atgawand

Hello all,

I purchased a 97 SC300 about a month ago and really love driving it. I would like to understand what are some of the quick power upgrades that I can do for this thing. By the way, about 10 years ago with some help from my friends I did a NA to Turbo conversion on a older style Supra, and unfortunately had a blown head gasket after engine swap but I still recall the turbo boost power and it was a lot of fun.

I am not sure yet if I want to go down the Turbo route yet on the SC300, although I will leave that option open. My objective with this car short term is for it to be a reliable car and at the same time have horsepower to have fun with. I will be doing the BFI upgrade and also upgrade the exhaust from Catback. Are there any suggestions on the exhaust systems from catback? Also, I am thinking of upgrading the wheels, currently I have the original chrome wheels. I do not know much about the spacers needed for new rims (bigger size) and would like to get some idea on how I go about shopping for new wheels. My preference is to get new Rims on the car w/o any modification to the suspension or lowering the car.

Thank you for you input.

97-SC300

iTrader: (17)

Spending money into anything but a turbo on these cars is a complete waste of money. Exhaust and intake/headers will give you some improvement but it's almost nonexistent aside from making it sound different.

atgawand

Thank you for your reply. I may eventually go the Turbo route.

KahnBB6

iTrader: (5)

I'm seconding the advice. Get a nice catback exhaust that you like but beyond that, don't bother with NA modifications. Really. The money you'll spend on those make a not insignificant chunk of either a 1JZ Auto swap or a basic NA-T conversion. An NA-T done right (with an Aristo GTE ecu) can be very reliable but any GTE swap with the maintenance done will be just as reliable as the stock engine. You can't go wrong either way.

Also, the MKIII Supra *chassis* is great but the 7M engines need some particular care. JZ series engines are completely different animals. They were made to be turbocharged even in NA form.

INTIMAZY

iTrader: (5)

HAHAHAH
Super harsh, but completely true.

atgawand

Thank you for the advice and appreciate it. I tend to agree with the return on investment w/o going Turbo. So, I will think about it. I have seen Turbo kits online anywhere from around $2K to $5K. I am just looking to do a basic NA-T conversion. I am in no hurry and can look for parts online for a good price.

Since I have done a conversion before I am mostly familiar with some of the key components but that was 10yrs ago. Is there a preferred list of items for the SC300 for the Basic NA-T conversion that I can shop for over time? Again, I am not trying to go overboard by changing the Injectors, fuelpump, suspension, brakes, etc., I prefer to just bolt on a Turbo and keep the rest of the car in its original format if possible.

I ordered a BFI kit from ebay (last one I think). I can tell here in Texas during hot days when the AC is on and the Air is real Humid, the throttle response is slow so I am hoping some cold air into the intake will help. Should I still do a Catback exhaust? I was thinking 3" from the cat and split it into 2.5" to the mufflers? Will that exhaust upgrade work ok when I decide to do the Turbo Conversion or will I have to change that again?

Again, thanks to the members for their input.

Studiogeek

iTrader: (6)

If you are going turbo, you need to change everything you are considering buying. I would STOP trying to buy anything for the car and read about 20 great NA/T build threads front to back. When you decide on a route to take, post your plan so guys like Kahn, AliSc3, Oumar, Gerrb and many others can look over it. Buying anything before your plan is solid usually results in wasted money. You will need every penny to execute your well thought out plan. You probably know, you can't just bolt on a turbo. The buy list is significant brother. I'm in the process of building one now, the more you learn, the more paranoid you will become about cutting corners. Your friend with the Supra knows that now i'm sure. It should have been a fresh Supra TT head gasket and ARP studs in there.
What are your power goals? Are you cool with auto or do you want manual?

atgawand

Hi Studiogeek,

Thank you for your advice, and for others (Kahn, 97-SC300 etc.,) who replied to my question. You seem to be very knowledgeable about the older Supra's and yes I did buy the ARP Studs and a new head gasket along with resurfacing the head that my friends recommended but the thing still failed. Lesson's learned. It was a fun project and I had a short period of fun for a lot of cash wasted and I do not want to go down that route again.

As most of you may be aware that in life you have limited amount of resources available for certain things, especially things considered as toys, unless you just happen to have it laying around. :-) So in saying that, my objective is to have more than what I have currently. If that means that a Basic NA-T will bring me around 400rwhp then that is fine. I am aware of the potential of 2JZ engine but I have no plans (or funds) to reach that level.

I would like to hear from the members about their experiences as to what it would cost me to have the Basic NA-T conversion. I will probably keep the Auto tranny that I have in order to limit cost. If there is a link I can go to for SC300 NA-T Conversion to understand the Power/Cost ratio I would appreciate it. It would be good to get a general idea of the Turbo Conversion Cost so that I know if I should go down that route.

Thank you.

Studiogeek

iTrader: (6)

atgawand,
Hi, I am knowledgable from the "obsessively reading recently" perspective but that's it. I'm just starting to have a fraction of a clue. These waters are deep man. I had no idea. There are so many options and loads of science behind every choice. I'd check AliSc3's TT ECU mod thread for management. I hear/read it's the most reliable, inexpensive option for mgmt. etc. I also have been advised, get a high quality turbo, BOV and WG. You can check my build thread and ill tell you what everything cost me as my builder works through it. My car started as a budget build and still is, but it's over double my starting budget.
Best of luck. I'll be glad to share my experience as it happens. I can't wait to get this car back.

KahnBB6

iTrader: (5)

^^ Ali SC3, Oumar and Gerrb are experts in the NA-T area. They're definitely the ones to run your revised parts list through for advice.

atgawand, as Studiogeek suggests, Ali SC3's NA-T TT ECU mod thread is probably where you should start to cover basic engine management:
https://www.clublexus.com/forums/sc-...t-ecu-mod.html
It is very ideal and easy to find compared to fighting any GE NA engine computer that cannot understand boost pressure.

Then visit the 12V Fuel ECU Mod thread. Needed to get a turbo-friendly fuel pump working in an SC:
https://www.clublexus.com/forums/per...tures-faq.html

Beyond those (and the head gasket, injectors, coils and intercooler) it might be good to go with a basic NA-T kit. Driftmotion has some which are basically the turbo, manifold and BOV. However, NA-T conversions can be as DIY as you want them to be and have so, so many variations.

Engine management is the #1 thing I'd start with, though, and using Ali's Artiso JDM 2JZGTE ECU conversion is a great place to start.

300whp-400whp is not at all that crazy to afford. It's only when exceeding a build goal of around 550whp-600whp that the cost goes up VERY considerably.

atgawand

Thank you very much Kahn (and the rest of the members). You guys have been great with the advice. I will surely start my research on the equipment needed (engine management first) and will probably stick to under 400hp in order to limit cost and still have fun car.

In the meantime while I am gathering and researching the Turbo equipment, I will go ahead and do the BFI and Catback exhaust upgrade as those should be still useful with the turbo upgrade.

Ash

Studiogeek

iTrader: (6)

Ash,
Check with others but I'm pretty sure your intake becomes intercooler piping on a turbo setup. Also, everyone seems to swap to three inch exhaust for increased flow. Lots of stuff changes man, I know ALL that stuff has been ripped out of my car for different parts. My recently purchased Magnaflow exhaust and BFI and old Injen intake all must be sold now. I'd hold off buying.

atgawand

Hi Studiogeek,

I think you are right about the Intercooler sucking air thru piping, it has been years since I did my last turbo project so I did not remember. Appreciate it. I will Cancel my BFI order and hold off on the Exhaust as well.

So, I guess I am starting my Boost Journey again and want to do it right this time around.

Thank you.

Vrank

iTrader: (4)

Here's one of the biggest potential issues with what you could possibly be facing going boosted that nobody seems to have touched on: what do you need in order to pass inspection? Here in Texas, I happen to live in one of the crappy counties that requires a plug in diagnostic scan for all obd-2 equipped vehicles. So if it's 96 and up, you can NOT have any check engine light for any reason whatsoever.

If you have to pass something similar, your only option will be an OBD2 usdm supra ecu which will require more work with wiring and resistors and all sorts of other fun. Otherwise, you can try boosting the stock ecu with a piggyback, but I 100% guarantee you will be retuning constantly. Or you could use a standalone as a piggy back to get a proper tune to hold as you can take complete control of fuel/ignition without alerting the ecu, but this is a pain and has small hurdles to clear when obd-1/JDM Ecus are much more straight forward, cut/dry.

Best bang for the buck is a manual swap if you're auto, front suspension refresh, and coilovers. Night and day. Again, obd2 auto to manual swap requires manual ecu if you gotta pass the scanner. But the bushings/coilovers/manual Trans will change the entire feel of the car. An IS300/celica gts/rav4 steering wheel is also a game changer having a smaller diameter. I know that doesn't sound like true performance upgrades, but the small things add up in feel.

atgawand

Thanks Vrank. Man, it does seem more complicated than I imagined. I am in Collin County and yes it is a plug-in diagnostics. Doing a Manual swap seems like another hurdle to overcome.

I am not sure what I want to do. I was willing to do the Basic Turbo kit for around $3K but if it requires these additional things for it to be right then I am not sure. I have a beautiful running car right now and I don't want to screw that up.

I will be talking more to the local people here in North Texas and get their input about reliability and cost.

Thanks again.