JBrady

Below is a picture I have looked at DOZENS of times... and it just NOW struck me... this is a picture of the 1st gen 1UZ-FE being dyno tested... now, I ALREADY knew this... what I just realized was it has a LARGE air feed hose to the throttle body and what look to be glowing tubes in PLACE of the catalysts!!! What does this mean? Well, if the engine dyno'd like this and it made 250hp then when you restricted it with the production intake and catalysts it probably truely only made 230hp at the engine. I have always wondered WHY a 250hp engine lost 75hp in the drivetrain leaving just 175rwhp!!! That is a 30% loss!!! Not reasonable. If we compute for 230hp vs 175rwhp we see a much more reasonable 24% loss. When you look at the typical rwhp of a GS400 at 230rwhp vs its factory 300hp rating you get 23.3% loss. This makes MUCH more sense. So, David, use 24% loss on your TT LS400

Check out the glowing area where the catalysts should be:

Lvangundy

Aren't those headers supposed to glow red?

And yea..the intake thing. how are they running it and getting those numbers especially with the finicky MAF.

Lextreme

I can just imagine my turbos glow like the headers. I think this is a test engine and its be stress to the max. WOT for hours. That is why headers glow like that.

According to John's calculation (24% Lost):

324.5 rwhp divided by 76 time 100. The flywheel HP is 432.67

JBrady

Lee, actually I spoke to the glowing manifold situation in the GS forum and that was where I took another look at this pic and realized my above post. The answer is YES. In low light or dark the manifolds will glow when the engine is under full load. Take a look at the GS engine forum for my complete response.

Lvangundy

J- So you're guessing the 250HP was acheived most likely from the dyno test shown in the picture right?

This seems to make sense but what if they somehow dyno'd the car in it's production form and got the 250? Why would they sell the car with a 250HP rating when the numbers were only acheived on a proprietary test? Do msot car manufacturers do this?

Shouldn't Lexus have sold the LS wit ha 230HP rating instead?

lawsuit.. j/k

JBrady

Lee,

I think the picture is off the actual dyno stand with some photo backdrops to make it stand out and hide hoses and wires. This type of testing is common. Some manufacturers are conservative and other report optimistically. BMW tends to underrate their engines while Nissan/Infiniti tends to overrate.

Any way you cut it... it does NOT make sense that the cars loose 75hp on a 250hp engine or a staggering 30% loss. Regardless, the REAL and IMPORTANT number is always the power that MAKES is to the ground. RWHP and RWTQ are the only important numbers. Remember, the 1990 Corvette was 250hp and offering a luxury car with the same HP as a Vette definitely brought some people into the showroom. Now, the Vette was MUCH quicker with 350lbs/tq and probably 200rwhp/300rwtq vs. the Lexus with 230-250?? and 260tq with 175-180rwhp and 180-190rwtq. Once Lexus had claimed their number any improvements MUST have a bigger number. The 1995 LS400 was rated 260hp/270tq and was slightly lighter weight but MUCH better performance... much more than 10hp would suggest. Did Lexus LIE??? It doesn't really matter. The bottom line is the 300hp GS400 makes apx 235rwhp for a 22% loss and that number is very much in keeping with this type of drivetrain. Take 230hp and subtract 22% = 179hp...

LOTC

So where are the aftermarket headers that were in development so I can get those 20hp's back?

retrodrive

Ya, me wants them toys too!

JBrady

Cels and Retro, since I have a VvTi 1UZ-FE the first shorty headers will most likely be designed for the 98 and newer engines. I BELIEVE that the mounting flanges and exhaust port layout is the same for all years but I haven't confirmed this. As soon as I do, I could offer the earlier cars an upgrade package consisting of headers and a Y pipe. I MAY offer "test" pipes. If not this package would require catalysts off a 98+ car. This would be the BEST setup for our engines as the newer manifolds are LONGER and allow for a better flowing part than the space available with the early manifold.

Question: Would you want to upgrade? Or... would you want a bolt in replacement for the earlier header? If you chose the 2nd option I would need to engineer 2 different parts, 90-97 and 98+. This would take longer and increase the cost.

Let me know.

retrodrive

What would make most difference? What are the costs we are talking about here? Just need to get the idea on price/performance issues here.

JBrady

Retro,

On the 98+ the outlet flange on the manifold (that the catalysts bolts to) is several inches away from the engine as compared to the same flange on the pre-98 manifold. Take a good look at the pictures in this thread https://www.clublexus.com/forums/sho...threadid=70132

Notice the 1st pic showing the early manifold... the bottom of the outlet flange is about even with the last bottom bolt hole of the back exhaust port. Now, go down 4 pictures and notice how much further this flange is from the same reference point.

This means that I can build a more efficient header because the tubes will be straighter and the merge sections MUCH more efficient. Cost for doing either design would be about the same but I would MUCH prefer to build just one design. Cost X 2 = twice MY cost!!!

Estimated costs??? I put down an explaination price and cost estimate in this thread https://www.clublexus.com/forums/sho...threadid=73337