Difference between L67 and L98 6.0L Engines

[PIR4TE]

Did they ever end up putting a better manifold on the ls2? Because they ran till what, 08? So that kinda means you were better off buying a ve ss than hsv right? (engine wise only obviously)

Better off with a GenIV with a different cam than a Corvette of a couple years before, yes. The new L92 heads were a breakthrough, meaning the old manifold was dropped. Interestingly the radius bar tumbling device used in the LS2 manifold was left behind. However I've found by retrofitting that, porting the plastic and a ported version of the better flowing LS3 TB, you get 290-310CFM using same lift as LS2. On G8s in the States, world records for our car are being rewritten every couple of weeks.

No, it flowed a bit better, uses radius bars, as above.

 

[Krupt]

Sorry for digging up an old thread, but i cant find the last bit of info on the differences between the L98, L77, L76. Why is it that some VE SS's have a 6500 rpm redline, and others ( my 07 manual ssv ) have a 6000 rpm redline...

 

[The 10th Doctor]

Sorry for digging up an old thread, but i cant find the last bit of info on the differences between the L98, L77, L76. Why is it that some VE SS's have a 6500 rpm redline, and others ( my 07 manual ssv ) have a 6000 rpm redline...

Might be because you've got the L98?

 

[WazzaVN]

Sorry for digging up an old thread, but i cant find the last bit of info on the differences between the L98, L77, L76. Why is it that some VE SS's have a 6500 rpm redline, and others ( my 07 manual ssv ) have a 6000 rpm redline...

I'd say the L76 would have the lower redline due to the gay lifters. I think the l77 got better lifters. My vz l76 stock tune won't let me rev past 6.

Anyway, waits for pirate :yarr: lol

 

[PIR4TE]

I'd say the L76 would have the lower redline due to the gay lifters. I think the l77 got better lifters. My vz l76 stock tune won't let me rev past 6.

Anyway, waits for pirate :yarr: lol

Haha thanks but I've never seen the dash of an L98. What I can contribute is that my car is an auto and the dash has red marks starting at 6000 too. As far as redline being a recommended safety limit - the fastest, farthest, or highest point or degree considered safe - revving the engine past it's peak HP RPM with diminishing return and increased mechanical friction is possible but just because you can why would you want to do that?

All GenIV 6.0 engine variants officially hit peak HP at 5300 rpm, the L77 has been revised to 5700 rpm in some literature, however I personally doubt the veracity of essentially same engine achieving same output with same valve events at higher RPM. That's marketing, as it is flat-lining and there is no point revving the stock engine past 5300:

That's because with a stock GenIV 6.0 engine the Intake Valve lift to prevent choke at 5300 is .482, spot-on same as the cam, i.e. the stock engine begins to choke at 5296 RPM. Given at that engine speed the amount of air induction @ 28" is between 175 to 185 CFM, this equates to the engine's output - 270 kW and 540 Nm.

Yes there is a difference in the published redline between L98, L76 and L77 because of slight variance in the valvetrain. However since the world record holder runs a naturally aspirated L76 with AFM lifters in place and revs waay past that published redline, so is incorrect to assume that the lifters are holding back the engine from higher RPM or more performance.

FWIW I think the stock fuel cut-out is at 6000-6100 for good reason, increased performance from an unopened GenIV doesn't come through wringing its neck 5300-6100 (or beyond) without better control (safety) of the valve train and increasing the Trapped Ve%. With correct control and valve events plus usual bolt-ons you can rev reliably up to 6400 no matter which variant. You can rev past that (up to 7000) but you will need to open the engine and essentially rebuild key components.

 

[07GTS]

my ls2 when stock made power to 6k and u could feel it not make any more after that so i pretty much never took it to the limiter at 6600

 

[WazzaVN]

Haha thanks but I've never seen the dash of an L98. What I can contribute is that my car is an auto and the dash has red marks starting at 6000 too. As far as redline being a recommended safety limit - the fastest, farthest, or highest point or degree considered safe - revving the engine past it's peak HP RPM with diminishing return and increased mechanical friction is possible but just because you can why would you want to do that?

All GenIV 6.0 engine variants officially hit peak HP at 5300 rpm, the L77 has been revised to 5700 rpm in some literature, however I personally doubt the veracity of essentially same engine achieving same output with same valve events at higher RPM. That's marketing, as it is flat-lining and there is no point revving the stock engine past 5300:

That's because with a stock GenIV 6.0 engine the Intake Valve lift to prevent choke at 5300 is .482, spot-on same as the cam, i.e. the stock engine begins to choke at 5296 RPM. Given at that engine speed the amount of air induction @ 28" is between 175 to 185 CFM, this equates to the engine's output - 270 kW and 540 Nm.

Yes there is a difference in the published redline between L98, L76 and L77 because of slight variance in the valvetrain. However since the world record holder runs a naturally aspirated L76 with AFM lifters in place and revs waay past that published redline, so is incorrect to assume that the lifters are holding back the engine from higher RPM or more performance.

FWIW I think the stock fuel cut-out is at 6000-6100 for good reason, increased performance from an unopened GenIV doesn't come through wringing its neck 5300-6100 (or beyond) without better control (safety) of the valve train and increasing the Trapped Ve%. With correct control and valve events plus usual bolt-ons you can rev reliably up to 6400 no matter which variant. You can rev past that (up to 7000) but you will need to open the engine and essentially rebuild key components.

Thanks, good info!

 

[Krupt]

Thanks for the info. Still Confused as to which variants rev to 6500. Is it just Auto VE's ? or a certain year model ?

 

[426Cuda]

Any L98 I've seen had a 6,000 redline on the tacho, same as the L77. From memory my LS1's were 6150rpm? This was raised in tune's though. I thought only the LS2's and 3's revved to 6,500 due to the cam profile and compression ratio creating decent HP at a higher rev range, so naturally HSV would have had the fuel cut off set higher? I could be wrong though.

I agree, it's not worth ringing their necks. Although even as power starts to drop off, there are probably a few 10ths to be had over the quarter by holding gears due to the current ratio spinning things a bit quicker before the change and also resulting in the engine being in the sweet spot on the torque curve in the next gear. that's racing though and we're talking street cars here.