Guys,

Even after the valve body upgrade I am still getting stuck on the rev limiter. Since I cannot find anyone who makes a shift kit I am thinking my only option is to get rid of my RMM LSD 3.76 . Does anyone have any other ideas before I sell it??

I am using Amsoil and I have the VB upgrade.

Anyone??

Jonny

 

Jonny,

What stall are you running on your TC? That might be the problem. You probably have to have PI lower your stall (it's free). DaveGS4 has his TC at 2400 I think with no issues hitting the rev limiter.

 

Hmm, I hadn't considered this. Hopefully Dave can chip in. I gotta do something though, cuz right now 1st-2nd gear sucks!!

Jonny

 

Yes, getting rid of the 3.76 gears will help but then you lose a little bit of the performance. The logical answer is to either find a stand alone ECU that will change your redline or do a full tranny race rebuild. I don't believe doing a shift kit on top of a VB upgrade will help anymore. If anything, it may shorten the life of the tranny and cause not so good driving conditions .

 

I had the same problem even with the OEM gearing (I use the TRD LSD). As part of the fix I upgraded my torque converter to one with a lower stall speed and switched to Amsoil synthetic.

Here are some details.

https://www.clublexus.com/forums/sho...ht=rev+limiter specifically at the end https://www.clublexus.com/forums/sho...2&postcount=44

I ordered one with a slightly lower stall speed at 2600 and something called a 'turbo stator pump' at the suggestion of Mo at SRT. Might help, but it will still be hit or miss with that 3.76 gearing IMO. Even if you switch to the OEM 3.23 and keep that PI TC with the high stall speed you might still have the same problem now that you're boosted (I did)....

I guess my advice is to pick one (stall speed or gearing), unless there is some economy of scale to doing them both at the same time.

Option 1) PI will swap the stall speed for you for free within the first two years, after that its $225 plus shipping. OR you can easily resell it and just buy a new one to reduce your downtime.

Option 2) If you go to OEM gearing you'll have to either do that inside the Supra Torsen rear end (something that is surely possible but I've never read about it on this forum, will need to go to Supraforums and research). If you put OEM rear end back in, you'll lose your LSD and will need to add a TRD Unit or you'll have just one wheel spinning.

 

You can also give this a try, I personally dont have any firsthand experience with it. though.

http://www.powertraincontrolsolution...content-4.html

 

Well I had the 2800 rpm converter and now I have the 2600 stall speed converter with the stator pump. I also have stock 3.23 gears with a TRD LSD and I still have the problem of hitting the limiter at times. Of course I am boosted but the problem remains.

 

I have emailed them concerning having something made for our cars. I will let you know when I hear back from them.

Thank you everyone for your input,

Jonny

 

OK guys, this is what I got from them...

Me - "Hi,

I am writing to you in regard to a transmission controller application for a Lexus GS400. So far there are about 5 people, along with myself who are having problems hitting our rev limiters. We are all using a 2800 Torque Convertor with some type of 3.76 LSD differential and valve body upgrades. We all have some type of forced induction - turbo or supercharged. Stock is 2400 with 3.23 gearing.

What would be necessary to get a kit made for us? How many people would you need and at what price. Please let me know asap,"

Russ -

" Jonathan,
We have installed our controller on many of the IS300's with the A650e transmission. The GS400 uses the same transmission. The only problem your going to have is the check engine light. When you remove the transmission control from the ECU the check engine light is going to come on. We have done 2 type of harnesses for the IS300, one that plugs in directly to the transmission or one that plugs in at the factory ECU."

Me - "Russ,

When you say the CEL will come on - do you mean indefinitely it will stay on - or just when you unplug it? If it stays on indefinitely, is there any way to stop this from happening?? I have a scanner that can reset it - but obviously that isn't going to help if it stays on 24/7.

When you say it plugs into the transmission - where exactly does it plug in. Is it a plug and play? What is the cost for this and the one that plugs into the factory ECU? How many would need to be purchased to get a discount?

Thank you,"

Russ - "Jonathan,
The check engine light will stay on. The only way to stop it is to keep the factory ecu running the transmission. Think of our controller as a standalone engine management system but for a transmission. It does not communicate with, simulate, or care what the factory ECU is doing. It gets data directly from the sensors and controls the solenoids in the transmission.
One harness is typically used for engine swap applications. It plugs directly into the transmission and the customer is required to wire the necessary sensors, power, backup lights, neutral safety, etc and is only specific to the transmission. Allowing the transmission to be used anywhere in any application.
The other harness will provide a plug and play solution. The only issue being the check engine light. This harness is specific the vehicle and wouldn't work on a different vehicle with the same transmission.
Sorry but due to the high level of technical support required we only offer volume discounts to our dealers."

Me - " Russ,

OK - just to verify I am understanding this correctly. If I were to go with the transmission harness then I would not get a CEL. It would plug directly into the transmission ( is there a plug here?) and then I would need to wire in the additional connections for backup lights etc.

1. Does any part of the transmission need to be removed for this?
2. How many additional wires would need to be wired in for the backup lights etc?>
3. How hard a task would the install be??

What would be the cost for this?

Thank you,"

Russ - - " Jonathan,
The reason we offer different harnesses is because people have different reasons for needing our controller. Example: If you want to take the GS400 engine and transmission out and put it in a 69 camaro using an aftermarket engine management system you would need the transmission harness. If your keeping the GS400 in the original car with the original wiring harness then the plug and play harness would be recomended. The backup light, neutral safety, speedometer, etc. are already wired.
If you have the stock ECU then the check engine light is going to be on regardless of what harness you are using. You can't take the transmission control away from the factory ECU without it knowing and setting a check engine light regardless of how its wired.
The cost for the kit with either harness is $850 plus shipping. I can recommend a few dealers who have experience with the Lexus who can provide you with better technical support."

So what do you guys think??

Jonny

 

Well for 850 it sounds like a good deal if it works that is. The other thing would be the install, if you have to drop the tranny thats gonna drive up the install costs. It would be great if we can just crawl under there and plug it in.

If I rember you also either had to or could program the shift points and general transmission behavior but I guess that wouldnt be too hard to do.

The CEL is a pain in the but though, with the FI I play very close attention to the CEL to alert me of any issues. If it is always on then you loose that as an early indicator of a problem. I just managed to get rid of my CEL

 

maybe you could short out or put a resistor on the stock harness that we are unplugging so that the ECU thinks it is still plugged in?

 

I was hitting the limiter on 1-2 shifts on my n/a SC, turned out that the car was running a bit lean as this was during the tuning shakedown period after some porting etc. Everything is fine now after getting the mixture corrected via fuel pressure changes.

 

Morris,

I wonder if that is possible I will email Russ tomorrow and ask him. You are right about the CEL though - I couldn't drive around with it on all the time - would drive me insane.

Surely there has to be some other way to be able to electronically change the shift points???

Jonny

 

Dx3 how do you feel about the 3.73 gears with the FI, do you think it is too much?

 

Morris,

To be honest I would have to say yes.

Because of the limiter I cannot bring my car to redline in 1st or 2nd gear - which kind of sucks when you are running a centrifugal supercharger and all your power is highend. I don't actually think I have even got to enjoy the car with FI because of this. Hitting redline in 3rd gear I am already doing 90+mph so about the time it is starting to get fun I have to shut her down

If I cannot find a cost effective fix to the problem pretty soon I am going to go back to stock gearing and at least enjoy the car for what it is.

Too much ( and I know you understand this) damn money has gone into this car to not be able to drive it how I want!!

I forsee stock gearing in my near future!

Jonny