WTB: GMPP TBI / Vortec Intake Manifold

[devind]

Devin,
Just wondering if you have given any thought to converting to the 1996 ~ 2000 Vortec MPFI system using the '427 PCM? It could be done in two steps, first upgrade to the '427 PCM, then install the 1996 ~ 2000 Vortec MPFI system. I have experience doing both conversions, and would be willing to share my notes.

dave w

Have I thought about it? Yes
Am I intimidated about it? Yes
Worried about expense? Yes
Worried about time it would take to start over? Yes
Concerned about starting over when this close on current setup? Yes
Concerned about complicating the efi setup? Yes

With all that said I am still interested in what you have to show me.
I would really like some kind of TPI or ram setup like used on the Ram Jet engine. But that is definitely is out of the budget I would imagine.

The set up now makes more than enough power for the Jeep but anything I could do to improve overall drivability would be good. But I would like to keep it simple; I am a big fan of simplicity.

[dave w]

Have I thought about it? Yes
Am I intimidated about it? Yes
Worried about expense? Yes
Worried about time it would take to start over? Yes
Concerned about starting over when this close on current setup? Yes
Concerned about complicating the efi setup? Yes

With all that said I am still interested in what you have to show me.
I would really like some kind of TPI or ram setup like used on the Ram Jet engine. But that is definitely is out of the budget I would imagine.

The set up now makes more than enough power for the Jeep but anything I could do to improve overall drivability would be good. But I would like to keep it simple; I am a big fan of simplicity.

I figured in you area, used 5.7 Vortec intake systems / parts would be affordable? Seems the Vortec heads were the "In Demand Items" not the intake systems.

Would it be as simple as a TBI? No
Would it be as complicated as an 0411 PCM? No
Would the fuel pressures increase? Yes
Can you reuse the TBI distributor? Yes
Would the current belt drive system need modification? Maybe ~ Depends on what is bolted to the current intake manifold.
Is there any additional wirng? Yes ~ Injector Pod and sensor connectors ends.

I'll post additional information soon.

dave w

[devind]

I figured in you area, used 5.7 Vortec intake systems / parts would be affordable? Seems the Vortec heads were the "In Demand Items" not the intake systems.

Would it be as simple as a TBI? No
Would it be as complicated as an 0411 PCM? No
Would the fuel pressures increase? Yes
Can you reuse the TBI distributor? Yes
Would the current belt drive system need modification? Maybe ~ Depends on what is bolted to the current intake manifold.
Is there any additional wirng? Yes ~ Injector Pod and sensor connectors ends.

I'll post additional information soon.

dave w

Dave,
I have been thinking about this and as much as I appreciate your willingness to help me and share your notes with me. The more I think about it, I am not sure this is the vehicle I want to learn to do a MPFI on. I kind of like the the simplicity of the TBI system being on this vehicle.

I know there will be a MPFI project in my future and I hope your offer will still stand. However I still might be interested in upgrading to the other ecm. You mentioned this to me before.

[1project2many]

I lost track of the Vortec needs. The TBI Vortec is still not the best choice. It is a copy of a factory manifold. If you are not forced to use EGR there are plenty of good carby intakes available that would work with adapters.

Coolant under the manifold is to aid emissions. It is not there for cooling. The bypass in the old block exists to circulate coolant from below the thermostat ensuring warm coolant reaches the 'stat and causes it to open. You can do the same thing by adding a small hole to the 'stat (about 1/8"). If you aren't in an area where it gets really cold this won't cause problems. If it gets below 20 deg the engine might not warm enough. Additionally, you can install small nipples and use 3/8" hose to create a small bypass path to the water pump. What you do not want to do imo is use 1/2" heater hose to create a bypass path. The stock intake has a dual valve 'stat that closes the bypass as it opens the radiator. A traditional 'stat cannot close the bypass path and a 1/2" hose may allow large amounts of coolant to bypass the radiator.

[devind]

I lost track of the Vortec needs.

The TBI Vortec is still not the best choice. It is a copy of a factory manifold. If you are not forced to use EGR there are plenty of good carby intakes available that would work with adapters.

Coolant under the manifold is to aid emissions. It is not there for cooling. The bypass in the old block exists to circulate coolant from below the thermostat ensuring warm coolant reaches the 'stat and causes it to open. You can do the same thing by adding a small hole to the 'stat (about 1/8"). If you aren't in an area where it gets really cold this won't cause problems. If it gets below 20 deg the engine might not warm enough. Additionally, you can install small nipples and use 3/8" hose to create a small bypass path to the water pump. What you do not want to do imo is use 1/2" heater hose to create a bypass path. The stock intake has a dual valve 'stat that closes the bypass as it opens the radiator. A traditional 'stat cannot close the bypass path and a 1/2" hose may allow large amounts of coolant to bypass the radiator.

I have already been running a Weiand Intake with a custom adapter I machined for a while now.

The first problem I had when I got this setup going a year ago was when I went to break the cam in the engine warmed up and started to overheat right away. After some diagnosing the problem, I came to the realization the water pressure from the water pump was forcing the T-stat closed. At the time I cut the center out of the T-stat and was able to break the cam in.

Later on I got a high flow T-stat with 3 – 3/16” holes drilled in it and it worked fine except when it is cold out it allows too much water to bypass and it won’t warm up above 150*. So to cure this problem I got a high flow T-stat without the bypass holes and it works good but now the heater core make funny sound when the T-stat opens and closes from the water the bypasses through it.

So what I am wanting is an intake that will ether flow coolant like the GMPP or has provisions to plumb the water from the back to the front. I was going to drill and tap the intake I have but there really isn’t much material there to do it. However I have found some cheap carb Vortec intakes on ebay that I can plumb this way. http://cgi.ebay.com/ws/eBayISAPI.dll...m=171073251560

I am planning on running a standard bypass hose straight from the intake to the water pump. Then I will either add a nipple to the radiator next to the lower outlet or make a tee to go inline in the lower radiator hose so that I can plumb the heater from the intake to heater core, from core to lower radiator hose. I am running a high flow reverse rotation Edelbrock water pump, I wish there was a way to just add another bypass port to it like the big block water pumps have.

I have done some internet searching about this issue and really wasn’t finding a whole lot of people having this problem than just the other day found some guys on the Tri 5 forum that was having the same issue with their Ram Jet crate motors and this is what many of them did to cure the problem.

[dave w]

I have done some internet searching about this issue and really wasn’t finding a whole lot of people having this problem than just the other day found some guys on the Tri 5 forum that was having the same issue with their Ram Jet crate motors and this is what many of them did to cure the problem.

The pictured adapter looks very similar to the design I came up with . See pics below. I've made a few improvements since I made these screen shots.

dave w

[devind]

The pictured adapter looks very similar to the design I came up with . See pics below. I've made a few improvements since I made these screen shots.

dave w

Yea, the picture is of the one I made earlier this year.