What does it take to get the is350 below 5 seconds or under 13 seconds 1/4 mile? Is it possible/easy to do and would any of it void warranty? Are there piggyback tunes available?

 

don't tune it.. you'll see people complaining about issues after the tune on the forum. tune only adds a few horsepower and changes redline to 7200 rpm for $500.. risking issues with your vehicle for minimum gains, can't be me. tough to do any performance mods to these cars tbh

 

Enjoy it stock for what it is. Very nice from the factory.

You'll never go as fast as you want, especially not without serious compromise.

 

There is the RR-racing/D3 tunes, bolt ons, lighter rims/tires, you can do. Calling up RR racing and talking to them is probably going to be your best bet with regards as to what is best to do to achieve what your looking for. There was a guy that posted in one of the tune threads in late august/early September that said he was getting just over 5 sec 0-60 on his AWD IS with the RR racing tune, exhaust, (maybe some lighter rims too, can't remember) and was told by RR racing that headers could get him from mid to high 4 sec 0-60. Personally I have a AWD IS with a F sport intake/axle back + RR racing tune that I'm getting low to mid 5 0-60 times with.My testing was done using stock rims and heavy cheap tires put on from the dealer that are set to be changed in the coming week.

 

I don't think the feeling between 5.5s vs 5s flat isn't all that great. It's only like a 30hp difference at the wheels to get that right. Doesn't seem like spending thousand dollars on that is worth it.

 

What specific issues are people complaining about after getting the RR Racing tune? If it's with regards to potential slip on the 8-speed transmission, I believe that has to do with the lack of being able to tune the TCU. Engine-wise, the tune uses a conservative map and is highly reliable (I've had my tune for 4.5 years and have done multiple track days and autocrosses without any problems).

With regards to the OPs question, I believe the biggest hinderence for you to achieving a 0-60 time of under 5 secs and a 1/4 mile time is the final drive ratio used on the 3rd Gen IS350. Even with Full Bolt Ons (FBO) and a tune, the 3rd Gen IS350 struggles to break these thresholds. If a shorter final drive ratio can be swapped (along with being FBO+Tuned), it's very possible to achieve these metrics.

Case in point, the 2nd Gen IS350 has the same engine and fairly similar dimension and weight but when tuned and FBO, it is capable of 0-60 in the low/mid 4s and high 12s in the 1/4 mile (this is my FBO+Tune 2IS350 as an example):




I attribute the acceleration differences between the two generations to the gearing as the 2IS350 is statistically quicker from 0-110mph than the 3IS350. If someone can swap the final drive ratio to a more aggressive version (an old hot rodder technique), you'll see a big improvement in acceleration. My two cents.

 

Expensive. Fastest stock time I’ve seen was a 2014 350 AWD doing 0-60 in 5.3 by MotorTrend magazine. Realistically you’ll need headers, exhaust and tune and even then don’t know if you’d be sub 5. They are so heavy and don’t have a lot of torque...not ideal for 0-60.

 

A shorter differential gearing would be the easiest way to go. Engine output is multiplied by your transmission ratio and then your final drive/differential ratio to equal torque to the ground. Increase your final drive ratio and your are increasing torque without touching the engine and that equals faster acceleration. That's assuming you can maintain contact with the ground. The downside is a higher rpm for a given mph but there usually is a happy compromise between the two.

About a 15% difference should result in a huge improvement. Stock gearing is 3.13 so going to somewhere in the 3.59 range should be nice. On my last car I did a 3.06 to a 3.91 and the difference was insane but the revs got a but too high on the highway.

I would check if there are any drop-in differentials or gears available (with a qualified installer if it's the gears themselves).

You can also replicate this with a smaller overall tire diameter but there's only so small you can go.

 

I thought AWD 3is’s had a 3.73 final drive ratio

 

Yes they do.

 

3.13 is RWD? Compared to a 3.73 that would be worse off the line but better than it top speed?

 

The RWD has the 8 speed so the first gear ratio is 4.60 vs a 3.52 in the 6 speed awd models. Torque multiplication is 14.3 in rwd vs 13.2 awd in 1st gear. Rwd should be better off the line in 1st, assuming the same tire diameter and traction is maintained. Rwd will also hit 2nd more quickly so awd may have the upper hand since it can hold the higher multiplication in 1st for longer before entering 2nd. Both transmissions have a similar dropoff of ratio as they enter 2nd.

I haven't mapped out the other gears fully but you will hit 60 in 2nd so a tune that raises your shift point would likely be beneficial. The vehicle would stay in 1st longer and enjoy the extra torque multiplication of 1st vs. 2nd gear for more acceleration.

The engine may not be in its peak torque range at that higher rpm but it's likely that the higher torque multiplication in 1st gear will make up for that.

Overall, your torque to the ground (engine output × transmission ratio × final drive) will be higher over that additional mph range that a higher rpm shift point would deliver.

 

Buy Audi RS3, you'll do 0-60 under 5 sec and beat every Lexus out there, lol

 

RS3 is mid $60k. Way more money.

 

Not only is it RCF/CPO GSF money. It's a Audi...Good luck with it out of warranty. And when something dose go wrong, have fun pulling the entire front of the car off to do anything. When I had my S4 I drove the 2.0T A6 loaner car almost as much as the S4 I bought.