Mariusz

I need some advice (preferebly objective) on a NOS kit. I've spoken to several installers and heard a wide variety of opinions as well as applications. This sort of left me little confused since I'm not really an expert on NOS systems.

To date, I have considered two systems. One is designed by Venom-Performance and the other is by NOS. Since there is no "official" GS4 application from VenomP yet, I would like to know more about the NOS.

The most promisong/appealing application untill now, was a wet NOS Kit. It would come with a 75HP shot, but it would be double rail so the output would be doubled to 150 (please correct me if I'm wrong). The switch would be incorporated into the WOT. It would not be a "push button" style since I heard that if you spray too early or too late, you can blow the engine. the kit would also include a sensor that detects air pressure. In case the pressure drops down drasticlty, the NOS flow would be cut off.

OK. SO now, here is the million dollar question. Can the GS4 engine handle this additional HP? If so, should any other mods to done in conjuction with the NOS system? What are the chances of blowing the engine (how often could it be used)? The price this system would be 1190+200 installation.

PS. Mean Gene, if you're reading this........do you know the status on that venom nitrous kit?

Thanks in advance.

SuperLex

$1190 for the system, That's kind of expensive. What does the kit include?

The GS400 engine should be able to handle the extra HP no problem. The engine is bulletproof!

LexusRules

superlex, thats not entirely true the GS400 has an aluminum block which makes it less strong, the problem with the 400 is the fuel injectors, marisuz you cant go above 400HP or the injectors can't handle it so you might want new injectors and pump... not sure what kind of electronics might mess that up in the ECU, sorry man

hey marisuz, COME HERE MORE OFTEN!!!

Mariusz

This is exactly what I've been hearing. Either the engine will definitely take this HP, but I also remember reading some discussion on the injectors. If anyone can elaborate on the fuel lines, it would be a great help. For exaple, what exactly needs to be changed or done to assure the car doesn't get towed

Mean Gene

Mariusz - Still waiting on Venom to return my E-beam but here's what I've gathered from other members on the board - if I get ya'll all confused, well, it's because I'm old!! Pann just had an NOS kit installed on his GS4 a weekend or 2 ago - look for the post "got NOS" over on page 2. Think that kit was about $600 plus installation of around $300. gs300haltech is using a Texas Nitrous kit on his GS3 - it goes for the same $600 plus Tony with them told me that they charge $450 to install. Tony also recommended a pump change to one of higher pressure ( like the TT Supra fuel pump ) - believe they did the same to haltech's ride & he says he's squirting about a 100 HP shot. Again, my problem with the nitrous is the fuel system being able to support even a small 50 HP shot w/o leaning out. For those of us with Mo's mods, that would put us up near the magic 400 HP ceiling. I will concede that a higher pressure pump would force a little more fuel through the injectors & MAYBE enough to buy us that little bit of extra safety margin as long as we keep the jetting to a reasonable ( small ) setting. Not sure about the NOS term "double rail" meaning twice the nitrous? The GS4 has a fuel rail for each cylinder bank so I'd THINK that NOS taps into EACH rail for the additional fuel delivery & that's what they mean by "double rail". Gonna get on the phone & speak with Venom & NOS to see how much they'll tell me about their kits. BTW - Nitrous Express has had a GS kit for over a year now but haven't heard anything about it. Also, Tony w/Texas Nitrous advocates a "wet" kit for those of us with nitrous experience & a "dry" one for newbies to squeeze - they offer both types but he says the dry's safer while the wet yields more overall power. Also, U R correct that nitrous should ONLY be used at WOT. The system is designed to operate with those parameters alone & a partial throttle application of squeeze can cause either a lean condition ( burned pistons ) or a rich one ( backfire through the intake plenum ). Neither one is what we want!!

gs300haltech

the problem with the GS4 is the fuel system the block is stout and reinforced very well. Actually the tundra block/lx470 is the ultimate v8 block with gs400 cylinder heads is the way it should have been done, but i guess that cost money. But back to the subject. The fuel system on the gs4 does not have easy acess to tap a return line to the stock location. What you would have to is create your own return system as well as increase pressure using a high hp pump plus get larger injectors with a SAFC or some sort of fuel management unit. the GS4 is the harder model to nos than the GS3 model. The 2jz motor is heck of alot easier.

SSMOKEM

For what it's worth, I've got some advice for you guys. I've been running a 200 wet shot in 2 stages, 75hp 1st stage and 125hp 2nd stage. The reason for the staging is easier take-offs.

I've been running this for the last 2 years on my stock LT1 350 block with hypereutectic pistons. This is an NX kit. Haven't had a lick of problems.

A good way to determine how much maximum power your motor can support: 2hp/sq.in. of piston bore for near stock cars and 3 to 4 hp for fully built motors.

Rule #1: F U E L !!!!

You need to have plenty of fuel with NO pressure drop available to the top of your rpm range. With enough fuel, it's almost impossible to hurt the motor. I totally redid my fuel system, which now flows 364lt/hr at 43psi through -8AN braided lines.

Rule #2: NEVER ACTIVATE THE N2O MANUALLY.

Always use a combination of WOT switch and RPM switches. Additionally, ALWAYS add a fuel safety pressure switch which will shut the N2O off if pressure drops.

If you use a dry system (with fuel through injectors) you must determine at what pressure the injectors lock up since with a dry system, fuel pressure is increased, possibly up to 80/90psi. If the injectors lock up, you're dead.

RULE #3: 100HP OR OVER, RETARD TIMING OR USE 100+ OCTANE FUEL.

I'm able to use 93 octane, because I retard timing 5 degrees. If you detonate under Nitrous, the knock sensor and computer module isn't fast enough to pull timing out before engine damage occurs.

Given all this, Nitrous is probably the best mod I've done. There is no feeling like an instant additional 300lb.ft. of torque hitting the small of your back

Good luck!!

Mariusz

Thanks for all you help guys. Seems like there is still a reasonable risk associated with NOS and a few things that need to be taken care off. I'm not sure if I'm going to pursue this if I can find "the perfect" installer who knows enough about NOS yet is aware of other "higher" issues associated with the system. Hopefully venom might come out with something soon since it seems like their kit is fool-proof. Guess I'll have to wait and see.

Mean Gene, let us know if you hear anything on that Venom. I called them today and the guy told me to go to their website and fill out a request form. I must have filled out like 5 of them already. Lol. Maybe we need a few hundred Lexus owners to voice our desire.

http://www.venom-performance.com/Pro...ent_reques.htm

BLiu

MariusZ,

You may want to contact Todd at TMEngineering (310) 537-6800...

He put a NOS kit on his SC400 just before he took it apart to build his new twinturbo engine and tried to blow the engine. He didn't succeed and that's a good thing. The block is very strong. Give him a call - I am sure he can tell you more.

Brent

ktrends

Ok here is my $.02

My family owns a few performance shops here in Kansas City of which I work full time at one. I have sold hundreds of nitrous kits for eveything from a 1.5L honda up to a big block chevy, and have installed my fair share as well.

First off Yes I do own a 1999GS400 on which I will be installing a nitrous kit very soon "more than likely" becuase I am sick of waiting for SRT. Anyway there are two basic types of nitrous kits "wet" and "dry" basicly the wet systems spray fuel into the intake as well as n20 which is great for boosted cars OR cars without return lines <cough> gs400 </cough>.

I have been doing my homework on the GS400 motors and have found them to be very very well put together. The fact that they run forged pistons, rods, and crank is somthing that not even the supra TT can brag about. Not to mention the SIX BOLT MAINS! come on guys the mustang fellas have been spraying 200+hp shot of nos for years and still running TWO BOLT blocks..

So my answer is this!

Buy a NOS, or NX *WET* kit. Also purchase a MSD rpm window switch to turn the nitrous system on and off at preset rpm's. Install 150jets and let her rip I promise if the kit is installed properly the car will take it for a VERY long time!

<ok done with my rant>


____________
Later
James
GS400 Lsportline Demo Car...

bitkahuna

iTrader: (20)

James - when you get it done, I'll be VERY interested to hear how it works out, and if all goes well, I may well drive my *** to Kansas City to have you stick one in mine! That would be a hoot.

Bobcat

do you lose your trunk when you go with a nitrous kit? I saw some pics a few weeks ago and this dude had some huge bottles taking up his whole trunk.

also, do you have to open a valve on the bottles in your trunk before you leave your house in order to be able to use it? or is it there whenever you want it, so long as your bottle is full?

Mean Gene

Bob - Yep, the bottle must be opened in order for the nitrous to flow forward to the engine but U have two options. Either do it manually ( open before leaving the house & s/d the bottle when U get back home ) or use a remote bottle opener ( NOS makes one that will work with any standard bottle ). It works with an electically controlled solenoid ( much like the ones on the system itself ) & are great for trunk mounted systems. I've used both the manual way ( in my 'Vette, the bottle was mounted behind the seats so I'd just reach around ) & the remote ( in a Camaro ). I'd still manually close the bottle if I was leaving the car for a long period of time in case the solenoid leaked - BAD thing to have a plenum full of nitrous when U start the car!!:eek: They also offer different sized bottles. I saw the pics of the GS ( wasn't it gs300haltech's? ) & those appear to be twin 10# bottles. They even have a 16 oz "Sneaky Pete" bottle U can hide under the seats but it only lasts for about 1 full 1/4 mile pass. If ya R worried about weight, NOS & NX offer some of their smaller bottles in carbon fiber wrap for about a 2# savings per bottle.
James is correct in that it's the returnless fuel line system on the GS that is causing most of the R&D problems, although NX just adapted a late model Dodge fuel system kit for use with the Lexus ( it's the same system in principle - relies on pulsing the injectors just enough instead of just pumping fuel to the engine & allowing a retirn line to recycle what's not needed at that time ). I'd also agree with James about the "wet" kit but personally, I'd jet mine down to a more "sane" level like 50-75 hp. I'm confident that the engine integrity is top notch but still don't have enough info about the GS fuel system to get that bold!! Plus, if I blow up my wife's car I'm dead meat!!:eek: BTW - I think the rpm range idea's a good one as the GS seems to come alive from 3k rpms & up ( kinda like turbo lag below that ). My personal favorite for that would be the Jacob's Nitrous Mastermind but MSD good as well. Will post what I come up with from NOS & Venom later today.

gs300haltech

I am good freinds with jimmy oconner ill see what i can get the venom guys to do. Since i race a honda i been pretty good with the venom guys.


I ll see what info i can come up for you guys today.

Mariusz

Great feedback guys. Thanks.