Some deep thinking on getting Best MPG in a VAN

[racprops]

Talked with Comp Cams and THEY say I should run their Exreme Energy Cam # 08-500-8 with:

Description

Engine Family: Chevrolet 262-400 c.i. 8 cyl. 1955-1998
Description: Hydraulic Roller-For throttle body 305 or 350, very good economy and power.
Cam Family: XTREME Energy™ Computer Controlled 1987-1998 305-350 Originally Equipped With Hydraulic Roller Camshaft, Except LT1 and LT4.
Specifications Intake Exhaust
RPM Range: Valve Lash:
Valve Timing: Duration:
Lobe Separation: Duration @ .050" Lift:
Intake Centerline: Valve Lift:
Lobe Lift:
Valve Timing @ 0.006 Lift:
Exhaust
Closes 16
ATDC
Opens 68
BBDC
108 Valve Timing Diagram
Intake
21 Opens BTDC
57 Closes ABDC

He made the point that this will work best with a low compression cast iron swirl port heads.

He also claimed it make great power from 1000 to 3200 RPMs.

Has anyone run such a cam??

I feel the cam is the heart of this project.

Rich

[Ecky]

2 more cents,

I expect the low hanging fruit probably includes high compression, and modern electronic fuel injection.

The common cam swap on this forum which is proven is the Geo Metro XFi cam into the other Metro engines. The XFi cam (to my knowledge) reduces max power. It doesn't breath well enough at higher RPM and reduces max horsepower, but it improves economy at low RPM. I'm unsure if it actually improves torque. You might look into exactly how the cam profile differs to get an idea of what works in that engine.

Honda is most famous for its VTEC, which is just having two different cam "settings". As I understand it, at low RPM, there's a low lift cam profile which is used which promotes swirl (one valve opens only partially) and gives a smooth idle and better combustion. At higher RPM it shifts to a high lift cam which reduces economy, but allows the small engine to get a lot more air into the cylinders and improve horsepower. This let Honda retain small displacement (helps economy) with a smooth idle and good low RPM operation, while having as much peak power as other manufacturers' slightly larger engines.

[racprops]

Anyone got those cam specs???

[racprops]

This why I had not brought my plan to this site: Everyone here seems to be working on tiny engines that already get 30/40MPG and trying to reach 50/75 MPG, BUT no one seems to be working on everyday V8s and Vans…where WE need all the help we can get, 10 to 14 MPG is not good for the environment nor for our wallets.

I was surprised to see this thread: https://ecomodder.com/forum/showthre...4-a-22944.html so after all this time talk was about V8s with mileage cams, so I dropped in…

But I was kind of hinted I should get out of it and started my own thread.

Rich

[rmay635703]

Originally Posted by racprops

Gentlemen, PLEASE
I am not at all interested in Diesel in any way.

I do ask for help on my planed project as outlined above.

Help with the questions I have asked.

Thanks for your suggestions they just are not in my plans.

Rich

Again...
https://ecomodder.com/forum/showthre...mpg-33961.html

The concepts used on the 46mpg 350 gas station wagon are the same as a 350 gas van or suburban.
Well worth contacting the op in that thread,

In terms of cams and other goodies most folks here don’t find much Fe improvement
A normal GM forum can comment on 350 mods if that is your intent, this forum is mainly concerned with gearing, warm air intakes and streamlining. CAMs are high hanging fruit, tires and gears are low hanging


My 438,000 mile 6.2 Diesel was not a 5.7, some like to think they are similar
They are not

[racprops]

Two “out there” ideas were Rhoads Lifters, and Power Valves, a special pressure control add on to the intake valves that closes very early, building higher pressure for real low rpm power.

[racprops]

Interesting read on that thread, https://ecomodder.com/forum/showthre...mpg-33961.html,

I plan on keeping the automatic as 8l90 ...point is 8 gears...and with a super low 1st and 2nd gears can pull strong even with a 2.43 of lower rear end.

As for the airodymatics check what I have already done there: https://www.facebook.com/richardacoy...0309951&type=3

Note the same kind of air damming and side skirts..and the vortex foils on the back side of the Van.

I found this setup kills the effect of passing big rigs, my van does not jump around or be pushed around by them.

I have wondered if a air foil pushing air back into the back end (Like the old keep your back window clear on old station wagons...) would help or hinder its passing though air.

I do not plan on any more Areo changes...Unless the air foil pushing air back into the void behine the van is a good to great idea???

He did a bunch of TunerCat changes and I will be doing him one batter using the add on board that besides all he was able to do includes a automatic lean cruse setting allowing the leanest running with a clean transfir to normal and even power ranges again automatically...and all adjustable by its tuning software.

Two thing I will also stick with is by wide tires and brakes, I feel I MUST have the best brakes possible and have good brakes and wide sticky tires are the way to be able to stop a Van at high road speeds of 70/80MPH.

And he seems to be running a TBI system where I will be running a TPI which is reported to give 30% MORE torque, HP and MPG.

I will rethink my final gear ratio lower to his 2.14 gears...

Thanks very interesting read.

Rich

[arcosine]

Put a 4.3 v6 in it for mpg.

[racprops]

arcosine Dude.....IF I was going to something so small I would put a Ford 4.6 in BUT it will not fit.

[19bonestock88]

If you’re going to spend large money on the engine, why not do an LS swap? The 6.0 (L76) would be a good candidate for the swap and since you’re already planning to do an 8L90 trans you’ll have a decent engine to go with it...