Kharizma

iTrader: (6)

interesting thread... i'd also like to know if it'll be ok to use PI TC/LSD/S&S Headers/S.C. Kit together?

V8Lexus

any truth to even remotely close horsepower gains from the SRT intake with ecu? they claim around 9-12% gains both horsepower/torque. if thats the case ill buy that in a heartbeat but im not entirely convinced. can anyone vouch for this?

TeeLex

iTrader: (24)

Ths 3.76 LSD works great at any speed - except over 135mph The gear ratio will limit you top-end to ~135mph, but the car will be more responsive at all speeds below that.

I would say that the S&S headers give more power increase than the SRT Intake, based on my personal experience with both. As I said before, installing the S&S headers and fabbing up a custom mid-pipe will give you an actual power increase that you'll immediately feel. The other benefit of the headers and mid-pipe is how usable that extra power is - mid-range on up, significant improvement in drivability. The SRT does more for the top of the rev range - not as usable or noticeable on an everyday driving situation.

The LSD does do a much better job of using the available power, but like the PI TC, too, it does not actually increase torque/horsepower of the engine. Both the PI TC and LSD allow you to be in the meat of the power earlier and more often - but they do not actually increase torque/horsepower. That being said, you will definitely feel the difference immediately with the 3.76 LSD and PI TC.

Everyone has their own ideas of what they want from their GS4, and for me NA is ok, with the appropriate 'breathing modifications'. Others will desire FI and that's cool, too ( with more power, but also more involved and more $$$ ). Depends on how far and how much you are willing to do and spend.
The 'appropriate breathing' mods include the SRT intake with ECU, S&S headers and custom mid-pipe. Throw in the 3.76 LSD and this combo works well for me. As I've stated before, I would like to do the PI TC, but I'm still holding off due to the CEL problem.

Lexy GS430

I got to get on this. Of all the modds that i did the Lsd&Tc are worth every penny and i mean it. Damn i'm just so mad that i had to get rid of my GS, and those two modds. They make a huge difference on how quickly the GS responses when you step on it unlike stock setup. BEST BEST BEST modds period.

KevinGS

And don't forget about significant increases in overall noise levels after installing some of these mods. The headers are LOUD. They just about drown out everything else...and then your quiet Lexus cabin turns into a real monster. The SRT intake produces quite a bit of sound too, so be ready....especially if you don't have an aftermarket exhaust to compliment that roar.

The beauty of the LSD/TorqueConverter combo is no discernible noise-level gains, but good performance gains you can feel. Yes, with the LSD, you sacrifice a little fuel mileage, and it adds a little more wear&tear on the engine over the long haul (because of increased RPMs across the whole power band), but together they provide a great (and quiet) bang for the buck.

Having said all that...I have the SRT intake (with custom built silencer box to reduce noise levels about 25% or so), and the torque converter, and an aftermarket Tanabe exhaust, and I now LOVE the combo of the three....but they each had to grow on me (TQ excluded). I simply was not thrilled with all the increased noise to my cabin after the addition of the intake, and then the exhaust. Nevertheless, my initially quiet cabin now sounds like a well-tuned Vette's....not quiet, but certainly sexy with a low deep precision tone eminating from the exhaust coupled with the lion roar of the intake at WOT. It makes for exhilirating burnouts for sure (which is one reason why I think I never want the LSD, I'm addicted to a good burnout )

I suspect that the exhaust and SRT intake HP gains are minimal, but the added punch of the torque converter from a standstill is certainly present. The SRT intake provides an important benefit though that is rarely mentioned: a reprogrammed ECU. The ECU is reprogrammed to give you better breathability, and better throttle response. My throttle response on the highway is much crisper than it was stock. And once I got the intake, my gas mileage increased a bit.

And of course, to get the most efficiency out of ANY intake, an aftermarket exhaust is preferred, but not necessary if you just want a nice roar added to your cabin, with better throttle response (because of ECU).

Just wanted to give you more info...never hurts to have as much info as you can before you open your wallet.

V8Lexus

ive got an aftermarket exhaust sorta, since i can do minor fabrication(cutting and welding is about it.). i bought 2 magnaflow mufflers with dual tips, rolled edge straight cut double wall and chopped off the old mufflers, got some mandrel bent 90 degree pieces of exhaust tubing welded it all together with some new muffler hangers, also i used straight tubing and eliminated the resonators. anyway i know it sounds like a hackjob but i'd say i did a pretty damn good job considering i did it all in my garage. anyway ive pretty much got the aftermarket exhaust covered except for in front of the resonators all the way up to the stock exhaust manifolds. so is the consensus that the SRT IS or IS NOT worth the 450 dollars + shipping? also i read in various places on here that some people have been having issues with the car not starting with the SRT intake. bad install? defective part? anyone else heard of this? Mo (CEO of Swift Racing Technologies) says hes been selling the intake for 6 years and never heard of this. I read on here a while back of people complaining of these problems. im not going to spend the 450 on the srt intake if it doesnt give me that claimed 30hp or more, i'd rather put that 450 towards the LSD, TC, or supercharger. although im sure its entirely possible, i think it may be a bit far fetched for just an intake with a piggyback ecu to add 30hp. UNLESS the stock intake is SO restrictive for the purposes of mileage and noise reduction that it actually kills those 30 ponies. im pretty much already set on the TC and LSD.

KevinGS

I'd be STUNNED if I was getting 30HP from the SRT intake. If you have to get the 30hp boost to think the intake is worth it, then just get the TC and LSD. It's a guaranteed boost in performance across the power band (LSD's aggressive gearing), and from a start (TC's altered torque characteristics at standstill). And no increase in noise levels.

I really just got my TC for better burnouts , and I got my intake for better breathing and a crisper throttle response...I didn't really expect significantly better perfomance. And when I got my exhaust, I wasn't concerned in the least about any claimed HP gains from the manufacturer, it's all negligible to me since we have such heavy sedans producing 300 hp already. When I got my Tanabe exhaust, I was only concerned about how it looks, and how loud it was.

For me, unless I'm adding at least 75-100hp at once, it's all about the sound and the aesthetics. If I wasn't so in love with burnouts, I'd get the LSD in a heartbeat though, because the car responds so much better across the power band. For performance addicts, it's a no-brainer....especially coupled with the TC.

By the way, I've had the intake for almost 18 months, and never had a problem starting the car, actually never had any engine problems with my car and I drive mine hard when at times....and mine's a daily driver pushing a 100k miles. (now let me go find some wood to knock on )

fstrnldr

SRT intake will manipulate the maf signal to lean the car out similar to the APEXi SAFC, thats where its getting the other portion of the power over the intake alone.

couple questions, what code does the torque converter throw? and w/ regards to hitting the rev limit w/ the gear change has anyone tried the emanage ultimate on the V8? i know w/ the 2JZ's it allows the rev limit to be raised, this would be a sure fire fix for that issue, as well as give some other tuning ability to the car.

V8Lexus

kevin, good sound advice. im heavily researching all aspects of these mods since with my wrx it was all pretty damn simple and the stuff was all cheap. but since all of these parts are much more complex, much more expensive, and much harder to install then i want to be sure im doing this all right. also i was going to have LMS do the install on the torque converter and limited slip diff, your opinion of them? anyone else here worked with LMS and can provide any advice? i went to research any problems with the srt intake and came across a couple threads that really bashed LMS's quality and service.

V8Lexus

still on here reading about various products and pros/cons. stumbled across a thread concerning tranny issues with GS4xx's? anything to worry about with regards to tranny longevity if doing the torque converter? engine longevity with 3.76 LSD? this is my only car and although it has 15k miles left on an extended warranty i still dont want to have to worry about 9 grand for a tranny or XX grand for a new motor if i blow these up. So that being said im going to forgo the supercharger and stick with naturally aspirated. No nitrous either just a good intake. seems like SRT is the way to go. ill definitely get the torque convertor and LSD. at first i was looking for some performance to beat an M3/S4/C55 AMG but now that i think about it our cars being as heavy as they are probably werent designed with fighting those cars. so for now i'd rather have better performance and still keep that awesome lexus reliability. any input is greatly welcomed and appreciated on this. you guys rock!

TeeLex

iTrader: (24)

Quote
'The headers are LOUD. They just about drown out everything else...and then your quiet Lexus cabin turns into a real monster'

This is just not true on my GS430. In fact there is very little, if any, increase in noise from the header install. The SRT intake is much louder than the headers and it's not even close. My S&S headers and custom mid-pipe ( 2.25" tubing and where I removed the 3rd cat and replaced it with and X-pipe ) as a combo are not as loud as the SRT intake alone. For those of you that have not done the headers on the GS430 - well your missing a great mod - every bit as effective as the LSD on my car.

KevinGS

Tee, did you have the SRT intake first, or the headers? Or did you install them at the same time? Just curious.

Both cars with headers I have been in were significantly louder than my stand alone SRT intake. And I mean LOUD, especially at WOT. One sounded like a Harley when you stood outside the car. They must have had some other piping done as well that caused the loud rush of sound. It had a mean growl, definitely an attention-getter, but for a daily driver, fuhgehdabowtit.

Thanks for more feedback. I thought it was the headers themselves, but it must have been the piping.

TeeLex

iTrader: (24)

I had the SRT intake first, along with Carson Tuned Exhaust ( which is relatively quiet - more so than the L Tune Exhaust which I had prior ). I added the S&S headers and did not really notice any noise increase - if so just about imperceivable. When I changed the mid-pipe to my custom 2.25 inch tubing and x-pipe there was very little change again - maybe some incrase under wide-open-throttle conditions.

Sounds to me the cars you heard had changed piping completely. Do you know what kind of mufflers they had? I mean HK's are definitely louder than my Carson Tuned mufflers.

Like I said before, the S&S headers are a great mod for the GS430.

KevinGS

Hmmm... interesting. Dont recall their muffler setups specifically, but definitely aftermarket.

Question: when you got the headers, but before you changed to the custom tubing and x-pipe, was there a significant increase in performance you could feel? After doing just the headers, why did you feel the need to go one more step and get the custom tubing and x-pipe?

DaveGS4

iTrader: (2)

Kevin,

Were the cars you heard S&S Header cars or were they custom headers on SRT TT GS4 cars?