What's the reliability of GM's factory 5.0L's that make 420hp. Error: divide by zero!

 

Better head flow numbers, from a stock LS derivative casting, let alone a modified head.

4.030” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 74.9 109.4 154.4 193.5 225.3 252.8 274.6 292.7 308.8 321.0 328.7 326.6 310.0 316.6
#1 Exh. 63.6 97.9 126.1 148.7 162.3 178.6 189.6 197.6 205.5 210.7 214.6 217.8 221.2 223.5

321 cfm at .600 lift, which is where a LOT of "mild" LSx cams end up, 210 cfm exhaust

Yes those engines make that HP number, however you know just as well HP and torque are two different things, that bmw engine that makes 500 HP you want to compare to the LS7 makes it at 7750, peak torque ONLY being a whopping 383 ft lbs @ 6300, compare this to the LS7's 475 ft lbs @ 4800, i'd like to see a dyno graph of each overlayed, this also doesnt take into consideration that the LSx i'd have to bet is a HELL of a lot smaller than that V10 bmw engine, making things when considering a swap considerably easier.

Oh that audi 420HP 4.2 ? 420 HP @ 7800 rpm, a whopping 317 ft lbs @ 4500 rpm, compared to the LS3's 436 HP @ 5900, along with 424 Ft lbs @ 4400, that extra 107 ft lbs will be a little bit noticeable, again with an engine that is more compact, and quite possibly weighs less.

You are comparing small displacement high rev'ing vs larger displacement lower reving, airflow in the heads isnt an issue, its just designed to make its power down low using displacement.

On that honda head note, whats impressive is that those numbers were probably (im guessing) obtained using a test bore similar to an actual honda engine, if so those are pretty impressive from such a small bore.

 

Sorry, small displacement V8, or V10 with turbo 4 cylinder torque levels does not compute


Oh and since you didnt catch it, I doubt there is any sort of issue with the IS-F's engine, it was a poke at burgy stating that since 3 guys he met, had some issues, all Gen3/4 sbc's most likely have issues.

 

I was refering moreso to the C-5 Z06's than the C6's. I do agree with your point that they are aluminum chasis and are significantly closer to a street trim race car than before. But I beg to differ about the punching thing because a vast majoritry of Z06 owners are old fucks with too much money, but yes there are some younger people who I'm sure track the shit out of it.

 

Z06 owners do not have to much money, they're not exactly expensive cars in in relative to other performance cars. They just perform very well for alot less. The chassis and motor are there but the interior is much to be desired.

I've never understood why Chevy wont put recaros in the nicer Vettes from factory. They're factory seats are total garbage and thats been a shit point on those cars for years, its not like 2 seats would drive the cost of the car up 10k.

 

A k series motor was brought into this why?

As for the seats, sadly if the zo6 only came in pink it wouldn't effect sales. People would still buy it because they think it's the "shit".

 

Oh I know all about how torque and horsepower are related. How power under the curve affects acceleration, where gearing comes in, etc. I built the knarliest spreadsheet around for comparing 2 setups, all coded by hand. It'd be a different story if GM had some OHC motors so they could actually make power over 6000 rpms where your tq/hp multiplier is higher. LS7 might make 475tq but that drops to about 350tq only 1800rpms later (8000rpm). Torque is all about peak cylinder pressures and displacement. It has a lot less to do with flow rates, which was the point I was making against your flow rate arguement. Lets compare 5L class engines then, since we're equating displacement with torque. Lexus 5.0L 2UR makes 371tq. The most powerful 5.3L L-series (including LS4 and the truck L's) is 340tq. Hey, what happened??

HP = airflow end of story. Your L92 (or L99 or whatever) head is great for having 300cfm in, but the 200cfm out is the limiting factor here. You might as well only have 250cfm in. If I can completely fill a 5.0L motor 7000 times a minute and you can only fill your 7.0L motor to 60%, guess whose doing more work?

Here's a little exercise. Car1: 500hp at 7500rpms, which is 350tq. Car2: 500hp at 5500rpms, which is 477tq. That's all just math. Adjust gearing so that they're going the same speed while making 500hp. Figure out which one has the most acceleration. GO!

 

Because we're talking about how bad the LSx heads are to a head that is known to flow well. Take your biases elsewhere. We're talking about hunks of metal here.

 

Make up your mind, first you post the K20 head as an example of something that flows awesome, LSx heads cant touch it modified, then a stock casting, truck head outflows it, both intake and exhaust, then you run off trying to complain about the exhaust flow, when it still flows more than the K20 head, on both sides of things.

Uh comparing the 5.3L lame production truck engine to a performance lexus sedan engine ? Really now ?

As far as the 500 HP car comparison goes, like I said show me a comparison of the two dynographs overlayed, good adjust the gearing so both are at the same speed @ 500 HP, great for a theoretical comparison, now adjust the gearing so the LS7 is in its torque range within a useable speed range, with the included transmission, chances are you are going to end up with something that has you over 400 ft lbs from 1800-6800 or so, oh whats that you say the V10 from your audi doesnt even make 320 ft lbs ?, the bmw engine barely into the 400's ? Ouch. I know which i'd rather install, oh yeah, pssssttt by the way, thread was for v8 discussion, i think was his point above, as now everyone wants to bring in honda 4 cyl heads, and bmw / audio V10 engines to make weak attempts at putting down the Gen3/4 sbc platform.

 

Ahh here we go, this should add to the fun:

2006 M6 dyno, around 300 ft lbs to the tires from 4-8k, would really like to see the numbers below this, but oh well, hey all this from only 12:1 compression, variable timing, etc..
2006 BMW M6 Dyno Results Graphs Hosepower - DragTimes.com

Stock 2007 Z06, over 350 ft lbs at 2300 rpm, at 3500 we're over 400 ft lbs, 450 ft lbs to the tires at 5k, still over 400 to the tires at 6300, and finally backing down at 6750 down to 350 ft lbs again.

So over the whole usable rpm range for each engine (dont try to turn this into a put the same gears in both cars game ep, we know your gearing should match the rest of the drivetrain), we've got the weak, 500 HP corvette engine only besting the M6's 317 Ft lbs by 132 ft lbs at its peak, and no matter what in its 2300-6300 band by generally 100 ft lbs....


You can have the M6 engine and some 4.10's, i'll take my inefficient, cant flow much air sbc and 3.54s