jinos

I have had an IS300 since the 2002, originally a 5-spd, in 2003 I bought the Sportdesign with e-shift. I love the body style of the IS but I want more power (common issue I see). Anyhow, I have the money to buy a GS430 or I have been considering putting a Stage 1 Turbo or SC into my IS. Before getting into various stages of turbo / SC etc.. I really want the car to stay as stock as possible, I am not into the radically custom look nor do I want to drive my SUV for weeks while my car is in the shop...

So my honest question, should I spend the 10-11k to get a solid turbo / sc installed or should I just go buy the GS430?
Factors to consider:
1. I love the IS300 body style. Will a Stage 1 Turbo / SC IS have the power that the GS430 has?
2. From others experience how will the IS drive with a Stage 1 upgrade?
3. Whose kit should I buy if I really (and I mean really) don't want to put gauges, brakes, rims, etc onto / into the IS?

Thanks much in advance,

rominl

iTrader: (4)

the is300 with sc or turbo will most likely be faster than the gs430 i think, and of course it will handle even better. i got is3 and gs4 so i know how fast the gs4 is. with sc and turbo the is3 will have at least 240 at wheels i suppose, that's about the same as stock gs4 but the is3 is quite a bit lighter

however you said you like to stay with as stock as possible on the car, that's kinda opposite of what the sc and turbo do? that's big project, and relaly you car will probably be in the shop for at least a month or so (to do it right with all the tuning). not sure if that's a good move considering what you do NOT want to happen

and you want to put that much power on the is3 without even getting rims? all i can say is you will have no traction at all man.

and about the gs430, it's just a different car, it's a very fast car imho for its size, and it's very luxury and way more comfortable than the is3. handling it can use a lot of improvement

so that's your choice now

bchau_gt

It'll take some work to get a supercharged or turbocharged IS300 to work well. You will definitely get a more sporty feel by boosting an IS, but if you really want to keep the stock feel, then I'd recommend getting a GS430.

Also, when going for forced induction, I'd recommend getting gauges regardless of whether you really need them or not. It's always better to know what's going on with your car in case "bad" things start happening. I didn't want large gauges on my dash, so I chose a wideband system that has a small digital display.

You car will likely get louder with a turbo or SC as well. There will also be a lot of other things you'll want to change or add to your car and it can become expensive. Many things like new wheels, exhaust system, brakes, suspension upgrades, transmission upgrades, etc aren't required, but almost everyone will recommend them. In the end, you can keep the stock look on the IS, but it won't feel stock.

mmarshall

Rominl has a good point about poor traction on a blown or turbo IS300 without a wheel / tire upgrade to handle it. I would say go with the GS430 for other reasons, too. First, it comes with bigger rubber than the IS does to start with. Second, it gives you roughly the same HP / torque a turbo IS would, but without the added complexity, heat, and potential durability problems a turbo has....and you probably won't have to use expensive synthetic oil either. Third, it will probably be cheaper to insure...insurance companies generally don't like turbos. Fourth, unless you strictly use TRD parts, there MAY (depends on the specifics) be some warranty issues with non-Toyota aftermarket stuff.
Before you get an existing GS430, however, you might want to wait a few months and look at the new All-Wheel-Drive model due for 2005....the AWD will be an enormous benefit in handling, especially in lousy weather.

rominl

iTrader: (4)

actually insurnace of gs430 would be a lot higher (if compuare new to new) coz' it's a v8.

jinos

Thanks for the info guys/gals.

I am going to stick with the IS and go with the modifications.

1. At 300 +/- rwhp what size tires do you recommend? 235's? 245's?

2. I am going to go with the TBKO Stage 1 turbo, it is shippable and my local tuner has already been in touch with Jeff, I also think I will order the 3 gauge module that goes where the Navi would have, what gauges should I have put in? Turbo Pressue, Oil Pressue... and?

3. In addition to the Turbo kit I am paying for the VB upgrade, aside from tires and gauges will I need anything else? Will the extra hp/tq warrant brake upgrades? Will I want to go with suspension upgrades? Sway bars, shocks, springs?

Again, you all rock and I do appreciate the help, I am not going to have a clue what has been done to my car, but I will take good pictures and try to document the performance as I go.. looking forward to putting down the power that this car should have come with from the start...
Thanks again

rominl

iTrader: (4)

300 at the wheels? man you need at least 275 to be good. but that's not the case without a lot of mod. try 265, if you can get a good offset that's good to go.

rominl

iTrader: (4)

just think about this. my gs400, 300hp at crank, i got 20s, heavy car itself, and i can still chirp a bit tires when i floor it. putting in lsd and tq converter and i will spin my tires all day already. that's with 275 in the back!

jinos

I was thinking of these:



In 18x9.5 in the rear and 18x8.5 in the front.. What size tires would fit on the rear and do you think they would provide the stick that I need?

jinos

300 rwhp was wishful thinking I guess.. TBKO reports 365 at the flywheel with the stage 1 kit, not sure what % to give up to actual rwhp..

bchau_gt

There are a bunch of different gauges you could get. A lot of people have different opinions. For a turbo, I think my top 3 choices would be boost (what you called turbo pressure I believe), oil pressure, and wideband air/fuel ratio. People also get fuel pressure and EGT (exhaust gas temperature).

For tires, I agree with rominl, the wider the better, but it's not really necessary to get the widest possible. It depends more on how your drive. I don't expect that you will be flooring it every where you go, but who knows, maybe you will with your new found power.

Suspension and brake upgrades would also be good. It'll help keep your car more planted to the ground and help you handle the power.

I'm glad you're getting the valve body upgrade as well. I have TBKO/TurboEast's VB upgrade in my car, which will help your car shift with the added power. However, expect harder/shorter shifts afterwards, which will take away from the stock Lexus luxury feel.

Now that you've decided to turbo your IS instead of getting a GS, please realize that you're going to lose a lot of the stock Lexus feel. I'd also recommend that you learn as much as possible about turbo'ing your car before actually doing it. Learn more about the car in general. Be prepared to expect problems and expect your car to not run correctly right away. Getting the car properly tuned after the install is extremely important.

bchau_gt

With an auto, you can assume approximately 22% power loss to the drivetrain. So 365hp * 0.78 = 284.7whp.

rominl

iTrader: (4)

i have a stick thread in the tires/wheels forum on all the offset numbers for the is300 and gs, you can check it out. but i cantell you fitting 8.5 and 9.5 on the is300 isn't easy at all, require high offset and need to be very precise, plus you have to mod the fender... so....

LXOGOOD

Also, there is one other very important factor you have missed. If you decide to get the GS430, you will soon realize that the car will need numerous mods to get it to handle better. Many of us GS owners have spent over a $1000 just on mods to get the GS to handle right. Basically, it feels like a boat in stock form. Best bet is to stay with the IS and boost it. Good luck!

rominl

iTrader: (4)

1k is an understatement

i think in order to make the gs handles as good as a stock IS, you have to spend at least 2k. that's just to get to the stock level of is3