BlexusGS

Thanks guys...I am prinitng out your posts so I can show my mechanic. Maybe you guys touched on something that they haven't thought of. I'll let you guys know what happens.

Thanks,

Nick

I need help and advice. A while back I was getting a CEL and its code was PO171 (engine bank #1 too lean). I went to my mechanic and he was hesitant to work on my car because of my air intake. He mentioned that it was probably my O2 sensor. I told him that I'de rather him work on it than the Lexus Dealer because of their high price. He said he would only work on it if I sign something stating that if the CEL does not go out he cannot be held responsible; I agreed because I didn't know if my intake was the cause of the problem. Anyway, he replaced the O2 sensor and guess what... the damn CEL came on again. I drove back to the mechanic and they checked the code; still PO171 (engine bank #1 too lean). What the hell??? He told me to clean out my MAF (and be delicate about it). I searched on this forum and found suggestions to spray rubbing alcohol and use Q-tips carefully; so I did and also reset my ECU. About 5 miles into driving the CEL comes on again!!! What can this be??? Can my MAF be bad, how can I tell? Also, how would I know if my custom ram air setup to my intake isn't the real culprit. I don't want to replace the MAF or the "other" O2 sensor (there are 2 O2 sensors regarding A/F on the GS) just to find out that I'm changing out good parts. Please advise!!!

JDM...I agree with your rotating mass example but my rim might be wider than the stock rim BUT if you put my new wheels w/tires next to my stock wheels with tires it's only 1/2" difference in width. The stock rim width is 1.5" smaller (7.0" vs. 8.5") but the stock tires kind of "balloon" around the rim whereas my aftermarket tires are flush almost inward as compared to its rim. I don't think 1/2" more patch contact will make my car feel that much slower. Oh...BTW my car was running lean for almost 1 year!!!! There was always a CEL appearing then re-appearing. I thought it was because of my intake when it actually was a faulty o2 sensor all along. Now fixed, the car runs MUCH better!

For that price your better off spending $500 more and buying a set of coil-overs ($1100) and install ($400).

Thanks DCfish...that's all I needed was some input. I'll check out ClubLexus as you suggested.

It's funny because someone once said on this forum that this was more of the performance forum and ClubLexus was more of a repair and maintenance forum; I think they have it backwards...

BTW...I searched this forum already; I always do first! I only found out:

"it is a lot faster off the line"

"you'll go through tires 2x as fast"

"you'll lose 1-2mpg"

"RPMs at 70mph will be at 2800RPM"

I would appreciate if someone can bless me with some more defined results such as approximate performance times. Thanks...

Intake

Exhaust

3.76 LSD

PI Torque Converter

Thanks guys,

I know that MANY of you have this setup already. I just want an idea of what these mods are capable of before I do something stupid like sell my car for newer technology. I know these times will probably be estimates so if you would mind by giving examples of say...taking out a new mustang or WRX - this would help a lot!!!!!

-Nick

Anyone with opinions?

Sorry, not sure why the heading got so screwed up. I was asking if anyone every started out using a regular air intake such as Weapon R or K & N then switched to the SRT intake. I would like someone that experienced both to respond... does the SRT with the piggyback ECU make a very noticeble difference in power over other air intakes?

Thanks,

Yeah, maybe NOW you can probably blow my doors off after $10K of engine work/turbo using your 2.93 gears. Stock vs. stock a GS4xx will take out a 528i anyday! BTW thanks for your advise maybe I will consider doing some port and polish work on my engine in the future. Unfortunately this whole thread did not help my situation...I am still showing a lean code. My mechanic won't even change out my o2 sensor because he feels that it might not fix my problem. I really don't know what to do at this point. If any1 else would like to contribute your responses will be greatly appreciated! Nice modding on your Beemer BTW.

"I don't understand why your stock ECU can't compensate for the additional air seen through your CAI"

Why not...why do you think everyone on these forums re-set their ECU from time to time? In the beginning your ECU will re-learn your driving habits and intake and such but after a little while your ECU will go back to stock settings. IT IS TRUE! Right now my car is hesitating (almost like turbo lag) when I hit the gas. Whereas when I re-set my ECU the car feels and responds so much better - it is FACT!

I cleaned the MAF sensor once before last summer, (before I added the ram air port in my bumper leading to my intake filter) it needed to be cleaned as dirt and oil build-up was present. However, just 2 weeks ago I checked the MAF and it's clean. So a dirty MAF is NOT the problem.

If I had the heads ported and polished then my after-market warranty is out the window for my engine. I would rather NOT have my tranny covered than the engine! Plus I heard that the gears make a big difference... why does it seem like you think otherwise?

I see that you own a BMW, not sure if you own Lexus also but if you did you would realize that the GS models are running 3.23 gears and still manage to be pretty quick off the line. A lot of the new cars like Infinity G35, Nissan 350Z, Maxima, Altima Etc. are all running with 3.7x gears THAT is HOW they are ALL able to hang with the GS4xx ... stock vs. stock! (I know they are a little lighter as well) but still it makes me wonder IF I should even BOTHER modding my GS400 to KEEP UP with the newer technology! Now I'm upset :-(((

Future mods to be added very soon:

S-AFC controller - because right now my car IS running lean and throwing off check engine lights and sensors. Stock ECU doesn't know how to add MORE fuel for the increased air. I am going to have a local shop that I just found run a baseline dyno, then install the S-AFC, then run more dyno's to tune. I feel that my car COULD be running slower than stock right now due to the lack of adjusting of the stock ECU.

3.76 gears - Although costly for the bolt-on Torsen type unit ($1599) I feel that the results are that of the PI torque converter or better however without the excess wear on the tranny (I understand gas mileage will decrease). Also, I just finished reading a post from a sorry Lexus owner that had his tranny blown from a faulty PI Torque converter. (Eventhough it is rare to happen I cannot take that chance.)

If the stock GS4xx produces 300HP at the crank I would like to see 350HP at the crank but FEEL like 375HP because of the greater torque feel of the 3.76 gears. I have researched and been told that changing the stock gears to 3.76 reduces 0-60 by about .5 seconds. If these cars SUPPOSEDLY run 5.9 (0-60) and 14.2 (1/4 mi.) doesn't that mean the new 0-60 will be around 5.3-5.4 and 1/4 mi. 13.7???? If not...why not? Please advise.

Hello,

I had a couple of questions for the gurus on this forum.

1. Is it possible to see better gains in HP/TQ when intake pipe is reduced in diameter?

2. Is it possible to see better gains in HP/TQ when intake pipe is reduced in length?

3. Which should you see better gains in HP/TQ; when the intake is built with a smaller or larger cone-style filter?

During some research I read that if you go too large you will lose substantial low-end power but sort of make up for it in the top-end and vice versa. It seems that a lot of people on both this and the CL forums say that the car feels slower off the line but around 3000 RPM it hits hard. This leads me to my final question...

4. Would you suggest perhaps mixing intake pipe sizes for optimal low-end and top-end performance? For example, use an Apexi power filter (3" dry-type filter...supposed to be the best for filtration AND flow) on a 3" pipe then connect it to a 3.5" pipe to the throttle body.

What do you guys think? Will the gains be too negligeble to notice?

Thanks

You the man! I appreciate the follow-up bro. Let me know what you find. BTW what part of NY are you located?

I'm thinking of purchasing a TRD 3.76 LSD (complete unit). Pros and cons of same would be appreciated! :)

Appreciate it...let me know bro.

jezz, I just sent you a PM. Let me know if you got it..

Thanks for your reply but the L-Sportline grille does NOT exist on their website; I just checked. I really need to find this grille. I have only seen pics of this grille on the net. It is similar to the TRD & TTE grilles but NOT the same.

Please help... can't find it anywhere on the net! :chairshot:

The ones with the green tint. Having them installed on Fri. Probably going to sell my old housings on Ebay or something. About 3 months ago I noticed that one of my headlights weren't auto-leveling at night when I turned them on. Went to get an oil change at the dealer and asked to check out the problem. Sure enough the auto-leveling mechanism was broken. They had to replace the entire housing! Good thing it was covered under warranty. It wound up costing $1,100.00 with the part, labor and tax; not a dime out of my pocket. :P But now I had one brand new headlight and one noticebly old one. This is what prompted me to upgrade to new on both sides. :) How much do you guys think I can get for my old headlights? One is only 3 months old (like new; no scratches) and the other is great condition (which I am also going to do a 3-stage wet sand).

Also, off topic... I restored my old stock exhaust from my car to like new condition (it shines now). How much would you suggest I try to sell them for?

I'm 26 and had my 2000 GS400 for about 3.5 yrs now. I Pay $406.07/mo over 5.5 years. $10K down initially. (6K cash / 4K trade-in for '92 Acura Legend w/164,000 Mi!) Still about 28 pymts. left.

Good question... I'm sure it could happen. What does every1 else think? If I am taking in more & colder air can it be that my car (stock ECU) cannot compensate by adding more fuel and therefore throws a lean code. Not necessarily that there is something wrong with my car... just indicating that for the amount of air (& temp.) coming in I am not getting the correct ratio of fuel. Is this right???

Thanks for your responses guys, I am bringing it to the Lexus dealer around here anyway to get an oil change, winter check-up and replace my old HID headlight housings with the new 2005 green tinted HID housings. I will get the car scanned then.

Thanks DC! I cleaned the MAF about 3 months ago, the check engine light came on about 1 - 2 months after. Is it poss that i could have damaged it? If i broke it wouldn't i still have the check engine light?

Thanks

Please.... any1!