Yawn

Well,

I upgraded my 98 gs400 with the following:

S&S Headers
Weapon-R Air Intake
3.76 Limited Slip Differential
PI T/C
Tanabe Touring Exhaust

I am loving the way this car drives now! So much more fun and power! I am also waiting on some front and rear upper strut bars. But, what else can I do?

I have to let the wallet cool off for awhile but before X-mas I want to get some more performance into this car.

Thanks for all the info from this board its made my life and my car so much more fun!

jcat_350

well torquemaster plugs would be a good idea. Apexi Neo to get a few extra ponies on a good tune. Unless you plan on shelling out some serious money for FI you've kind of hit the ceiling. However, you may want to look into high flow cats if you can pass smog in cali. Much outside of that, you've got a lot of it covered except suspension (coilovers or air, RCAs, etc.)

evil00017

If you are looking for more power really the only thing that will give you a nice kick in the pants is a SAFC. With all the mods you have I bet you would see nice numbers from a good tune. Id go with the apexi neo personally.

Alexus_300

iTrader: (4)

Before you splurge all your money into power adder, you might wanna invest in some suspension parts. To start off, I recomend the daizen steering rack bushing along with front suspension polyurethane bushing. That will be give you a totally fun ride. Then after that, some properly dialled in coilovers.

sakataj

iTrader: (182)

and before u splurge all the money on suspension...........try doing the upgrade most people over look and the one that matters most. BRAKES......some simple pads, synthetic fluid, good rotors, and some steel braided lines or some supra calipers or a BBK but these are overkill. before you start adding power and suspension make sure you have a system in place 2 handle the upgrades you do. all the hp and grip wont do you ANY good if you cant stop! oh also let me ask...since u said u just got s & s headers YAWN, whats your opinion of them?

Rock-a-Lex

iTrader: (4)

I pretty much have the EXACT same "performance" setup as you. Only I have:

Torque Master spark plugs - new ones should be here any day now
Apexi Neo - Got some great results from this A/F controller

My S&S headers are still down in my basement waiting to be installed. lol. When I have the new plugs and headers installed it's back to the Dyno for a re-tune on my Neo...hoping to see 290whp or more! GL!

Yawn

I know there were issues with cracking in the past. I have also heard that issue has been eliminated in the newer sets like mine. So far I love the headers. I do not personally think that they added that much engine bay noise at all but you can definitely hear and feel the engine flowing better. I only have a few hundred miles on them but they are performing excellently. I tried to do this install myself. But then my mother got cancer so I had to send it to the shop which was a relief because on the GS400, there is definitely NO room on the driver side to get to those headers. It would have been a major install had I done that one myself. Hopefully I can get pics up in a week or so.

One unrelated thing that may be a concern is that with the new LSD and the Tanabe Exhaust, there is very little clearance between the two. I hope it does not become a problem where I will have to have a shop re-route some of the exhaust tubing.

evil00017

Hurry up and intall them!! I wanna know if you hit that 290 mark

Donuts

i would suggest:

-Torque converter
-Light Weight Drive Shaft
-A Good PiggyBack ECU
-Your Pefferd Racing Spark Plugs
-Maybe a Fuel Pump as well
and when the injectors duty are to the max injector upgrade would not be a bad idea at all !

im wondering what is PI T/C ? (somthing to do with Traction Control am Assuming)

Rock-a-Lex

iTrader: (4)

It's a high stall torque converter made by Precision Industries. The second gen. GS owners mainly buy these converters set anywhere from 2800 - 3200rpm stall (stock is set to 1800rpm). I have a 3000rpm stall...which pretty much leaves a 15' stretch just by mashing the gas; so now I need wider rear wheels/tires for more traction. lol

Alexus_300

iTrader: (4)

Half of the stuff you have on your list is not needed at all. The light weight drive shaft will do nothing along with fuel pump and injectors as you're not ramming enough air into the A/F mixture to compensate for the upgrade. Those items are only needed if you are boosting. Most people don't realized how important your suspension is in a vehicle. You can make all the power you want but if you can't put it to the ground, then you'll just have a nice black skid mark on the ground to look at...

evil00017

agreed!!!!!!!!

Rock-a-Lex

iTrader: (4)

...your right! But, in my case I still have a nice Bilstein PSS coilover setup and still can't get traction; my tires are a little worn now too though.

kit cat

iTrader: (6)

from your sig... "Toyo Proxes 4's"
thats your issue. I have a bone stock (power wise) GS4 with Proxes4 and I can break them loose. When I had the Proxes T1S, I never had issues with traction. Screw all season, get a set of Proxes T1R, and run snow in the winter.

jcat_350

lets go down the list:

-OP already has a Torque Converter
-driveshaft won't do a damn thing.
-piggyback ECU is overkill unless FI, an Apexi Neo a/f controller is sufficient
-these lexus engines are particular about plugs, already suggested a good set (torquemaster)
-fuel pump and injectors, again will do nothing without FI.

use your head, and read what has already been posted. Every piece of information you posted was either already covered or useless.