How much does dual exhaust help a stock 4.7 QC? How much more power does a HO cam and heads produce? Did a search, but didn't really find anything. I am thinking of regearing to 3.92, dual exhaust, HO cam and HO heads of my '03 QC. Thanks guys.

 

I've read that for the 4.7s....dual exhaust creates less back pressure. Right now I have dual and I was thinking when the muffler goes, I'll try single. As far as HO cam and heads... (which I believe HO cams are usually on backorder) You a 4x4 or 2wd? Honestly imo, for 4x4s it's probably not worth to get HO stuff or any kind of big spending on performance upgrades unless ur actually towing and etc, cuz ur not going to really feel too much of a difference considering the weight of the truck...especially a QC. Unless, of course you have money to spend..(if only i did).

 

I agree I think when all is said and done, I don't think you will see the gains you would like.

 

So bang-for-the-buck what do you guys think are the best mods for my truck? I know I would like to go to 3.92 gears and have been wanting to give a TransGo shift kit a try. Are you saying that duals would hurt the low end or help it? It is a 4X4 QC that I will do a little offroading in and some towing, but mostly just running around and playing. I just want it to get-up and go when I punch it w/o spending too much money, maybe a cap of $2000.
Thanks guys

 

Programmable tuner = best bang for the buck

 

true duals will kill your bottom end and maybe give you a little on the top end.

programmer and re-gear will probably give you the most. I'm going to (when i get paid) get the HO cams which are rated at giving like 45 rwhp which isn't bad, but in terms of headers, unless you can find longtubes, it won't give you much.

 

Thanks for your input. Does everybody agree/disagree? I just want the most ***** out of a 4.7 QC 4X4 that you can get for $2000 or less.

 

heh, well since you're capping it on that....HO stuff would be good; I was VERY tempted in buying that stuff myself...but I just need to keep money saved. +1 on the headers. The performance isn't much different than the stock manifolds. Tuner and gearing I have nothing to say about since I never tried them yet. I mean, I've heard they're good. 3.92 gear....I'm assuming you're going from 3.55s? higher gear will probably help city mpg, i believe, and also you'd be able to get off the line quicker. Once again, I don't have personal experience with those. Generally those upgrades should be all good.

 

Why would duals kill the bottom end? What if it is done with an X pipe design (heard this helps)? Also been reading about the FM TB's, do these really help? I'll do a search as well ans let you know what I come up with.

 

if you do a true straight pipe (no cats no mufflers) you lose all the backpressure involved. our engine's need back pressure since there is no forced induction to make up for it. it will sound good and will give you a little on the top end but will be slow as **** until you get the engine working really high.

an X pipe will probably help, as will keeping the cat and putting in a high performance muffler, giveing you good sound while keeping at least some of that all important backpressure.

not only that but with duals you will lose a huge % of your gasmileage. the reason for this is, as the air is passing past the O2 sensors, with no backpressure it is moving by too quickly, causing the computer to think its running too lean. to combat this, it (computer) will literally dump gas in to try and solve the problem. more gas being dumped in will result in terrible gas mileage regardless of your driving style, giving you terrible mileage.

hope this helps a little. lol