Topic: heated intake vs. cool manifold ?

[cz777]

i have a amc 2.5 liter ...I am thinking about a mod of putting a MPI manfold under a TBI injector ..yes a bit of moding the pro and con of this one ,anybody did this one yet?

[chardrc]

you may run into issuses with the mpi intake manifold since it doesn't have coolant running through it where as the tbi manifold does. the tbi manifold has the coolant run through it to help atomize the fuel into the air (same concept as for carbs). based on a members results with the tbi setup with the manifold coolant bypassed id say it wont work well. if you are considering doing the swap i would first bypass the coolant through the manifold like in the other thread and see how the jeep runs to test if the other jeeps poor results where a fluke. 

http://4bangerjp.com/forums/index.php/topic,2016.0.html


and other than the coolant issue you would need a way to plug the holes for the fuel injectors in the mpfi manifold and make an adapter for the tbi.. you would also need to get the thermostat housing for a mpfi setup so you have a space for the engine temp sensor for the ecu, would also have to check fitment iat sensor..

[cz777]

well i got a jeep water neck with ECT boss and fitted with a brass adopter[home made] with coolent sensor from a volvo 240 dl [1987] and by-passed manifold heater  straight to the heater core ....now the testing /running of it gas mileage etc will be posted ....so far all is well next the manifold mod -i will be making an adopter plate 1'' thick with a upside down ''Y'' shape so better fuel/air flow and dimple  the bottem of the manifold with 3/8'' wide -1/8'' deep ............ok please dont flame me on this one thxs

[chardrc]

sweet. i didn't mean to flame you on my first post if it came across that way. Im all for trying to get a little extra power out of our tbi's, i just wanted to let you be aware that soemone had troubles with tbi without heated manifold so you should test it first before the swap which you are doing already which is great. I'm glad to hear that other jeep was a fluke.. good luck ill be watching this thread. 

[sharpxmen]

cold weather would be the test you're looking for, due to vacuum the temp in the intake would be way lower than the outside temp

[dwtaylorpdx]

I did this on a carbed toyota years ago, just added a valve to turn off the water.
Turned out I got better mileage with the hot water on, but when pulling long hills
I had better power with it off.

Hope this helps somehow?

Dave