Thoughts on MPI for N/A in a dakota

[moparzrule]

I need to make a custom intake for my MPI conversion in my dakota. I don't have the resources to make any kind of custom sheet metal intake, and I also need a low buck solution. The problem is the stock intake puts the 90* elbow into the firewall, so I have to figure out a way thats decently efficient to chop off the elbow and mount the throttle body somewhere else.
Since I have plenty of hood clearance, I thought something like this. Chop off the 90* elbow and weld a flat plate there, then cut a hole in the center top of the intake and mount the throttle body facing back toward the engine. Here's a couple pics I fabbed up real quick just to show what I mean.
I'm not a very good drawer, so this is extremely crude-
http://i105.photobucket.com/albums/m216/87wagon/customintake.jpg
http://i105.photobucket.com/albums/m216/87wagon/CustomIntake2.jpg

Just picture our engine inline in the engine bay. What I drew will face toward the drivers side. The only thing is the intake pipes will be draped over the hot engine kind of, but I could do a 90* elbow and out toward the front of the truck for a CAI all with 3'' pipe to maximize flow. My main concern is the throttle cable, I don't really want to change anything with the throttle cable, like for example if I face the throttle body in the opposite direction the cable would have to be lengthened to reach around there. This method seems simple, and putting the TB in the middle of the intake may distribute flow a bit more evenly. And like I said I have plenty of hood clearance.
Any thoughts?
I plan to run turbo electronics with a custom cal with the fuel backed off. Plans are to eventually perhaps fabricate a tubular header for a turbo setup, but this will get me started and should make decent power of the stock TBI setup. Now I will also have a knock sensor and in the custom cal I can enable the knock sensor CEL flash and max out timing advance for better fuel economy and power.

[moparzrule]

Anybody? Good idea? Bad idea? Any ideas on improvement? Different ideas?

[Turbulence]

Have you considered using the Mexican MPFI cal? I believe they use the turbo harness and all associated parts. There was a thread on the other site about that.

Martin
89 Horizon
90 Sundance

[ShelGame]

The Mexican MPFI cals are meant for the SBEC-II. Not sure if the code is 100% compatible with the SBEC(-I). The Mex MPFI cals are also nearly identical to the Spirit FFV cal from '93 (?).

[moparzrule]

Is it hard to switch the SMEC electronics? Ideally if the bulkhead connectors are the same as my 90 SBEC, I'd like to just swap a wiring harness from a minivan in there. Friend of mine has a turbo 5 speed mini harness and SMEC.

[Turbulence]

The Mexican MPFI cals are meant for the SBEC-II. Not sure if the code is 100% compatible with the SBEC(-I). The Mex MPFI cals are also nearly identical to the Spirit FFV cal from '93 (?).

Hmm, this is what a guy by the name of R2D2 posted on the other site, and why I made the suggestion. From what he says it sounds like SBEC 1. What do you think?


I know this is a little bit late, but maybe will be helpful to someone, so I will resurect this thread!

I live in Mexico, recently a friend of mine ask me for help to make a NA MPFI - Turbo conversion. We took a Mexican 1991 2.5 MPFI Shadow and put a 2.5 Turbo II complete engine with a T3 Garret Turbo. We were planing to use a 1990 or 1991 Turbo SBEC, but we were unsure if the wiring harness has the same pinout.

For information: all Mexicans MPFI cars (1990 +) have 2 BAR MAP , 1 Piece Intake (with CTS), 46mm Throtle body, they use the 4554130 injectors (that were the same ones used here in Mexico on turbo II engines from 1991 - 1995 , I had these injectors flowed with a set of 4418213 & a set of 5277895, and the 3 sets flow almost the same), after 1991 they introduce the use of O2 sensor. So as you can see almost is identical to a Turbo engine except for the engine internals, all the sensor are the same also.

The 1 million dollar question was if the NA SBEC will have the same internal components as the Turbo SBEC, and if thery were compatible, so we open the SBEC and it looks they were identical. The next step was to socket the NA SBEC ... the EPROM on that SBEC was a M87C257 Texas Instrument. I read the eprom (If someone is interested on this cal PM me with your email and I will sent it to you) and then program it with the cal from a 1991 Mexican Shadow 2.5 TII, and install it on the NA SBEC. It work perfect, the only modification we need to make in wire harness was to wire the solenoid for the wastegate and the BOV (the mexican use one for the BOV but it doesn't have one the for the purge canister).

The good news is that this cal will work on any US Turbo SBEC I, and the wiring harness of a Turbo II or I (just need to wire the CTS) will work without any modification. We have test some US cals with Mexican SBECs, in Mexicans cars and they work just fine, without any modification on the wiring harness (only the code 31 appears for the Purge Canister Solenoid).

Conclusion: The US and Mexican Turbo SBECs are compatibles (also the Mexican MPFI SBEC), and the Mexican MPFI cal will work on any of these ECUs.

If anyone need more information, I will be glad to help you !

Erik G

Interesting for sure,

Martin
89 Horizon
90 Sundance...dreaming of mpfi

[daytonaturbo87]

If anything, I would cut the elbow off and rotate it 180* so it points the other way. If that won't work, would it work to move the elbow to the other side? I don't like the idea of having the inlet right in the top/middle. My thinking is you'll get much more air flow to the two middle cylinders and less to the outer cylinders, and if you ever go turbo, I think you're looking for trouble with that idea. Just rotating the elbow or cutting it off and moving it to the other side isn't going to change airflow characteristics much from stock IMO.

I'm not an airflow expert, but to me your idea just screams uneven air distribution....

Good luck with it tho.:thumb: If you really need the room, you can always run a log intake w/ stock log electronics + turbo.;):eyebrows:

[ShelGame]

Yeah, I have that cal from him. I know he said it came from a SBEC-I, but the code looks a lot like the FFV code.

It's different from the US turbo cals, and the MPFI is similar to the Mex Turbo SBEC cals. I can post it if anyone wants, but I haven't dis-assembled it very far at all...

[moparzrule]

If anything, I would cut the elbow off and rotate it 180* so it points the other way. If that won't work, would it work to move the elbow to the other side?


That would be ideal but how would I go about the throttle cable? It's not nearly long enough.
For the other side, thats what I originally thought of doing but here again the throttle cable issue.




I'm not an airflow expert, but to me your idea just screams uneven air distribution....


I think the stock intake screams uneven air distribution far more. Think about it, the inlet is at the whole other end from the number 1 runner. The stock TBI intake has the throttle body in the middle, how can you get any more even air distribution than going with the middle of the intake???




Good luck with it tho.:thumb: If you really need the room, you can always run a log intake w/ stock log electronics + turbo.;):eyebrows:

No, don't have the firewall clearance for that. There's literally only like 1 inche from the engine to the firewall, and even the log intake sticks out some. So I would never be able to get the intake 90* elbow that bolts onto the compressor housing on there.
I also don't think converted to logic module is even possible. Well, I know the bulkhead connectors are different for sure there so it would require a heck of a lot of fabrication to the wire harness.

[Turbulence]

Yeah, I have that cal from him. I know he said it came from a SBEC-I, but the code looks a lot like the FFV code.

It's different from the US turbo cals, and the MPFI is similar to the Mex Turbo SBEC cals. I can post it if anyone wants, but I haven't dis-assembled it very far at all...


I figured there was more to it than that. Would be cool to be able to swap though,

Martin
89 Horizon
90 Sundance

[ottawa rogue]

could you get around the distribution issues by adding some sort of divider or "turtle" to the floor right under the new elbow location?

[Aries_Turbo]

if you are going to that trouble, cut the elbow off, weld a plate there (or machine that area flat and tap and bolt and seal a plate over that area. then have an aluminum plug welded into where the steel plug is in the other end. then bore a 2.5" hole and have a 2.5" elbow on the other end and a bead welded on the end of the elbow. then take some 2.5" exhaust piping and weld beads on the ends of them and extend the manifold over to where the throttle cable will reach and weld a plate on the end of the pipe where the throttle body will bolt. that would be more even than the one in the top and just as much aluminum welding as the first idea.

make sure you put a brace to hold the pipe up and spray a little oil inside to prevent rust or hook the PCV valve after the TB to auto oil the pipe inside. :)

Brian

[moparzrule]

Heh, remote mount throttle body, cool idea Brian. Aluminized exhaust pipe shouldn't rust, right? I could even use SS pipes.
Why doesn't the throttle body in the middle of the intake make for more even air distribution than on the end???

[Aries_Turbo]

it will mostlikely make cyl 2 and 3 lean as it will be dumping right by the ports.

Brian

[moparzrule]

What about the stock TBI manifold? Is it making 2-3 lean?

[daytonaturbo87]

TBI intake was designed from the factory to work with a TB in the middle. Plus you're injecting the fuel right there, so if airflow is uneven, so will fuel flow be. And TBI's weren't the most efficient designs either.

Look at the log intakes, they flowed more air to intake runners 3+4 than 1+2, so the LM was programmed to fire two injectors a tiny bit more rich to compensate. The later intakes were designed much better from the groud up. With larger plenum areas and the throttle body inlet being elevated, airflow distribution between the cylinders must have been quite good, good enough for chrysler to do away with the two richer injectors that the log needed. By putting the intake elbow on the top you are taking something that was designed for even air distribution and throwing the factory engineering out the window. For that reason I still think adding an elbow in the middle/top would cause the middle two cylinders to run lean. You might get away with it in a n/a application, but if you're going thru the trouble already, might as well do it right.

Can you find someone in your area who can weld the aluminum for you? If so, IMO you're better off making a manifold from scratch. Ideally you could take the bottom 1/2 + fuel rail from a two-piece intake and design your own top plenum. There are a few places online that'll sell you the aluminum stock to do it, just need to have a guy weld it up after, which you intend to have done anyway...

[moparzrule]

I actually think I might use Brian's advice, making a remote mount TB with the inlet on the opposite end of the intake with a aluminum elbow welded on.

[Aries_Turbo]

if you do that, you should probably raise the plenum some so that you keep things evenly distributed. it shouldnt be a big deal though.

Brian

[moparzrule]

Yeah I thought about just getting a 2 piece intake for this, but the expense really isn't worth that for what 2 pieces go for.
Even still with a 1 piece intake (no raised plenum), don't you think it will be better than the stock TBI setup? Or will I have gained nothing for all that work?

[daytonaturbo87]

Oh you'll still be better. I drove a log T1 car with a blown head gasket and it still had better throttle response than any TBI car I've owned.

That plug on the other side of the one piece intake sits kinda low in the intake IMO. It does sit lower than the elbow does on the other side of the intake. Not sure how much of a problem that would be tho.

You could cut off the elbow and seal that side up, pull out the plug on the other side of the intake and bolt a throttle body on right there. Wouldn't be hard to have a local guy weld it on, then you seal it up with jw weld for good measure.

The truth is, how well this runs after is going to be a big factor of how well you can retune the stock computer. Without a wideband and a datalogger you will really just be guessing as to what's going on.

[Vigo]

if you're looking for a 90* elbow with the tb on the end, use one off a 3.3/3.8 manifold instead, way better than the 1-piece elbow section and exact same tb setup, pre ported for 52 mm < lol.

[moparzrule]

No I think I'm gonna use a real aluminum elbow, and then aluminized exhaust pipe with silicone couplers to remote mount the throttle body to a good position.

[Vigo]

i just cut up a tbi manifold a few hours ago looking for ideas..

post up pics when you get goin :thumb:

[moparzrule]

What were your ideas?

[Vigo]

well, im not sure how feasible it is yet, mostly because i have no fab skills, but i was thinking about cutting the tbi manifold at the two y-points between the runners, putting a flange there, and basically doing a dual tbi setup.

id use 3.5 dual tb setup with shortened throttle shaft, tps works the same, throttle cable from a t1 car should work, and for the fuel, the actual fuel part of a tbi is just the top section, it unbolts and mates up perfectly with the bore of the 3.5 tb's.

so the tricky part is getting a nice transition from the oval of the runners to round tb bore and making a flange. the tb setup will be easy, and tuning it to run decently on stock tbi electronics shouldnt be too hard with simple stuff like a fpr, im hoping. ms if i have to.

So thats my goofy thought. i have a pile of tbi manifolds and tb's and 3.5 parts to mess with so i just cut a manifold up for exploration purposes.