j0hnyboi

Can someone honestly tell the truth, and no bull please..Has anyone turbocharged their sc300, and was able to run fine without all the trouble of higher rpms, bad gas milege, this and that.. bla bla bla... after installing their kit? I understand having to tune the vehicle is necessary to bring up the horses, but must we always have to figure out this and that if we have everything already? I have pretty much everything setup already, and just waiting for the install process. I'm really afraid this would take me months. I only plan on spending no more than a month. I need the car to be drivable after the turbo kit is fresh installed. I won't push it, but just want to be able to drive it, and tune along the way.

jj

motorheaddown

I think you're getting the truth. These cars aren't Hondas, and if you're planning to run some decent boost, it'll require that you pull the head to install a new hg. That greatly increases the probability of errors and makes the installation much more difficult and time consuming.

I took on an NA-T conversion without the aid of a complete kit, and it was 10 times more difficult than I planned. If you're concerned about the installation... good! Hopefully, it'll make you 1) pay attention to details, 2) ask questions before moving forward on the install, and 3) double/triple check your work.

-scott

aliga

iTrader: (147)

Are you installing it or a shop?

SC300T

It all depends on how involved you want to get. If you just went with a stage 1 Toyomoto kit with 6-7psi of boost, its pretty much plug-n-play. Its a complicated but reliable bolt on. Untuned, you'll get 300-325rwhp. It really is something that you can install and forget.

The main thing is that once you get started, you just keep upgrading until you get into a hornets nest of stuff that you've altered, which is what I did. I pulled the head, upgraded a bunch of stuff in there, put the head back on, and blew a head gasket. Of course, it was something that I did wrong, but the complexity just goes up every time you fiddle with it. Main thing is, my car isn't much faster on the street than it was when I was running 7psi out of the box.... Reason is the SC300 chassis just isn't setup for that kindof speed without major alterations, ie. 6spd, LSD, bigger clutch, axles, etc.

That said, nothing in the initial kit from Toyomoto has ever failed in the years since installation. I've put well over 40k miles on it since installation, the engine has over 145k miles on it and is still in good shape.
If you keep your goals low, the kit is simple and reliable, and you don't need much in the way of electronics or gauges.

If you don't want to mess anything up, get a Toyomoto stage 1 kit, TT sidemount intercooler, fixed wastegate at 7psi, MSD 6BTM ignition box, an extra injector with controller, HPF clutch and call it a day. No need for fuel controllers, gauges or any else other than a simple air/fuel gauge. I'd also do the complete exhaust, though. The least amount of stuff you can do the better. Oh, one other thing, get a Supra MK3 turbo fuel pump. I wouldn't mess with electronic boost controllers, they are not as reliable as a simple wastegate spring. I'd also suggest a T60-1 .58 a/r as the minimum for turbo size if you're staying simple - I'd actually do a .81 a/r if I were to do it again.

awj

So what went wrong Scott?

motorheaddown

**EDIT**

Oops... I thought Awj's question was directed to me. Well, here's what went wrong on my install, anyway:

I did strip the #2 knock sensor out of the connector on #5 cylinder (fixed that), stripped the bolt to the water pipe under the distributor (fixed that), partially stripped one of the threads holding the timing belt tensioner (left that alone). All of those issues are due to pulling the head off. Plus, if you have head work done, you'll have to re-shim the valve train. I also had to put grounding points in the head for the LS1 coils.

It took about 6 iterations to get the fuel system right. The fuel system either leaked, or the wiring was wrong. I also had a fuel line burst in the tank (never use fuel injector hose; go with ss braided lines, always).

I didn't tighten the flywheel bolts to the necessary torque (I think), The crank pulley isn't tightened to the necessary torque (that, I know).

I also had to go round and round on the turbo fitment with Toyomoto. That was just a communcation problem. If you get Lance's *complete* kit, fitment will be fine.

Because I'm running the AEM on LS1 coils, I had to completely re-wire half the engine bay to convert to wasted spark, peak-and-hold injectors, and speed density air measurement. I also run an EGT sensor, W/B O2, boost control solenoid, and meth/water injection (soon). The wiring is *not* trivial.

The most disappointing thing, however, is that I have low compression in 4, 5, and 6. That's probably due to my impatience turning up the boost. Unfortunately, I made pulls with the boost control solenoid disconnected, and the sp63 spooled to 20psi before even hitting 5k rpms on pump gas. Plus, the fuel line burst I experienced cause a lean condition for about a day. I took the car to the dyno, and I can only run about 11psi of boost before getting misfire. That's what low compression will do.

So... my point is that it's all a learning experienced that can get expensive. Fortunately, I have a spare GE motor with 67k miles that works perfectly. I'll start building that one up while I run the current motor around town.

-scott

SC300T

I'm not sure yet.... the car barely runs---sputters. Idles somewhat rough, as soon as you touch the gas, it falls on its face, A/F ratios are all over the place. Under boost it actually makes power, but in the -20 to 0 mmhg vac range it won't run worth a sh!#. Its drinking coolant. The head gasket is what I'm suspecting. I think that at idle, there isn't enough vacuum and the cylinders arent really doing much, so it runs ok there. but when you touch the gas and get some vaccum going, its sucking coolant in to the cylinders to snuff out the spark. When you cross back into boost, its no longer sucking coolant into the cylinders, so its ok there too.

I get no smoke and no crazy noises, so the engine internals are intact.

My only guess is that I've heard people talk about getting the head done, yet the surface afterwards isn't clean enough or machined to a close enough tolerance to mate up properly. Either that or I didn't get the top of the block clean enough? Needless to say, I've got to do a leak down test to find out exactly what is going on. Fortunately, I have a Toyomoto gasket and ARP studs just sitting around, so it shouldn't be an expensive fix, just time consuming.

Does that sound like a good guess as to whats going on?

awj

Wow...

motorheaddown - good luck to you.

SC300T - it makes sense to me. Sorry to hear about it. Good luck to you as well.

I'm tearing into mine this winter - if I ever get some tables built. She just won't boost like she used to but I think it's a leak. Nothing too major like you guys.

Keep us posted.

D2-AUTOSPORT

Scott, this is the perfect post for a "non mechanic" type person. I UNDERSTAND many of the theories and such behind turbos, but i could not install a kit if you put a gun to my head. Also the finer points (turbine housings, alphabet soup of parts), can get me hung up. Alot of members(or at least me) are interested in running a turbo that will let them spank the 'one-up' model, ie, SC300 can spank SC4, GS3 can spank GS4, etc, and stay everyday stable, rather than running 600rwhp.

One quest, does this apply to VVt-i cars as well? VVti seems to be taboo around these parts, but I see that SRT, FMAX, etc makes kits for the 2nd Gen GS, which is VVTi, correct?

aliga

iTrader: (147)

LL can comment on vvt-i, also DaveH mentioned that he has a friend with a 98 supra vvt-i running the fmax kit with E-manage. So defintely doable.

D2-AUTOSPORT

Thanks Gazi

Lex Luthor

Yeah, D, second gen GS's are VVT-i. Certain mgt strategies will not work on these motors - i.e. VPC (alphabet soup again DGOT....it stands for Vein Pressure Converter and allows you to change from mass air to speed density metering....up oh getting complicated again.....let's say in layman's terms that it allows you to change the way the computer measures how much air is being ingested into the motor). e-Manage IMO is the way to go on a VVT-i motor, that will be my route also, just so you know DGOT - Willie from Lujan Motorsports had a '98 Supra VVT-i NA-T that ran nines, street car. You've got the digits, hit me on the jack if you need 411 brother.

D2-AUTOSPORT

I was waiting for the MASTER to log on and share his infinite wisdom!!!

Whether I get a GS or SC, if its a 6cyl, i want to be able to whup up on 400s, thats all I care about (my college buddy has a 99 GS400, dont want to deal with his junk talking!! LOL)

I understand the technical terms (speed density readings), it just that guys like you and Ed are so deep into it that basic turbo kits (320-340rwhp), are BARELY in your vernacular!!!

If it aint puttin out 600hp and better, I almost feel embarrassed to ask!

Thanks again Jon, you be good

SC300T

As far as one upping other Lexus models, an SC300 at only 6psi demolishes a GS400/430 with no problem. An SC300 on stock compression at 9-10psi pummels a GS400 and runs away from in at a rate of about one car length per second. On race gas its not even worth racing a GS400 as an SC300 in that condition will cleanly pull away from a 405 horse Z06 vette (from experience).

D2-AUTOSPORT

In all honesty, that is all I want. That way if I have a 300 and someone says, "Oh, you dont have the 4, your slow", I can just push the gas, and show them tail feathers!!

I have done searches before, but have never been able to get the recipe condensed (although Ed walked me through it over the phone once). Could the forced induction masters please chime in on the recipe for a everyday driver SC or GS kit with all necessary ancillary parts.

Turbo Kit
Engine Management
Method of Cooling
Tuning parts needed (S-AFC, ABCD123doremi)
Tranny uprades neeeded (torque converter, valve body etc) (98+ SC3s are ALL auto )
Would proper tranny upgrades allow flooring of the throttle through upshifts (Ed you KNOW why I'm asking this!!)
ETC, ETC. (gauges, etc)

Oh yeah one last thing: OUT THE DOOR COST!! (And dammit, I cant install NOTHING so dont suggest it)

I really appreciate you guys all slowing down to a snails pace (no pun intended) to lay these things out.