LS400 - Twin Turbo V8

[`nigno]

Hey, my names James, im from the Gold Coast in Australia, have been reading your forums for almost a year now and finally decided to join as I have some pertinent questions

I currently own a 1998 Subaru Impreza WRX (Rally Edition) and have been offered the opportunity to trade (plus a cash adjustment to my benefit) for a 1991 Lexus LS400.

This is a very tempting offer to me as I yearn for a nice cruising car and this thing is PIMPED, 3 x Screens, 18 inch mags, dumped on its ass, twin exhaust, leather interior (retrimmed) etc

The only things that turn me off are the fact my WRX has just ticked over 120 000km's whereas the Lexus has 180 000km's, plus the WRX is much faster, and I have ALWAYS owned performance vehicles and know I will be pissed with the lexus's sluggishness.

Question 1: With 180 000km's on the engine, how much longer can I expect the V8 to run well and survive, it seems to be of good health and has a full lexus service history which is very impressive, however im afraid I will go swap a relatively new car and then in 20 000km's time have nothing to show for it.

Question 2: I would obviously look at rebuilding the 1uzfe before any forced induction modifications were undertaken. Approximately what costs are involved in Rebuilding the bottom end and freshening up the engine.

I am well aware of the processes and parts involved, I am just looking for approximate costs as I havent had experience working on or buying parts for a 1uzfe before and ppl I have contacted so far have been vague and unhelpful.

Basically after costs for stuff like Rods, Pistons etc

Also how do the 1uzfe's perform in an LS400 standard, I have standard power figures/specs etc, but as a first hand experience I would like some feedback. For the time being if I decide to go ahead with the trade I would be hoping it is very smooth and cruisy with enough pick up to still put a smile on my face on the highway.

FINALLY, I have left over parts from the WRX, most of which I will sell some of which I thought may be helpful and useful for the 1uzfe, the main one was a 400hp rated VF22 turbo.

I was originally going to just sell it and use the money to start stockpiling parts for the Lexus but thought If i purchased a second turbo it may be suitable for the TT conversion when the time comes. Would this be a suitable turbo, im after power figures of around 500rwhp (long term) with an initial goal of (300rwhp).

Please feel free to add any input or ask any questions as I have been thinking and dreaming of a twin turbo 1uzfe project for some time now and im beginning to get excited now it is coming to fruition. Unfortunately excitement sometimes makes you overlook things...

*thinks back to his last rotary conversion into a 1977 Mazda 323*


One last thing, drivetrain wise, what will a standard LS400 diff, tailshaft, and gearbox be able to handle power wise before it needs to be improved/modified with shift kits, stall converters, replacement gears etc ?

Sorry for the long post thought I'd better make my first one a good one, thanks in advance for the help

 

[1UZ-MX83]

Question 1: With 180 000km's on the engine, how much longer can I expect the V8 to run well and survive, it seems to be of good health and has a full lexus service history which is very impressive, however im afraid I will go swap a relatively new car and then in 20 000km's time have nothing to show for it.

I think you'll find that, if the 1UZ has been well maintained over the years, it will easily outlast a WRX engine. Anecdotal evidence suggests long-term mileages (before needing any kind of reconditioning work) at somewhere between 500-700,000kms given appropriate and timely maintenance.

Question 2: I would obviously look at rebuilding the 1uzfe before any forced induction modifications were undertaken. Approximately what costs are involved in Rebuilding the bottom end and freshening up the engine.

For most applications, you would not touch the bottom end of a 1UZ. With 6-bolt mains, forged steel crank etc, they will withstand large amounts of horsepower. A search around the site will give info. on various projects where people have used after-market rods and pistons etc, although there are plenty of reliable FI 1UZs going around with stock internals. (A local TT 1UZ - unopened - recently produced 320RWKW - or 430RWHP - ).

I am well aware of the processes and parts involved, I am just looking for approximate costs as I havent had experience working on or buying parts for a 1uzfe before and ppl I have contacted so far have been vague and unhelpful.

Most basic consumables are available at Lexus or Toyota (look for a Toyota dealer which deals with import bits and pieces - the parts are the same, but the Toyota part numbered item retail for considerably less than the Lexus ones). As for other mechanicals, again check 'round the site.

Basically after costs for stuff like Rods, Pistons etc

Again, check around...Largely depends on what you spec/buy.

Also how do the 1uzfe's perform in an LS400 standard, I have standard power figures/specs etc, but as a first hand experience I would like some feedback. For the time being if I decide to go ahead with the trade I would be hoping it is very smooth and cruisy with enough pick up to still put a smile on my face on the highway.

My father has a Celsior (which I sold to him) and it goes quite well. It will never be in the league of a WRX (or my own 1UZ-powered Cressida), but it does "waft" it's way to the 180KPH speed-limiter in reasonably quick fashion.

FINALLY, I have left over parts from the WRX, most of which I will sell some of which I thought may be helpful and useful for the 1uzfe, the main one was a 400hp rated VF22 turbo.

I was originally going to just sell it and use the money to start stockpiling parts for the Lexus but thought If i purchased a second turbo it may be suitable for the TT conversion when the time comes. Would this be a suitable turbo, im after power figures of around 500rwhp (long term) with an initial goal of (300rwhp).

I'm sure one of the more knowledgable FI blokes will be along shortly to discuss the pros and cons of different turbos...

Please feel free to add any input or ask any questions as I have been thinking and dreaming of a twin turbo 1uzfe project for some time now and im beginning to get excited now it is coming to fruition. Unfortunately excitement sometimes makes you overlook things...

Definitely the right engine (and, IMHO, the right platform) to start with!

*thinks back to his last rotary conversion into a 1977 Mazda 323*

What were you thinking? (j/k)

One last thing, drivetrain wise, what will a standard LS400 diff, tailshaft, and gearbox be able to handle power wise before it needs to be improved/modified with shift kits, stall converters, replacement gears etc ?

The diff "should" be OK for most things. The ECU (which controls both engine and trans) will "slow-up" shifts under hard acceleration in order to make them as smooth as possible. This heats up the transmission. Obviously big hp + lots of hard launches will eventually shorten the service life of the transmission. Fitting a large trans. cooler is the first step. Quickening up the shifts (and perhaps an MV automtics-style full rebuild) is probably the next step here...

Sorry for the long post thought I'd better make my first one a good one, thanks in advance for the help

Welcome to the site.

 

[`nigno]

My father has a Celsior (which I sold to him) and it goes quite well. It will never be in the league of a WRX (or my own 1UZ-powered Cressida), but it does "waft" it's way to the 180KPH speed-limiter in reasonably quick fashion.

Yer, im really really over neck snapping acceleration anyway... hence the want for change. As long as it will spin the tyres without much fuss and be fun to surprise some of the imports n local barges on the highway with i'll be laughing.

After something a LOT more comfortable to drive, the days of cramped 2 doors and rigid coilovers are done for me. Need something I can drive in comfort and style but will still go when it gets on the noise.

Seems like im heading down the right path...
Thanks for your input.

 

[rac]

tell you what i was considering a simmilar turbo choice to you. Vf23 x 2. As the one on my 89 rs leggy seems to work just fine.

 

[`nigno]

Yeah they are really responsive, yet still have the legs to continue to pull up high, I figure if they are on full boost on a 2Litre boxer engine by 4000rpm then they would be on the noise maybe by 2500 - 3000rpm on the 1uzfe and have no trouble holding steady til about 6500 - 7000rpm on 18psi (just when they start coming into their efficiency range).

The positives are they are smallish (in physical size) so wouldnt be too hard to fit them in in comparison to other turbo choices, roller bearing and relatively cheap for the performance they are capable of.

Negatives: Strange flange pattern so upgrading in future may be more complicated (manifold modifications) as it is the largest turbo in its range (VF). I believe AVO make a few turbo's with the same flange that are slightly higher in terms of HP rating however responsiveness and efficiency arent as good. Plus the increase in HP is only slight.

So it may be worth looking at selling it and buying a set of turbo's similarly sized from the garrett range to allow for greater ceilling in future modifications.

Would appreciate any thoughts/advice from hands on experience. ALSO I have looked around the site and used the search function but to no avail.

Is there anywhere that makes pre-fabricated twin turbo manifolds for the 1UZFE or is it a custom job only ? (doesnt matter either way really) But the only thing I could find remotely related was the rush imports headers.

BTW I have a die grinder, a press bender, a mig welder and limited skills
I am VERY GAME and always willing to learn, if anyone can give me some help with design eg. pipe diameter, runner lengths etc. I have a fairly good knowledge of engineering just not any hands on experience. Would love to get in there and have a go at fabricating my own gear, problem being wouldnt have a clue where to start in terms of design process other than checking available space etc.

Sorry to keep making long posts... just very excited and genuinely interested in learning more abotu these great cars/engines

Cheers
James

 

[rac]

hey you have everything you need. just get some steamtube bends and a case of beer and go for it.
and profile cut some flanges out! as for pipe dia. do not go any bigger than port size and you will be fine.
give it ****!
good luck!

 

[`nigno]

Still plenty of questions before I leap in the deep end.
Wouldnt mind having a go at some equal length headers, much liek the concept diagram lextreme has posted in one of his previous topics.
Still to decide whether to go high mount or low mount, and havent even checked space for dump pipe clearance, turbo placement etc etc which will all contribute to header design. Also how the collectors meet at the final flange, I have seen some headers with individual pipes (intact) merging into the flange, then I have seen some others with an open ended design where the collector pipes have had the inside walls cut out so that all runners meetin one area at the final flange.

I don't know anything for sure and haven't really researched but in my opinion and with my limited knowledge to me that would create turbulence affecting flow and exhaust gas velocity, yes or no ?

Anyway, still waiting for ppl's opinions/advice on the first round of questions I'll leave the rest for when the time comes

Went to inspect the car yesterday, and it is EXTREMELY nice, im very excited at the prospects of hopefully purchasing it. There are a few problems here and there which I have asked for the owner to sort out, he ensures me he will get onto it straight away and I can go for a second inspection next week sometime. So if all goes well I could have the car as soon as next weekend. If not Im still going to get rid of the WRX and buy one as I have fallen in love with these cars and they suit my needs/wants perfectly

Thanks again for all your help.

 

[rac]

well im doing it to a pick up and i dont have space problems as tomorrow im cutting out my inner guards so i can lower it another 3 inches, and so i can hang the vf 23's over the tyres.

 

[`nigno]

Well negotiations have been pretty good so far and I should have the car by next week if all goes to plan
Will post up pics sometime today site that hosts them is currently down atm

 

[`nigno]

This is her, add a couple of turbo's and I think I might have the ultimate cruiser. Not too mention the sound system pumps out an insane 149dB, apparently its advised you dont close the windows at this level as the roof may bubble out hehehe

 

[stevechumo]

The car looks really hot. It could make a girl to take off her layers due to its heat. Just joking! For the design of the turbo piping for single turbo, I thought about running the 2 exhaust pipes from both sides, under the engine, and into 1 big pipe to the turbo. Merging 2 to 1 should only be done when it's a little higher around the radiator. Then from the turbo exhaust side to the downpipe, do the same. The point here is to leave more ground clearance. Since the LS is not lowered that much, the piping should have more than enough ground clearance. Having about 4" of ground clearance is good enough. I've driven a lowered car with only 3" of ground clearance and rarely had a problem.

The single turbo could be on the battery side, which the battery is relocated in the trunk. Otherwise, the turbo could be on the passenger side with the relocations of the steering fluid reservoir and the coolant reservoir. My choice of turbo would be a T60-1 for daily driving.

 

[`nigno]

Well I now actually have the car, have done for about 3-4 weeks now. I cant believe how comfy and smooth it is, i am in LOVE

Now If I could get some of these questions answered I'll be in business