97-SC300

iTrader: (17)

just had a quick question, i tried to search but came up with nothing. im in the process of swapping a JDM Aristo engine into my SC300, wanted to know if i switch to the USDM twins and DP, and USDM cams, would i be able to retain the JDM ecu and 440cc injectors with out any problems? any help would be greatly appriciated.

pourSc

I am not a 100% sure on this, but I do know that the USDM turbos flow better than the jdm's and the cams are larger. You will be able retain the JDM ecu and injectors. But, I think that you will have a fuel issue due to the smaller injectors.

stockhatch

iTrader: (12)

Provided that you run at or near stock boost levels, you will be fine with the USDM turbos. Don't try to run 18-20 psi on them and you should be fine. I am running GT28 twins at 11psi with stock JDM fuel and have no issues.

soarer93

Im not an expert, by any means but:
JDM:
440cc injectors, high impedance
map based, no afm
no egr
ceramic turbos (spool faster)
smaller cams

USDM:
550cc injectors, low impedance, requires resistor pack
afm/maf + map
larger turbos
bigger cams
steel turbos, (spool a bit less quickly)
egr

Also jdm ecus tend to have more aggressive timing maps for high octane vs US??

So maybe.. you can get away with using usdm turbos.. but only if you keep things at what stock ceramics would be.. otherwise.. You need a new ecu and to change everything out because Different Cams require a change in the ecu tuning.

so why bother?

but maybe an expert can chime in .. im pretty sure changing Anything with your cams requires you to make changes to your ecu mapping to run properly.

Justin727

I wouldn't. I would get the rest of the USDM stuff to go with it. In theory you should be able to but do you have anything to watch your afrs? I would suggest getting the USDM injectors and ecu if you could

Vwpride12

I agree, as long as your air fuel is good you should be fine. It probably just wouldn't be at it's full potential.

Justin727

It won't be at it's full potential. JDM 2j is rated @ 280hp and the USDM 2j 320hp.
But if the OP did buy the rest of the USDM components matched with what he already has (anything BPU) the car would be a night and day difference that's for sure!

Good luck

account2x

iTrader: (5)

Yes you could.

Still they have an eBay down pipe for the JDM twins. If you haven't bought the USDM twins yet I wonldn't get them. Better turbos for sure but not worth the money to swap them in. Cams likewise. Should just go aftermarket 264/264 instead.

Justin727

If he keeps an eye out stock twins and cams could be had for $500 shipped together. I've come across a few people selling either or on the few supraforums I've browsed.

But if he has the extra change I would agree with your statement

97-SC300

iTrader: (17)

i found a set of cams and turbos USDM with 19k miles from a supra for $600. but i dont ahve the funds to go full USDM like MAF, ECU, Injectors, resistor pack for injectors. what if i get the turbos and cams and get a boost controller and keep the boost lower or at JDM level will that be ok?

Vwpride12

Won't the jdm ecu keep the boost at the jdm level?

97-SC300

iTrader: (17)

not sure.... anyone???

Justin727

Yes it should. BUT if you keep the boost lower you'll ok too

Ali SC3

iTrader: (10)

just swap cams and turbos and keep an eye on the AFR.
if you change the ecu to usdm you should change the injectors to 550's.

you could use a piggyback on the USDM ecu instead of changing the injectors...
but why not just add 550's and a piggyback to the JDM ecu and save some time/work.
Im not convinced the USDM ecu is that much better than the JDM one.
Its most likely the cams/turbos/exhaust that changed the USDM rating by 40hp, not a less aggressive timing map for sure.

stockhatch

iTrader: (12)

You will be fine dude. Just don't crank the boost to the bleeding edge and you won't have any problems. Pay $50-$75 and put it on a dyno. Crank the boost till you start to run out of fuel, back it down to a safe level and you are set.