You lucky I'm not going to Covina for my vacation or I be paying you a visit for volunteering me!

 

Hey now... whats up with the attitude? Here I am going to all this trouble and....

Loule, does your car have the stock intake still? I thought you went to a pod set-up or maybe I am thinking of someone else. You did take off the SRT/PI TC right? Anyway, would be cool to have a 1st gen to look at and make an assessment.

If it doesn't rain... and my girlfriend stays calm and doesn't freak... if... then I will be going to Houston Raceway Park (HRP) this evening for some back to back with and without air intake mods. One of the beauties of this setup is the ease in changing. I can do it in under 5 minutes...

My goal is to run a couple of 1/4s right off the street, hot, and get a baseline with the mod. I will then put the stock cover on and try for another couple runs. If time and traffic permit I will try again with time for the car to cool off some. My 96 ran back to back near identical 15.5 @ 90mph and after a cool down ran 15.4 @ 91mph. The factory Lexus page lists the 97 LS400 (mechanically identical to the 96) at 15.6... so I was somewhat pleased with the outcome. At that time the air temps were in the mid 80s and will probably be in the 90s when I test my 99. The Lexus page list the 99 at 14.8 seconds ET so I am hoping to at least do that.

Generally, every tenth and/or mph gained is aproximately 10 horsepower. I anticipate this mod being good for right around that amount... this should give me a straight up 300hp

 

Loule, you probably noticed the 1st gen mod at: https://www.clublexus.com/forums/sho...threadid=55911

If you get a chance I would still like to look over your car.

You probably also saw my times listed here: https://www.clublexus.com/forums/sho...threadid=55640

And my exhaust plans here:
https://www.clublexus.com/forums/sho...threadid=55774

and here:
https://www.clublexus.com/forums/sho...threadid=55729

since you replaced your cat back system it would be good to have your observations in either exhaust post... so... get off your... and post

 

Jbrady...

can i just take this one in order to make it high flow??

tks..

 

the pix

 

Something else that helps the early cars is to radius the flat surfaces inside the opening of the airflow meter.The surfaces that are facing the incoming airflow that is.The only possible hangup is when rounding off the vane between the bypass port,and the main venturi;you have to round from the bypass to the main section to keep the same amount of air going to the bypass,and not whack out the settings(pita to set after getting way off).
Also,the ring(leave the screen in)that redundantly holds the screen will often obstruct a bit,and everything helps in this dept,as you have shown.
I always take the sensor out of the housing and place somewhere very safe before attempting any grinding,btw.
The effect is very nice,getting rid of turbulence,and making the throttle,and power delivery much smoother.
Later.

 

SF, I do not understand your question? The picture is of a modified housing next to a non modified housing. This is one of a series of pictures showing the amount I cut away.

I got the spare part by calling the Lexus autobody shop and making friends with the manager. This one was off a 95 LS400 (part is same on 95-2000 models) and had very slight damage to the front retaining bracket and therefore was replaced as part of the work. They just throw damaged parts away and he gave it to me free. From the factory it is only available as part of a $300 assembly including the front cover, rear cover and air filter. If your car is under warranty or you ever expect to return it to stock I would suggest getting a spare like I did.

 

SCV8, thank you for wanting to help but you may be hurting the performance. I am assuming you are talking about the air horn formed inside the rear of the box around the MAF opening as seen here:
http://www.users.bigpond.com/pgscott...rboxfront3.jpg

The above is from Peter Scott's excellent site "Planet Soarer". He has done more testing including air flow, pressure loss and dyno testing than anyone else I have seen post information. Here is his quote in regards to the picture link above:

"The inside of the airbox is great. Check out the bellmouth around the square opening to increase flow. The airbox is large, the flow is direct, you can change the filter real quick. It is the perfect adapter to the Air Flow Meter. Nothing will outflow the back of the airbox - buying an aftermarket adaptor can only make the flow worse."

I would HIGHLY recommend anyone contemplating any modifications FIRST read through his site. It is VERY large and there is a TON of information but education is much cheaper than buying parts that are not as good as stock or changing stock to a worse configuration.

Main page:
http://www.users.bigpond.com/pgscott/

 

Uh,no,that's not what I was referring to:read airflow meter,not airbox.
That page is just some inconclusive testing imo;there's nothing to test actual flow, just the pressure drop at one point in the system,no mixture correction to go with the performance testing either.
Gotta have respect for having gone that far to try and figure out some real answers though.
The sensor is held in place by some screws on top of the airflow meter,pulls out of the way of harm.
After tuning cars for many years,this has to be one of the "no brainers" in my book,like port matching,but even easier.Had my car for over a year before I took the time to figure this out,noticed that the newer cars don't have the hesitation like the early ones,and they have a better airflow meter design as well.

 

.

 

SCV8, I see, upon re-reading your suggestion I agree with you. Of course, as you say, this is for the earlier rectangle MAF meters. On the LS400 the meters were changed in 95 to a round unit and then again in 98 to a MAF meter with a removable element. On the SRT system they remove the element and install it in a larger diameter tube. This changes the meters reading vs flow and leans out the engine. I believe the factory uses a rich fuel setting under full throttle and a leaner mixture would make more power. A slightly larger diameter tube would reduce the restricton and lean the mixture. I may experiment with this idea. The SRT part does not fit neatly into the LS compartment and I believe the stock parts as I have modified them are flowing the most cold air that can be had considering the box area.

 

So what's the size of the newer airflow meters,if you've ever checked,that is?

There's a way to use a different airflow meter with an afc unit,but I haven't heard of any Lex owners trying that yet.I've even thought how the area where the EGR is,opposite the throttle body could be used for a second throttle body.
But for basically free,the filing thing works for now I suppose.

 

I never measured but on the 96 it was apx 3" (maybe 75mm) with a plastic venturi inside. Unlike the 98+ with a removable element the 96 unit was sealed. As far as swaping with the type you have I can't say if it is possible or not but the one on my 99 is externally the same size (as the GS400 as well) and obviously supports 300hp. The more functional route (if it worked) would be to replace the meter with a VPC (vein pressure converter) from HKS which does away with the meter entirely. Could be expensive though. Another way may be to try one of those electric mini-superchargers claimed to provide 1psi manifold pressure. Many scoff at the idea but there is no reason it should not work.

 

This is want I did with my SC4...

http://photos.yahoo.com/the_ikon1911

The Ikon

 

Hey Guys,

I finally got the nerve to try this on my 91 LS400 this weekend. I took off the filter housing, traced out a circular shape avoiding the internal stiffening vanes in the housing, made a pilot hole with the drill, and made the remaining cuts with a jigsaw. Hole is maybe six or seven inches across. It looks very similar to JTJerryLS400's mod shown here https://www.clublexus.com/forums/sho...threadid=56619 , but the hole I made is a little bit larger.
Results so far? definitely more power from 2500 rpm and up, not sure yet, but my fuel gauge seems to be going down slower as well. I also cleaned the entire air intake path from on top of the radiator to the gold mesh screen behind the filter.

Thanks for the tips, everyone.

GA400