Last post on Nov 07, 2008 at 12:44 AM
You are in the Chevy Express & GMC Savana
What is this discussion about?
GMC Savana, Chevrolet Express, Ford F-100, Engine, Van
#3 of 8 Re: Plastic Intake Manifold BEWARE!! [phil88]
Nov 01, 2007 (5:33 pm)
I hear you phil88. I talked to my mechanic at length after he fixed it and he said the main things were a cheap gasket (no metal in it) and using the Dexcool coolant GM put in as standard coolant. It is very hard on those parts, even radiators (part plastic). I got a new gasket with metal sandwiched in the middle and put in prestone. Still hate the idea of a plastic or nylon manifold! Take care.
#4 of 8 All lies....well partly
Nov 04, 2008 (10:43 pm)
Plastic intakes have been used for soem time, even by imports too. They are cheaper, and primarly help produce more hp by not conducting engine heat to the intake tract air. The more dense air help with hp. Gm has been using composite intakes on all the ls gen 3 and gen 4 engines for years. Every truck, every avalanche, escalade, awd van, camaro, ta, vette, all use interchangable intakes. The truck intakes do not fit in the car chassis, but they do fit the engines. They are basically free. I have atleast 4 intakes that have beengiven to me. If you "need" one they can be had used for 50$ and is a pretty easy swap with hand tools. The gaskets, are rubber formed o rings that are located n the intake by a receiver groove. No coolant runs through the intake. Any mechanic that charges more then 200 is a crook.
I build turbo engines, using these intakes all the time. Ive run as much at 30 psi through these intakes and have never broke one. I have seen one bolted down with a rubber line mistakeningly under it at the time, cause acrack that ruined the intake though. Install error.
The intake on the savana awd and express awd is the same as the rest of the trucks, 4.8, 5.3 6.0 all the same, all interchangable.
#5 of 8 Re: All lies....well partly [1320jon]
Nov 05, 2008 (1:08 am)
I didnt think anyone stayed alive on this forum.Have you ever heard of the fitch fuel catalyst? it is an aftermarket fuel conditioner like an inline filter.ive installed it in my 04 express and its hard to say if it is working as claimed.Also,i have a 4.8 liter v8 in my van.Is this an Ls engine or vortec? I tried to by a oil changing pump from summit that draws the oil from the crankcase,but the pathway is convuluted so the dip tube wont make it down to the oil pan.I was pissed at summit and made them give me a 40th anniversery leather jacket with their logo on it for selling me a piece of shit like that.
Nov 05, 2008 (9:01 am)
I have herd of the fitch fuel catalist, I have no experience with one though. I generally dont buy into things like that. Fuel distribution, via a better atomizing injector can boost mileage, less rolling resistence, better aerodynamics, and most of all for intown driving, less weight. I do have a honda insight that my wife uses for commuting, that is a "paper hybrid" but in reality just a good gas inengine in a light car with good aero. It gets 60+ mpg every tank. They stop making it, because they cost honda money to sell.
The 04, express, use a 4.8 gen 3 engine that is identiocal to all other LS series engines. (gm may have called it "vortec" though on the plastic cover, I m unsure of that. It is infact a ls engine. All the 5.3, 5.7 6.0 parts fit it directly. If you need a part, (except for internal engine parts) they are likely the same part number as the 5.3 and in most cases the 6.0 also. The 5.7 never came in a truck, but you could swap a 5.7 in, but they are aluminum blocks (no down side and still identical on the outside). You can even without to much trouble, swap in a 6.2 ls3 crate motor, from gm for about 5900$. Thats a 430 hp engine and Id bet the mileage would be pretty close. If someone was to do that, it would require a couple parts swapped from the old engine, and a few small wiring changes, that companies have already addressed with plug in extention wiring to make it easy.
You can also, probably go to almost any good "tuner" shop for vettes, camaros, ta's and have your pcm retuned. You can defeat and change almost any thing, including the vats system if it has become an issue (I read about some people having vats issues and stalling restarting problems). Youcan also have the transmission shifting chnged to be more crisp, different mph'ers if you like, remove the mph limiter's, make the speedo correct to run taller or shorter tires (which also effect shifting), and if they are good, even change the air fuel ratio to get noticablly better mileage. This would be the hard part for them, as they ussually tune for power. I happen to know that the awd 1500 does fit on the mustang awd chassis dyno, and run testing can happen while logging the actual air fuel ratios with a road simulated load of any kind. This allows adjusting the air/fuel to achieve better effiency or power.
Oem's ussully tune fairly rich for safety and all concievable conditions.
#7 of 8 Re: [1320jon]
Nov 06, 2008 (10:34 pm)
I have a obd performance tuner that changes almost any of the above settings you mentioned.The only company that makes them for the express/savanna is a place called JET performance in L.A. calif.Ive already changed the shifting and rpm limit.I did put 17 inch wheels with 265 tire on my van from the stock 16 inch 225 tires.The speedo is only off by 2 mph wich i can change with the computer but dont know if i should bother.The unit from jet also shows trouble codes and meanings and can adjust up to a 44 inch tire(if you go body lift and monster on us all with your AWD)actually,that would be killer,having your van jacked like that with some mudders.but impracticle for trips to the 7-11.I get looks all the time on my van with all the after market stuff i put on it like the wheels,cargo rack,rear rack with diamond box,offroad lights,side steps etc.
#8 of 8 Re: [jgarnaas]
Nov 07, 2008 (12:44 am)
There are several tuner software programs that are compatable with the express and the savanna. I have two of them, that are laptop based, with everting from.....
timing maps, knock sensor sensitivity, maf freq,fuel ve tables, pe tables, idle control,ac control,rpm limiters, speed limiters, shifting control for probably 400 parameters, shift pressures, lockup control, gear ratio, diagnostoc control (kill codes permanatly), emmission codes, vats, etc etc etc etc.....the list is pretty endless, even vin number reassignment, speed density conversion, and data logging of every pcm function.
I have found that you can add a rear sway bar to reduce the understeer pretty easy from the ss truck.