Fair enough, I apologize (and I ahve read it before btw). The use of the quote button would have made things a lot clearer though.

 

Grand-Am prototype specs, just for the fun of it. Copied from the Grand-Am site because I couldn't c/p. "LEXUS (TRD) 5.0 L V8 cylinder bore: 3.702 Stroke: 3.500"Minimum crank weight:38 lbs. Maximum compression ratio 11:1 Cylinder head intake runner maximum volume: 139 cc's Cylinder head exhaust runner maximum volume: 81 cc's Intake Valve 1.356" Exhaust Valve 1.147" piston w/rings,pin connecting rod 1000gm minimum. Maximum camshaft lift @ retainer with zero lash: .478" Maximum cam duration 260(degrees)@ .050" lift. TRD intake # 17112-GA008 top. #17110_GA-008 bottom. Toyota throttle body # 22030-OFO10 maximumum fuel pressure 5 bar (75.4 psi) Maximum rpm: 7000; minimum crankshaft weigth 38 lbs. Cam profile on file cannot be changed. " For whatever copy right infringement I don't want to break, thats from the Grand-Am website. The reason I post it is because its supposed to be 500 hp (they don't say brake or wheel) TRD is supposed to have new heads by the next race and it's supposed to be based on the production Lexus LS, CS and GS V8

 

That's a totally different fuel system. Direct injection uses MUCH higher pressure than 5 bar. Figures they'd abandon DI for racing....

 

Lobux, what do you think the cam lift(s) will be for the F engine and what about the duration(? or whatever 4 cam engines have) for 400 to 420 bhp that passes smog>?

 

With VVTi the numbers are funny compared to fixed timing. They're also playing some games with the new electronic VVTi actuators and I suspect they may be able to vary duration according to software, not just hardware. At least I hope they can with their new actuation methodology.

I'd expect lifts to be typical Toyco, around 8.7 to 9.0mm. Lift isn't usually a good indicator of anything unless you know what the port will do at varying lifts. I always work for more flow at low lift anyway, I'm not as concerned about peak flow because peak duration is so short. I'd take a 20% increase at 1mm over a 20% increase at peak lift any day. It will mean a lot more to the engine's ability to breathe.

As a for instance, the 2JZ-GTE head doesn't flow much more above 8mm of lift, so big lift cams (10mm or more) on the exhaust are useless unless you port the head, and then you run into velocity problems and reversion, so you have to have a plan from the get-go to compromise for power where you want it. It's always a big balancing act.

 

What's interesting is that the 5.0L V8 in the Grand Am Series in fact is still a 3UZ, only bored out to 5.0L. Lexus has not yet made a race-spec version of the UR engine, even though many people thought that 5.0L was a UR block.

 

Did you forget something?

Car Chat: New Lexus 5.0L V8

 

My initial enthusiasm and expectation that it was a UR block was put out after reading this:
http://www.lexus.com/magazine/q207/D...Daytona_3.html



Not sure why they would continue with the UZ block. It just doesn't make sense to me, unless they haven't had time yet to make a race-spec UR block. A UR race engine would just be superior to a UZ in many ways. Here's hoping they move to a UR block in the 2008 season where also the engine manufacturers play a larger role in the car design.

So far, the Lexus prototypes have consistently been losing out to the Pontiacs this year. Pontiac will easily take the engine manufacturer's championship this year. Word is that GM was aggressive with the Pontiac V8 development and so far over the course of the season they've upped the power on the engine by about 30HP. The Lexus engines get new cylinder heads for the season-ending Utah race that reportedly add 20HP, but it also begs the question why the Lexus engine development this year was less aggressive. My only hope can be that we see a UR race engine for the 2008 season.

 

Those photos and specs I got were directly from Lexus Motorsports. The writers of the Lexus Interactive magazine are 3rd party vendors which publish out of Washington state.

Doesn't really make sense to bore/stroke an old motor considering the race engines need to be a derived from production model vehicles. There is no such thing as a 5 liter UZ series block used in production form. I'll re-confirm it with them.

 

It would be quite strange for the Lexus Magazine to be wrong about the specs since the magazine is official and on the Lexus website. I double-checked the rules and regulations for Grand Am and stroking/boring a production engine is allowed to some extent.

Re-confirming with Lexus Motorsports should settle this matter of whether or not the engine is a UZ or UR block.

 

Here's specs from the e-mail from a year ago. (8/22/06)

HP: 500 (regulated by Grand Am)
Bore: 3.702"
Stroke: 3.5"
Compression Ratio: 11.0:1
Max rpm: 7000
Cam Lift : .478"
Cam Duration: 260 degrees

I'm waiting for a response from them in the meantime.

 

Yea, this is not even Lexus' work. The obvious sticks out like a sore thumb.

"First Lexus F badged performance cars to compete with Mercedes AMG and BMW's M division"

Lexus has specifically stated on several occasions the the ISF Will not be competing or compete with BMW's M division.