stevechumo

iTrader: (5)

I'm currently building a turbo system for my SC400. I'm thinking about changing out to thicker steel head gaskets (with 100% stock internals) to be safe for around 12 psi of boost.

I don't know if it's possible for this engine with stock head gaskets to withstand this 12 psi. If it's possible, then I'd stay with the stock head gaskets to save the hassles. I might retard some timing (if it's required) and save the stock head gaskets. I've run 9 psi safely on stock Honda engines previously, which are relatively weaker than this 1UZFE. Has anyone tried more than 7 or 9 psi on this SC400 or SC300 with stock internals? Did anyone have to pull out the timing at all?

Any info. is greatly appreciated.

DIrEctQL

Search would do you good.

https://www.clublexus.com/forums/sho...d.php?t=258635

c0wboy

Change headgaskets to at least an MLS. The stock headgasket on the 1uz is that aluminized fiberboard material, it's weak when compared to a good MLS gasket.

Eric

MJHSC400

FWIW-- I've read where numerous guys put more than 14 psi of boost into the M50 and M30 BMW engines on stock gaskets, even up to 18 on occasion.. It was probably a new gasket I believe that was taking the 18 lbs, but you get the idea..

With great respect for the BMW engines design quality and bulletproof durability, I believe the 1UZ is no exception here, and can handle lots of abuse, but I would consider several things---- age and condition of motor, compression, bearing clearance, and changing the h/g to a thicker metal to improve strength and lower compression, -----

I'm not reccomending this, nor have I tested it on a 1UZ to be for sure, but lextreme has a lot of info on the subject that suggests these earlier 1UZs are super robust engines.....

BMW did supposedly copy/reverse engineer the early 1UZ for their 4.4 M60 ---- if that tells you anything.....

Tuning would play a huge part in whether this motor lasts, as well as the driver's foot, and efficiency of the turbo system, of course higher boost will equal higher temp's-- so you may consider a 2 stage boost controller, with a safe daily tune, and the "fast" button tune for a 1/4 mile bragging rights pass or two or three..

I wouldn't be afraid of doing it personally, as SR20's are also known to withstand 14 psi on stock internals and gasket readily, and is built very similar to the 1UZ, but really not quite as strong in my opinion...

Of course this is all speculative and theoretical information derived from the "SEARCH" button... But good luck with your build, and post pics of all the stuff--

TOYRACR

it does depend on a number of things.
If you get detonation, material of the gasket, compression, ect. . .
If you have the right combination of Cooler air and right amount of Fuel dialed in You'll be allright. But it will be best if you get a nice safe tune.
My stock motor MR2 turbo takes 17psi all the time and I haven't blown a gasket yet in the 4years i've owned it.

MJHSC400

That's a turbo motor though right??? They've got lower compression, better pistons, better headgaskets, and piston squirters to handle the boost properly.

He's asking about NA+T---- it's totally different--

Dyno time here is super important, you can tune it yourself if you feel like spending the time on a fuel map to keep it from running lean, or there are a few piggybacks that work with a lambda o2 sensor to tune the a/f ratio for you--

But, 12 psi on this motor calls for new engine mounts all the way around also, and if you've got any worn rear bushings, you're about to find them and wear them out much quicker as well too.... Not to mention you'll be making over 400 hp, and nearly 500 tq at the crank-- I think 8 psi on stock internals with a good shift kit in a good healthy motor with a good radiator will be a super fun 350 hp 400 tq monster that will run qreat with a professional tune and will be be a serious performance upgrade.

The SC is already faster than a LOT of the cars that will be trying to steal your spot on the interstate anyway, now it will be fast like a porsche.

574-SC300

I might be missing something here but it depends on the size of turbo or turbos you are running. I have boosted a stock 240sx KA motor past 12 psi for almost 2 years, with a 50 trim. Depends on the tuning and how the motor was taken care of.

c0wboy

Change your headgaskets to MLS gaskets....lower your compression.... go with a quality EMS... don't cut corners..... do it once, do it right, and never have to do it again...

Eric

stevechumo

iTrader: (5)

This is the most favorable method, but I'm a little restricted on time. That's why I'd like to gather all info. before I do. And the thing is I'm doing this by myself so I'm a little hesistating to change out the head gaskets....Too much work & time. I'd like to enjoy the powerful engine as soon as possible. However, once the headers are off, it's better to do them at once.

I don't know about the engine mounts to be replaced, but I know some of the FI SC & LS have been boosted over 400 rwhp with the stock mounts.

I appreciate some of you have pointed out the moderate to high boost your engines hold. But your engines are all built turbocharged from the factory. So it's a big difference from a N/A high compression, weak piston & rods & valves engine. Several stock '93 - '98 turbo Supras have been making over 700 rwhp safely.

MJHSC400

Early 1UZ -- Weak Rods--- sure

over40driv

Im not a turbo pro., but if my 98,000 mile Buick G.N. with plain jain 3.8 stock motor hit 18 psi regular, surely a 1uz can take it.

SUPRMSC

iTrader: (7)

Contrary to popular belief, the motor can take more damage then you might expect. You have to remember its all in the tune and supporting mods. The one thing you should worry about is the transmission if you're planning to make that much power.

MJHSC400

shift kit.....

semdaddy

how many miles u have on ur car?
im planning to turbo my sc300 i just hit 100k
should i rebuild my automatic tranny?
my goal is between 300 and 350 hp..

stevechumo

iTrader: (5)

My car has 147,000 miles respectively. This SC400 or your SC300 engines will last forever. The average life is about 400,000 miles, which means we'll have more than another 20 years for fun. I don't think you'll need to rebuild the tranny if you'll only run for 350 hp. The tranny or engine shouldn't break if they're properly cared for in the past and in the future. I've known several guys that have hit 400 crank hp safely for years. For this 400 hp, I'll go for a rebuilt torque converter but not the whole tranny.