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Discussion Starter #1
I"ll be doing my turbo install pretty soon, and wanted to ask those who race their IS how the car handles with the extra power? I just recently started Autox and there isn't another one till Jan 7. I'm worried the extra power will throw off the balance of the car so any input would be great, thanks.
 

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Well your going to have to get use to the car for sure...Suspension and brake upgrades will be needed and tire/rim selection is key as well...
 

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Bezik is right. You'll definitely want to upgrade your wheels and tires. Suspension (sways, coilovers, rear rigid bar, LCA/toe links/trac links) will definitely compliment a turbo setup. Last but definitely not least, some upgraded pads to reduce brake fade are a must, rotors, brake fluid and SS lines would be nice also.
 

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Controling the power will be something you will need to learn, with a good tune it shouldnt be too bad. Staying competitive in a modified class wont be easy.
 

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Besides the obvious suspension tuning needed, Roadcourse will surely need brake upgrades, as Teckis demonstrated- possibly more dramatic than simple pads/rotors/fluids, but something like Fig's +1 upgrade or more. Autox IMO you could still rock OE calipers/rotors.

Autox driving w/ turbo, IMO it will be tricky- IMO this is where a centrifugal S/C shines if not staying N/A. If turbo, Standalone engine management can give you gear/speed boost control, programmable traction control etc to further mitigate the Autox un-friendly turbo powerband.

The balance is surely changed, you will see why so many seasoned autox'ers insist on N/A being the best power-band. But in my case, Autox was always about having fun, and of course a little competitive- improve technique, learn, have fun and keep that type of driving off of the street. Turbo systems can be made to work great (essentially putting controls in place that makes it drive more like an N/A car with more balls), the question is how much $$ do you have and how much energy do you want to put into the management, tune and extra systems (track control, boost control, hardware upgrades etc). Without those systems, its all on your foot/brain, and don't be surprised if your times are no faster, or in-fact slower as you adjust- and may not get much faster at all.

Shedding BTUs will be a new concern also, you will be making larger surges of heat- a healthy cooling system is a must, an oil cooler and radiator upgrade would be an affordable insurance.
 

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Discussion Starter #6
okay, well im aiming to get about 300rwhp out of the turbo. its going to be a very basic kit, it pretty much based off of madchyers 1st turbo kit. its on the 1st page of his build thread. im using a greddy emanage ultimate for management. i just got new tires in the rear, potenza sp04 PP 225/45 on stock rims. i already have tokico illumina shocks and new springs with a 1.25in drop. i have axxis ultra pads and do plan to get the SS lines. but now after reading this i really am starting to realize that maybe i should wait on the turbo since it seems i will need alot more to make the IS still take the turns fast. i started buying the parts way before i started doing autox, i really dont wanna go thru the hassle of selling the turbo parts as im on a tight budget...rotc doesnt pay much
 

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Grip is grip- if you want to take the turns fast, tires first, suspension around them. Brakes for when your doing more than autox- simply for heat soak reasons. The turbo IMO will be for fun's sake. But if your very serious and actually keeping a points card, then I don't see the turbo actually helping your autox times. On a road course however, it should make things heeps funner and faster depending on the course.
 

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IIR.. .one ofthe OG members here posted a lot of great info on his car setup for his autocross and road course racing and that 1.25 drop is goign to hurt you Vs help... with the OEM susp. geometry on this car a drop of more like 3/4 to 1 inch max is optimal... lower than that you start introducing some geometry changes that as the car transitions from right to left etc make for a less than stable platform to really push the car heavily and stay in control with out really taxing your skills.... i cant remember who it was but he hasd a crazy setup with minimal lowering and no rear sway bar at all after trying several going back to stock & finally just ditching the rear sway all together.... this car is fairly tail happy as it is I know with 340-350 + rwhp and 275/35/18 or 19 inch rear tires my car is super easy to light up the rear tires

It will ceratinly work fine and it wil lbe hella fun to run it like it is,... but if you really want to maximize the cars potential and your potantial performance against the clock, a set of proper adjustable coilovers will make a bigger difference and allow you to set the car up with the most optimal ride height as well as adjust damping etc. as possible for the best peroformance.

& Sean is right on... you are WAY better off just doing basic IHE mods for power right now and investing in the suspension setup & wheels & tires do al lyou can afford to do there & take the time to run it and make adjustments to help dial it i as yo udevelop your skills, there is always tiem to go for more power later when you may have more fuinds available to afford to get more power

now to argue against my own logic above.....:)

If I was you and I was really set on a power jump for this activity, I would look into the SC option,...there are a couple used kits available now that would be MUCH cheaper than a turbo setup and the power band and lack of lag would be much easier on the drivetrain/suspension/tires and easier to control overall at the limit as you adjust to the new power....I saw one avail here in the FS forum and another one posted to the IS300 owners group on FaceBook this week as well..

good luck man!!
 

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Discussion Starter #9
thanks for all the help, i just gotta decide now. I do the autox just for fun, but i wanna win. and the turbo just sounds like so much fun...tough choices...
 

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thanks for all the help, i just gotta decide now. I do the autox just for fun, but i wanna win. and the turbo just sounds like so much fun...tough choices...
All the guru's are right on with the suspension. But the turbo is a blast and definitely transforms the IS into a different car.
 

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You can build whatever you want depends on $$$$ you want to spend ...
 

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Discussion Starter #13
budgets low ha, im in rotc for the marines and dont have time for a job because of it and i only get payed 300 a month. its taken me a couple of months to get the turbo parts i have right now
 

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If thats the case i would wait on boosting the car...it cost more then just the price of parts
 

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If thats the case i would wait on boosting the car...it cost more then just the price of parts
^X2... If I were you i would save up at least 10g's and i know alot of people here will say that is over kill and can be done at half that price but in the end you want to have a solid reliable car, build it right and dont take any shortcuts.

Keep picking up more and more parts and then when you have everything needed get it installed and tuned at a reputable shop. In the time being do suspension mods and really feel out the car so when you jump up to 300-400whp you can control the car with the new power.
 

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Discussion Starter #18
well i was planning on doing the install myself, and i found a MAP for a emu on a thread somewhere, same injectors and power, so i was gunna use that on low boost to be safe. but yeah the more i think about it, and read stuff like ya'll said maybe i need to wait on that and get the suspension finished
 

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It's not the IS, but here's my experience with autoxing the 240SX:

My set up: N/A single cam KA, mild lowering springs, Tokico HPs (blues), no-name front+rear strut tower bars, stock sway bars, raybestos brake pads (ha ha)

Unless these guys named J.D. and T.C. show up, I can pretty much get the fastest 240sx time at the autox that day. I've beaten 240SXs with dohc KAs, SR20DETs, RB25s and full coilover suspension set ups.

This set up is pretty neutral going around Laguna Seca Raceway, but definitely need bigger brakes, because the smallish brakes faded quickly.

My suggestion? Hold off on the turbo kit and get lots of autox seat time. Remember, fully adjustable suspension set ups can bump you to a different class. Same thing with the turbo.
 
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