[Coupes33]

Originally Posted by Hoper

Hi Coupes,
Not planning on taking the car to standing start drags, I don't have an LSD yet, it's a manual and I'm not sure I want to put my drivetrain through the launches that drag racing requires

Would also require some drag radials I guess

I am going to head to the roll racing in Sydney soon and will also rebook my track day soon, missed it due to COVID

So I won't have any 1/4 mile times to share but will be able to let you all know how it goes around a track and how it fares at the roll racing

also since my engine now has forged internals, I do watch the single turbo updates quite a bit and may eventually head down that route if my twins play up

oh and yes I trust myself far more than any shop, I care deeply about the outcome, it's hard to find shops full of mechanics who'll be as careful as you can be yourself

engine now has 10k km on it post re-build, has freed up quite a bit over from the 5k-8k mark, and like everyone else, timing corrections are a thing, but the more octane I put in the less I see, so more fuel upgrades on the horizon

I'm running E40 at the moment, and sometimes up the E content to check what it does, e50 really stretches the fuel system on my car, so a stage 3 lpfp and helix is on the list now

Yes Hoper, to get a good time at the drags, a LSD and some drag radials are a must. It will be interesting to see whether you lose traction even in roll racing. Normally, you gun it from around 40 kph which i would imagine you would be in second gear. I ran drag radials on mine at roll racing because of that reason. Mine will spin the rears in third on street tyres with DTC still engaged. A few years ago, I got to use E60 but I had a stage 2 LPFP and Throttle Body Injection both from Fuel-it. I achieved a 11.2s run with this combination and a set of old Classic RB turbos.

[rev210]

Originally Posted by Hoper

Hi Coupes,


also since my engine now has forged internals, I do watch the single turbo updates quite a bit and may eventually head down that route if my twins play up

oh and yes I trust myself far more than any shop, I care deeply about the outcome, it's hard to find shops full of mechanics who'll be as careful as you can be yourself

engine now has 10k km on it post re-build, has freed up quite a bit over from the 5k-8k mark, and like everyone else, timing corrections are a thing, but the more octane I put in the less I see, so more fuel upgrades on the horizon

M18 released their top mount cast single manifold. Looks super compact so RHD solution possibly. Just have to route the dump and either internal gate turbo or weld it to the turbine housing.

What's the build spec on the motor and who did you get to do it?

[Coupes33]

Originally Posted by JimiP

I've been running GC's for about 2 years now.. Ive put about 30,000kms on them at 20psi making 300rwkw on 98.. they do rattle a bit but I run the MHD rattle fix set all the way to the right (less lag) and its OK..

Good to hear your experience with the GCs JimiP. Sounds like the GC's have been performing ok apart from the rattle which I would imagine is the wastegates. 30,000kms indicates good reliability but with 20 psi boost you should be able to extend that quite a bit. Have you ever given it a run down the strip?

[rev210]

Originally Posted by Coupes33

You have mentioned before that you have been chasing timing corrections. Hopefully, you can sort it out soon. I have always had timing corrections and could never solve the issue apart from when I used octane booster with 98 fuel and they disappeared. Ken Atkinson said the timing corrections come with the N54 engine and not to be greatly alarmed by them. With outlets, I originally installed a set of RB outlets with the Super RB EVO turbos. They worked ok but were a pain to install and required either installing a LHS coolant expansion tank or modify the RHS tank. I did the later. Also, the rear pipe required strapping to the body work so as not to foul the steering shaft. Eventually, I fabricated a set of aluminium outlets which didn't foul with the steering shaft and allowed the stock RHS coolant tank to be installed.

Attachment 2534231

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I have the relocation done with the TFT intakes . The VTT nee RHD alloy units look like the go, I can't imagine the stock outlets are doing me favours.

Pretty sure I have the corrections down to either the Low pressure fuel system fluctuations from and some variance in banks STF trims on occasion. After getting the eldeors ;34deg day with E70 and I had a clean 8.2 deg timing 26psi in 4th at 6100rpm no corrections. Same day with E80 it went wobbly on one run and settled for another.

[Hoper]

Originally Posted by Coupes33

Yes Hoper, to get a good time at the drags, a LSD and some drag radials are a must. It will be interesting to see whether you lose traction even in roll racing. Normally, you gun it from around 40 kph which i would imagine you would be in second gear. I ran drag radials on mine at roll racing because of that reason. Mine will spin the rears in third on street tyres with DTC still engaged. A few years ago, I got to use E60 but I had a stage 2 LPFP and Throttle Body Injection both from Fuel-it. I achieved a 11.2s run with this combination and a set of old Classic RB turbos.

Hi Coupes, mine spins in 2nd if you jump on it while rolling along, even on good roads, maybe it would be OK at the strip if there's enough rubber down, but not sure if that happens at roll racing

I currently have the load limiting on in 1st and 2nd gear
which makes it quicker as it's not completely breaking traction anymore, but it will still activate the traction control if I haven't turned it off, the default values in MHD seemed to work out pretty good for me, so I haven't changed them since turning it on

can't remember the values that were there

[Hoper]

Originally Posted by rev210

M18 released their top mount cast single manifold. Looks super compact so RHD solution possibly. Just have to route the dump and either internal gate turbo or weld it to the turbine housing.

What's the build spec on the motor and who did you get to do it?

I put in eagle H Beam rods with ARP rod bolts, and pure performance motorsport 9.5:1 forged pistons

the whole rotating assembly is balanced, bores were honed and given a .06 clearance for the forged pistons

block and head were decked

spewing that I didn't get the head ported while I was at it

with the exception of the machining and balancing I did it all myself

So at the moment it's built to handle quite a bit more than I'm currently asking of it

[Coupes33]

Originally Posted by Hoper

I put in eagle H Beam rods with ARP rod bolts, and pure performance motorsport 9.5:1 forged pistons

the whole rotating assembly is balanced, bores were honed and given a .06 clearance for the forged pistons

block and head were decked

spewing that I didn't get the head ported while I was at it

with the exception of the machining and balancing I did it all myself

So at the moment it's built to handle quite a bit more than I'm currently asking of it

How do find the 9.5:1 compression ratio Hoper? Generally, with lower compression, the engine will make more power because the volume of air/fuel in the chamber is larger resulting in a larger explosion/more energy when ignited. However, this power is in the higher rev range (3,000+ rpm) and is normally at the expensive of low rev performance. Personally, if I built my engine I would stick with the standard compression ratio so I like good performance for normal driving and drag racing on the strip. With my 3.25 diff ratio, I very rarely go over 2,500 rpm during normal driving around town and in 6th on the highway, I am doing 1,700 rpm. Do you still get that piston
rattle you initially had after the rebuild?

[Hoper]

Originally Posted by Coupes33

How do find the 9.5:1 compression ratio Hoper? Generally, with lower compression, the engine will make more power because the volume of air/fuel in the chamber is larger resulting in a larger explosion/more energy when ignited. However, this power is in the higher rev range (3,000+ rpm) and is normally at the expensive of low rev performance. Personally, if I built my engine I would stick with the standard compression ratio so I like good performance for normal driving and drag racing on the strip. With my 3.25 diff ratio, I very rarely go over 2,500 rpm during normal driving around town and in 6th on the highway, I am doing 1,700 rpm. Do you still get that piston
rattle you initially had after the rebuild?

Hi Coupes,
yep still have the piston slap, but used to it now so I don't notice it that much

TBH I haven't noticed any real degridation in low RPM performance, I was worried about that but it hasn't materialised

Possibly due to decking the block and head, which shrinks the volume a little, I'm not smart enough to do all the maths and work out whether that's substantial in terms of compression ratio change

upshot is that it still pulls hard from low in the rev range, when I drive friends n54's with stage 2 MHD tunes they don't feel as responsive as mine so I'm happy with the results

[Coupes33]

Originally Posted by rev210

I have the relocation done with the TFT intakes . The VTT nee RHD alloy units look like the go, I can't imagine the stock outlets are doing me favours.

Pretty sure I have the corrections down to either the Low pressure fuel system fluctuations from and some variance in banks STF trims on occasion. After getting the eldeors ;34deg day with E70 and I had a clean 8.2 deg timing 26psi in 4th at 6100rpm no corrections. Same day with E80 it went wobbly on one run and settled for another.

Do the VTT alloy outlets have the same size connection as the OEM outlets or are they larger. The outlet diameter on the RB EVO compressor housing is larger than the stock turbos and require a hose fitting to connect to the outlets which makes it a bit easier in fabricating a set of aluminum outlets. The OEM outlets would certainly being hampering your turbo performance somewhat. Timing corrections appear to be intermittent on your engine for some reason.

[Coupes33]

Originally Posted by Hoper

Hi Coupes,
yep still have the piston slap, but used to it now so I don't notice it that much

TBH I haven't noticed any real degridation in low RPM performance, I was worried about that but it hasn't materialised

Possibly due to decking the block and head, which shrinks the volume a little, I'm not smart enough to do all the maths and work out whether that's substantial in terms of compression ratio change

upshot is that it still pulls hard from low in the rev range, when I drive friends n54's with stage 2 MHD tunes they don't feel as responsive as mine so I'm happy with the results

That is good that you can maintain your low down performance.

[Brule]

You need a single turbo with that built motor! I have a 6466 waiting for you.

[rev210]

Originally Posted by Coupes33

Do the VTT alloy outlets have the same size connection as the OEM outlets or are they larger. The outlet diameter on the RB EVO compressor housing is larger than the stock turbos and require a hose fitting to connect to the outlets which makes it a bit easier in fabricating a set of aluminum outlets. The OEM outlets would certainly being hampering your turbo performance somewhat. Timing corrections appear to be intermittent on your engine for some reason.

They do both styles, I have the Pures so it's the stock V-band connection. One difference they seal on the top as opposed to the stock which has a piece that intrudes ' into' the turbo outlet and that part drops the exit diameter to 1 inch as opposed to 1.5 inches. The VTT has an O-ring to seal but, apparently can be fiddly to sit on there.
Martymil apparently helped the design of the VTT units which route perfectly in a similar path to stock.

[Hoper]

Originally Posted by Brule

You need a single turbo with that built motor! I have a 6466 waiting for you.

Yeah thinking about it Brule, not sure I want a top mount though, looking at the low mount options, I like the stealth look

[JimiP]

Originally Posted by Coupes33

Good to hear your experience with the GCs JimiP. Sounds like the GC's have been performing ok apart from the rattle which I would imagine is the wastegates. 30,000kms indicates good reliability but with 20 psi boost you should be able to extend that quite a bit. Have you ever given it a run down the strip?

Hey Coupes, yeah nah I haven't run it at the strip yet.. I'm about to do a new fuel system with a 3x HPFP overdrive, -8 lines, flex fuel sensor, external filter and a radium FHST - will be pretty keep to run it once I get this all done...

[Coupes33]

Originally Posted by rev210

They do both styles, I have the Pures so it's the stock V-band connection. One difference they seal on the top as opposed to the stock which has a piece that intrudes ' into' the turbo outlet and that part drops the exit diameter to 1 inch as opposed to 1.5 inches. The VTT has an O-ring to seal but, apparently can be fiddly to sit on there.
Martymil apparently helped the design of the VTT units which route perfectly in a similar path to stock.

When I fabricated my aluminium outlets, I looked at trying to have the rear pipe run between the steering arm and engine but this required an immediate tight 90 deg turn off the compressor housing outlet which wasn't very good for flow. I would imagine the VTT outlets would be similar. Although, looking at the photos of the RHD VTT outlets that Marty put on another forum, it doesn't look too bad and would certainly be an improvement on the OEM item.