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what turbo parts needed: 94 sc300 with 8.5:1 comp block

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Old 07-01-13, 02:43 PM   #1
JenovaI
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Question what turbo parts needed: 94 sc300 with 8.5:1 comp block

Hi Guys,

I'm in the process of building a NA-t sc300. The intention of this car is to be budget. I'm also in southern CA so making this as easy as possible to get back to "passes sniffer test" for smog is a bonus just in case. This is what i have so far:

-- mostly stock 94 sc300 auto, only mods are 3" exhaust and good 18" wheels/tires
--full w58 swap from a sc300 5 speed. and i mean everything. tranny,full driveshaft, all pedals, all cylinders, hard line, throwout, clutch, flywheel, m/t ecu, m/t cluster.
--newly rebuilt 2jz-gte block, ge head, gte headgasket, stock cams. some peices are upgraded but for all intents and purposes it's a 8.5:1 comp ratio gte block with ge head.
--plan on buying a meth injection kit since 91 octane is crap. So please factor that in on your advice.


My question is this, what's the bare minimum turbo parts I need to boost this setup between 300-400 whp? I've read a lot on this forum and from what I gathered a good turbo kit is:

--fairly small turbo, the ones i have cheap access to are gt35 and turbonetics 7868 benita
--Manifold
--BOV
--Wastegate that can be adjusted on the fly with boost controller without spring changes
--FMIC + piping. ill probably go DIY universal kit
--Downpipe
--Dumptube
--vband clamp + flange (wtf is this anyway? I'm not a turbo guy yet until after this project)
--Oil feed and return lines
--boost controller
--some sort of piggy back. Emanage blue is the only one I've seen explained.
--Fuel pressure regulator or other fuel system upgrade
--spark plugs and upgrade distributor
--bigger injectors
--pro tuning on dyno

My question short and sweet is, with my set up and low power goals what do I actually need from the above?

I'm already on 8.5:1 comp ratio, and will have meth boosting my octane level so I'm assuming higher than 10psi boost is safe. Do i really need a piggyback, tuning, injectors, all that? OR can i just get turbo,manifold, bov,wastegate,fmic, oil lines and exhaust connections and be done with it?

I really appreciate your help.
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Old 07-01-13, 03:08 PM   #2
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the ge head will actually increase your compression ratio a little bit from 8.5:1 but not a whole lot.
you don't need meth you should be able to run at least 18 psi on that block/head/gasket combo on pump gas.

all of those things seem fine except for the piggyback, na-t you cannot skimp on engine management.
the easiest way to get a good running setup is the tt ecu mod, you can do a search in the main SC forum its in there, that will give you a setup that can handle boost and run well and you get to go coilpacks and put in some larger injectors, get it all done at once basically, and runs reliable enough for a daily driver.
http://www.clublexus.com/forums/sc-4...t-ecu-mod.html

you could also go standalone but thats alot more expensive and for those power goals you will not have as much of a need for it and takes alot of tuning to get everything just right. not the most suited for daily driving but many have done it.

A v-band clamp is what connects your turbo to your downpipe, or any 2 things with the same size v-band flange.
stock fuel pressure regulator is fine, what you will want to do is get a better pump like a walboro or TT denso.
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Old 07-01-13, 05:48 PM   #3
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Thanks for the info. Are there any other opinions? I've read several NA-T 101 and NA-t bible threads and none of them mentioned needing any engine management until larger HP numbers.. I didnt really budget in $500 in ecu mods and injectors and coils for that modification. I read that stock injectors should be good up to 350-400hp. I'd really prefer to keep my stock ECU and especially not rewire any plugs that i would have to change back later if necessary.

What's the minimum i can get away with was my main question. I listed so much stuff and i shouldnt need all of it since that was a part list for a 600hp+ build...
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Old 07-02-13, 09:30 AM   #4
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Sure, you can realistically hit 300-350 with the stock ecu but its not even fun or enjoyable when the ecu is constantly fighting the boost. The stock injectors are 330cc, you will not be doing anything over 330 safely.

It is very unpredicatble most of the time, tends to stall out after boosting, and if you ever build partial boost on partial throttle (happens all the time), the ecu tends to either swing full rich or full lean and then will idle funny. All you can hope is that it figures itself out by the time you plant the pedal down and doesn't have any ridiculous trims or timing pulled at that point. all of these swings keep happening unless you get a super piggyback like the FIC and intercept every signal, and then it runs ok but still not great for investing that much money (when you could have had the tt ecu mod for the same price).

you said you didn't factor in $500 for the ecu+coils, but I see the piggyback emanage blue on your list which is like $3-400, and your car still won't drive all that well with an emanage which only works decent on the jdm 2jzge ecu's.
If you run the tt ecu with 440cc injectors, you won't need a piggyback at all, so take that $3-400 save up another 200 and then you will have something that works really well.

my advice is to keep your car stock if you cannot afford the proper ecu for a turbo car, many are stubborn and insist on trying to use the stock ecu from what they read on the old turbo forums (I read those same threads and tried using that overly regurgitated information that is mostly bad advice). Well I have personally tried alot of the piggybacks with the stock ecu, and I wanted to rip my hair out and put my car back to stock it drove so badly if it was not idling dangerously lean, it would misfire, sometimes backfire on partial boost, and stall pretty much everytime the BOV goes off, but its your build you can decide how much driving experience matters to you.

I would consider getting a swap almost which will come with the motor, turbo's and ecu, but you will have to work on the harness or pay extra for that. twins would be better in your power range anyways than a single turbo.

Believe it or not, the 2jzge is built so well you don't have to do much anything for 350hp. you don't need a built block, you don't need half of the things that are on your list. The one thing you do need is a proper turbo ecu or standalone.
It is the single most important thing on a na-t, and is also the most overlooked.
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Old 07-02-13, 09:54 AM   #5
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Ok i guess i will have to go with the aristo TT ecu mod.

What are the other minimum components I need? Or do i need everything in my list. If the gt35 will work for me I guess i can just ebay kit it for 1000 or less like this package:



Do you see anything i would need besides that kit, aristo tt ecu mod parts, and dump/down pipes to connect flange to my exhaust? probably need upgraded fuel pump at least right?
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Old 07-02-13, 12:25 PM   #6
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Also what do you know about the usdm supra tt ecu mod specifics.. i have access to that ecu but the writup doesnt say if i can use my stock sc300 maf or anything specific. I wish people would write up exact details for each version after 60 pages.
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Old 07-02-13, 12:50 PM   #7
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you don't have to go with the mod, but its the most inexpensive way to have a reliable na-t and you get coilpacks and a setup that on par with the gte. you could go standalone or even run the stock ecu it won't bother me at all.

your question was short and sweet of what you need, and the most important thing on there you have left to "some sort of piggyback", which is a red flag. I have been there, done that, listened to the bad advice, tried to make it work, lost alot of time, lost alot of patience, and almost parted out my entire turbo kit after installing it.
everyone has a different definition of what works, for some as long as it starts and boost they could care less about whats happening in between, but I can tell you whats happening inbetween is not good for your engine, or for making power.

I know everything about the tt ecu mod seeing as I wrote it. USDM ecu will need a TT MAF, if you could use a sc300 maf I would have put it on post 4 where the info is for the USDM ecu that says you need a TT maf.

the 92-95 sc300 maf is completely the wrong kind of air flow meter, it is a karman vortex like the 7mgte and completely incompatible with the 2jzgte ecu which uses a hotwire maf.

the 96+ maf's from the sc300 are the right type of hotwire maf, but are smaller in diameter than the TT maf which is 3", this will affect your tune. putting a 3" maf in front of your turbo that can take a 4" intake pipe is bad enough, let alone trying to stick a 2.5" maf in front of it and then using something to correct your fuel ratios.
some people have removed the 2jzge vvti maf from the housing and fashioned a new 3" or 4" pipe for it, but that's another level of mods I wouldn't mess with at first unless you have a vvti maf, and the 4" pipe will affect the tune as well.

the usdm ecu is generally more expensive and will be harder to set up initially and uses a maf + map = more wiring. for your power goals the thing that makes the most sense is a JDM ecu with a simple map sensor and 440cc inejctors, takes me a day to install (your results will probably vary) and you will be fine for 400hp and it will drive factory smooth.

here is what you need for your list
-fairly small turbo, the ones i have cheap access to are gt35 and turbonetics 7868 benita
--Manifold
--BOV
--Wastegate + boost controller
--FMIC + piping.
--Downpipe
--Dumptube
--vband clamp
--Oil feed and return line + Is300 union bolt for oil feed
--high flow fuel fuel pump recommended over 350hp
--spark plugs (BKR6eIX under 1 bar of boost or BKR7EIX over 1 bar)
--bigger injectors (440 for jdm ecu, 550s can be run also, or even 660's with piggyback.

things you won't really need
--some sort of piggy back if you get the right size injectors for the tt ecu
--Fuel pressure regulator
--upgrade distributor
--pro tuning on dyno (this alone can cost as much as the whole tt ecu mod)
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Old 07-03-13, 12:16 PM   #8
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What's your recommended fuel pump? Walboro 255 seems to be everyone's advice but is it GSS342 or GSS341.. They all say high pressure and i thought i wanted low pressure high flow?
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Old 07-03-13, 12:26 PM   #9
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the walboro will get the job done but can be noisy if your gas level is low especially, the better pump is the TT denso but its much pricier.
the one that ends in 1 is the universal and the one that ends in 2 is the one for a ford.
they are both 255LPH not sure on what kind of connections the ford one has though.
you want high pressure, low pressure pump would be for a carburetor.
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Old 07-03-13, 04:48 PM   #10
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for your tt ecu mod, i searched the thread but did not find this answer: does it matter if my aristo tranny is auto or manual if i have a w58 manual sc300?

Sorry i keep asking you questions, if you have chat or something that makes it easier to answer stupid little questions let me know.
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Old 07-03-13, 11:55 PM   #11
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Also, will a mines aristo tuned ecu work or be even better if i get a good deal on one?
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Old 07-04-13, 02:50 AM   #12
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You can run an aristo auto with a manual transmission but you can't run a manual tranny with an auto ecu.
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