5.9 Magnum FI cam upgrade

-
falconvan

falconvan

Member
Joined
Jul 1, 2013
Messages
13
Reaction score
0
Location
Festus, Mo
Hi, I'm new to the forum. I dont have an A body as I've been into the 46-52 Plymouths for a long time but you guys have the best small block Mopar tech I've seen on just about any of the Mopar sites so I signed up. Lots of great rides and mechanics on here!

Im planning on doing a 5.9 magnum swap and utilizing the factory fuel injection along with an AX-15 5 speed and a 3:73 geared 8.8 in a 49 Plymouth coupe. Can anyone recommend a cam upgrade that will work with the factory fuel injection? I'm assuming I'll have to have the computer reflashed but would like to stick with the factory FI main componants. I dont have an engine yet but plan on using an OBD II setup.
 
Comp XR265HR. I run this cam with a carb but it is actually designed for efi. You will need valve springs and a tune.
 
You can get a nice custom grind that will be EFI friendly. I use Comp Cams for my stuff, but almost any good manufacturer will be able to make something to suit your needs.

How are you planning on tuning it?
 
Thanks for the cam recommendations! Im not sure on how to tune it; this will be my first FI swap other than a stock 350 TBI swap I did in a 69 chevy truck. Computer stayed stock on that one. Im assuming there are places I can send the computer for a tune or a way to access the factory programming where a laptop can be used?
 
MegaSquirt is a good way to do the tuning yourself if you're interested in building and controlling it yourself.
 
falconvan said:
Im assuming there are places I can send the computer for a tune or a way to access the factory programming where a laptop can be used?
Click to expand...


Not sure if there is anyone on this sight that can do this. I'm sure someone will chime in if there is. I know you can contact "hemifever" on the Dakota durango forum. This is what he does. I don't know of any way to tune them yourself though.
 
cdavis said:
Not sure if there is anyone on this sight that can do this. I'm sure someone will chime in if there is. I know you can contact "hemifever" on the Dakota durango forum. This is what he does. I don't know of any way to tune them yourself though.
Click to expand...
HemiFever has a bad reputation from a lot of the Dakota crowd on forums that aren't named Dakota-Durango because of drivability issues.
 
I read a little about the megasquirt system; that's the built it yourself EFI like the old Heathkit projects? Im hoping to use the Mopar computer; I'll have to do some research on the programming.
 
When you have the "beer keg" intake off, there are a few important mod's. Most important is that the sheet-metal bottom cover blows the gasket and leaks, sucking in oil. You can get a thick aluminum plate replacement on ebay ~$50. For better high rpm, some people cut the internal intake runners shorter. There are plans on ebay, or just wing it.

I haven't heard of anyone hacking the Mopar computer. It might be easier to use a proven solution like a GM computer. Howell Engineering does that and might be able to work with your Magnum. Another choice might be a Holley Commander 950. I got the ECU alone for just $120 on ebay. It uses GM type connectors and I may wire to a Magnum engine harness I have someday. It might also run fine with the stock computer. I suspect the cam would matter more if using alpha-N control. Mopar uses Pman and rpm, so if the displacement doesn't change, it might be close enough that the O2 feedback tweaks it in. If a really wild cam, the Pman signal doesn't well correlate to air flow, so may cause problems. Some hot rod kits add electronics to bugger with the Pman signal, but I don't know if there are any for Mopars.
 
B&G would be my first choice for having a tune done. I used them for tuning my wild nitrous fed 318, and Dave did a great job with it.

They don't come cheap, though.
 
I saw a few people mentioned a "performance computer". Is that something available from Mopar or was that a factory offering on certain models?
 
rnaz said:
HemiFever has a bad reputation from a lot of the Dakota crowd on forums that aren't named Dakota-Durango because of drivability issues.
Click to expand...

Devilbrad said:
LOL@Hemifever. You're better off with a stock tune. Try these guys: http://www.bgperformance.com/ Or if you are going OBDII you can use SCT, just find a local dealer with a good reputation and the full tuning software.
Click to expand...

Red r/t said:
i would use flyinRyan instead of hemifever or PIE
Click to expand...


I didn't know this. I haven't used him. Most of the people on that forum seem to like his tunes. Only reason I suggested him. I have SDS stand alone efi on mine.
 
falconvan said:
I saw a few people mentioned a "performance computer". Is that something available from Mopar or was that a factory offering on certain models?
Click to expand...

Here is one similar to what I put in my 93 Dakota. It provides a more aggressive timing and fuel delivery, bumps the red line from 5500 to over 6000, and gets rid of the top speed limiter. You need to run premium fuel with it though.

http://www.ebay.com/itm/Mopar-Perfo...Parts_Accessories&hash=item19dea80303&vxp=mtr
 
falconvan said:
I saw a few people mentioned a "performance computer". Is that something available from Mopar or was that a factory offering on certain models?
Click to expand...
There is a Mopar Performance PCM available for some of the trucks with OBD 2 diagnostics. (96 +)
 
cdavis said:
I didn't know this. I haven't used him. Most of the people on that forum seem to like his tunes. Only reason I suggested him. I have SDS stand alone efi on mine.
Click to expand...

Understandable.

The people who rave about him are the ones who don't know any better. I had fuel puking out of my exhaust when I had my stroker motor in my Dakota.

That went away when I bought the Dart and swapped the Magnum 390 over to a carb. LOL!
 
Do you guys think I should be looking at an OBD I setup rather than an OBD II or does it matter? Basically it's going to be a stock motor with a cam upgrade and possibly a performance tune if needed; not sure if one system would work out better than the other.
 
OBD2 is the way to go. There are way more options for tuning it. If you start upgrading past a basic cam swap, the OBD 1 isn't going to play as nicely with it as you'd like.
 
rnaz said:
OBD2 is the way to go. There are way more options for tuning it. If you start upgrading past a basic cam swap, the OBD 1 isn't going to play as nicely with it as you'd like.
Click to expand...

Gotcha, thanks. So that's a 96 and up?
 
I don't think Dodge switched over until 97. Also have to watch the lobe separation, the stock FI will throw fits with a narrow lobe separation. I'd stay 112 or higher personally.
 
dartfever said:
I don't think Dodge switched over until 97. Also have to watch the lobe separation, the stock FI will throw fits with a narrow lobe separation. I'd stay 112 or higher personally.
Click to expand...

Agreed on the LSA of the cam. Stupid PCM goes nuts if it's too lumpy, and gives random misfire codes.
 
You must log in or register to reply here.
-

Back
Top