Headers, Exhst, Axle Changes?

[Sav'h Steve]

Headers, exhaust, axle ratio

I have a '01 Expedition w/ 4.6L and 3.31? rear pulling a 25' Excella. I originally bought truck for my smaller A/S and was well within limits. Now I'm on the edge.

Financing $35K for this truck means I can't trade to a 2500 Burb without taking a big hit. So I'm thinking of air flow to help this small 4.6L on any hills for now.

Reading the MH Forum, I saw that the exhaust was first on the list - like from the Cat back. How much to have a 4.01 rear put in? Trying to keep investment under $1,000, cause like Peter said, probably won't get but 20% back....

I don't expect to make this into a 454!! What your advice?

Steve Martin, Savannah

[BobbyW]

95 Chevy Siverado 350(5.7L)extended cab.

I am not sure what my rearend ratio is but, I installed:

Gibson headers $500
Borla Stainless exhaust $450
Airaid intake $280
Poweraid throttle riser $80
HyperTech Chip $180
Labor $Bloody knuckles

Prices are 1996 dollars and not exact.

It opened the engine up quite nice. According to the Mfger's this should have added 30-50hp. I take it with a HUGE grain of salt, but seat of the pants, I noticed quite a difference. Plus it sounds REAL nice.

The nice thing about the HyperTech chip is it changes the shift points and removes/raises the top end throttle cut off (rev limit) which was 95mph. I have had it well over 120mph. Before the chip change, the first time I hit the rev limit, I thought I had killed the engine.

-BobbyWright

[Sav'h Steve]

Thanks for your input Bobby!

Great forum and super bunch of owners!!!

I see you used different products than those talked about over in the MH Forum. They mentioned Hedman headers and Flowmaster exhaust as well as less expensive Stinger and Git-Kit alternatives from Camping World.

You used AirAid intake and others used K&H. Another was Jacob's which I believe creates a hotter spark helping low end torque. Maybe some of these are Chevy or Ford specific. Would smaller blocks make a diff compared to larger blocks?

I'm a do-it-yourselfer but not a mechanic as I have stayed away from under the hood and don't know how to install these things. Some would be simpler to do, I'm sure

My question is for a stop-gap measure, which of these 'engine breathers' provides the greater effect to get started with. I understand the best result is the 'whole enchilada' !!!

Steve

[74Argosy24MH]

Changing gears in your axle is going to cost well over $1000 because you have 2 to change. You will also take a real hit in mileage from 3.31 to 4.01. Think about how much you tow before you make that decision.

The simplest cheapest change would be a new chip for the computer. The convertor is the biggest restriction in the exhaust so a new cat back exhaust won't do a lot for you. Jacobs ignitions are expensive, the expense probably won't be worth it unless you do the "whole enchalida." Most of the newer vehicles do try and get some fresh cool air from before the core support. It might not be the best system as far as restricitons, but beats the heck out of preheated air from the radiator.

John

[BobbyW]

All of my "tuning" was done before I got the Airstream. I hauled a 20' DeepVee Bayliner I/O boat then. The parts that I used came from reading SportTruck and Truckin'magazine and evaluating their reviews in side by side shoot-outs. I do not have a Dyno', but they did, so I went by their results. I used Gibson and Borla because they are stainless. I do not like to do things twice if I can help it. This exhaust should last the life of the truck X 2.

The AiRaid uses a K&N filter. K&N has in the last 2 years begun to sell whole assemblies. In 1995, they only made the air filters that other aftermarket companies used to make up the rest of their units. They also now sell oil filters. The AiRaid unit I have now, replaced a crummy plastic unit from Stillen that they still sell. I tried it and discarded it because it did not seat tightly on the carbs throat. It sucked all kinds of crud into the carb. The AirRaid is a much better product. The best is a cold air induction unit, but they did not make one for my '95. I have a RacingBeat Cold Air Intake on my "tuned" Miata that lowers the incoming air by 30degrees just by pulling the air from in front of the radiator. Made one heck of a difference.

The catalytic converters inlets and outlets are usually bigger than both OEM pipes coming into them. That is why the aftermarket guys make their pipes and header Y' connectors bigger than the OEM, to open things up.

-BobbyWright

[wflorencejr]

Steve, From my experience, the best simple upgrade for you would be to add dual exhaust and headers. I am assuming that your Expedition with 3:31 differentials does not have a factory tow package but that you have added trans cooler. Your situation reminds me of one I got myself into several years ago with an E-150 Ford Van with Windsor V-8. Even with added cooler for the tranny, it breathed hard on the hills with a 3800# A/S. The duals made it livable even in the mountains. You just have to take it easy and realize you will be slow on the big hills.
Hope this helps.

Bill Florence

[Sav'h Steve]

Thanks for all your input. Wish I had a 400+ cu in engine...

I have not thought of John's idea of the computer chip. So I stopped by the Ford dealer and asked some questions. Then I did some web searches and found that Diablo and SuperChip were the ones to consider. Then I found Ford Truck World on the net and surfed many of their respones. And there were literally hundreds of comments. After hours of reading I felt that the Diablo Delta was a better choice.

The reason for the Diablo Delta is because of being able to switch back and forth from Performance to Stock without removing the chip. Perf. means using High test only to avoid spark knock cause of the increase in timing. And stock will allow reg gas for non towing trips. But many say they don't want to go back to stock after tasting the power! ! Kinda like not having air cond.. eh?

Seems that the torque curve is increased all along the RPM range which is what I'm looking for.

Later I may get a bigger truck.... spell that 'Burb'....

Steve

[BobbyW]

As I noted in my original post, I have the HyperTech chip. Just to let you know, the real reason for the switch on your chip choice has a real purpose. If/when you have to take your vehicle in for service, diagnostic or state inspection, be sure to put the switch on the Stock setting. When hooked up to diagnostic/smog equipment it will give false information to the diagnostic equipment. The technician will keep trying to get the vehicles settings back to factory and won't be able to, making problem diagnostic impossible or they might think something is wrong when its not. Just a heads up.

-BobbyWright

[davidz71]

Also be aware that some aftermarket chips tune for WOT (wide open throttle) and that is where the performance is. Check the manufacturer closely to see that you do not have a chip of this type. Also, if you haven't already done so, go to www.pickuptrucks.com and post your question there. You will hear all kinds of comments on Hypertec, Superchip and others. Take it all with a grain of salt.

Also, check out the cold air systems from Volant. I think it is at www.volantperformance.com.