SC400 Twin Turbo Selection

[LTLRKT]

Hey guys,

In the process of putting together a Twin Turbo setup on an SC400.
Just wondering if anyone has had much experience with this and if they could offer any advice from their experiences, etc.

At the moment we're most likely looking at something like a T3 with .86 a/r and a 60 trim t04e with .60a/r. Or same setup with 60-1 compressor & .70 a/r.


Keep in mind the engine is being ripped out soon to be rebuilt with forged pistons & rods. Aiming for approx 8.0:1 Compression, and some decent head work.


We're aiming for 450-550 kW @ the wheels or more as the car is a GT ltd and weighs almost 2 ton according to the books! Need some real power to make move.
Already has a supercharger setup, extra injectors, Standalone Engine Management, extractors, etc... 190kW @ the wheels on about 7-8psi


Really appreciate any help as im not very familiar with 1uzfe... yet



Thanks,

Riste.




PS - Anywhere cheap i can order the turbo's? Ready to order 2 Turbos and 2 Wastegates ASAP.

 

[Lextreme II]

The best deal for turbo and accessories is www.boostedsystems.com Tell Joe u r refer from Lextreme and you might get better deals. With forged internals and head work, your engine will handle lots of power. If you are aiming for 550 KW that is about 650 rwhp (guessing) A pair of GT25R or GT28R will do the work very well. Here is a page that might interest you www.lextreme.com/GT.html

If money is an issue, you always try Twin CT26. Chrisman made 370 rwhp at 8 psi with CT26. I made 325 rwhp at 8 psi with dual RB25.

 

[chrisman]

hi riste, welcome to the site.. i dont have many post here either..
im in the states, and over here were way behind you guys in aust.. seems like you guys have been playing with these v8s for a while..in any case, i have put 2 turbos on an sc400..i put the turbos on top-in front of the engine.. i ended up removing the aircond--in the interest of saving time.. but you should still be able to keep the air..also on the alternator side, i removed the large lexus alt, and installed a smaller corrolla rebuilt alt with a modified housing to place it closer to the engine.. i also moved some componants around, but everything is still used--even the hydraulic fan.. anyway--go ahead and ask specific question..i have not posted any pics on this site yet, but i will give it a shot later.. i dont know how many sc400 have been TT'd in AUS. but in the states there are not many.. very few is probably more accurate..

 

[chrisman]

heres a pic of the engine in the sc400 TT-- if you look around carefully, you can see whats moved around..

 

[Lextreme II]

Chris,

Nice.. post some more Love the heat shield. Here is my Single Turbo LS400.

 

[chrisman]

lextreme, thanks.. you placed the turbo almost exactly as i placed one of the turbos on the sc..i bet in the future there will be alot more Lexus turbo cars with a similar solution/placement of the turbo-turbos..

anyway,heres a pic of the (slightly moved,and smaller) alternator.. you can also notice i rerouted the belt slightly differently to keep it away from the ex mani..also take note of the heat shield..

 

[Lextreme II]

Chris,

Great minds think alike. If you have to do it all over again. What would you do differently? I noticed you modified alternator and eliminate the AC compressor. What would you do differently the next time around?

I am building a motor with forged rods, forged pistons, MLS gaskets, ARP studs, Port heads, Supra TT Springs and Retainers along with Supra TT adjustable Cam gear. I might also throw in a set of cams. Wanna max it out or you can say want to make it Lextreme! This project will be power by two Garrett GT30R.

 

[LTLRKT]

Thanks for your replys guys. Bit of background - Ive had a lot of experience in turboing Pulsars here. Engine conversions, and large turbo setups, etc. I love the SR20. I got so into it that i ended up quiting my job last year Jan 1st and have been doing it for a living lol. After 1 year, i am now opening a workshop for wierd turbo conversions and basic turbo upgrades, etc.

My best buddy (for over 10 yrs now) has owned an SC400 for a approx 3yrs now, and as stated before he's gone the supercharger way. We're pulling all that off and wanting to go for really stupid power. Because there will be no labour charge (on my part) we're putting the money elsewhere!
Although we're staying away from the GT series turbo's as to cut costs so that money can be thrown at the engine. $2000 for both turbo's or $5000 for both turbo's is a big difference.

Now i will admit i dont know much about these engines other than the little reading on the net in forums etc. The turbo's im looking at are rated at 500hp each. Do you think this is over kill? You mentioned Lex, that your going twin GT30's. Are you reffering to the GT3040 with the 56trim comp wheel, 0.70a/r and depending on what rear housing - .63 or .82 rates them at either 500hp or 600hp. Or the GT35R - 700hp 1.06 a/r turbine housing, to4s 52 trim comp wheel??

Im just trying to get a good feel for what thses things can handle, especially with some forged rods and pistons. Looks like we're leaving everything else stock for the time being, including the head. It will get the port and polish and cams later after its all run in for a while and done some dyno time to get an idea of where we stand.

What im affraid of is either going overkill, or going too small and having to upgrade later. I want to get the turbo's right from the begining! Can anyone tell me what kinda boost the 1uzfe's can handle? I pretty familiar with the yellow Celica in Western Australia that ran something like an 8.9 or 9.8?? I cant remember... but i saw it mentioned on this website i think about the rediculas boost it was running withh stock internals? I spoke to the guys that built it about a year ago, but they were very secretive and "never called back". What i do know is that the stupid power they were getting out of it at 10:1 compression is because they were running a water to air setup with a dry ice sump in the boot. From memory the guy did say that they were getting below freezing intake temps on full boost. Something silly like 30psi. I personally wouldnt try pushing more than 10-12 psi on 10:1 comp on the street, and even then - good intercooler and good tuning.

The Cleica is by no means at all a street car. Im looking for as much power i can get out of this thing - reliably - on pump fuel, on the street, all day every day. So front mount cooler setup using 4.5inch core, 200mm tall, and as wide as can fit in there! Looking to drop the comp to 8.0:1 or 8.5:1 (any recomendations?) Also it will have a custom intake and plenum made with either two 2.5" throttles or one single 4". And yes this will be daily driven hehe (cant wait!).

In saying this, woud two t3/t4 or t3/60-1 be too big? Maybe the power figure i stated is lower than what we're trying to get. I guess we just want anything over 400kW at the wheels, but a lot more than that if possible with what we're building. So will a stock engine with forged pistons and forged rods handle 25psi... or more from a turbo that can push something like 60lb/min? The GT3040 is rated at about 55lb/min and the GT35R 50lb/min but bigger power gains from the huge turbine a/r. Im thinking of going a balance of these two with a .82 (or .86 cant remember specs) turbine a/r with a simmilair compressor flow of something like the 60-1 which was rated at 61lb/min, or if thats over kill, something like the much more efficient to4e 60trim? Which flows i think 53lb/min with a .60 a/r comp cover.

Im hoping you can see where im at here and i havent confused anyone (i had to read all that 3 times over lol)

Also, there is so little availble for these engines, i was going to get everything custom made here in Melbourne, or have special order pistons made by someone like Arias and rods from a company overseas. Any help would be awesome guys.

To give you an idea of when this is happening, i was ordering the turbo's and wastegates tommorrow (monday here) but i decided to wait... see what you guys have to say! The more information i can get together, the faster this car is going to go!




Thanks heaps.


Riste.

 

[chrisman]

hi riste, i found myself in almost the same situation.. a friend has had his sc for a while..the car was great, but he wanted more power.. he also wanted to keep using the car for an everyday car, so it had to stay as reliable as it was.. one of the first things i will say is that so far--from my experience- these are very well built and well engineered enigines and autos.. i think the more you work with them, the more youl come to realize this.
there are many ways to proceed--your gonna need to work out with your mate on what he is willing to go thru--money,time,expectations..once its is clear on what both of you expect, the path should be evident..
in my friends case, money was a major factor.. so i ended up using some used toyota turbos, and kept the total cost way down..alot of the parts were sourced from the net,, my friend spend alot of his free time searching for deals..
i do all types of welding and fab, so the piping and fabrication was not bad..
again, in my case, i did not open up, or even need to touch the engine in any way.and he does drive the car every day-- even in this winter snow and slop we get around here..i wish he wouldnt, but he likes his car alot.. i dont blame him..
something else to consider is what im doing-- i was also able to source a spare motor and trans for real low cost.. according to my engine supplier, there is no real demand--so the cost of a replacement is real low..i have the spare at my shop, and have been looking and gathering parts..
in the meentime he his driving his TT sc and having fun..also, like you had mentioned, when i made the parts in the first place, i made them with the intention of eventually making some big HP.. i hate remaking parts..and once people get a taste of a turbo car, it seems we always want more boost..
i have read, and believe the stock egine can take a frair amount of abuse--so i wouldnt worry about breaking it untill you start putting extreme demands on it..without major mods/work, at 8 psi, you should end up with healthy amount of daily HP, and although i have not tried, i have read that the engin can withstand upto 20 psi before lifting the heads..although at 20 psi, fuel and timing would be a major cosideration.. at the 8 psi we have runthe car at, the only supporting mod i have done is the addition of a rising rate fuel pressure regulator..
Lextreme had asked me" what i would do differently next time" thats a good question-- one thing i would do differently is-- i have the 2 turbo outputs joining together befor the intercooler,, i think onthe next one, i would end up making the intercooler end tank differently, with 2 seperate inputs..Also i would spend the xtra time and leave the air-cond compressor on.. i did leave it off --made my job a little easier at the time..but i did use 3 inch tube in and out of the turbine/turbo..

 

[Lextreme II]

I am thinking not to reinvent the wheel. The Tundra headers you use is very affortable and good quality too. SS pipes are expensive and i am thinking about using the same headers and chop it off, flip it upsidedown. It cheaper and easier. Instead of 3", i will be using either 2.25 or 2.5" SS pipe on the exhause inlet and 2.25" or 2.5" for exhaust out let. Trying to make the pipes smaller for faster spooling and easier to make room.

Most likely i would got 2.25 inlet exhaust and 2.5" out exhaust.

As for turbo selection. I will go with either .48 or .61 A/R. I know he .48 will give me lost of lower end, but suffer at higher end. However, the .61 will give me little more higher and slight delay in boost. I would love to have lower end, but his car is build with max hp in mind. I would like to max both GT30R with build motor.

As for intercooler, I was thinking a duel inlet from the bottom and one outlet on top. However, i will make it in 4.5" thick. SC400 has lots of room for thick IC.

 

[chrisman]

lextreme, yes the tundra ss headers did save me time and trouble.. out of the 8 pipes, i only had to change 1.. and the 2.25-2.5 exhaust/turbine pipe will make it a little easier to route all of the piping-especially around the ac+steering shaft..and it would also keep the velocity high for quick spooling.. your idea for the thick IC is a good one.. you could stack 2 cores--and have the tanks made..
i am hopefull that soon there will be many TT sc400s..

 

[LTLRKT]

As for turbo selection. I will go with either .48 or .61 A/R. I know he .48 will give me lost of lower end, but suffer at higher end. However, the .61 will give me little more higher and slight delay in boost. I would love to have lower end, but his car is build with max hp in mind.

So you think .82 is too big? Or will suit for bigger HP application?

Here is a pic of the intercooler im considering using. 4.5inch thick and about 7.8inch in height. I will either use this, or same idea as you Lex with custom radiator, etc, run a big cooler upfront with tanks on the bottom and outlet direct to throttle from the top. not sure yet.

Riste.

 

[Lextreme II]

I was thinking this configuration.

The measurement for SC400 IC would be 12"H x 32"W x 3"D to 4.5"D The Top/Bottom is more effecient and less pressure drop than the traditional configuration.

 

[LTLRKT]

Well after carefull consideration today we have decided that if we go twins they will most likely be T3/T04E

OR

The other idea that we were discussing alot today is to have both equal length exhaust headers running to a central mounted single turbo. The turbo of choice being a GT35R (700hp)

Advantage of this is the new GT series turbo which is much more efficient i believe than the older T series. Also after careful consideration, i begining to think that there will be better gains from a large single turbo as all 8 pulses on equal length manifolds push the one turbine instead of spliting into 4 for each on twins. Its also ball bearing so should still be just as responsive, or maybe better, with huge gains in higher revs.

It would be setup very similar to the way chrisman's header are, except once the single pipe comes to the front instead of mounting a turbo, they would turn inwards towards eachother to mount the single GT35R. This makes intercooler pipes much easier, also cuts uneeded costs. Leaves more money for the custom plenum chamber & throttle body.

so the setup will change to single Wastegate Tial 44mm with screamer pipe, and 4inch dump off turbo to 4inch electric cutout for awsome free-flowing performance hehe



The specs for the GT35R are 84trim Turbine wheel with 1.06a/r and 52trim T04S compressor with .70a/r @Max flow of 50lb/min

Or considering the 56trim GT40 front wheel @Max flow 60lb/min





What do you guys think?

My mates getting impatient with me lol. I got to start buying everything!




Thanks,

Riste.

 

[Lextreme II]

Single would be alot cheaper and less complex. GT35R would be a great choice.

 

[chrisman]

everything sounds/looks good.. i think whatever route you choose, you should get very good results.. try and keeps things simple--less things to go wrong
the alternator i used was from an early (87)RWD corrolla.. but i did make some changes.. first of all..believe it or not, the wiring/connector was similar..but the housing was different.+. it originally was a smallerribbed belt/pulley, but the place that rebuilt it put a wider-lexus pulley on it.. i also had them UP the output to 100 amp.. thats the most they could do with the smaller housing..but before i had it rebuilt, i modified the housing.. it originally,on the corrolla, was and adjustble housing.--what i mean, is that you adjusted the alt away from the engine to tighten the belt.. on the Lexus, the alt. is stationary-not adjustable.. so i welded a new upper bolt boss to it..
i hope im explaining it so you will understand.. its kinda difficult explaining..the lower bolt hole on the alt is fine, although i think i had to drill it out a little because the lexus stud that goes there is lager in diameter..i used some alum and welded an upper bolt boss to the housing, and i placed the alt as close as i can to the engine when i fited it.. this gave me some more clearance on that side of the motor... il look and see if i could find a pic or 2..

 

[chrisman]

heres another view of the alternator-placement.. again, you can see how i rerouted the belt to keep it away from the exhaust.. also, notice that the AC compressor is gone.. the belt tensioner still works like it should, and it was just a matter of getting the correct length belt.. again notice the heat shield that i placed between/over the exhaust.. the power steering pully looks close to the exhaust in this pic, but sofar, no probs..

 

[chrisman]

also note in the above pic.. i routed the poweer steering line up and away from the pump.. i think i remember taking the high pressure line and flipping to face upward.. the reservoir was relocated to the drivers side.. actually, all of the fluids reservoirs ended up being almost next to each other. a convenient coincidense?..

 

[Lextreme II]

Chris,

I did made two headers with 3" on both sides of the engine and i didnt have to remove, change or relocate any accessories.

 

[LTLRKT]

Lex: Was that in an SC400?