Guys - Been working the phone pretty hard lately with both JET & a new company called AEM in search of any additional performance gains to be made via the ECU & here's the latest:
JET - They have an available ECU reprograming program in place for the 1998-2000 GS4 & R working on one for the GS430. Sorry but I forgot to ask about the GS3 since I was looking for options for my own GS4. They will take the factory ECU & reprogram it for you - U will need to remove yours & ship it to them for the work. The turnaround is generally within a day or 2 so calculate the downtime for your ryde. The cost is in the $375 range. The reprogrammed ECU is designed for use with either the stock intake or any aftermarket intake ( RMM, WeaponR, etc ) WITHOUT it's own ECU. That leaves we SRT intake owners still looking but the JET technician was honest enough with me to say that the SRT piggyback piece probably does the same thing ( richens both the spark & fuel curves ) as the JET ECU so why change? For those who want more info, call JET at 714-848-5515 & ask for ECU sales. Just be prepared to be on "Hold" for at least 5-10 minutes!!
If any of ya have seen the latest issues of EuroTuner ( yeah, I know BUT they used to have some features on Toyota/Lexus rydes at one time! or CarSound, U'll see mention of a new company called AEM. They make an adjustable ECU utilizing Window's based software - they have both a "Plug & Play" version & a "Race" version. The P&P version comes with preset MAPS which enable U to just replace the factory ECU with the AEM piece ( using the factory harness ) & away U go! By this I mean that U can leave it programmed as is OR strap the GS to a dyno & use a laptop to fine tune the engine for maximium power!! This ECU has provisions for use with forced induction ( be it super, turbo or squeeze ) or U can just max out the tuning for a naturally aspirated motor. Then each time U make a change ( intake, exhaust, etc ) U can tweak it some more! There's good & bad news here, though. They only have a "Race" version available for the GS4. The technician told me that the big difference between the 2 versions is that the "Race" variety doesn't come with ANY driving MAPS in it. This means that the car will start & not much else until U tune it yourself. This pretty much necessitates the use of some dyno time just to get the car to run. He told me that the programmability is greater with the "Race" version ( greater memory available ) plus it uses a universal wiring system so it fits multiple cars. The bad news is the cost - MSRP $2368.75!! However, they don't sell direct so they said it would be cheaper if U got it from either Summit Racing or NOPI - try their websites. It's part number #30-0001 if anyone's interested. Good luck to those that try it. Myself, I might step off there later this summer when I look into using some nitrous. BTW - AEM's nitrous program is designed for use with Nitrous Express kits but will work with virtually anyones.
www.summitracing.com
www.nopionline.com
www.aempower.com
www.jetchip.com

 

Gene - Did Jet give you any idea of what kind of improvements you will get with the ECU on just a stock GS? It would be really great if these guys would quote some dyno numbers AND 0-60 and 1/4 mile so you can be sure that you are not just adding a few top end hp at the expense of lower range hp. May give this thing a try with my stock induction and see what happens when they get the 430 setup. Thanks for the report.

 

Gene - thanks for the info. On the JET ECU - I'd be interested if they actually quoted some numbers, OR if they offered a money back guarantee if the customer isn't satisfied.

 

Bit - I've dealt with JET before ( my Corvette ) & they're straight up guys. Craig ( one of their techs ) told me that if I was unhappy with the modded Lexus ECU that they could easily restore it to factory specs & return it to ya ( for a nominal fee - don't ask me to define "nominal!!" ). They also told Craig Werlin ( another CL member with whom I've been doing some serious nitrous talk with ) the same thing. Still, I'd want to get something in writing BEFORE I sent them my computer.
I did notice that they don't have a Lexus dyno sheet on their site but both the older Toyota 2.7 engine & the late model Mustang ( similar fuel system as the GS ) both showed gains of 10 HP & more. This was, I assume, with a stock intake. Remember that my SRT setup showed almost 18 HP more so that figure seems about right.

 

So I pay $400 to get the update and then an additional fee to reverse it, or I get back my $400 less the nominal fee?

 

I live in Orange County which is the home of Jet. Mean Gene, do you think I could drop my gs400 off at Jet first thing in the morning that they can get it done for pick-up at the end of the day???

 

Bit - MY understanding ( which, as we've all seen lately AIN'T that good!!:eek: ) is that U get back the $400 minus the fee. best advice i can give is to call or E-mail them to be sure.
GS - They don't need your entire car, just the ECU which is easily removable by yourself. Just disconnect the negative terminal of the battery ( standard advice for working on ANY automotive electronics ) & break out the 10mm socket/ratchet/extension. The ECU board is located in the wedge-shaped box right next to the washer fluid reservoir. It's also held in by (2) 10mm bolts so remove it & drop it off at JET if U're that close. Still, I'd call first to make sure they're available to work on it at that time. Good luck!

 

Gene,

I thought about using the AEM EMS but there are a couple of problems associated with it in terms of our cars. When you mentioned "maps" one of the most crucial maps that is missing is the automatic transmission map. My car is basically a Supra TT Automatic. AEM does not have any applications for the auto Supras yet. I took the EMS tech for a joyride in my battlecruiser to persuade him but all I got was a chortle.

Also, for those with the VVT-i based engine we have another issue. We have something called a drive by wire system which involves harnesses not found in the Supra's harness. The drive by wire system involves a stepping motor controlled by your ECU. I thought about using the TPS to loop a response to the motor to open the throttle but the circuitry is a tad bit complicated without the factory ECU.

In case if there are any updates let me know.

 

Gene,

I've had the exact OPPOSITE with the JET guys. I was trying out a ECU for a '95 and a '90 Grand Prix. The '90 Grand prix idled at 2500 rpm (awful high ... supposed to be 600) and the other ECU was a completely different harness than the '95 had. I tried to get returns and it took them well over 2 months to issue a credit...and that way harping on them every day with lots of heat. Turns out their application charts were wrong on both vehicles. IME, a pain in the a$$ company. But that was back then and things may have changed.

Percy

 

how much exactly more power do I gain if i'm going let them mod my chip?

is there any cons in that? is it bad for the car?