Result Of Mods To Sc400

[cyborgmaniac]

jibbby, you are the man. I've been looking for a thread just like this and here it is. I'm not a car expert so this really helped narrow down alot of research and testing (and probably money!). Thanks bro

[devir]

I seafoamed today. Huge improvement. Just the gasoline and oil for now. Once i feel comfortable (find) i'll use the break booster line to finish the job the right way.

I bought the Bosch Fusion (platinum and iridium blend) plugs for the car. I'll let ya'll know how that went.

I also bought the Fram boost performance drop in air filter. If it works great, if not, at least i'll have a clean air filter.

The main advantage of VVT-I engines is the valve timing is dynamic. This allows a greater range of Horse power and increased fuel efficiency, Hence the 30 HP gain and 4 MPG gain from 97 to 98 model years. They also did away with the distributor cap removing one more tune up hassle. It's a cleaner engine design. THe downside, is it's now very intelligent hence the "i" in VVT-I. This means the old tricks for HP gains dont work as well. The engine's ECU learns to spite you. I learned this the hard way with my last VVTL-I car...

I'll be working this car as a major project. My main goals are squeezing performance at every corner, while maintianing a decent gas milage and quiet. I may later go for a super charger option if there is one. I prefer them over Turbo for the daily driver friendly aspect over turbos.

[JIBBBY]

lexus082 - I believe all the 93-98 Supra LCA arms all fit our early model SC's... That is what I have read, and actually my Supra arms which I purchased from the dealer was 95 model Supra LCA's...Doesn't hurt to call the dealer just to make sure...

cyborgmaniac - My pleasure, I started this thread to help out people just like you...When I first started I had to search forums here and there, talk to all the experts, still had to use the trial and error methods to find the best results, etc.. I just made it easier for the rookies with this thread who wouldn't mind making their Lexus's perform better....I prefer to share info rather then hold back, that's just me...

devir - Seafoaming the intake chambers is what is really going to make a difference with your car...If your car is older and never been seafoamed then you are going to have major carbon buildup on your intake combustion chambers, etc...Removing all that crap should make your engine run crispier, as most have reported...Some made as much as 10whp gains on the really high mileage engines.... So find the brake booster line and seafoam that baby...

Also, In regards to your VVT-i yes it does make for some tunning efforts with certain forced air induction applications, but you can still do all the external engine mods that I did, such as exhaust, intake, torque converter, etc.... So don't be shy, you have a better power base then most for starters...(Sc speaking).. With just a torque converter upgrade, and an LSD you would probably give me run for my money on a flat out race 0-60mph without the use of my nos...Do all the external mods I did and you will blow me...but not if I use the nos....

[92Lex]

Hey Jibbby, are you using a level 10 torque converter? Has the car seen any dyno time yet? Howcome you decided to go piggyback instead of stand-alone for engine management?

[lexusalex]

Not a bad Job Jibby, months later and the thread is going strong.

I just bought a 1998 SC400 and would like to mod the thing out. Currently it has 68k miles on it and is in great condition.

Exhaust - I'd like to work this first with stock pipes. for the Magnaflow Cats, The two front sizes are 2.25 inch and the back 2 in 1 is 2.25 in and 2.5 out? Any part numbers to use would be a help.

Once I replace the 3 cats, i'd like to replace the back 2 resonators, with a Straight through design, but I want to keep the ghost quiet sound the car currently has. People tend to get freaked when i suddenly floor it and disapear without a sound. I like that. What should I use for this?

LSD - I dont know what i've got for a differential. Going straight i've peeled out with both tires for a long while. HOw can I tell if I have stock or aftermarket LSD?

Breaks - They not bad, the rotors are ugly and semi rusty. I'd like to go slotted cross drilled for style.

Supra Control arms - Where can i get these and what year/model Supra would fit on a 98 SC? so far I've found front lower arms for 250-400 a pop. Do I need upper and lower or just one of them?

Seafoaming - Would you suggest I do this now? I found some old oil change reciepts and it was texaco station that did the work. Would putting in a high quality Synth oil be bad at this stage of the game?

Intake - What drop in filter and part number can i Use with the stock intake ?

just a drop in filter will not do anything, it has been proven. You should do BFI intake type as described in www.planetsoarer.com you will see at least 10whp + with this mods and same oem filtering quality.

[JIBBBY]

Hey Jibbby, are you using a level 10 torque converter? Has the car seen any dyno time yet? Howcome you decided to go piggyback instead of stand-alone for engine management?

I am using the Precision Industries "Dragon torque converter" I don't know what a level 10 torque converter is... I do know the Dragon TC is a perfect stall rate for our SC's....

The Stand Alone ECU's require a complete rewiring job, and deletion of your stock ECU.....Very involved but the stand alones offer you more options when tuning...It is also 2 to 3 times as expensive as the piggy back ecu's.... The piggy-back ECU's wire directly up to your stock ECU, which then allows you to tune the air to fuel mix being delivered to the motor as you would like.....It is easier and effective for the stock engine's without your turbo's and superchargers...Easy to install and cost effective...

That is why I went with a piggy back ECU...Stand Alones ECU's are better but not necessary in combination for the basic mods that are discussed in this thread... Stand Alones are also great for engine swaps that require independant Engine control management..

My lastest dyno was 213whp without nos and 308whp with the Nitrous....That was after tuning my ECU Apexi about a month ago.... That is horsepower measured at the wheels and not at the crank for those that don't know the difference between WHP and HP...

[calismenreth]

Hey JIBBBY. How do you have your iPod hooked up to your SC400? I just got an SC400 recently; I want to upgrade the sound system, and getting my iPod hooked up to the car is the first thing that I want to do. Please let me know how you did it. Thank you.

[JIBBBY]

Hey JIBBBY. How do you have your iPod hooked up to your SC400? I just got an SC400 recently; I want to upgrade the sound system, and getting my iPod hooked up to the car is the first thing that I want to do. Please let me know how you did it. Thank you.

I use a BELKIN am/fm transmitter....Turn the radio to 88.3 fm and set the transmitter at 88.3 and the IPOD nano sounds come out as good as stock CD's... There are other transmitters out there but I would say Belkin makes the best....Ebay $50.00 or less...K-mart too...

They also sell a tape insert transmitter where you push in a tape with a cord that is hooked up directly to your ipod. However being that the tape decks are so old in some of our SC's the sound quality can be compromised with that setup..Good luck...

[handcuff]

BTW, I do have the number and address of the guys out in Cali who fix the HVAC bleeding LCD if you or anyone else needs help with that. They only charge $195, includes return shipping. They're actually the ones who repair HVAC for the guys on eBay that charge $335. I thought about having Lextech "whiting" them out after I get the LCD up and running again.

Can I get the contact info for this company that will fix the HVAC LCD black-out issue? I don't know who may have it, but can someone post it? I just got my SC300 this past weekend, and this is one of the problems I would like to have fixed.

Thanks!

-Scott

[GaDawg]

Hey JIBBBY. How do you have your iPod hooked up to your SC400? I just got an SC400 recently; I want to upgrade the sound system, and getting my iPod hooked up to the car is the first thing that I want to do. Please let me know how you did it. Thank you.

I use a BELKIN am/fm transmitter....Turn the radio to 88.3 fm and set the transmitter at 88.3 and the IPOD nano sounds come out as good as stock CD's... There are other transmitters out there but I would say Belkin makes the best....Ebay $50.00 or less...K-mart too...

They also sell a tape insert transmitter where you push in a tape with a cord that is hooked up directly to your ipod. However being that the tape decks are so old in some of our SC's the sound quality can be compromised with that setup..Good luck...

Hey Jibbby,

I have the Alpine that you have, but I haven't installed it yet (3 weeks from now and I'll be good). I thought our Alpine's had a plug-in slot, is that not the case?

[lexusalex]

BTW, I do have the number and address of the guys out in Cali who fix the HVAC bleeding LCD if you or anyone else needs help with that. They only charge $195, includes return shipping. They're actually the ones who repair HVAC for the guys on eBay that charge $335. I thought about having Lextech "whiting" them out after I get the LCD up and running again.

Can I get the contact info for this company that will fix the HVAC LCD black-out issue? I don't know who may have it, but can someone post it? I just got my SC300 this past weekend, and this is one of the problems I would like to have fixed.

Thanks!

-Scott

I can get you a perfect shape unit for $285 with 90 day warantee...pm me if interested

[GaDawg]

BTW, I do have the number and address of the guys out in Cali who fix the HVAC bleeding LCD if you or anyone else needs help with that. They only charge $195, includes return shipping. They're actually the ones who repair HVAC for the guys on eBay that charge $335. I thought about having Lextech "whiting" them out after I get the LCD up and running again.

Can I get the contact info for this company that will fix the HVAC LCD black-out issue? I don't know who may have it, but can someone post it? I just got my SC300 this past weekend, and this is one of the problems I would like to have fixed.

Thanks!

-Scott

Mikado Technology Company

1435 Huntington Ave, Suite C

San Francisco CA 94080-5974

(650) 615-9966

If you overnight it to them, they will overnight it right back atcha (e.g., send it out overnight on Monday and you'll have a fully functional HVAC back in your hands on Wednesday). They charge $195+shipping.

They are legit...got it from Hennessy Lexus Service in ATL. Enjoy!

[handcuff]

Dawg,

Thanks for the name and address! I appreciate it.

After reading this thread, I am thinking of doing a couple changes to my 94 SC300 Automatic. I have a mechanic friend who is doing the majority of the work for me on these things, on the condition I find out about the same enhancements for his 92 SC400. He doesn't want to spend a huge amount of time reading through the various threads and posts, so he figures if I dig up the 'gems', he will do the work. Before doing these, though, I would ask a little bit of advice/questions to make sure I am not digging myself in too deep:

Exhaust: Thinking of going to a single CAT (instead of the 2 or 3 that my 300 has) per side. This single cat would be a magnaflow or some such that would provide better flow while still keeping me OK with emissions. Is a single CAT sufficient, and if so, is there one I should get? I saw this one posted earlier: Single CAT for SC's and though it would probably work, but wanted to check with people who have gone through this.

Second, on the exhaust: Going to a less restrictive, oval muffler (probably a Magnaflow again - especially if anyone has a distributer from Ebay that I can get them for with less expense). I live in a nice neighborhood and most of my driving is strictly commuting to work/non-aggressive, so I would prefer a little more subdued sound (oval vs. round). Is there a muffler / dealer that you guys would suggest? Do you know if it is it a straight-through, or an off-set?

BFI Intake: Bouncing this back and forth - I hear that both the BFI and the Exhaust give you more HP plus better gas mileage (this is my daily driver and I commute a fair amount each day to work, so that is a concern for me), so I was thinking of doing this also. I haven't seen a DIY post/article about this, though...don't know if there is one that I haven't found through search, or if it is such a simple thing that the idea of a DIY walkthrough is silly...I'm just not incredibly mechanical, so don't know if it's hard or not. Does the BFI make a significant difference in HP? In gas mileage? I was hoping that by doing the exhaust and the intake, I could get an extra 3-4 mpg out of the car, while making it a little more exciting to drive.

Torque Converter: I am really interested in this, but when I brought it up to the mechanic, he said that if you do a TC with a 2800 RPM stall speed, you usually have to rev your engine up significantly before it releases, then it jerks off the line. I would like the ability to have more throttle response, but not if I am jeopardizing the 'normal' ride (normal being the 95% of the time when I am not sticking my foot into the gas) - plus, I don't want to kill fuel mileage. I wasn't sure if that was correct or not, so I figured I would ask a couple guys here what they saw as the difference in drive after doing the TC, when they are NOT trying to jump off the line? How does it act? Can you tell a difference in it if you are not pushing the car?

Piggy-back ECUs: I was thinking of possibly going with an ECU, but (1) woudn't know which are good for our cars, and (2) heard that the computer in our cars 'learn' what the piggy-back ECU is doing, so they are only good for a short period of time before having to do a reset of some sort. Is that correct? How difficult/expensive is it to have these 'tuned'? How tuneable are these piggy-back ECU's? Is it possible to tune for efficiency if your foot isn't in the gas, and then a secondary (higher RPM?) 'power' setting for when you stick your foot in it? I know nothing about these things except what I am reading here, and while I am learning a lot, I am still an idiot...

Thanks again for any advice...

-Scott

[handcuff]

Forgot to mention, I did a SeaFoam clean on everything but the oil a few days ago...saw huge improvements. Then I did a general tune-up, changing the plugs (NGK Platinum irrodium somethingorother) /wires (Beldin kit) /cap & rotor (and re-cleaned the deeper portion of the Throttle-body while I was in there) and saw another huge gain. This car doesn't act like the same one I bought a week and a half ago. It's driving much smoother and nicer, with a dramatic increase in responsiveness and noticable amount more power (enough that after doing it, the wife took it to the store and called me on the way saying "What did you do to this? It's got a lot more 'oomph' to it!").

I didn't do the exact seafoam thing, in that I used a valvoline kit instead, but from my understanding it works the same way. The mechanic uses these kits regularly, and puts trust in them so that's what I got.

I suggest that anyone who hasn't done this to their car in a while, go out and do it...see what gains you get.

Very nice!

-Scott

[92Lex]

If 95% of the time your foot isn't on the gas...then there's no need for any of those mods. You wouldn't feel the other 5%.

[handcuff]

If 95% of the time your foot isn't on the gas...then there's no need for any of those mods. You wouldn't feel the other 5%.

That's probably true, but the exhaust and intake each lead to better performance and better gas mileage (or so I have heard). The better performance may only be felt during the 5%, but the better gas mileage is pretty much across the board, so I figured that was as good of a reason for doing them as any. The TC isn't a fuel saver, but compensates for the exhaust's reducing your low end performance.

-Scott

[JIBBBY]

Handcuf - Ok where to start???

Exhaust - You can replace the center cat with no problems, however if you want to delete the two smaller cats you may effect the O2 ECU sensors reads and that will effect emmissions and your idle just a bit...I am not sure you will pass emissions if you delete the two smaller cats altogether... My two small cats are deleted and I don't think my car will pass a California smog check, I have not tried... That in my opinion is a judgement call, and if you have a really good exhaust mechanic I do think he can pull it off for you but I would be careful...They do sell high performance little cats too for our cars....... Oval mufflers are a good choice for noise reduction...Straight thru mufflers are bit noisy on our SC's....

Intake - BFI intake design instructions can be viewed at planetsoarer.com if I am not mistaken...Very easy to fabricate...

Torque Converter - The Precision Industries "Dragon Torque Converter" that is made for our Lexus's does not compromise driveability and or comfort what so ever...No head jerks, rev's, etc...however the throttle does become very responsive after the change.....I could hold a hot cup of coffee with my DTC and drive all day in the city with no problems... Your mechanic is 100% wrong....Get the T.C. I have had mine for over three years and love it... Wakes up our SC's...

ECU piggy-back - Spit Second and or Apexi piggy back ECU's are good choices for our SC's... However, you will also need to find a good tuner to tune your car for peak performance...

Hope this helps....

[92Lex]

Small cats or resonator's?

Intake, headers and exhaust can be felt through your butt dyno. It's bread and butter though....there's more power to be had.

[JIBBBY]

Small cats or resonator's?

Intake, headers and exhaust can be felt through your butt dyno. It's bread and butter though....there's more power to be had.

I deleted the smaller two cats near the headers, custum made two short down pipes to mount up with the S&S Headers and the rest of the exhaust system...Main Center Cat I saved but swapped out with a high flowing Magnaflow cat with high flowing Y's...Larger exhaust piping that is stream lined compared to stock...Also on my exhaust I have two high flowing straight thru stainless steel Megan N1 racing mufflers....To reduce the excessive exhaust noise from my mufflers I had to install 4 high flowing resonators as well...The exhaust now flows effortlessly, but I suppose it could be a little better with straighter mandrel piping and no center cat at all...

92lex- I am thinking of installing the Garrett GT35 single turbo onto my SC in the next month or two, what's your thoughts on that turbo size for the 4.0L V8 motor? I see you are running one on your 2.8L motor. I would think you would get some serious lag time with that large sized turbo on that motor?

DYNO JUST IN - Just recently dyno'd with a heated nos bottle and got 314whp and 476ft-lbs of torque...I am pleased with the results for now... The nitrous really gets the torque numbers up....

[92Lex]

No, not much lag at all. It's a large turbo but I'm using a .63 a/r housing so it spools up much faster. GT series turbo's reach full spool very quickly because they are ball bearing turbo's. My car reaches full spool at about 2000 RPM's. With good tuning you shouldn't experience much lag at all. It's all about the tuning.

A 35r would be a good choice for your engine. Just stick with a .63 or .68 a/r housing and you should be fine. If you're aiming for 550+ RWHP and wouldn't mind the extra lag (maybe an additional 300 RPM's) go with a .82 a/r housing. Keep in mind that the 35r doesn't shine under 18 psi., it would be a waste to run them under 18 psi anyways. What are you power goals?

[JIBBBY]

Cool, exactly my thoughts..

[Lee TT]

Cool, exactly my thoughts..

Jibbby, this is lee from alberta, ca, i have a 93 sc400 and i'm trying to find internet sites where i can order, performance parts. My plans are to install 2 turbo inline at the rear of the car where the spare tire sits, just wondering if you have info on how much boost that engine can take, or what to do to make it handle more. Any internet sites you know of would be handy too.

Thanks

Lee

[JIBBBY]

Lee TT,

Lextreme.com is a forum that is directed entirely to modifiying Lexus V8's....Turbo's, Supercharging, Nos....you name it... That forum is all about instructing you on how to turbo charge your lexus.... That is my information based forum and the owner of that forum (Lex) is actully helping me start my Single turbo project shortly... A very nice guy whom is willing to help out just about anyone... Check it out...

Another very informative forum is CLublexus.com... Many threads on those same subjects and probably the most successful Lexus forum on the internet...However, I got banned for life on that forum because of my continued fueding with the forum Senior moderator named GSDave..The guy is unfair and really abuses his forum powers... I let him know how I felt and he banned me for life....I wasn't even that rude either, Oh well, I guess the truth hurts... Anyway, another very informative forum...

Many performance parts can be purchased on Ebay and Lextreme.com....Good luck with your exhaust turbo's...

This forum is very nice for your everyday repair information, and good basic info. chats..etc...I love it....Very nice members and moderators on this forum....

[92Lex]

ATPturbo.com

CheapTurbo.com

Full-Race.com

RaceTep.com

[BrokenPath]

Hey I am glad you enjoyed my thread....Really all you need on these sc4's is a true progressive 150hp nos system and the car will fly....The Dragon torque converter is really great for non NOS runs... With NOS and the Dragon TC you will get major traction problems in first and second gear...unless you plan on getting a limited slip differential, fat rear tires, and or a progressive nos system.. I don't recommend the combination with the stock traction setup.....

It is nice to have the car motor well without the nos too....The exhaust, DTC, LSD, intake and ECU piggyback makes that possible...For rude power NOS, turbo, and or supercharging is where it is at for sure...If you got money a Eaton M90 supercharger would be nice and fit right in, or turbo's can and have been installed on these engines too...Your looking at $5000 for those in most cases, and nos is closer to $1000....

Hey Jibby, Great to know that you're posting this amount of very helpful information. Thank you.

I had a quick question, Will an Eaton-M90 fit for a fact? Can it be coming off of any junkyard motor and still fit?