Since starting life as a NA 5 speed SZ-R, this MKIV Supra has had all manner of different engines, gearboxes, diffs, turbochargers, fuel systems and electronics configurations over the 10+ years I've owned it. As I intend to continue with this tradition, welcome to the build diary of the latest iteration of work.
This car has and continues to serve as my R&D platform, so I push my own abilities, continue learning and stay on top of the latest and greatest products out there and filter that out to customers if a good combination is found.
The last iteration of the build had me running a rather tasty 900hp 1.5JZ VVTi setup on a 5 speed dog box. For a bit of an oddball build, it performed well, earning the title of fastest 100-200KPH (4.1s) street driven Supra in the UK (at the time). I had been running various 1.5JZ engines for a little while previous to that to gather some data on that engine combination, as there wasn't a huge amount of information online about what the limits of the setup were.
I found that the 1JZ VVTi head with small exhaust ports meant that the exhaust flow at higher RPM was severely restricted, even though the midrange torque was pretty crazy. Rather than porting out the 1JZ head and continuing down that avenue, I swapped back to a 2JZGE VVTi head as it has both good intake and exhaust ports for flow from factory, and I was in the mood to get back to an engine that had the potential to rev above 8'000rpm with minimal work.
So even though there wasn't anything wrong with the car, it was now time to pull it to pieces and get it ready for the next round of modifications. It's going to get fairly hardcore, the days of being a somewhat pleasurable street supra will be few now I think.
On top of my plans for the hardware being used in the car, the only rules I have set to myself to keep the budget vaguely in check is:
Build Rules
- Chassis must remain completely factory, no cutting/modifying anything unless it's related to roll cage fabrication or fitment of brackets etc.
- Safety must be improved to allow for legal use of cage at UK motorsport events, as specified by the UK blue book.
- The main focus of the build once completed is to be able to do well at straight line events, then adjust/change a few components to have it ready to go round circuits.
- All changes must conform to UK road laws, so it can legally pass through an MOT and be road legal.
Here is how the car sat a few months ago after some time sitting idle. Other than potentially some wider front wings to give better clearance around front wheels, I'm content with the look of the car, so I don't think I'll make any major changes to the exterior. Main focus will be on the interior, safety systems, electronics, powertrain and drivetrain.
Some interior photos to record what it looked like before the coming transformations. The focus with this setup was to keep it fairly civil inside, but with a few added extras like the Rollbar, bucket seats and harnesses to help with safety as the car never came with airbags!
Haven't run a radio or speaker system in a few years, and will continue that way. I enjoyed the touchscreen toucan as I could make changes on the fly, but as I'm a shortie with proportionally longer legs, it was always slightly uncomfortable to make changes to the toucan whilst strapped in with the harnesses as it was just out of natural reach for my little arms :3 So the toucan is now sold and will be replaced with a CAN based steering wheel button system.
Moving forward, I decided to ditch basically all the interior, other than the dash, so an intricate cage could be installed. A rendering of the design of the cage done by JP Cages.
Really nice cage, but interior will have to be sacrificed for the pleasure. Between this cage, a seat upgrade, 6 point harnesses, Hans Device & other safety equipment I will have some confidence for the future usage of the car (more details in future!)
So a few months ago I took her back into the workshop, assumed my fighting stance and got to work on removing the engine and gearbox.
Goodbye 1.5JZ!
Engine on the stand looking a bit more naked
Luckily have a friend in Finland with a cool Chaser who wanted to go a bit mental on a build, and we struck a deal for him to buy my built head, turbo & intake setup so he could transplant onto his. Leaving me with my old shortblock to put towards a new setup that I can use for some testing.
My weapon of choice this time round was a 2JZGE VVTi head. Sometime last year I purchased a number of 2JZGE engines whilst they were still somewhat cheap, so I could use towards this build and have a surplus of spare parts that I can use for development or replacement on this new setup. Here we have my new GE head and old 1J head heading off to the machinist. 1J for a quick skim, check over & clean. 2J head going off to get skimmed, cleaned and have head machined for Kelford 202D VVTi cams & valves set.
I'll go into the details of the engine & associated parts in future posts, but the initial engine setup will be somewhat "basic". We have had some fantastic results using relatively basic setups on the 2JZGE VVTi head as it flows so damn well in stock form. So in the name of science I will start with a setup similar to this and push it as hard as I can to gain a baseline of data in terms of performance. From there I'll advance the development of the head and short block and record changes relative to the baseline at each stage.
With the world getting turned on it's head over the last few year years, the supply chain for parts in the after market has taken quite a bit hit and delivery time for parts are sometimes painful. I had hoped to get most of my parts in by August 2022, and whilst I have a nice stash of new parts to go, I have been waiting over 6 months for some, likely to need to wait until the new year for delivery. So the project has been delayed considerable, which has allowed for some significant project creep to set in.
But as we all like photos and shiney parts, here is one of newest parts that I can't wait to test.
Garrett G40-1150 is garrett's newest offering to replace the GTX4088, and going off compressor/turbine sizings put it in competing range of a precision 6870-7275. Although the turbo is offered in a vband housing, I opted for a T4 housing just in case the turbo is a bit of a flop and I want to change to something else that uses T4, otherwise my new exhaust manifold would be locked into a garrett vband which only runs a few garrett turbo's. I opted for a 1.06 A/R housing and bought the larger 1.19 housing to do some back to back testing to see what would suit my new high revving 2J head better.
Sending off my 1JZ parts to my friend in Finland, which also happens to be the home of PGS transmissions who built my R154 dog engagement box. On a rather vigorous night of testing I managed to damage the dogteeth on my 4th gear dogring with a horrible shift my side, so box will be returning to PGS. PGS have also kindly offered to beef up my input shaft and a few gears with an uprated design after I told them the kind of power and abuse I plan to give this thing. I am enjoying how ridiculous it is to run an R154 based gearbox at these levels, and will keep going till I split this box in half or similar catastrophic failure, then maybe I'll re-evaluate.
So fast-forward to today, my wiring room at SRD is nearly overflowing with parts ready for the new setup, but until it's all ready to go in I need to prepare the car to get its cage installed.
The strip down has begun. Have a few more days to remove all the sound deadening, remove the glass and prepare the engine bay.
Till next time
Michael Yazgic @ 0x33