Case Studies : Clocking a Turbo

After my diagnosis on the CT26 turbocharger, I’ve determined that the best path would be to service and sell the turbo, rather than put it on the 2JZ as a starter kit.

To do this and get the maximum return however, I’ve decided to just sell as a replacement MKIII Supra turbo. Problem is, the CT26 I have now is not clocked correctly for a 7MGTE motor, and the compressor housing just isn’t the correct outlet or shape.

While this CT26 is being sold, this method can be used to rotate any turbo or service any center cartridge when the need arises. While the need may not arise, there may come a time when a new intercooler, different feed and return lines or other details may dictate a new turbo orientation.

First we must remove the old compressor housing, install the new one and clock the center cartridge so that the oil lines match up and charge piping mates to the turbo.

Using a needle nose and a small flathead, you must first loosen the tension in the circlip holding the compressor housing to the CHRA.

Now, undoing the compressor housing will give you a full view of the compressor wheel, make sure to not damage the outer ring when installing the replacement compressor housing.

Now last but not least, you must rotate and loosen the bolts / circlip holding the exhaust housing to the hot side of the turbo. Installing the new compressor housing and moving the internal wastegate mounts and arm over are the final steps.

Make sure to line up and adjust the wastegate actuator, so that there is no excess slack or tension in the rod before installing into your car.

Happy boosting!

Project SC : Setting the Stance with Megan LP Coilovers

Welp, it’s about that time to get off my lazy behind and finally get some work done to the SC. While the car was lowered by the previous owner, the KYB shocks weren’t up to the kind of punishment that only Bay Area highways can provide.

Where else to go for a good coilover set that won’t break the bank? After much deliberation, I went with the LP series Megan Racing coilovers for the MKIV Supra.

These Megan LP coilovers provide a 32 levels of damper force adjustment and separate spring perch height and shock length adjustments. Without camber plates however, it essentially ensures I cannot lower the car TOO low as the SC300’s stock camber adjustments do not allow for anything greater than -3 degreees.

First we begin by removing the rear trunk area and deck lid, allowing us access to the rear shocks and the gas tank.

Now undo the 3 14mm nuts holding the top perch of your coilover in place. With these nuts removed, you can now go under the car and remove the 19mm bolt that goes around the lower control arm.

After removing that 19mm bolt, you can now pull out the old setup and put in the new Megan Coilovers.

Depending on how low you decide to set your SC, you may or may not have an issue with the rear sway bar linkage not fitting.

To remedy this issue, we’ve gone ahead and installed some BLOX adjustible end links to tie things together.

After lowering the car, the LP’s put me as low as I need to go ( maybe a tad TOO low to be honest ). With the car’s stance figured out, we move on to POWER!

Next up, swapping in the Aristo 2JZGTE and WIRING it up… yay?

Happy boosting!

Project SRT-4 : Back on the road and tuning with the AFC

Project SRT-4 has been on a long hiatus, and after popping the headgasket late in 2008, we’ve finally gotten back around to getting this monster back on the street. Since it’s been a few weeks since our last update, let’s run through a quick recap.

Staying with the stock bottom end, we’ve chosen to run a Cometic head gasket for the SRT-4 along with ARP head studs to keep the 2 halves together.

Head is assembled, cams and cam caps torqued and assembly lube generously applied. Next, we torque down the head, following the SRT-4 tightening sequence.

Now onto the real challenge, installing and fabricating the downpipe, chargepipe and turbo kit on the back of this motor. What you are looking at is a 50mm Tial wastegate, DNP Turbo manifold and the back of the motor.

Project SRT cracked 350 whp on my Dynojet448x using a slightly upgraded stock turbo and stock fuel. Since then, we’ve stepped up to a 62-1 Garrett T3/T4 turbocharger in hopes of chasing down 440 whp on 91 octane.

Unfortunately, that also means ditching the stock manifold, turbo and downpipe, and if you’ve ever seen the SRT-4 Engine bay, you know how much of a bitch this is going to be.

After quite a bit of cursing and yelling, we’ve mounted and installed the turbo, manifold and wastegate, but our problem is still the dumptube.

Here’s a shot of under the car, looking at the back of the motor between the firewall and subframe. If you see the 2 power steering lines going into the rack there, that is about the only space we have to route a dumptube.

Time to get lucky.

Using a Vibrant V-band flange, we weld a 1.75 inch J pipe and completely hack up the bend to get the radius as tight as humanly possible.

After a lot of cutting and hacking, we’ve got a pipe that allows us to bolt it to the wastegate egress, but the bend is not tight enough to clear the power steering lines or alternator properly. Further, the opening is not large enough for us to cut and reweld, and instead of removing parts again, we’ve opted to heat up the pipe and bend as need be.

Unfortunately, we forget that the dump tube is 304 stainless.

It look a whole lot of heating and bending, but we finally got the screamer pipe to bolt on and clear all the lines properly.

A look at the finished product, note the clearance on the power steering lines as well as the clearance to the charge pipe coming off the turbo.

Now with that out of the way, we go to tune the SRT-4, only to find that the AFC NEO has a blank screen and refuses to turn on. This is a fairly common issue for these piggybacks as people love to yank and pull on the wiring loom, pulling the daughter board out of the AFC PCM.

To fix this issue, simply remove the hex bolts on the back of the AFC NEO and gently pull apart.

After plugging the harnesses back into the daughterboard, we snap the NEO back together and reinstall the hex bolts.

Your NEO may or may not go into DEMO mode, a mode in which the screen flashes and is not responsive to any button inputs. To solve this issue, turn the car off and then turn it back on while holding the UP button on your NEO.

This will force it into a diagnostic mode, where you must select to “reset” the NEO to gain control of it again.

After all the little BS issues are taken care of, we dial in the boost at a very low 10 psi and hit the streets with a datalogger to get some rough tuning out of the way.

Next up?

Dyno time for the SRT-4 as we chase 400hp on 91 octane.

Happy boosting!