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tex55 · 04-21-2007, 05:50 AM

Hey Chevy nut are you using the harness for your engine that has the computer mounted to the intake? I have a RJ 502 that surges and tries to die when you put it in gear. These motors were designed for marine application, and seem to run a bit sloppy in a vehicle. I am considering changing the harness to run a automotive type computer under the dash.

Chevynut · 04-21-2007, 01:42 PM

Tex55, I am going to run the Holley Commander 950 ECU. It can run closed-loop and you can tune it with a laptop computer. I have no experience with the stock MEFI unit, since I pieced my Ramjet together with a combination of GM and aftermarket parts (Holley TB and 42 lb/hr injectors), and a GMPP ZZ502 longblock.

Rick_L · 04-21-2007, 04:02 PM

Both the Ram Jet 350 and the Ram Jet 502 have a reputation for not having a sharp tune.

Did your 502 come with O2 sensors?

Converting using the controller that comes with them is pretty expensive, and I've heard it's still troublesome. I would definitely consider going to a GM computer from a car, or the Holley.

If you were willing to do some pioneering, you could actually control the thing with a computer from a TPI small block. You'd be kind of on your own with the base map for it though. With the Holley, there should be a base map on the Holley site that would get you going quicker. Chevynut probably has one picked out already.

The other aftermarket EFI controllers such as Megasquirt, FAST, and Accel could be used too.

Chevynut · 04-21-2007, 04:47 PM

Street and Performance actually sells a harness and ECU for the Ramjets that's based on the TPI setup. I thought about going that route, but to program it they have to burn you a chip at $300 a pop. I figured you could pay for a C950 pretty quickly at that rate.

55mike · 04-21-2007, 04:51 PM

I'm CERTAINLY no expert on these fancy new FI systems, but I do know that my friend has a crate 502 FI, and he changed it from GM (before even firing it off) to a brand new latest-wiz-bang Accel Gen-? computer system which allowed the use of a lap top to adjust the entire fuel curve at any RPM. It works very well... check out the BLACK 55 on my website under friends rides..
55 Mike

Rick_L · 04-21-2007, 05:20 PM

Chevynut, I'd say the only extra value from the Street and Performance deal is getting a base tune. Otherwise it's a lot of extra $$$. You can get the s/w, cable, and all the other stuff to do your own tuning on a TPI style computer for about $300. And you may even be able to convert the chip to a flash programmable style for that money.

For anyone that's interested, there's a lot of info at thirdgen.org.

But even after you got all that programming stuff, you'd still have to come up with a TPI computer and harness. And maybe a sensor or 2. So this is not going to be dirt cheap.

Going with the Holley is a lot simpler, but obviously higher cost.

NTSOS · 04-21-2007, 08:02 PM

Also, check out the new MSD stuff.

http://www.msdfuelinjection.com/

John

Rick_L · 04-21-2007, 08:58 PM

Interesting. I had heard that the developer of some other aftermarket systems was working with MSD. First thoughts say it has promise. I wonder where they are on pricing? Looks like the way the MEFI-4 is built that it would be durable.

It's nice to see more products in this arena - it can't help but add capability and affordability.

tex55 · 04-21-2007, 09:35 PM

The MSD set up looks like you could use the same harness that came with the RJ 502. I will look into this, thanks for the info guys.

NTSOS · 04-21-2007, 10:22 PM

Quote:

Originally Posted by Rick_L

Interesting. I had heard that the developer of some other aftermarket systems was working with MSD. First thoughts say it has promise. I wonder where they are on pricing? Looks like the way the MEFI-4 is built that it would be durable.

It's nice to see more products in this arena - it can't help but add capability and affordability.

Yes, I agree.....I'll check Goodies for a price on Monday.

John

04-21-2007, 05:50 AM	#1
tex55 Member Join Date: Apr 2007 tex55's Garage Posts: 56 Member #2534	Tuning a Ram Jet 502 Hey Chevy nut are you using the harness for your engine that has the computer mounted to the intake? I have a RJ 502 that surges and tries to die when you put it in gear. These motors were designed for marine application, and seem to run a bit sloppy in a vehicle. I am considering changing the harness to run a automotive type computer under the dash.

04-21-2007, 04:51 PM	#5
55mike Senior Member 2 Gold Stars Join Date: May 2006 55mike's Garage Location: Pensacola Florida Posts: 2,571 Member #608	I'm CERTAINLY no expert on these fancy new FI systems, but I do know that my friend has a crate 502 FI, and he changed it from GM (before even firing it off) to a brand new latest-wiz-bang Accel Gen-? computer system which allowed the use of a lap top to adjust the entire fuel curve at any RPM. It works very well... check out the BLACK 55 on my website under friends rides.. 55 Mike __________________ Mike Check out my link.... http://www.trifive.com/webs/55mike/ Hear it run... http://www.youtube.com/watch?v=2wEETd57ubs A little power run... http://www.youtube.com/watch?v=_BJ8P2rP9-g

04-21-2007, 09:35 PM	#9
tex55 Member Join Date: Apr 2007 tex55's Garage Posts: 56 Member #2534	Fuel injection The MSD set up looks like you could use the same harness that came with the RJ 502. I will look into this, thanks for the info guys.

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04-21-2007, 01:42 PM	#2
Chevynut member Join Date: Jan 2007 Chevynut's Garage Location: Fort Collins, CO Posts: 12,277 Member #1769	Tex55, I am going to run the Holley Commander 950 ECU. It can run closed-loop and you can tune it with a laptop computer. I have no experience with the stock MEFI unit, since I pieced my Ramjet together with a combination of GM and aftermarket parts (Holley TB and 42 lb/hr injectors), and a GMPP ZZ502 longblock.

04-21-2007, 04:02 PM	#3
Rick_L Trifive Leaders Club Join Date: Mar 2007 Rick_L's Garage Location: Katy, TX Posts: 20,317 Member #2256	Both the Ram Jet 350 and the Ram Jet 502 have a reputation for not having a sharp tune. Did your 502 come with O2 sensors? Converting using the controller that comes with them is pretty expensive, and I've heard it's still troublesome. I would definitely consider going to a GM computer from a car, or the Holley. If you were willing to do some pioneering, you could actually control the thing with a computer from a TPI small block. You'd be kind of on your own with the base map for it though. With the Holley, there should be a base map on the Holley site that would get you going quicker. Chevynut probably has one picked out already. The other aftermarket EFI controllers such as Megasquirt, FAST, and Accel could be used too.

04-21-2007, 04:47 PM	#4
Chevynut member Join Date: Jan 2007 Chevynut's Garage Location: Fort Collins, CO Posts: 12,277 Member #1769	Street and Performance actually sells a harness and ECU for the Ramjets that's based on the TPI setup. I thought about going that route, but to program it they have to burn you a chip at $300 a pop. I figured you could pay for a C950 pretty quickly at that rate.

04-21-2007, 05:20 PM	#6
Rick_L Trifive Leaders Club Join Date: Mar 2007 Rick_L's Garage Location: Katy, TX Posts: 20,317 Member #2256	Chevynut, I'd say the only extra value from the Street and Performance deal is getting a base tune. Otherwise it's a lot of extra $$$. You can get the s/w, cable, and all the other stuff to do your own tuning on a TPI style computer for about $300. And you may even be able to convert the chip to a flash programmable style for that money. For anyone that's interested, there's a lot of info at thirdgen.org. But even after you got all that programming stuff, you'd still have to come up with a TPI computer and harness. And maybe a sensor or 2. So this is not going to be dirt cheap. Going with the Holley is a lot simpler, but obviously higher cost.

04-21-2007, 08:02 PM	#7
NTSOS Member Join Date: Feb 2007 NTSOS's Garage Location: San Jose Posts: 64 Member #2147	Also, check out the new MSD stuff. http://www.msdfuelinjection.com/ John

04-21-2007, 08:58 PM	#8
Rick_L Trifive Leaders Club Join Date: Mar 2007 Rick_L's Garage Location: Katy, TX Posts: 20,317 Member #2256	Interesting. I had heard that the developer of some other aftermarket systems was working with MSD. First thoughts say it has promise. I wonder where they are on pricing? Looks like the way the MEFI-4 is built that it would be durable. It's nice to see more products in this arena - it can't help but add capability and affordability.

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