I Have a Dodge RAM B250 Royal Van -88 with a 318 TBI-injected V8. I have read about Chevys Tuned Port Injection system which is better than TBI?
I understand that it is called "Multi-Port Fuel Injection" on Dodge?
Can i replace my TBI unit with this Multi-Port Fuel Injection-system? Is it hard? What has to be done? Do i need to rewire any cables?
How would the fueleconomy be? My 318 consumes 1.1-1.2 litre/10km at a speed of maximum 90-100km/h.
Dodgevanman
05-09-2006, 01:06 PM
Yes MPFI. When Chrysler debuted the Magnum 5.2L V8 in 1992 they went to MPFI and was far superior to the TBI set-up.
Unfortunately it's not a bolt-on swap to the older engines. You have to use Magnum engine heads, intake manifold, computer, wiring, etc.
Edelbrock and Holley do make a kit for older V8's but it can be expensive at a couple thousand dollars depending on which kit.
Elajten
05-09-2006, 02:58 PM
Yes MPFI. When Chrysler debuted the Magnum 5.2L V8 in 1992 they went to MPFI and was far superior to the TBI set-up.
Unfortunately it's not a bolt-on swap to the older engines. You have to use Magnum engine heads, intake manifold, computer, wiring, etc.
Edelbrock and Holley do make a kit for older V8's but it can be expensive at a couple thousand dollars depending on which kit.
Canīt i use Chevys TPI then? What cable must be rewired? Doesīnt TBI have all wiring that MPFI needs?
You say that MPFI is superior to TBI, in what way is superior? Can you tell me more about this kit from Holley/Edelbrock?
Do i only need:
* Magnum heads
* Intake manifold
* Computer
* Wiring
Nothing else? Which one of MPFI and TPI is the superior one?
Dodgevanman
05-10-2006, 06:45 AM
No, you can't use the Chevrolet system. None of the parts would fit a Dodge engine.
MPFI is superior to TBI because it is more efficient. Instead of two injectors squirting fuel into the intake (much like a carburetor), you have an injector for each cylinder. The intake manifold's job then is to just distribute air, not air & fuel. You can get more power out of a MPFI system as well.
Personally I can't tell you if the Edelbrock system is better or the Holley system is better...I've never used them. I just know that they're available.
By the time you gather all the parts to convert over using genuine Magnum engine parts, you would probably be better off just swapping in the complete engine. Best to find a donor van to do this however.
Elajten
05-10-2006, 06:51 AM
No, you can't use the Chevrolet system. None of the parts would fit a Dodge engine.
MPFI is superior to TBI because it is more efficient. Instead of two injectors squirting fuel into the intake (much like a carburetor), you have an injector for each cylinder. The intake manifold's job then is to just distribute air, not air & fuel. You can get more power out of a MPFI system as well.
Personally I can't tell you if the Edelbrock system is better or the Holley system is better...I've never used them. I just know that they're available.
By the time you gather all the parts to convert over using genuine Magnum engine parts, you would probably be better off just swapping in the complete engine. Best to find a donor van to do this however.
What must be rewired? Is it much? If i can find 2 magnum heads and manifold and the computer to a good price? That must be better than swap engine?
Intrepidacious
05-11-2006, 11:28 AM
When the multiport injection was introduced on the truck engines, there was a nice boost in power and smoothness to go along with it. But you wouldn't see much benefit converting an engine from throttle-body injection to multiport. There may be a modest boost in fuel economy, but all else being equal it won't be enough to pay for itself.
Probably the entire fuel system is different. Multiport injection usually operates at much higher fuel pressures than throttle-body injection. I'd imagine the fuel pump and possibly even the fuel lines would all have to be changed to provide the pressure safely. It may be best to get a wiring harness from a donor vehicle along with computers etc. It may require an updated transmission controller as well.
Dodgevanman
05-11-2006, 12:00 PM
Yes...TBI operates on roughly 7psi or pressure whereas MPFI is around 45psi. This won't be a simple weekend swap I'll tell you that. Honestly, you'd probably be better off going to a 4bbl. carburetor, but I'm not sure of your vehicle laws over in Sweden.
Intrepidacious
05-11-2006, 01:03 PM
Oh, and I cannot imagine the difficulties adapting a Chevy MPI system... :huh:
Elajten
05-11-2006, 03:43 PM
Yes...TBI operates on roughly 7psi or pressure whereas MPFI is around 45psi. This won't be a simple weekend swap I'll tell you that. Honestly, you'd probably be better off going to a 4bbl. carburetor, but I'm not sure of your vehicle laws over in Sweden.
the vehicle laws in sweden sucks.
the fuel economy has the highest priority in this case, thats why i want to upgrade the system.
but what is the difference between TBI-wiring and MPFI-wiring?
Intrepidacious
05-11-2006, 04:10 PM
With Multiport fuel injection (on any vehicle), you have a wiring harness that spreads out to all of the fuel injectors, rather than far simpler wiring to a carburetor-like throttle body. I'd imagine there may be different types and quantities and positions of sensors, etc.
But let's say it was an easy modification -- the difference in fuel economy between the new FI system design and the old TBI system would be minor. The vehicle has a lot of weight, a lot of frontal area, a lot of coefficient of drag. In fact, you could make the modification and have an O2 sensor positioned in a bad place, making the mixture a bit rich or lean, hurting power and fuel economy.
Basically it would be like a power modification (exhaust system, cold air intakes, etc.) in that you'd have to put it on a dyno to fine-tune the system to know if you've accomplished anything good, or whether it just made things worse.
I'd think the TBI system would sure be better than a carburetor at least! ;)
Driver habits have the most to do with fuel economy.
Try driving it like drivers of early Volkswagens: get off the throttle earlier when you're approaching a red light, so that maybe it will change to green before you get there so you won't have to stop at all. Keep your highway speeds down a little, keep momentum up, maintain a more constant speed overall... Cruise control usually helps on highway economy. There's only so much you can do...
Elajten
07-16-2006, 12:34 PM
Yes MPFI. When Chrysler debuted the Magnum 5.2L V8 in 1992 they went to MPFI and was far superior to the TBI set-up.
Unfortunately it's not a bolt-on swap to the older engines. You have to use Magnum engine heads, intake manifold, computer, wiring, etc.
Edelbrock and Holley do make a kit for older V8's but it can be expensive at a couple thousand dollars depending on which kit.
How much does the Edelbrock and the Holley-conversionkits costs?
