DaveGS4

iTrader: (2)

Henry, over the years there have been several members with non-FI cars who have hit the rev limiter at WOT after putting in the 3.76 gearing. More often they descrived hitting it 'occasionally' instead of 'regularly' and there are definitely more people with no issues than those with. But it does happen to some and I suspect we may find it be more prone to happen with the 3.92 gearing. Lets hope not, but definitely something to be aware of.

rominl

iTrader: (4)

ooops, i stand corrected then. can't recall that from my memory, but if someone has that issue then it's definitely something to look out for. one thing off the top of my head i can think of is what type of fluid they are using for the rear end. i would expect if it's something that's not thick enough that might cause problem?

anyway, if the limiter problem is happening occasionally on the 3.76, then on the 3.92 it will probably be more likely, coz' the car will just rev up even faster for the computer to react

DaveGS4

iTrader: (2)

Yah, there are a number of threads (many before your time).

mean gene, cyberseano, cwerlin (although sometimes he was on N02), Dex's did it occasionally (witnessed by me while I was in his car), theseth, skier1, mkilty, etc

Couple of example threads
https://www.clublexus.com/forums/sho...76+rev+limiter
https://www.clublexus.com/forums/sho...76+rev+limiter
https://www.clublexus.com/forums/sho...76+rev+limiter
https://www.clublexus.com/forums/sho...76+rev+limiter

edit - one with discussion about wheel size that may be relevant here
https://www.clublexus.com/forums/sho...76+rev+limiter

Many more people with this have absolutely no problem, but if it happens it may drive you nuts (it did on mine). With my FI and even 3.23 gearing I had to change my TC stall (which may be an option to help alleviate the issue).

rominl

iTrader: (4)

i know this might be a bit off topic, but dave you ever thought about doing the valve body upgrade?

and thanks for the links dave, i am going to read those threads (man they gotta be old)

DaveGS4

iTrader: (2)

Already have it. Did it at the same time I put in the supercharger.

daleer

Ive got a 2800 pi tc sitting in my garage waiting to install on my 2001 gs430. I've also located a rear differential off a 2000 gs300 for cheap at a nearby junkyard. Do you guys think I should get the diff off the gs300 and have that installed as well when I get my tc installed?? - or do you think I'll have rev. limiter issues?? I don't have eshift, so I need to just be able to mash the peddle in automatic. All the threads I saw posted of people with rev.limiter issues where gs400's - I wonder if the shifting is faster or less prone to hitting the limiter in a gs430?? Anyway, since it looks like I'm staying NA, I want to make my car as fast as possible and am tempted to get the gs300 diff. but don't want rev. limiter problems

DaveGS4

iTrader: (2)

I'd guess the GS430 will be equally susceptible as the GS400 but there really is no way to tell until a few people do it.

Keep in mind the two things you are talking about doing (high stall TC and 3.9x gears) are going to create the propensity for impressive wheelspin and massive burnouts... with one wheel. The 2001 GS300 is an open differential and has no LSD.

rheiy

Not to go off topic here, but when u install your TC, let us know if u get the cel problem.
btw...I have the 3.76 lsd and no rev limiter issues. Don't know what a 3.9x will do with the
limiter but I bet you'll be smoking the rear tire at lot with a tc/3.9x combo

daleer

DaveGS4 - thanks for the info - I guess I'll just have to give it a try and see what happens. Rheiy - I'll be sure to post how it turns out when I install the tc.

rominl

iTrader: (4)

yeah definitely let us know. a tc is probably going on my sc430 pretty soon too

and i wonder how the 3.92 is going to work on the 430 as well. the 430 is more restrictive in terms of shifting and mapping, i wonder if the more aggressive gearing is going to help it a tad more

rheiy

Well the 3.76 has helped in terms of shifting (right up to redline) I'm sure the 3.92 will also help but hopefully not to the point of hitting rev limiter.

RMMGS4

iTrader: (5)

As far as the topic of hitting the rev limiter on the 3.92, yes that will be one factor that we'd all like to hear more about.

I don't think people should lose sight of the fact that that there is such a thing as "too much gear".

My analogy to this would be to take a 15 speed road bike. For fastest acceleration from a standstill on a level surface, first gear would be "too much" gear. That gear would be better for uphill climbs, but not the fastest for level surface acceleration.

The second part of this analogy is power. Someone like Lance Armstrong is gonna gear his bike based on his strength, which will be less taller gearing than someone who is a casual biker. Again, too much gear would not take advantage of Lance Armstrongs strength. The same holds true for our cars. The gearing needs to balance with the power available from the engine.

So what we know is that a 3.76 is good for a NA car, but that stock gearing is better for an FI car. Let's assume this is a given. Those of us with 3.76 and have the TC, LSD, mods. , wider rear tires, mild intake / exhaust mods can tell you that we are still fighting for traction, to the point where the power we achieve with the 3.76 is not getting to the ground. Power is nothing without traction.

Several of us are in the process of going to wider tire choices such as 295 and 305mm widths in an effort to get the power gained by the 3.76 to actually benefit our 0 to 60 acceleration times. The quickest 0-60 times I've seen posted by an NA car are in the range of 5.2 to 5.3 seconds. I will soon be moving to one of these wider tire options and will also be selecting stickier rubber than current. My goal is to push the envelope to see how we can achieve faster 0 to 60 times without going to the FI route.

So it is my contention that a 3.92 gear will not add any real improvent unless you can control the traction any better than what people with the 3.76 are doing currently. Furthermore, if you are thinking of any engine upgrades to increase power, I only see this issue worsening.

The bottom line is, the more power (compared to stock rating) you add, the less you will benefit from 3.92 gearing and as you go towards FI, even the 3.76 appears un-neccessary.

Anyone who has or will go to 3.92 gears, it would be great info to report what other performance mods you have, if you are dealing with traction issues when launching hard from a standstill, and any measured 0 to 60 times.

I have no comment on the benefits of the 3.92 for high speed acceleration from say 60 to 80 mph, etc. Those of us with the 3.76 can attest that the mid -level acceleration feels better and I'd bet the 3.92 would have similar impressions, but which one is better in this speed range is a little more difficult to quantify.

rominl

iTrader: (4)

if there is a 3.92 with lsd i would probably have tried it, since i got 20s

lex400pshR

so get the 3.92 gears from the 300 and get the TRD LSD put into it... that way U 100% will have traction and faster gears...but top end is way less and If U want to push the car on the highway...then 200km is the most based on theory.. and thats no fun because all the top end model cars (BMW, porsche, audi) will just hall to 250km and up.... example M5

RMMGS4

iTrader: (5)

Yeah the top end is definitely going to hurt. With the 3.76 we are maxed out at about 135mph, since the speed limiter thinks we're going 150mph. That limiter is defeatable I heard tho.


All of us with the 3.76 already have LSD and still not enough traction*. 3.92 will only make that worse.

Rominl can even spin his tall 285/30-20's. I have 19"s and can lay down a 20ft + scratch.

*Also consider most of us have the TC mod, intake and exhaust mods and 275 -285 rear tires too.