Twin-Scroll GTS-t

June 3, 2016

I attended the recent Japanese Cars Meeting 2016, which has now turned into the premier JDM meeting in Italy, and I was incredibly impressed how popular and contemporary the Italian JDM scene is considering the majority of the country is more interested in European and domestic cars. Over 700 cars dropped by over the meeting with Honda being the most popular by far; there were plenty of tuned SR20s, 13Bs, B16/18s and K20s and even a few lightly tuned RB26s which are going to be very similar to most other builds, but this particular car stood out thanks to its exquisite turbo choice.

Its not a hugely powerful setup, developing just over 400hp, but the top mounted twin-scroll Borg Warner turbo must provide incredible torque and superb response. The top feed injectors were also a not so commonly seen change, where the owner decided to run Evo 560cc injectors, who happens to be Federico Sceriffo’s builder.

Would have loved to hear and experience it.

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Twin external wastegate F20C. Look at the size of the turbo in comparison to the engine.

GD V2 – Part 22

May 15, 2016

The final preparations are being carried out on the car before I can give it a test drive, so in the meantime I thought I would highlight all the engine specs and parts for those interested (parts not mentioned are OE, and I’m sure I’ve missed things):

Bottom-End:
ACL Race crank bearings
ACL Race big-end bearings
Apex Performance conrods
Wossner 86.5mm 8:1 pistons

Top-End:
Tomei 256 Poncams intake and exhaust
Custom rocker shims
Cometic 1.1mm head gasket
Apex Performance rocker arm stoppers

Intake:
Front mount intercooler with custom piping
Apexi Power Intake filter

Exhaust:
Garrett GT2871R turbo 0.64AR
XS Power tubular manifold
Japspeed downpipe
3.5″ catback with decat

Fuel:
Walbro 255 fuel pump
Nismo 740cc (JECS) injectors
AEM fuel pressure regulator

Cooling/Fluids:
Billet oil sandwich plate
Thermostatic oil filter relocation block
Mocal oil cooler
Driftworks Supercool alu radiator

Ancillaries:
Apex Performance alu pulley kit
ACT Performance clutch kit
AH Fabrications oil catch tank
Apex Performance short shifter

After the mapping session I also checked the valve clearances again as everything has bedded in a bit and should have settled. Unfortunately the clearances are a bit higher than I would like which explains the elevated valvetrain noise, and will no doubt cause accelerated wear on the cams. Valvetrain is something that I have limited experience with and have a lot to learn; I assumed that the clearances would close up a bit after the valves have set in their seats but instead the clearances opened up a bit which means other parts have settled.

Also, I had to change the fuel pressure regulator to an AEM unit, as the “Aeromotive” unit started leaking. It was probably some Chinese knock-off unit, despite it not being that cheap. The good thing is that AEM unit is much smaller and nicer.

GD V2 – Part 16

April 4, 2016

Tomei 256 Poncams arrived so I was able to finish off the internals. I still need to do the valve clearances, which I am currently sorting out now, but I’ll cover that in a more detailed post due to the issues I faced.

Finished off the bottom end with the various baffles and sumps. If I drop anything now its going to be more tricky to get out!

XS Power tubular manifold and a new Garrett GT2871R turbo, all plumbed with braided turbo lines. The lines were actually one of the first things I changed on the car after the original hard lines broke. I think they’re plumbed correctly but people run then in either direction, which I don’t think it matters.

The vacuum line from the valve cover is pretty much touching the manifold, which I am going to have to sort out somehow.

Intake manifold and water lines also went in. As I’m running the oil filter sandwich plate I no longer have the oil to water heat exchanger, so I’ve had to reroute lines around to omit it.

Once the shims are made and back in I’ll be taking the engine off the stand and start to put the clutch and transmission back on and hopefully the engine will be back in soon!

GD V2 – PART 11

February 20, 2016

The engine has been at the machine shop for the past 2 weeks getting a bit of work done, but I’ve now picked it all up and I am officially putting things back together now. The shop that completed the work is Officina Rettifica Motori Renato Di Pesenti Renzo in Bergamo, just a few minutes from my house.

The block has been cleaned and skimmed, and the cylinders have been bored out to 86.5mm after they were found to be just out of roundness. I will be running oversize pistons.
The head has also been cleaned and skimmed, and additionally the valve seals have been redone together with the exhaust side stem guides.

I’ve given the block a final clean and I’ve started putting a few of the auxiliary parts back on it. The crank and big end-bearings are on their way so I won’t be able to build the bottom end until then. In the meantime I will taking the head and head parts to work to reassemble it all.

GD V2 – Part 8

January 17, 2016

The engine is now pretty much all apart, with the bottom end completely disassembled. I was finally able to get a superficial look at the condition of the components on the bottom end. So far all the bearings, both crank and big end look in amazing shape; it almost seems a shame that I am going to replace them all. The cylinder bores also looked in great shape, with all the honing marks from production still visible in all the cylinders.

From an initial look I don’t think I will be going for oversize pistons, and save myself the additional work of boring the cylinders; but I will need to measure them for ovality before I make a final decision.
The next steps on the engine now are to remove the final pieces from the crankcase and then get it sent for cleaning, then I also need to finish disassembling the head, which can then also be sent for cleaning. In the meantime I will need to go through the process of measuring the crank to check wear. Once everything is measured I can begin ordering the bottom end parts.

Spent the weekend taking the interior out and finishing a few items, as I’m currently waiting on quite a few parts that’ll allow me to drop the car and run it. The car needs to be running next week to ensure I can give it a good shakedown and get the tracking done.

With the empty boot you can see the relocated battery. I’m also retaining the oldschool 6 disc CD changer as I’ll be ripping my antenna out after it got stuck up. Gotta burn some sweet CDs with motivational music for on the way to the track.

I also finished fixing the turbo and it’s now ready to go back in. Managed to drill out the 2 bolts that snapped at Monza, including the bolt extractor that I snapped inside. Had to get some Carbide ball nose end mill bits to plough through the extractor. Was then able to drill and rethread the holes to the same thread.

I installed new longer studs at the rear as I’ll be running spacers now. Had to drill them to 14mm as the studs are Evo extended units which have a 14.4mm spline. Having access to a press made it a breeze.