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Discussion Starter #1
hey guys new to the forum but have been doing lots of reading. I have a 87 mkiii supra with a 1jzgte. motor is completely stock, 2.5 i/c piping 3" turbo back pipe. stock ecu. has an r154, rebuild with drift motions mc kit. act 6 puck lightweight fly wheel.
I've been doing a lot of reading and from what I've seen, hearing a lot of good things about the precision 6262,also see a lot of 6765, gt35r, gt40r. I'm looking to push 500-600hp on a big turbo with little lag. I've heard of people hitting full boost at 4K. looking for all that power but still have some low end for the streets.

my question to you guys is what route have you guys taken (out of the above) and what parts do I need exactly to complete the conversion. everything from ecu, injector size, fuel pump size, turbo sizes, any work to the head, cams. in order to meet that goal.

I'm interested to get some responses for my car specifically, any and all experiences welcome, new to 1js but want to learn. thank you all
 

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Engine management and tuning, could be a tall hurdle.

Do you have e85 in your area?

Plan on only 93 octane?

Cams will help for over 500whp, may not be required but highly recommended. Even with stock twins. Nothing too crazy, even a 264 degree cam will work great, 272's are what most people are using. Springs and retainers aren't REALLY required with mild cams and the power you're looking for. Not a bad idea to decide for yourself, but 10mm lift large core Crower camshafts have been tested on the 1JZ with factory valve springs/hardware, with no negative effects, revved out to I think 8500rpm (Thanks ZaZZn). Regardless, be ready to check the gap between the shims and the lobes and follow the Toyota Service Repair Manual (TSRM as it's known) for the proper procedure/measurements. Brian Crower makes and stocks 1J cams in the US. Jun still makes them in Japan, and Kelford can grind anything you want out of New Zealand. I would not use any 2JZ cams machined for a 1J. Find some true 1JZ cams to upgrade to.

I'd recommend doing it in steps, to justify the next step.

I'd swap out to a single turbo/manifold, with at least a 3.5 inch downpipe. 3 inch will work, sure, but you may make more power with a 26% increase in exhaust volume to reach your goals easier. You can still keep boost within factory limits, and should be fine for a while, until you're ready to upgrade the rest for the power... A 6262 is great for a 1JZ, and should make the numbers you are looking for. A 6266 is what I'd recommend, to reduce back pressure and possibly help the turbo survive longer. A .84 divided housing/manifold will be a good balance between spool and flow up top.

The newer Walbro pumps are making great power, I think it's the 485? For 600rwhp max, one may do. A new fuel filter at this time is a great idea. I'd do the fuel pump swap when I do injectors/fuel rail. Single fuel rails are cheap these days for a 1J, and any name brand fuel regulator will do, just make sure to use some teflon tape to seal up any adjustment screws that may leak air. Factory feed is like, a -5 AN size or so ;) and will work fine for your power, and a room for more.

Good standalone or piggyback. ECU Master, AEM, MegaSquirt, etc... The list goes on and on for standalones, it depends on your budget, and if you're needing "on the fly" flex fuel abilities, consider the standalone that can handle the duties.

Dyno time scheduled with a good tuner, is probably the best mod you can do on any engine. It should be the final step to look forward to. It would benefit you to use the standalone your tuner is very familiar with, but that is just getting the most out of your money.


Side notes:

If you are on factory coils, I'd recommend you either swap them out with some 1ZZ coils or, get new OEM JZ coils if yours are really old and a HKS DLI ignition amplifier. Making good torque and power, you can expect a plug gap of .22-.25 or so, depending on what your engine likes, when you get to making max power.

4644 NGK plugs, copper and a 7 in heat range, are going to be a great plug. Iridiums in a 7 heat range will last longer, and if you do decide on 800rwhp+, I'd go to a 8 (colder) plug.

Wish you the best of luck!
 

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There's just not too many readily available options for 1J cams.

I waited three months for cores from Kelford, and they cost more. Now they have cores, no more long waiting.

I was going to try out Jun cams, but RHD Japan shipped me a 2J cam on my last purchase.

BC cams are cheapest.
 

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Discussion Starter #5
thanks for all that info! lot to take in.
I'm looking to run on pump gas preferably
parts I've been thinking about starting with. I've heard good things about the AEM standalone, not trying to run piggyback. but I'll need that and an a/f before I can even go any further. then I'll probably build my head a little. I don't mind spending extra on cams or springs and retainers because I want it to be strong and reliable. so I'll probably do cams. maybe head studs. then the snail! still undecided on what I want to run. lookin to hear from people who have ran/drove with one of the above turbos on a 1j. what's the biggest turbo I can spoil and still have no lag?
what turbos have you used what rpm you hit full boost? how much lag? dyno numbers
thank you everyone
 

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Stock JZ head bolts are actually fine for 600+rwhp, and much more.

My old 74mm turbo got full spool around 6000 RPM (635rwhp pump and methanol/water)

My 6466 was getting 27 PSI around 4,800 RPMish. Decided to just do a full rebuild, and am in that process.
 

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Discussion Starter #7
yeh 6 is wayy to high for me I'm looking to hit full boost at like 4-4500. 5 latest. need more opinions. ik people run the turbos I've listed
 

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Running a Comp 6265 (.70 divided) ball bearing here. No boost control helping at the moment, simply running off the wastegate, and it will start spooling around 3k, comes on good about 3500, pretty much anything over 4k and it's instantly pulling hard. Then again, I'm at 6500' elevation here, and extensively modified, you know the old saying, YMMV.

Things I would recommend, without going too crazy:
-Cams
-Porting
-Valve springs, retainers, shimless bucket conversion (let that 1j do it's thing, which is REV)
-Engine management, I'm working with MS3-Pro, and so far, loving it
-Gearing might be a consideration. The stock 1j cars had a 4.10 ratio for a reason... daily drove one with a 3.73, it was a dog after 2nd, but this was only with 320-350whp, for comparison.

Otherwise, 220 has a very nice list of things for you to look into. I would also recommend re-thinking the "big" turbo idea if you are after response. I did about all you can do (short of perhaps titanium rods) to lighten my engine and make it responsive, but it's still a little more lag than I like. Depends on the tracks you intend to drive though... short tight tracks, small turbo setups will easily outrun the big laggy turbos, and vice versa on more open and high speed tracks.
 
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