I have a 04 Tahoe (around 5400lbs) with a stock HD pick-up 6.0 short block under AFR 205's with Dynatech headers, stock Escalade cat back, stock intake, stock air box, stock conv, 3.73, 32" tall tire, LS1 Edit tune. The problem is the cam> recommended/installed was a Comp 3712R .562/.564 218/220 on 114. The RWHP (only about 200 miles on engine) was 321. Granted it is 4WD, so there is some power losses because of the transfer case, etc... I still believe is it short on power.

I installed a 2500 stall conv, Corsa cat-back, gutted the stock air box, K&N filter, put 8K miles on it, and polished up the tune with EfiLive> RWHP is now at 368. The mid range is torque excellent 3000 - 4500, but HP starts to fall off after 5900 rpm.

Should I have expected more or is this average?

I am finishing up installing 4.11's, loosening up the conv to 2800 and
contemplating a cam change >in the range of .580/590 lift with more duration on a tighter lobe sep.

Any input will be greatly appreciated.

 

those numbers sound pretty accurate as far as what I have seen in the past... a little bigger cam would get you a nice gain though... what size you thinking of?

 

That is the truck intake manifold. It runs out of air in the upper rpm range. It just doesn't have the plenum volume to keep up. Kano was experiencing similar problems with his LQ9, but he went through the lengthly process of swapping on a LS6 intake and it made a big difference.

 

Those numbers seem strong to me for what you have. Id be happy with that on my truck (ok Im lying, Ill never be happy, I think I have a problem)


Hi my name is Matt, and Im a HP addict.

 

Some other cam #'s are .580's/.590's with 230's/220's dur. reverse split, more aggr. intake lobe ramping (more lift & sooner).
I didn't realize the truck intake was that poor.
Also, I am running the stock injectors which I was told are abbout 28lbs/hr.
Is the LS6 swap intensive?
I am trying to keep it low profile/sleeper image. With the stock intake manifold, I can keep the engine cover and you don't notice the heads as much.

 

the car intake is very noticable. if you watch the clip you will how my engine bay looks with one

http://videos.streetfire.net/search/...F01F09C6A0.htm

sorry i deleted my engine bay pics

 

I'm not sure a 218º/220º cam is a wrong choice. A bigger cam will only start to narrow the power band. Sure you'll gain a few hp in the upper rpm range, but the loss of torque in the lower end of the band will make the truck seem doggy when driving around town. As tdrumm and others suggested, switching to a car type intake would be the best way to get the mid range and top end power your seeking. The truck intake manifold is a restriction to making upper rpm power. Swapping intakes is not a snap of the fingers job either, but it really helps make the power.

Good luck,

Richard

 

i understand that when switching to the LS1/6 or FAST intake one must buy the intake ~500-800$$ then buy new fuel rails and injectors also right? where can you buy corvette or LS1 fuel rails and injectors? if you had a pro install everything how much do you think it would run considering it is pretty intense? finally, if i had something in the 226 range shifting at whatever point i need, i think about 64 or 6500 rpms, how much more horsepower would the car intake free up? just trying to see if the gains will be worth it for the money now, i know down the road when more money pours into this vehicle it will be a must but how far away is that day

 

the ls6 intake alone is worth about 20hp over the stock ls1 intake in a car application and to go from truck to car you should gain around 25 to 30 but this would only be on hte upper side of the power band. if the combo doesnt make the power then you dont need the car intake. in mechincal skills its not a hard swap but its pricey if you dont have access to all the parts needed.

you can do the truck fuel rail but it wont look as neat, you can do the truck accessoires but it wont look as factory as if you did it like mine with Fbody accessoires. ive seen conversions and they dont look factory but if you look at mine it looks like it belongs like it. also the truck harness isnt designed to look neat. i spent hours lengthing and shortning and wire tieing/looming my wires to make it as neat as possible along with soldering new injector plugs on the harness............was it worth it you ask? yes IMHO would i do it again? yes but if i had to pay full price for it would i do it? probably not

and heres another thought a Fbody crank pulley is physically smaller and you can somwhat consider it an underdrive if you wish.

in a mag test years ago they gained like 5hp by swapping over to Fbody accessoires, probably due to the fact of the pullies

 

yea im not really worried about the intake looking stock or not, i found a few on ebay for about 200 bucks used and IMO there isnt much you can do to the intake to make it crappy used unless theres something i dont know. ill need to buy a 90mm throttle body too i think. if you can use the truck fuel rails and injectors and all what makes the install so intensive? if i had a 226 cam installed what rpm should i shift at? 6500? i just dont want to get a cam that rolls all the way up to where i need new rod bolts and all