GS400 Performance...

[Supra4Ever]

Hey all,
I am in the process of purchasing a 99-00' GS400. I have been looking at the available engine modifications for it such as the exhaust, intake, ECU, etc. I do have a couple of questions for everyone.
1-Has anyone ever used or is using either the Carson Tuned, A'pexi WS, or the JIC Magic Bullet exhaust systems? If so, what are your opinions on them.
2-Is the SRT intake worth $500.00? I am in complete debation on this one.
3-Will Injen's intake for the GS430 fit the GS400?
4-Is the SRT Racing ECU the only option for engine control, or can I run something like a GReddy or A'Pexi piggyback such as the E-Manage or the SAFC?
Please help me out guys. The car WILL NOT ever see any track or race time. Its a family vehicle that I am looking to add a little more "zip" to. The main points I am concentrating on is the suspension, brakes, aero, wheels & tires, aside from a few basic engine-mods.
Thank you so much and have a wonderful day!

 

[johnnygoodlife]

if you want more zip

upgrade torque converter to 2800 stall speed

upgrade rear diff. to toyota supra TT w/LSD 376 gears

i have the the TC upgrade and the SRT intake on my GS400

i love it
just need the TT LSd

 

[Lextreme II]

So the Supra LSD would work on GS? I wonder if it will work on LS.

 

[johnnygoodlife]

hmm im not sure ... do you know what your stock gearing is ??

 

[JBrady]

Hey all,
I am in the process of purchasing a 99-00' GS400. I have been looking at the available engine modifications for it such as the exhaust, intake, ECU, etc. I do have a couple of questions for everyone.
1-Has anyone ever used or is using either the Carson Tuned, A'pexi WS, or the JIC Magic Bullet exhaust systems? If so, what are your opinions on them.
2-Is the SRT intake worth $500.00? I am in complete debation on this one.
3-Will Injen's intake for the GS430 fit the GS400?
4-Is the SRT Racing ECU the only option for engine control, or can I run something like a GReddy or A'Pexi piggyback such as the E-Manage or the SAFC?
Please help me out guys. The car WILL NOT ever see any track or race time. Its a family vehicle that I am looking to add a little more "zip" to. The main points I am concentrating on is the suspension, brakes, aero, wheels & tires, aside from a few basic engine-mods.
Thank you so much and have a wonderful day!

The SRT CAI increases the MAF diameter which reduces the restriction at higher flows. The "race" ECU is needed to adjust the larger MAF to work with the stock ECU. This combination does increase power. The other CAI's on the market do not increase the MAF size and therefore pretty much just rely on leaning out the fuel map (if anything). I can't comment on other piggybacks.

The Supra LSD differential will bolt into the GS400s and the 1998 and later LS400s and SC400s. All three of these models has a 3.266 ratio. The Supra TT Automatic ratio is 3.769.

Most LOVE the Performance Industries Dragon torque converter.

 

[johnnygoodlife]

J brady

i have read some of your stuff on CL

always a great read

im looking to FI myself

possible RMM S/C from a friend in Cali

ive just joined this site looking to learn more

any heads up for a guy looking to supercharge

ive heard that with the SAFC there is a greater chance of runiing your engine as opposed to e-mange

also someone told me if you had the bracket

you can mix and match your won components

if this is true where can i get the piping

sorry for all these questions

total NOOb when it comes to this

i know i probably have a lot of searching to do

hoping you can lead me in the right direction

thanks again

johnny

 

[johnnygoodlife]

to the top

 

[JBrady]

Johnny, sorry but I cannot advise about ECU tuning other than it is definitely important to have sufficient fuel and proper timing on the ignition.

SC will be adding more air mass and fuel to the engine and that will need to get out... this increases the need for good exhaust. With the SC setups and assuming an aftermarket ECU tune of some sort... the SRT ECU is not going to be helpful.

You can match any components you like as long as the SC is solidly mounted and the pully system is in alignment and doesn't interfer with anything else.

Exhaust is very important and I am possibly going to be assisting a local GS400 owner on his application. If so, there is a possibility that an aftermarket Y pipe could be production built. Don't hold your breath. You will definitely want the dual 2.25 system with Y pipes.

 

[1youZee]

I may be able to help with the ECU tuning,
I had an S-AFC on a Skyline and switched to an e-Manage and can tell you they are a bout the same as far as wich one can hurt the engine... both, equally well. As JBrady said, it all depends on the A/F ratio and ignition timing you specify. Although with the S-AFC you cannot tune the timing events, the e-Manage requires a seperate harnes, but will do it.

some pros and cons to both:
e-Manage:
it has more tuning point throughout the rpm range, every 500 RPM you can adjust it. this can also be a hasle as there are a lot of point every 500 RPM from 2000-7000.

they both have a built in "anti-stall" wich will aid the stalling of your motor if you lift while on boost and have a blow off valve that vents to the atmosphere. it tricks the ecu into thinking you stepped on the gas to recover from the stall. the e-manage works much better in this area as the S-AFC only does this twice as the RPM falls, the emanage does it up to five times and works a little better.

they can both use different MAF sensors. and even dual sensors in the case of twin turbos/ MAFs

the e-Manage requires a laptop or the optional LCD screen ($$$$) to configure wich can be a pain if your battery doesn't last long. the S-AFC; tune any time, as long as the car is on.

the S-AFC doesn't handle MONDO injector changes as well as there is no setting to tell it they are different, just lean out the bigger ones, only up %50 bigger, the e-Manage has a setting where you specify the stock size and new size and adjusts corespondinly, also, it has previsions for additional injetors to be fired, for instance, two in the discharge tube before the plenum for that extra charge of fuel. the S-AFC does not.

all in all, I think if you really need the most HP out of the ECU, i would go with a replacement, as any piggyback computer can only modify the stock ecu to a certain extent. if it's just mild upgrades i would prefer the S-AFC as it is more cost effective.

hope that helps.
and if anyone is interested, i still have an e-Manage i may be willing to part with. software, harnesses and all.

 

[johnnygoodlife]

thanks for the great info guys

 

[Lextreme II]

If you have to spend money on fuel control computer. Invest in an Emanagement. It has fuel, timing and also able to control extra injectors. If you plan to upgrade from basic boost to 12 or higher psi, then Emanagement is a great investment. I love the intergrated extra injectors control.

Run stock injectors with two 550 injectors are extra.

 

[JBrady]

If you have to spend money on fuel control computer. Invest in an Emanagement. It has fuel, timing and also able to control extra injectors. If you plan to upgrade from basic boost to 12 or higher psi, then Emanagement is a great investment. I love the intergrated extra injectors control.

Run stock injectors with two 550 injectors are extra.

David, I agree with all of this except the two extra injectors. While extra injectors can be an excellent option I strongly advise against anything other than port or individual runner injector mounting. Adding extra fuel at a single point requires the manifold to distribute the fuel. Modern EFI manifolds do NOT carry air and fuel equally. The result is some cylinders run richer and some leaner. You must increase the fuel to the point where the leanest cylinder is safe. This leaves the other cylinders too rich. Poor compromise at best.

Running 8 larger injectors that are adjusted correctly or running 16 injectors staged is the way to go.

Actually, the older General Motors 4.3 liter V6 Vortec engine used a fuel block fed with a pair of electronic injectors and individual tubes running from the block to injector tips much like mechanical fuel injection. The tips are MUCH smaller than an injector and this makes them much easier to place. This type of system could use 1 or 2 or any number of injectors at a distribution block and then hard lines (fuel resistant plastic or metal) to properly located tips. I thought of this years ago but have never seen it done nor done it myself. Always liked the idea though.