Hi everyone! I am getting ready to pull the engine out of my 91 in order to fix the head gasket and reseal the engine. While it's out, I figured now would be an excellent time to upgrade some things to prepare for bigger horsepower in the future. I already have a turbo back 3" exhaust. Note that I'm not interested in anything external at the moment, since the stuff I'm already doing is maxing out my budget. I can add things like a bigger turbo later on. Below is the list of things I'm already planning on doing, is there anything else I should be doing while I have the engine out anyway?
- All new seals.
- New oil pump & oil squirters.
- Resurface Head & Block.
- MLS Head Gasket (Recommendations)?
- ARP Head Studs.
- Bosch 550 injectors.
- Tweak'd Wiring Harness.
- ECUMaster Black.
- New Clutch (Recommendations)?
- Resurfaced Flywheel.
- 12V Fuel Pump Mod.
- 460 / Denso TT Fuel Pump.
- New Starter (since they're a pain to replace).
- AFPR (Recommendations)?
- Driftmotion Digital CPS V2 Upgrade
I am so fucking pumped to see so many 7M-GTE rebuild/restoration threads! :beer:
When replacing the oil pump, read up on shimming the relief valve a bit and also read up on bending the oil pickup to be closer to the bottom of the pan. Inspect the oil pump drive gear because I've seen them crack and fail - typically on the 'spokes' of the gear.
Personally I have found the oil squirters to be of dubious value for most street builds - you're stealing oil from bearings to dump piston heat into them, and this is a benefit from an OE perspective because they need to ensure the engine has a chance to survive when trophy wife Debra fills that car with 86 and merges onto a freeway in 100*F weather.
If you're building a car that'll see extensive road race track days/long ass highway pulls etc, and you're running a good, ducted oil cooler setup and monitor oil temps, there's a good argument to keep them.
What Elibutton said was also 100% on-the-money about removing the factory oil relief valve and the partial-flow oil cooler setup - remove that whole oil filter housing from the side of the block and go to a 7M-GE style union bolt and a full-flow oil cooler on a thermostatic sandwich plate. That is a really good idea even if you're basically doing a stock build.
The ye olde HKS 1.2mm bead works great, there's also a Cometic 0.51" (about 1.2mm) with an 84mm bore that works a bit better with a stock bore vs the HKS's 86mm bore. The Cometics had an issue with rivets that hold the MLS layers together being in places that interfered with block/head sealing, so be mindful of rivet placement if you're going with the cometic and trim/drill out rivets as needed.
Personally I'd just go with the HKS HG and call it a day - it'll hold anything you can do on the stock pistons and then some.
Injectors - 550's are pointless with a stock CT26 turbo and the only benefit to old school EV1 style Bosch 550's is how they play well with the stock ECU and OG piggybacks. Since you're going to a ECUmaster which as far as I know only supports high imp injectors and requires a resistor pack to run low imp, I'd just get a set of modern EV14 pattern injectors of the appropriate size for your fuel and power level desired when the time comes - yes they are that much better. Get a set of EV14 pattern 725cc or 1000cc or similar for a non-vvti 2JZ-GE as that'll have the same injector length and 11mm feed used by the 7M-GTE, and it's a lot easier to find listings and options for the 2JZ-GE these days. You'll only use a fart's worth of their available duty cycle on the stock CT26 turbo but at least your base tuning will be that much closer to what you need when it's time to turn things up. This saves tuning time and also permits you to make tuning changes for drive-ability and environmental changes that'll carry over to your bigger turbo setup etc.
With the Walbro 460 pump, make sure you run an AFPR (the Aeromotive recommendation is proven, I've also had good luck with Fuellab regulators too) and run a larger return line that eliminates the 'j tube'. The J-tube has a engineered restriction in case of FPR failure and you'll have crazy high fuel pressures at idle and low load with a Walbro 460 if that's not eliminated. Driftmotion sells a very nice AFPR install kit that basically does all the hard work there for you.
If you opt for the TT Supra pump instead, I would leave the 10/12v switching in place. Walbros tend to make a lot of noise when fed less than 12v but that is not the case with the Denso pumps. I have never seen a 12v mod fix anything or improve anything unless it was bypassing a faulty fuel pump ECU, or someone installed a 255 and wanted to reduce the 'Walbro whine' from the 10v operation. There is no other major benefit performance-wise or otherwise. The TT Supra pumps are silent compared to the Walbros and will completely support ~450-500whp on pump gas as a single pump.
New clutch - do NOT get anything with an unsprung hub. Personally I have run ACT pressure plates with stock clutch discs to ~400-450wtq on several different setups and while the pedal pressure is a bit higher the engagement & slip-ability is very nice and easy to drive, especially with the stock flywheel. As an interim that matches your stock turbo, there's no need for anything more. Use new flywheel bolts!
With the V2 CPS, and the ECU master, consider ditching the stock 7M-GTE coils and going to IS300 coils instead and having your wiring harness made to suit those. They are hotter and support significantly more HP than most tired old 7M-GTE coils do. Doing this now will ensure reduced growing pains in the future when you build an engine and go for bigger HP, much like going for better injectors now instead of wasting tuning time with older, smaller injectors that will not support your end goals.
Speaking of which - what's your intended HP goal? If it's ~400whp or less I would honestly skip the standalone entirely.
Keep us posted on your progress! :beer: