jwynn

Im sure theirs post on here but I couldn't find any pertaining directly too it. Im looking to make my sc faster and bolder without turbo or swapping. What are some of the little things i can switch out to get more power and a better sounding engine when I hit the pedal? What things aren't worth buying? Thanks in advance

KahnBB6

iTrader: (5)

Hello! There is a lot of information on questions similar to yours. People have used many inconsistent thread subject lines but it's been much discussed if you search for specific terms.

In short, it isn't worth the trouble and expense for how little you might gain. Yes, there are a couple of headers and yes, there are a couple of aftermarket intakes... but your factory airbox is actually superior to an intake and the header does more to rob low end torque than to give you appreciable horsepower gains. You will still be better off with the factory torque band than without.

Sorry to echo what you probably have already read but this short version I'm telling you is true. The NA JZ engines are legendary for their response to boost... but not much else. Even superchargers are mostly non-starters with these engines.

Here's an example of what it takes to put out some respectable horsepower numbers with a full NA build. Less than 7-8 people in the world have done what this guy has:

http://www.supraforums.com/forum/sho...sphemous+supra

Now... here are some things you CAN do that will change your car's feel even though you won't actually have more horsepower:

-LS400/TT brake upgrade
-Wider tires
-Limited slip differential
-5-speed manual swap (W58 or R154)
-If beginning from an automatic SC300, leave the 4.272 final drive ratio in. It's fairly aggressive with a manual transmission (use a YellowBox speedo corrector for this)
-If beginning from a manual SC300 you can change out the 4.083 final drive to a 4.272 automatic rear diff. See above (again, YellowBox for your speedo).
-Daizen rear swaybar upgrade or MKIV TT rear swaybar conversion
-Suspension upgrade of your choice (Gixxer_Drew or any reputable aftermarket coilover) plus a "Lance" alignment.
-Replace front LCA's if needed. Use Supra MKIV spec arms, not SC.

For sound, try an M2 dual catback. I think it's a great near stealth but tonal change to the exhaust note. Alternatively, Tanabe and Borla also make good subtle catback bolt-on exhaust kits. There are other much louder and more aggressive catback exahusts but I feel they are better suited to turbo cars.

Especially if you have an automatic SC, you'll be surprised by the difference the suspension, wheel and tire package and a 5-speed manual conversion, LSD and 4.272:1 ratio make. Yes, V6 minivans and Camrys can still keep up with or beat you off the line but you will have a different car at all speeds. Your highway cruising rpms @ 70mph are still only 3,000-3,100 at that point.

What I have described is more or less the way my car has been set up for a few years now due to Cali smog rules making my engine swap take eons to complete. Very livable and capable DD/handing setup that, while not "fast", is anything but boring.

To reiterate though, I can't recommend messing with NA modifications to the engine itself. Other engines respond well to such things out of the box but not the JZ series.

Hope this helps and feel free to hit any of us up as you refine what you want to do with your car. Good luck!

jwynn

This seems like a lot of good stuff i really appreciate the time you spent to tell me all of this. Ive been searching for wider tires but don't know which would fit my rims ? Can you recommend any decent wide tires with a link? All this stuff is intriguing Thanks man

KahnBB6

iTrader: (5)

jwynn,

No problem. More on all the subjects I touched on are all covered here.

Without knowing what rims you have on your SC300 I am going to assume it's the original factory wheels. Unless you have a wheel style of choice I recommend the old reliable solution of finding a set of 93-98 MKIV Supra Twin Turbo rims. These are staggered: 17x8 up front and 17x9.5 in the rear. For NA use I recommend keeping the stock MKIV TT tire sizing of: 235/45R-17 front and 255/40R-17 rear.

Tire type varies with different preferences and needs but for a good summer compound with excellent rain traction at a reasonable price (in the above sizes) I recommend the BFGoodrich Comp2. But there are many other brand and types out there.

I'd just avoid an all-season and I recommend getting away from factory SC rims. The later '96 and '97-00 styles look good but won't give you a handling advantage. Additionally, by going with MKIV TT rims or another 17" or 18" rim with the same offset you will have clearance to upgrade to 95-00 LS400 front brake calipers (or Supra TT calipers).

Staying with the 17" rim size and those overall rolling diameters are better for acceleration with an NA engine though. The use of a 255mm rear tire helps with traction, handling and stability. Along with a Supra TT "Lance" spec alignment (see MKIV.com for that)

jwynn

I know i have 215/50R17 so that I'm assuming makes my rims 17 inches ( I'm not a tire guy) but I'm looking for thick tires in the back comparable to drag racing tires but maybe not as big but i need something that'll fit the same rims but are wider if thats possible. You said the BFGoodrich but those didn't seem too wide ( only saw internet pics) You've been a great help Kahn. Any knowledge you have id be glad to hear.

KahnBB6

iTrader: (5)

Yep. The numbers after the "R" in a tire sizing denotes the wheel diameter. In this case, a 17-inch rim. The "215" part of that denotes the actual width in millimeters and the "/50" refers to the sidewall height. The different combinations of sidewall height and tire width can affect your actual contact patch on the ground. The lower the sidewall height number, the "thinner" the tire will look. Very large factory performance rim and tire combinations will often have shorter sidewall heights.

The balance of what works and what doesn't just depends on the type of car and how it's set up (or will be set up to desired effect).

You won't be able to do that and have a good balance of tread wear and handling response ("turn-in" on the front tires). There is a limit to how much tread width can go on a certain width of rim and before you even it that physical limitation you'll hit the aforementioned limits of what actually works.

For an SC I think at least a 17x8 or 17x8.5 inch rim up front and a 17x9, 17x9.5 or 17x10 rim out back are good general ranges. You can do matched rims front and rear to a point... but I think staggered is more advantageous. This is why I recommend the Supra TT staggered rims which start you with a 255/40R17 factory-spec rear tire and can take a 265 or 275 very easily.

But with an NA engine I think the stock MKIV TT tire sizings are right at the sweet spot to balance handling, affordability and traction. I ran 275's out back for a while but found there was nothing gained with the stock engine output over more affordable 255's. Turbo engine power is an entirely different story with these cars concerning useful tire width.

And you're welcome! Hope some of this helps you figure out what you want to do. Though I'm no guru with wheels and tires. Other folks here are much more knowledgeable.

jwynn

Did you have to make mods to run the 275s? That sounds good I want to get thick and wide as possible without causing problems and making mods

KahnBB6

iTrader: (5)

Nope. I bought my car and within a week I switched to Supra TT rims. 245/45-17 front and 275/40-17 rear tires were the first sizes I threw onto the car. Though at the time I had no speedo (VSS) corrector. When I go turbo I might do those sizes again.

I believe 285 is also possible with those rims. Not sure.

However... believe me... you do not need anything wider than 255/40-17's in the rear if you will not be swapping to a GTE engine or doing an NA-T conversion. Your car will actually be slightly slower by using that much tire without more engine power. That's the primary reason I switched down to the 255 sizing (for that rim). Also because given that reality they are slightly cheaper than 275's.

I'm not sure what is entailed with going extremely wide but unlike, say, the 2003-2007 Pontiac GTO chassis which supposedly maxes out at a 265mm rear tire width, the SC and MKIV Supra chassis are known for their capacity for very wide rubber.

But do pay attention to reviews of summer performance tires as far as rain traction. The more you tweak an SC's suspension the more this is important. Fantastic car but you need to respect it in the rain. Especially if you install an LSD.

jwynn

I know you said you're not a tire guy either and you don't know what rims I have but would rims such as mine that fit 215 tires fit 255-265 tires as well or is it a must i go bigger? or how big could i go with these rims that have the 215?

KahnBB6

iTrader: (5)

I'm pretty sure if you have a rim width optimally set up for a 215mm tire it's not going to work very well with a 255 or 265. What is the exact rim size you have? That's going to determine just how much tire you can put onto it before you begin to have sidewall deformation (which you don't want). You can go a little fat with all rims, but not safely (or ideally for handling response) beyond a certain point.

Here is an article on Tirerack that can explain this better than I am able to:

http://www.tirerack.com/tires/tirete...sp?techid=198&

Here's an example I can give you:

Prior to my SC I owned a late model Honda Prelude. One of the great limitations of the car (other than the engine) was the 205mm factory tires. Because bigger (ie: bigger OD such as a 17, 18 or 19 inch) rims didn't equal more performance in that car, auto-x guys often went from factory 205/50R-16 sizing to 215/50-16 or 215/45-16. But that wasn't enough. Because lightweight 16mm rims in widths greater than 16x7 or 16x7.5 were hard to come by, it was a great thing when someone discovered that 16x8 1993-95 Mazda RX-7 rims had exactly the right bolt pattern and offset to fit the Prelude hubs. And that was about as wide a rim as you could fit in the fender wells.

This was a good thing for track cars because the rim was slightly lighter than the factory rims, had a full inch more width and could accommodate up to a 245/45R-16 or 245/40R-16. I forget which was the right size. Anyway... that's a lot more useful tire area to throw the car around in corners or use on an actual racetrack. Then the only trouble was that perhaps 2-3 tires total were available in that size... including one Hoosier slick.

Point being that the extra full inch of rim width was absolutely needed to allow the extra wide tire to even fit properly.

So I would say that, yes, you do want a rear rim for your car that is at least a 17x9 or 17x9.5 at least to run 255-265's. Front rims do not need to be so wide because you won't need such wide tires up front. Also your turn-in response is better with only 235-245 width front tires.

Although like all FWD cars factory SC's and Soarers came with matched tire/rim sizing to promote a more neutral driving feel, I'm a believer in staggered tire/rim sizing with a good alignment since you can allow for so much more contact patch in the rear to keep the car from breaking loose all the time.