"Best" way to tune a low PSI NA-T Setup? - Page 2 - Lexus IS Forum
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post #16 of 20 (permalink) Old 04-25-2019, 10:19 AM Thread Starter
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Originally Posted by Hodgdon Extreme View Post
I doubt there is any tuning solution that is NOT going to require time/effort/experience to sort out discrepancies - even the so-called "plug and play" units. This is speculation on my part, I've no direct experience with PnP units for IS300. Other PnP stuff I've messed with in other applications always had issues and anomalies to work out - which have always been time consuming.

I have extremely high expectations for how well my cars run/drive. 15 years ago, I was pretty satisfied as long as the car started, generally idled, and ran strong at WOT without blowing up. Not anymore. Now I demand the car start perfect hot or cold, idle correctly regardless of fans on/off, AC on/off, battery voltage, coolant temperature, inlet air temp, etc etc etc. The throttle response must be crisp, it must rev cleanly, I must be able to achieve my desired AFR at all times. Etc, etc, etc.

...which is not achievable with a piggyback. They simply do not have enough inputs or adjustments in the software to achieve it. It's kind of like a carburetor; you can get it set up to run the engine and make good power, but the calibration will always be a compromise in some regard and the "drivability" will never be as good as a properly configured ecu.

A quality, fully-featured ecu will allow the calibration to be as good as factory-stock, if (and ONLY if) the schmuck doing the calibration work has the knowledge and puts in the time. Which implies that you'll need to shop around for the right person to do the tuning, and be prepared to pay them for their time. Which also implies that you should be strongly considering their opinion on what tuning solution you get.

Obviously cost is a big factor in all this. My advice is to spend some time writing down very specific goals and outcomes you are trying to achieve - and then shop around getting "quotes" on what it will take to achieve those outcomes.

It's been said many times but bears repeating:

Choose any 2: Fast, Cheap, Quality
I don't like hearing it, nevertheless, I know it's true. Writing down my goals is a good idea and I probably shouldn't slack any longer to do so. I have heard of people using the AEM INFINITY before so I'll look into it. I found a used six-pin on eBay for a reasonable price and Mofab is a pretty reputable shop here if you ask around. I'm not as picky as you are when it comes to performance, I'll be aiming for it to run at the beginning and work off of that. I guess the only way I'll learn is to jump into major pain. What do you think about this listing?


Too old? Looks sketchy? Just right? Thanks to all for being courteous and worthwhile in this endeavour!
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post #17 of 20 (permalink) Old 04-25-2019, 10:53 AM
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That harness looks sketchy to me. Need more pics/angles to tell. The problem with PnP, is most of the time they are basic/generic configurations. It’ll have the injectors/ignition/sensors (map, ect, iat) and not much else. Just barebones, “get it running” kind of set up. So you end up running a lot of wires on your own. Honestly it’s not rocket surgery to build your own harness. You will want to use ALL the Infinity features (that’s what you bought it for, right?) like boost control, traction control, oil psi, oil temp, CAN data, MAF clamp, UEGO, 2step/antilag, etc. If you get a PnP, be informed what it will and won’t do. These new standalones have a lot of engine protection integrated in to the control. The more sensors you have, the more protection schemes you can set up. You can still outsmart it and blow things up, but it makes it a bit harder lol.
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post #18 of 20 (permalink) Old 04-27-2019, 08:31 PM Thread Starter
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Originally Posted by FRaCTioNaL View Post
I think most of us that have been here for some time agree on that. We can also agree that it probably takes some age to achieve that mentality. Not ragging on you OP, just calling it like I see it (for all I know you could be my age).

I remember I too went through that phase of having tha legendary 2jz and not having the money for a supra but calling it *cringe* a 4dr soopra.

The fact is that the car can be had for pennies but making it fast and reliable is not cheap or economical in any way. Taking into account your local tuners preference is a good recommendation...you could then try to source a used unit if money is an issue.

Good luck!!
No sir, you are spot on. I'm seventeen but I was very lucky to buy this car and have enough time and money to learn with it. Buying a used unit is a good idea but what is the potential for that to go wrong? How should I look for a good, used, item?
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post #19 of 20 (permalink) Old 04-28-2019, 11:26 AM
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Its kind of a crap shoot. Used stuff I will buy off of people I know...and even then....how can you be 100% sure that a something you cannot see the insides of will work correctly? That the item looks in good conditions could be a good indicator but who knows, other than testing it. Maybe ask whether the stuff has been removed from a good running car? Stuff like that. Unfortunately, there really isn't much you can do.

Originally Posted by Squareback View Post
1-8-7 on the undercova i-s-3-hundgy
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post #20 of 20 (permalink) Old 06-07-2019, 12:41 PM
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Sorry to revive an "old" thread, but I wanted to say a few things in case anyone was to stumble upon it:

As for "budget" FI builds, here's a link to a thread with a few decent "budget" setups. Like almost anything else, there are some parts that you can scoop for cheap/used, but there are others that it's best to pony up cash.


As for management, most often you'll be best suited going with a standalone EMS. Most, if not all, of the piggybacks that have been used on this platform are old as dirt and very limited in their functionality. And, if you don't know how to tune it yourself, you might find yourself out of luck as a lot of tuners won't touch them either. You have a lot of options for a standalone, with some being more expensive and offering more features and some being more "budget-friendly" (the megasquirt is a more budget-friendly option, for example).

To any young guys just getting into the IS300, make sure to take care of maintenance before anything else. Your car is, at the youngest, 14 years old. Do a suspension refresh, make sure you're not pissing oil all over the place, make sure bushings aren't spewing grease, etc.

Before you go looking for power, put on some fresh tires & brakes. Your ability to stop safely is more important than your ability to accelerate quickly. Then, get your suspension setup dialed in. Grab a decent set of coilovers and sway bars. Put in new bushings (either poly or new OEM will be much better than 15 y/o rubber) and ball joints. Don't be in a rush to add power. There's no shame in taking your time and budgeting enough cash to put together a proper FI setup.

Take. Your. Time. Do it right or do it twice.

Edit: I saw someone shared the link to the thread about a boosted setup on the OEM ecu. It can be done, and it seems that the OP's car is still alive and kicking. Anyone going that route needs to make sure that your wastegate spring is sized appropriately and keep a close eye on AFRs and fuel trims. And keep in mind, one person's success does not guarantee that the same will happen for you. You are taking a bit of a risk.

At the end of the day, it's your car and no one else's. It's your right to slap on a CX Racing turbo kit and give it a shot with the OEM ecu if that's what you want to do. Just keep in mind, it's that more often than not, shortcuts cause more headaches in the end than doing things right from the get-go. On the other hand, don't swing so far the other way that you spend way more money than you need or get in over your head. Scoop deals where you can, but don't sacrifice quality for internet points.

Build your car for your own enjoyment. No one else's. Don't try to be different, don't try to be unique. Just make it a car you're proud of, a car that makes you smile each time you drive it.

2003 GGP | "You Can't See Me"

Hotchkis sway bars, LS400 bbk, Stance coilovers, Customwerks rear strut tower bar & trunk brace, Megan diff. brace & traction bars, OBX short-tube headers, Fidanza exhaust cam gear, GTE cams, NX wet kit, winter camo wrap 👀

Last edited by The Nuke; 06-24-2019 at 01:33 PM.
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