nmp0098

I think the cam is a little too big, but nothing that can't be fixed. Another trip to the strip is in order sometime soon to be sure, but I think I may have lost too much torque between 3000RPM and 4400RPM. There is just that dead spot where torque doesn't really climb. Drivability is great, there's plenty of torque below 3000RPM to putz around, and now that I've got the hang of this thing it's really easy to launch. For me, the high RPM torque peak isn't the issue, or even the revs. Actually, I love the revs.

Heads:

I need more static compression to compensate for the loss of dynamic compression. Obviously some porting would help too, but all I really need is some milling. I could probably go higher than 11:1 static compression and still keep dynamic compression safe, but I don't have the resources to try several different combustion chamber volumes. Besides, 11:1 is proven to be safe on cam'd LS engines, and you can generally still run a good bit of advance. I would keep the stock valve sizes to keep the valve weight down so I can safely spin this thing.

Valvetrain:

I could go with Ti valves and retainers, but that's not really necessary unless I really wanted to push my revs. At that point, I'd probably need Comp R lifters or something similar. This is where keeping the stock rockers really helps, because they are much, much lighter than all of the aftermarket rockers.

Bottom End:

The crank is fine, but the rods really see a lot of abuse with revs. I can change the rod bolts with the engine in the car still, and I'll probably do that before anything else. Aftermarket rods would be next if I wanted to keep reving the engine, and maybe pistons if I wanted to fog it.

N20:

The universal "it's not fast enough" fix. While a 150 shot would be fun, I'm thinking that I wouldn't need much more than a 25 shot, maybe 50, to help below 4800RPM. If you've ever seen what N20 does to a torque curve, you know that you get a nicely fattened torque curve right when you hit the button. With my oversized (but easy to fit and install) injectors, I'd have plenty of room for a small dry kit. That wouldn't stop me from using a much larger wet kit later if I ever decide to get serious about racing the car.

Cubes:

A whole different approach would be to size the engine properly for the cam. This would be really expensive, and I've got a 12.5:1 351C looking for a rat rod that I would spend the money on first. I only have about $2600 in the motor right now, and a little over 5k total if you add in the trans and HP Tuners. But just for fun, I think that an L76 or L99 long block with the LS4 crank and accessories could be made to fit using the correct transmission adapter plate.

Gear:

If I do any of the other stuff I just listed, my 3.29s will be fine.


Finally, I could just go with a little smaller custom grind. I think Sittingmongoose's cam would be about perfect. But for now, the car is still more fun to drive.

DavidGXP

iTrader: (14)

sounds like your on the right track and just about dialed in. a little head work with some compression and you should be good to go. 3.69's with an 3200-3400 stall (depending on your peak tq rpm) should really wake that beast up! be careful with those stock dod lifters and if you do end up pulling the heads then you might wanna do a custom cam and say screw dod. when you do go to the track please get some tires that will help your launch
275's fit perfect!

nmp0098

It's definately coming together, and thanks to everyone for the support! I'm for sure gonna run 275's next time, but I've got a lot of tread left on my tires. I'm not in any hurry to have everything I want to do finished right now. I'm going to enjoy my slightly over cammed engine for a while. I would have prefered not to do the headers and cam at the same time, but it just made sense to put the headers in when I did the cam. Maybe next spring I'll do the heads, but for the moment this is my last mod:



I'm still going to run the car at the track and play with fuel and spark, and I'll post times even if they suck. I shouldn't have trouble hooking anymore though, because I've got the ECM mostly sorted out and I'm used to how my car drives now. I would go tomorrow if the weather was nice, if my wife wasn't having early contractions. I might dissapear for a while here pretty soon.

Since I was crawling under the car earlier to get pics for Curt, I also took a pic of the cutout:

Nacho SS

iTrader: (4)

Great job man, my hat's off to you. This should be renamed "How to Cam Your LS4," there's some really good, useful info for people in here that you and JDMC5 laid down.

JDMC5

iTrader: (3)

thanks NACHO.

I love the Pic of the baby seat hahaha, welcome to my hell!!! J/K, your gonna love being a dad.......after about 4 months, 300 diapers, 120 sleepless nights and half your hearing gone......and then the teething starts. Ok I'm done messin with you.

I agree, the bump in compression, or swapping cams altogether (which would be a nightmare) is about all you can do to increase power between 3-4K. You could bump it up to 12.0:1 and run E85 though. Porting and bigger valves will give you a little in that range but more in the topend. You could always go with a stall and bigger gear but kiss your traction good bye and I know that's not the route you want to go anyway. And as always you know I'm a huge fan of the spray.

blakss

iTrader: (4)

if i havent said it already i gotta say great write up

n i was wondering you do you think the low lift package would have worked with the stock injectors ?

jderou_GXP

Just wait till you have to fit 3 of those things back there. Major PITA!!
And my kids love the power.

nmp0098

Maybe, but in the L76 it's only 10HP less. The issue is the RPMs you have to spin the engine at. The injector pulse width is perfectly reasonable at 15-16ms iirc, but at 6000RPM the engine completely rotates twice in 20ms, which is something like an 80% duty cycle. At 7000RPM, the completely rotates twice in 17.1ms, which puts the duty cycle over 90%. The more you want to spin the engine, the worse this gets. I really want to spin my engine.

Regardless of the cam specs, if you are looking for a DOD cam and you don't want to really spin the motor I'd call New Era and ask for the high lift grind scaled down by 4 degrees or so. Everything would fall in line then.

For myself, I'd rather build the engine to be able to spin rather than use a smaller cam. That said, I may end up messing with the cam again, but only to advance it 4 degrees. That would move the intake valve closing point closer to ideal. The cam would still be "too big," but like I've said before I have more than enough low end torque to lug my Grand Prix around town. Here's an outstanding post by Patrick G with some research from SAM (2nd to last):

https://ls1tech.com/forums/generatio...ifference.html

I PM'd him, but he didn't know of anything similar for the 5.3L. But, just looking the numbers, it seems like whatever intake valve closing point would be optimum on a 6.0L would be about 3-4 degrees too late for a 5.3L. I think advancing the cam 4 degrees and bumping up compression will do wonders for my mid range torque.

My final note is that you can easily use David GXP's approach of clearancing an LS6 or LS2 fuel rail by grinding on the alternator bracket (although if you start failing alternator pulleys or belts, you could make a good guess why) and bending the fuel line to mate to the rear fuel rail entrance point. I'm sure that LS2 injectors would buy enough room for good fueling and cost less, although I should point out that the LS2 injectors are different from LS6 and LS4 injectors and require an LS2 fuel rail. The good news is that LS2 injectors have the same connector as LS4 injectors, so you don't need to modify your wiring harness. I would also like to point out that at these power levels the 90mm throttle neck of the LS2 intake might be beneficial, and that a ported LS2 intake can flow as well as the LS6 intake.

Good Luck! I can't wait to see this process refined by the next person that gives it a shot. Hopefully I won't look like too much of an idiot.

GXP25

iTrader: (3)

As always, your posts are very informative Nate.

By the way, do you have the roof-mounted side curtain airbags on your vehicle?

I ask because I noticed some weird logo/symbol on your pillar.

nmp0098

Thanks man. I put in as much information as I could without turning it into work.

Ha, one baby seat takes up a lot of room. The baby stopped kicking and listened the first time I had my wife in the car and punched it with the cutout open.

Yes I do. That was a key feature in my purchasing decision. This is my family/commuter car that I couldn't resist adding power to.

CenTexSS

iTrader: (2)

Nate, your baby seat looks like the front needs to be higher. I had this issue with my baby seat, I had to roll up a towel and wedge it under there.

blakss

iTrader: (4)

your info and all the research has been very helpful and inspirational i think imma go ahead and follow along but go the low lift package and see the results.as for right now i kinda F**kd up cause i went ahead and bought some big *** rims lol
i just wanna hurry up and try and get this bigger brake kit installed.and i refuse to sell close to a thousand dollars in parts cause of some simple modifying. and then i will by my performance parts.

JDMC5

iTrader: (3)

you don't plan on running it with that intake do you?

blakss

iTrader: (4)

who me?

nmp0098

I thought the same thing and adjusted it up, but there is a level on the side of the seat that shows blue when it is properly adjusted. I'm going to run by the fire department and have them check it anyway. Thanks for the heads up though!

By the way, the baby is home and happy! And now I'm back at work But, gotta make money to pay for all these diapers and wipes he's burning through!

94ss06gxp

iTrader: (5)

[QUOTE=nmp0098;13660104]

By the way, the baby is home and happy! And now I'm back at work But, gotta make money to pay for all these diapers and wipes he's burning through![/QUOTE]

congrats on the baby! and that is where all my car money went :

JDMC5

iTrader: (3)

yes you.

Nate, you should have had a diaper raffle at the shower. We still (5 months later) haven't had to buy any. Eminem was right, food stamps do not buy diapers.

blakss

iTrader: (4)

yea i think soo.. imma do the low lift and see how it goes and later on swap it out if need be.

nmp0098

Don't worry, we made out in the baby shower game (Thanks Everyone!). I'm just marveling that a bulk diaper box was lit on fire in the first week. It's not uncommon to need two diapers during a change because one thing is followed by another...

So as not to derail the thread completely, I have some more feedback. I think I've figured out a good temporary answer to my mid-range blues: 12.2:1 AFR and 32* advance. It goes against conventional wisdom, but in the few free moments I've had lately I thought back to when I was tuning and remembered that it felt really strong at 12ish down low, and 13ish up top. So, I'm running 12.2 until the cam starts to dominate at about 4000RPM, and then smoothing up to 12.7 near the torque peak and keeping it flat (safety margin at high RPMs, even though there's more power by going leaner). Now it seems to pull hard the whole time. I can also see more air coming into the engine according to the MAF, so I think it is real. By the way, I'm running 28* up top (I don't have any PE advance to keep my life simple) because it doesn't knock (ever) and pulls strong. I can't tell a difference if I go to 26*, but at 22* it does feel a little weaker.

I'm also having a lot more success launching the car by just flashing the converter, so I'm going to try that the next time I go to the track.

CenTexSS

iTrader: (2)

That's the truth. I was changing Jay's diaper the other day, got him clean and he started shitting again!!!!


Back on topic, can't wait to see some more 1/4 numbers. Any plans on bolting on some traction?