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Discussion Starter #1
I heard today that there was a person that took the IS350 gearing, and installed it into the IS-F. Guess it really woke it up on the low end and was able to smoke the tires thru the first 2 gears at WOT !!!!

Brought the top end speed down to around 150mph..... Oh darn.


That's gotta be a hell of a "awakining"
 

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ehh worth it to me if it makes the car faster in the 1/4. personally ill wait for the TRD S/C though, albeit i have no idea how this car is going to put that estimated close to 600HP to the ground. the 225/255 tires wont be enough and it doesnt seem like theres much room to go wider.

i have a N/A geared m3 that makes only about 390 at the motor and i can still light up my rear PS2s that are 285/30/19.
i had a Renntech stg2 E55 AMG that made around 550 to the motor and even more torque and that car lit up 295s in first and second. lexus needs to make sure the tranny can hold that power as well as solve some traction issues.

maybe finally make the Fsport rims in ISF offset but wider than 19x8 19x9?
 

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Discussion Starter #3
I heard it dropped the quarter mile times down alot !! I agree it's going to be hard to get the power to the ground. I'm not to worried about the trans holding as it's pretty much bullit proof. Tires and gearing well make all the diffrence in the world.

I run a 4.10 gear but my 5th gear trans gear is only a 0.058 !!
 

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Discussion Starter #6
No, I run a 4.10 in my Mustang that's a strip car.

Stock gearing on the IS-F is a 2.93
The IS350 is geared with ai believe I mid 3.xx rear end. That's why it woke the IS-F right up when they swapped it out from the 2.93....
 

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hmm. any idea on the costs of that?
that could be something fun to play with, although id still think they need to figure out how wide you can go for tires to get traction...

power without traction is worthless.
 

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Discussion Starter #8
I'm going to try to have it measured and see just how wide we can get the tires in the back. I agree power without being able to get down to ground is useless.
 

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please do so and get back to us asap. the first thing i do when i get my isf is im going to go to wider tires. first on the stock rims, until i can find a reputable company to comeup with offsets that clear the brakes, and allow me to go wider.
 

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will the dealer do this ? will it void the warenty? how much do u think it will coast? the car has so much power allready but i woudent mind a little more torque down low! and better 0 to 60
 

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Changing the IS-F rear end gearing

We have changed the rear end gear in our IS-F here at the dealership and it has transformed it into a street animal. Low end acceleration is quite a bit different than the factory set-up. Stoplight to stoplight driving provides quite a bit of excitement. With this set up you need to be quick on the upshifts at full throttle for sure. We also did some highway drive comparisons with a stock IS-F vs. the IS-F with the gear change. Obviously , the RPM range is a little higher with the new gear ratio but not obnoxious. I had taken 3 guys on a test drive yesterday in that car for a total of 4 people in the car. I was curious how it would perform as we headed out. I was please to hear the screech of the tires switching to second gear and to see all of our heads pop backwards on that same gear change. Oh what fun!

Doug
 

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Discussion Starter #14
Doug,
Wow, well you ar the second dealership to do it now. How did you get the GM to approve that???
 

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Hi Andy,
we had performed that swap back in June on the owner of Lexus of Dayton's IS-F. It went right passed the GM. :) John is a total gear head and has been involved in road racing for 30+ years. I am fortunate to have a automotive enthusiast owner. We were swapping rear end gears back in the early 90's on the SC300' and SC400's for fun. We are definately a performance oriented dealer. We've done some other work on the IS-F's as well, mostly cosmetic stuff. Powdercoated the calipers yellow, installed 20" black 3 pc wheels, installed 19" BBS 2 pc wheels,shaved emblems from the rear, painted engine covers to name a few cosmetic mods. I look forward to sharing stories with you and others on the forum. Were you the other dealer to do the swap?

Doug
 

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Discussion Starter #16
No I wish I was. We did however build a IS300 a few years ago with a full turbo setup, replaced the trans and whole bunch of other things. The dealership I heard that did it is in Texas. We will have to keep in touch !!
 

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No I wish I was. We did however build a IS300 a few years ago with a full turbo setup, replaced the trans and whole bunch of other things. The dealership I heard that did it is in Texas. We will have to keep in touch !!
Do you know the name of the dealership in Texas?! Might have to look into such a swap ;)
 

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FChampOH,

Did you just replace the ring and pinion gears with those from an IS350? Are the IS350 gears strong enough to take the increased torque over a long period of time?
 

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Who can tell us how many ISF cars have been produced to date?

My guess would be no more than 3000.
 

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FChampOH,

Did you just replace the ring and pinion gears with those from an IS350? Are the IS350 gears strong enough to take the increased torque over a long period of time?
We are kind heading into uncharted waters with this set up. Once we got all of the info as far as gear ratios and fit placement from the factory guys and then did our own research at the dealership, we made the change and put it on the road. The factory guys have their hands tied as far as what they can do, so fittingly they kept in touch with what we were doing. Time will tell as far as longevity, but if if the Lexus quality holds true, the parts they use are designed to take on more abuse than what they are actually sent out from the manufacturing plant in. As with and modifying of any car, it's a gamble. I'd say this one is worth it. You would always have your original unit to put back in if any problems arise! So far, so good in the one we have done. It is driven like this type of car should be....:)

Doug
 
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