/HY35

Is there any particular brand of Gasket that is better than others? I have heard that the Cometic is the only one worth looking at? Is that true?

 

[944 man]

The only restriction remaining will be the K26/6 turbocharger. Id fit an uprated fuel pump too, though.

 

[Starch]

I had thought about fuel pump, partially on the basis I am thinking of fitting a small race tank as I dont need to cover long distances ever with the car. Had been thinking about a Walbro or similar

 

[scam75]

Sytec motorsport pump is what I've got. Equivalent of Bosch 044 and good for 400+BHP and change out of £100. Search e-bay for 944 turbo fuel pump. Lots of the jap boys run them on modded subaru's and mitsi's.

As James says use a fresh Victor Reinz (standard) head gasket. Good for 350 bhp or so.

If you upgrade to a K26/8 turbo (standard on 250 bhp models) you can get to about 320 bhp with the rest of your set-up.

The standard exhaust only becomes a restriction around 360 bhp and at that point it's the crossover that becomes restrictive. Standard intercooler is in the same ball park.

Cheers

Stuart

 

[944 man]

Re-reading I see that you havent mentioned the fuel pressure regulator. This will limit power to 275bhp on the original injectors, so youll need to change it to a 3BAR type, although Id expect that to have come with the Lindsey Racing/Promax kit.


Simon

 

[Starch]

Yes sorry my error, I do have that. Just forgot to add it to the list.

 

[Ex Skyline]

Cometic is the way forward. Also, i was running an uprated Walbro fuel pump (think 6 litre Chevvy) on my Skyline (600 bhp +), no worries at all. Plus a big fcuk off turbo and plumb in a bit of anti lag.....music to your ears!![][8D][8D]

 

[944 man]

I think that theres an issue with Cometic HGs and 944 Turbos, although I cant remember what it is.

 

[u63af]

I am doing hg on my car at moment. I am using a wide fire head gasket which I got from promax. Your block and head mating surface needs to be absolutely perfect for a cometic so you really need to get the block decked/skimmed at same time as head.
I went down the route of the wide fire as it will deal with small imperfections like the standard on but has steel rings for extra heat protection. It was not much more that standard one.

Over 300 bhp you will need bigger injectors than standard. Turbo wise when I upgrade I am going to get my k26/8 hybridised to a garrett gt30. They use your hot side and mate it to a gt30 cold side and modify internals so basically you have a gt30 that mounts as existing with some changes needed to water and oil hoses. I fitted a 3" exhaust and it did freee things up a bit.

 

[MarkK]

My Cometic was fitted by Promax in 06 I think,no probs as yet.

 

[Starch]

Hmm interesting opinions on the HG, I had been initially recommended the Widefire. I have heard good things about Cometic on Jap stuff but the comment about it needing to be perfectly flat is interesting.

 

[George Elliott]

...It is perfectly flat, both faces have not seen the light of day since the engine was built, there were no slight imperfections when it was machined[]

my cometic's are perfect after 50k miles on one car and 22k on another. (never needlessly machined block/head as it knocks the cam timing out)

Previous victor reinz wide fire rotted away and one failed under boost

George
944t

PS you did list the 3 bar FPR in opening post[]

 

[Frenchy]

Cometic on my Turbo S, running about 310 bhp, it has been fitted at least 5 years and appears bomb proof, fan stat failed once end the temp needle was well into the red, headgasket was fine, another opinion is that the headgasket can act like a mechanical fuse so any problems would see the headgasket give and not say a piston or rings etc ?

 

[Starch]

Cheers for the feedback guys, sounds like the Cometic is the expensive but best bet

 

[Ex Skyline]

How much is a Cometic HG for a 44' Turbo out of curiosity?

 

[TTM]

Not convinced about the Cometic, it failed on several cars I know though they were properly installed.

On one car making a lot of power cylinder walls were shaking so much that they chiseled the HG which ended up leaking.

Too much care required for a proper installation perhaps...

 

[944 man]

For a powerful engine you want Wills rings. If yore going to that much trouble though, Id want a closed deck block too. The Wills ring machining shouldnt be too expensive, but I wouldnt know where to start with the deck closing.

 

[Hilux]

ORIGINAL: Starch

I had thought about fuel pump, partially on the basis I am thinking of fitting a small race tank as I dont need to cover long distances ever with the car. Had been thinking about a Walbro or similar

I would recommend a good pump with diversity (spare capacity) and to run a swirl pot/reservoir if using a small tank, you dont want to lean out at revs []