Im In Desperate Need Of Some 1UZ Knowledge

[LexStarr]

First of all I want to start by saying that I am completely self taught and Ive finally reached my breaking point of frustration.
I feel like I have been running in circles on the internet for the past year trying to learn more about cars, more specifically SC400s, but I keep hitting dead ends. I bought this car with the intent of building it into a track and show car (more track than show) but every time I try to find info on how to get more performance out her, Im either told its gonna cost twice as much as I payed for the car or that I should have got an SC300 instead .

So what Im asking is if there is anyone who is willing to help me out or get me pointed in the right direction of learning more about this car and how to tap its potential.
What I would really like to know about is how to get as much N/A performance out of my car as I can for now while also getting it prepared for FI in the future.

So far this is some of what Ive done.
4:27 SC300 differential

Flushed and refilled every fluid and replace all their gaskets

5 speed gated shifter

98 SC400 cluster

97 LS400 front brakes

Gutted the car for new upholstery and stereo/security/remote start/smart start

Newly upholstered dash with center channel speaker

 

[spf_lexus]

Headers + exhaust will open up around 20-25whp, and then if you decide to supercharge, you can compound that hp even further.

 

[4U2QUIK]

then install a 5 speed transmission

 

[Spinnetti]

Track/Show/Stereo car? Kind of a mixed mission. Performance and pimpin' don't mix very well. If you are serious about going fast on a real race track, every ounce of stereo or whatever will reduce its performance. Its generally best to be real clear what your mission is, set some kind of realistic budget, then do some internet shopping to see what's possible and reasonable. The forums here have some good stuff, but there is a lot more you can do realistically with a turbo on the 300 than the v8 on the 400...... I race my LS400 (used to drive one one the street too that was stock), but I took out everything - even the door inners.

 

[samsdad]

Back to basics here but weight has been mentioned so no need for me to touch that.

Air intake. They like to breathe so a cheap way is fit a K&N filter but to do it properly you will want to make a decent cold air intake and remove any restrictions from the system. Also a must for FI

Exhaust. The Soarer/SC400 does have the best standard exhaust manifolds but a decent set of extractors with hi-flow cats with a good system that gives a pleasant note but not loud enough that the cops can hear you approaching or too crackly would be the go, But given the stereo that you're fitting you could probably run open pipes and nobody would hear the engine..

Cams.. Kelfords now have a range of cams available for the UZ.. Price of around $1300AUD at time of writing plus freight. Valve springs do need to be changed and at this time supply may be a bit of an issue as they're based in Christchurch NZ and got flattened recently for obvious reasons. My local suppliers have removed their products from their on-line listings for this reason for now.. You might also want to look into aftermarket or "piggy back" ECUs to allow fueling and timing to be adjusted for best results

 

[4U2QUIK]

on the subject of cams, since you're in the states, kelford cams would be unbelievably expensive rout. Since there's several highly reputable cam shops here in the states I'd suggest looking around. I've found that there are a few of the cam companies that make cams for these engines, but don't list them anywhere. So some research and calling around will probably yeild the best resilts.

 

[samsdad]

kelford cams would be unbelievably expensive rout

Only on the postage but that is out of their hands.It just cost me $300 to send some bits to Canada for a guys Surf, instrument cluster, window switches and an ECU, Not the price of the bits but the postage.. Like anything you do need to shop around but I've used Kelfords for quite some time and know the product to be top notch from personal experience

 

[spf_lexus]

I'll add a bit to the posts above, Lextreme cams are $750/all 4 which compared to the other brands are a steal. You need to provide david with your core so initially its $1000 for all four cams until core is returned. he also provides lash caps so you do not need to spend $500+ on OEM shims. These can open up a solid 20whp on stock ecu and 40whp if tuned to exploit the extra flow.

 

[spf_lexus]

Forgot to mention custom stall rate torque convertors. These can shed about a 1/2 second off your 1/4 time.
http://www.lextreme.com/tc.html

Good price, good warranty and best bang/buck mod for the auto sc400. I have these in both of my lexuses. No complaints at all.

 

[XR8tt]

Kelford are billet cams though...

N.Z exchange rate is still approx 20% on U.S $$ side..

It could change ?? Depends how much money is printed ...

 

[loosecannon]

Hi,

Just another quick question on cams, do the billet cams need to be shimmed? as on other engines i have mucked around with ( over head cams) a regrind needed shimming, But billets were drop in and no shimming,

Dave

 

[XR8tt]

As with all valve systems..
They all require clearance [unless they are HLA]
The std shims can be used to get correct clearance
from Toyota or what you already have then machine valve stem / valve face for correct clearance...
Also keep in mind that shim over bucket and "narrow base circle" can lead to shims being spat out !!! At high rpm...
Moderate grinds, good valve springs correct rpm ...
The ground cams are fine..

 

[loosecannon]

Hi,

Thanks for the info,

Yes the ones I have done in the past were HLA style,

Dave

 

[LexStarr]

I guess I should've been a bit more clear on my goals for this car.

I am know my build is bit all over the place but thats always been my thing when building/customizing cars. I do want it to perform well on the track but at the same time I dont want it to be a track only car, I still want to be able to participate in car shows. So with that said, Im not going super crazy with the interior/stereo system, plus I made the subwoofers removable so I can take em out when I go to the track.
So basically, Im trying to give it a nice balance between performance and show with a little more emphasis on the performance.

Now the issue Im having is that, because Im self taught, I know what almost every single part of an engine is, what it does and how it works but I have know clue how to make them better.
On the topic of cams for instance, I know what cams are, what they do, and that, for example, forged cams are better than cast cams but what would changing out the cams do exactly? And whats the difference (other than material type/build quality) between my stock cams and the lextreme cams and why are they better?

On the topic of drivetrain, this is the only mechanical subject of cars that I am somewhat well-versed in. I have already replaced the my oem 3.91:1 differential with an oem SC300 4.27:1 differential and once I find/can afford a TRD 2-way LSD Ill be installing that too.
As far as transmissions go, my plan as of now is to swap out my a341 with an a650, control it with the suprastick V4 and use paddle shifter but theres still a chance that Ill just do an R154 swap instead.

The other thing that Im really interested in the air/fuel system. Ive read a lot about how changing the a/f mixture can show impressive gains but I dont know what I would need to do that. Ive read about standalones and piggy-back systems that will allow you to do all kinds of stuff that will increase performance but I dont know what I would need, what works with the 1uz or how to tune it.

As far as the intake and exhaust goes, Ive already done the BFI mod, I have an appointment for tomorrow at 9:30 to have a complete cat-back system done with 2.5" dual piping and 2 high-flow flowmaster mufflers but I cant find headers for life of me but on the other hand, I might be doing a twin turbo system in the future which would make headers irrelevant.

I guess the biggest thing is that Ive read on every forum regarding the 1uzfe, that this motor has massive amounts of potential and that tons of people have tapped it (especially you crazy Aussies) but I cant figure out how.

 

[spf_lexus]

Before you get that exhaust done, you might want to re consider you sizing. 2.5" is way too big for any N/A 1uz. Dual mandrel 2.25" supports up to 450whp on these engines. You will lose power down low and in the mid range for sure with minimal gains up top in N/A form. We have a load of into on exhaust specifications for N/A and F/I builds. Im running 9psi thru a dual 2.25" w/o no choke up top.

In a nut shell, for anything less than about 400 crank hp, leave the stock front "Y" section (proven to flow 300whp), and the front cats (stock is very high flow metal substrate) but replace everything else. For maximum gains, use mandrel bends versus crushed.

 

[XR8tt]

Cams make a BIG difference as these engines where designed to pull like truck engines... So induction side is designed for torque at low rpm...
More valve lift = more flow and more duration [the time the valve is open] gives the head time to breath...
Air can still travel in [or out on exhaust] even though the piston is going the other way!!! This is where extra power is made and why big cams idle like they do..
Overlap come into where both inlet and exh is open at the same time...
4 valve engines are way more responsive to cam changes than 2 valve engines...
Meaning very little change in cam timing [specs] can make a big difference...

Billet just means it's a blank cam to start with, the base circle is as manufacturers specs or close to..
A re-ground cam has some ground away from base circle to change it's specs which is why thicker shims are required..
Up to a point this is FINE.. But you keep taking things away to make them bigger !!!
What this does is make the cam geometry more aggressive...

Imo in this day where aftermarket ECU's are sooo available [down under they are !!]
I find forced induction sooo much easier to make power..
Have to be conservative power wise on std rotating assembly [rods & pistons] but forced induction still gives low rpm power and torque ..
You just have to decide what level your power goals are...
Then keep mods to that level.. No point in having a 280* cam on std engine engine for example..
As in exhaust size etc...

 

[spf_lexus]

Headers:

IMF http://imfabrications.com/product.sc?productId=1

RUSH http://rushimports.com.au/store/index.php?cPath=6&osCsid=3463555e5a69041e1546689e40786353

S&S (out of business but maybe still some in vendors stock?)

 

[LexStarr]

Before you get that exhaust done, you might want to re consider you sizing. 2.5" is way too big for any N/A 1uz. Dual mandrel 2.25" supports up to 450whp on these engines. You will lose power down low and in the mid range for sure with minimal gains up top in N/A form. We have a load of into on exhaust specifications for N/A and F/I builds. Im running 9psi thru a dual 2.25" w/o no choke up top.

In a nut shell, for anything less than about 400 crank hp, leave the stock front "Y" section (proven to flow 300whp), and the front cats (stock is very high flow metal substrate) but replace everything else. For maximum gains, use mandrel bends versus crushed.

Im glad you said something, Ill do 2.25 piping instead and post pics tomorrow.
You might not be able to post it in time since my exhaust appointment is in 7 hours but could you post some links to some good threads to read through about exhausts?
By the way spf_lexus, weird side note, I was born and raised in Riverside and Murrieta, CA and now live in Denver, CO.

Thanks everyone for your replies. So what would you guys suggest I start with, fuel/ecu, cams/engine internals, forced induction, drivetrain...?
I would prefer to start small and work my way up, but I also really would like to just completely gut and rebuild my motor since my valve covers and rear main seal are leaking, plus the motor has 140k miles on it (not that anythings wrong with it, its just lost a bit of compression over the years).

If I were to completely rebuild my motor, what else, performance wise, besides cams and valves could/should be done?

 

[XR8tt]

Depending on what ratio you have now ???
A lower final drive ??

 

[spf_lexus]

By the way spf_lexus, weird side note, I was born and raised in Riverside and Murrieta, CA and now live in Denver, CO.

What a small world. The only reason im out in Pueblo is because of their auto program. I wasnt cut out for the small town life Lol. The AIM program is 1 of only 5 schools in the US that offers a bachelors degree is automotive management so here I am. Im about to start my final bout of classes this summer and then I should be finally done. I just wish it was closer to Denver... all the shops/yards are up there.

I have lived off Nutmeg/Jefferson in Murrieta for about 15 years now. Ringing any bells? Lol.


In all honesty, if I had your VVti engine (1999 right?) I noticed your gated tiptronic shifter which usually means 1999. I would just swap a set of forged rods into your block and then buy a used vortech supercharger for about 800-1000 used and then go from there. The VVti engines have MUCH higher flowing heads and a MUCH higher flowing intake manifold and even have slightly better cam profiles. I wouldnt mess with the cams and head work as they will make 500WHP easy in stock form. I know Denver has a couple shops that should be capable of swapping rods and rebalancing. I know it sucks dropping cash on a mod that doesnt contrinbute any power but trust me, once they are beefed up... that engine should take a solid 12-14psi once properly tuned (pistons now being the limiting factors). Lextreme rods are converted chevy H-beams that can take over 500hp and even offers another set for hp levels even higher than that.