Hi everyone,
I am a newbee and just love my 98 GS 400. Wonderful, not a thing wrong and 95,000, fully serviced and running great. I was wondering if there would be any suggestions to move of performance a little. I did take her to the drag and recorded average times of 14.7 in the quarter. Best reaction time was .0062 at lights. I understood that this should be a little better. Any ideas on why, other than factory ratings are not always real world and age?
I would like to apply some upgrade and has anyone used Jet Chip upgrades?

Thank you in advance.

 

welcome to CLub Lexus

performance::

intake

torque converter

supra rear end w/lsd (limited slip differential)

supercharger/turbo

some say grounding kits

this is just off the top of my head

as far as the chip goes

https://www.clublexus.com/forums/sho...light=jet+chip

 

Welcome to ClubLexus! What track did you take your GS to? There are a LOT of variables including weather, elevation, launch method, etc. to overcome. Commerce in GA is known for being significantly slower due to their track prep and elevation.

Pass on the Jet ECU, start with a high stall torque converter and a limited slip differential (get a Supra TT one if you don't ever plan to do forced induction, it has better gearing at 3.76 vs 3.23 stock).

If you're not doing anything next weekend, join us (including a bunch of GA folks) in the mountains for the Tail of the Dragon meet ( www.lexusdragon.com for details) and check out a bunch of modified GSs, including a couple with superchargers.

Lots of Atlanta guys from ClubLexus are also on www.seloc.net and you can get info on local meets.

 

welcome to clubleux sa swell

if you want to stay na, your best bet would be (in the order of best to normal imho)

tc
higher gear ration rear end (supra one)
valve body upgrade
exhaust/intake
pulley

the next step would be extreme, meaning blower or turbo, manual tranny swap, etc...

 

Hi guys,
Thanks for the imput. I think I will skip the Chip. Everything else looks good, any idea how much difference the upgrades will make, and also of course where might I purchase with good mech to do change overs. Live in Woodstock, GA.
Think I will op for the intake, tc, and rear end first. Also how much is this going to effect MPGs, daily driver?

Also that was the Commerce track and I thought it seemed kinda squirrely. My launches were good, except one whereas, tried coming off in 1st, would not hold, backed off, shifted 2nd, hit it hard, would not hold, sitting at 6300 steady, still smoking, f-k it knew I had lost any time already, moved up to D,. so just kept into her and that single tire would not catch hold until 3/4 way down the track. Wanted to see how long she would keep spinning, impressive, steady at 6300 and loving it.
From the stands I am told they thought I had blown something, "there is black smoke coming from the right side of car", no, it was just the tire smoking like a son of a gun. If I did not need a new tire before, I may just need one now. I had a inch thick of tread hanging out of my fender.

My make it to the meet, awful close at hand, but may make it.

Thanks,
Tim

 

The intake and exhaust will give modest HP gains at best, but sure make the car sound a LOT better when driving aggresively! Whether or not the additional noise is tolerable is a personal choice-just need to be realistic about any performance gains... As mentioned, many exhausts and several intakes to choose from. Do some searching and you'll find all the info you could want.
Performance-wise, the best improvements (apart from FI) come from drivetrain "enhancements". The 3.76 LSD and torque converter swap together will give dramatic improvements without even increasing the engine's HP. Not cheap mods, but very effective. The Torsen LSD will eliminate your tire spin problem at the track too. Of course a set of 275 section width tires would help too...
As far as MPG, yes it will suffer a bit-more due to the fun driving the car with the mods than the increased rpm from the lower gearing.
Good luck and have fun spending your $$$$

 

Thank you'll for your time.

This is what I have been able to determine.
On my car there is a Akimoto intake system, and I am only guessing but someone has changed the ECM when intake system was put on. Looks to be factory original exhaust with 95,000 miles on it.
Based up track time of 14.7 and weight, this car looks to be:
246 HPRW
319 HPFW
Losing a lot in transfer looks to be: my reaction times are good with only the slightest chip of "THE TIRE", releasing her at 1800-2000 rpms. Car shift in Auto or me seemed to make not much diff., me shifting produced better times.

Questions: What is FI, Fuel Injection, and if so what improvement can be made there? Was this competed when ECM was changed for higher air flow intake?
Has anyone looked into the possible porting and matching of intake and heads?
Is there a possible better intake system out there, I have read where TRD has a very unique one, don't know if for the public or not.
Where can I find the finer details about how they build these engines, internal ****. Is it balance a blueprinted. Head and port designs, etc.
That TC change has seemed to have hand a number of failures very shortly after installing, in the reading I have come across.
Is upgrading transmission bad or good for these cars if they are just a little over stock? I read where 400HP is recomended before got that far.
Do you guys think that having car shift more within peak torgue would help improve times?
I will be adding soon and let everyone know the results as I go along.
LSD(not SLD), with Syn Fluid
Not loud good flowing exhaust
Trans Cooler with Syn Fluids
TC(?)
Steering and handling upgrades.

Thanks,
Everybody have a good day.

 

FI is forced induction: supercharger or turbocharger. This should answer the questions behind the initial question.

As for the TC, I've heard MANY more satisfied stories than failure stories. Since times at the strip are short and usually only involve 0-60, and 1/4mi times, the TC/LSD will help a lot. It won't get you below 14s but it will get you from the 14.7 to the low 14s. How low depends on conditions and driver skill on that day.

 

La pm ive got some info for you