mk4 performance

[kylej]

So basically I can go bpu++++ to 650whp eithout changing all that much as long as I buy the parts to handle the power? So what would you suggest I get this year (I want everything except the turbo kit) so what would I need so that next year I can just buy a turbo kit and install? Besides the clutch cause I'll do that next year too.

[pwpanas]

Originally Posted by kylej

So basically I can go bpu++++ to 650whp eithout changing all that much as long as I buy the parts to handle the power?...

Yep, other than the parts I mentioned above (downpipe, intercooler piping, etc.).

Originally Posted by kylej

...So what would you suggest I get this year (I want everything except the turbo kit) so what would I need so that next year I can just buy a turbo kit and install? Besides the clutch cause I'll do that next year too.

Go BPU++++, plus either a fuel kit or a very large alcohol injection kit. For the intercooler, do a GReddy 3-row. For the BOV, go with an HKS TypeII Racing.

At the BPU++++ level, you'll very likely burn out your oem clutch before you put the single turbo kit on. It starts slipping in 6th gear under boost on the highway first...then 5th, then 4th, etc.

[kylej]

I'll replace the clutch when needed so it should be about 4k for parts? (excluding clutch). Thanks for the help man.

[pwpanas]

Originally Posted by kylej

I'll replace the clutch when needed so it should be about 4k for parts? (excluding clutch). Thanks for the help man.

Yes, that's a good estimate without the rims.

Oem-width rims & rubber won't even hold 425rwhp (and definitely not 650rwhp!). Your rear rims need to be at least 11.5" in width (315 or 305 width z, y, or r rated rubber, and not low-profile). 11.5" is 2" wider than oem rims. It's easy to spend over $2K on just the rims, and some folks spend $6K or more if you also go for a large diameter rim too.

Don't forget to budget for the race fuel (unless you go for the alchohol injection kit). More than about 16psi on 93 octane {(r+m)/2} will gradually damage your engine (it won't grenade instantly, it'll just degrade the compression/leakdown numbers over time). To make 425rwhp, you'll need to hit about 20psi of boost...and to hit that safely, your gas tank should contain about 25% of 100 motor octane (or better) race fuel.

Oh, I forgot to mention the GReddy 3-row intercooler is available with both "oem twins" piping and "single turbo" piping. Ideally, you should buy it with both sets of piping so you don't have to worry about that when you get your single turbo kit.

[kylej]

Okay sweet dude thanks so much for your help, what size of rear rims will I need for 650rwhp, ill just get those off the start.

[pwpanas]

Originally Posted by kylej

Okay sweet dude thanks so much for your help, what size of rear rims will I need for 650rwhp, ill just get those off the start.

11.5" width on the rear rims is the main thing (with the correct offset and bolt pattern, of course). The diameter isn't that important ... any thing from 17" diameter through 20" diameter works fine - just be sure you can get the rubber to match. Don't forget - no low profile rubber on the rear - you need some flex to the rear sidewall to ensure traction. Check out tirerack.com ahead of time for available sizes. On the front, a 9.5" wide rim matches the 11.5" rear rim just fine. If you want to install a bigger front brake kit someday (roadracing application), you probably need at least an 18" diameter.

I'm glad to help! Welcome to the Mkiv Supra Turbo 'brotherhood'!

[kylej]

Nice man thanks you're a huge help.

[pwpanas]

Originally Posted by kylej

Nice man thanks you're a huge help.

You're welcome!

...forgot to mention you may not want to run an ultra-low-profile tire on the front either. Larger diameter rims bend when confronted with potholes, so an oem-height sidewall on the front may be desireable (depending on the street condition where you plan to drive your Supra). A really low profile tire on the front (of a rwd vehicle) is primarily used for roadracing/autocross, to make handling more precise. You can to decide whether you want precise handling or pothole protection.

[kylej]

Ah, okay.. So 17'' is probably good all around?

[pwpanas]

Originally Posted by kylej

Ah, okay.. So 17'' is probably good all around?

Yes, from a pure performance perspective, unless you want to upgrade the brakes.
Note that the oem rims are 17". When considering aftermarket rims, there's a good thing and a bad thing about the 17" oem rim size:

• The bad thing: Normally, guys that spend $$$ on a set of rims will want the rims to look more cool than oem. In 1993, a 17" rim was considered relatively large, but by today's standards it's really not. Most guys that buy aftermarket rims for the Mkiv Supra Turbo get at least 18" rims all around...and 19s are quite common. Beside a 19" rim, a 17" doesn't look nearly as 'bad@ss'. As much as I'd prefer for this analysis to be 100% about performance, the reality is that looks matter too. The rims are one of the most visible features of the car, and they're the easiest opportunity to upgrade its looks without doing any bodywork or repainting.
• The good thing: If you're looking to do this on a budget, or you want a 'sleeper' look, then get an extra set of oem rims, and run the back rim on the front (you may have to shave the lip of the caliper to do this - very easy - the caliper lip is not functional, it's only there to prevent someone from accidentally putting the rear rim on the front).
  There are companies that widen rims - so send a pair of oem rear rims to one of these companies and it comes back at 11.5" that you run with a 1" spacer. This is what I did for my Supra...before I got my brake upgrade:
  http://www.mkiv.com/techarticles/parts/oem_mkiv_rim_widened/index.html
  ..it's actually my Supra in that article.