Hey how's it going man. It's a long winded story but I think I got it figured out...I was down to the last issues a stumble and bucking condition that I believe is because I got the wrong spark plugs! Lolol. I needed the regular NGK BKREIX (2667) where I bought in error the NGK BKREIX (6988)...different gaps! So pissed.

From random website

"#2667 is the correct one colder Iridium.

The 2667 is a BKR7EIX, the 6988 is a BKR7EIX-11.

The 2667 comes with a gap of .030, the 6988 comes with a gap of .044 (1.1).

I have one of the last batches of the S&S headers not the PPE's. I bought new set of exhaust manifold gaskets straight from Lexus; I read they are MUCH better than the gaskets that come with the headers.

Hey dude, how is the SC workin? Hey what kind of header gaskets did you use for your PPE install?

cool. I have Torque Master spark plugs BTW. There have been a couple of tests done back to back with new OEM denso spark plugs VS the TM spark plugs. The test revealed that the TM's yielded around 6whp! They are about $11/ea. I am not sure if the SRT intake (for the GS400) is made for your SC400; I could be wrong though. I think my AF numbers were high 12's to very low 13's when they were tuning my car with my Apexi Neo A/F controller. Before I had the headers and this A/F tuner I was around low 250'swhp with just K&N intake, exhaust and TM spark plugs. Make sure the pulls were done properly...if my memory serve me correct the auto GS/SC4XX's should be dyno'd in 3rd gear. GL!

well first my car is a 98SC400. we were running it on a AWD dyno but only in 2wd form. I cleaned my air filter the night b4. I run amsoil 0w-30 signature series oil w/amsoil ea filter. The only thing i havent changed is the sparkplugs,I should do that i did check one about 6mo ago it looked good,its not missin. trannys good, diff
is good, it acts like it runs alot better than those #'s. i have srt performance intake for the gs400 w/maf chip, full mandrel bent cat back w/x pipe & tt 3.76 lsd rear end. im kinda pissed cause it should be more than that.what kinda plug do you have? those HKS plugs are proly not worth it. i spank g35's 350 z's all day and other cars like that, but maybe the dyno's off. Im gonna change the plugs asap. i fixin to get those headers my a/f ratio was 12.5 average during dyno. my lexus guy said that the sniffer in the tail pipe is the wrong way to test, it should be done b4 the cat.Hey i alos did a simulated 1/4mi on the dyno and ran a 14.20 @97. i videoed it so when i get it up on youtube ill send u a link so you can see it. it was 2pulls & the 1/4mi .

spdrcr771 - 221whp is not TOO bad...but I HOPE your GS4XX is BONE STOCK at those figures; if not something is severly wrong with your car. A normal GS4XX in stock form should dyno anywhere from 235-240whp. So your about 15whp shy on your baseline which could EASILY be from improper maintenance from the previous owner of your car. My numbers were achieved on an AWD dyno which appropriately sets the load as if the car was rolling on the street. There are some dyno's out there that inflate numbers and give non-realistic figures. My guess is that you used a dyno that does put into account loads (accurate) but you need maintenance - whether you know it or not. I would change out all O2 sensors, MAF sensor, spark plugs, clean air filter, change oil and oil filter, change tranny fluid and tranny filter, change diff fluid and re-set ECU when all done. Yes, unfortunately all of this could wind up being as much as $1K but then your car will be SET and ready for mods. Sometimes when you mod without KNOWING if your car is "healthy" to begin with you will not notice that the car "should be" faster with those mods. You only realize this until you either dyno your car or race another GS4XX with no mods or the same mods and lose by a good margin. This is why before I started doing a lot of mods I changed out the above noted. It's a PITA to drop money like this just on stock items but it will make the car run better (performance) and more efficient (mpg) which is much needed especially if your car is your daily driver like mine is.

man we gotta talk, i dynoed my car im compairing my # to your # aint even close so i gotta figure out what i gotta do to get there. rwhp 221 rwtq 231 let me know what u think.

No problem.

Thanks for the info rock

Yes.........

Do you mean the electrical pin-out sheets??