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I want a special title
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Discussion Starter #1
Hey guys, I'm new to the site but finding it pretty helpful so far, but I have a few questions. I see a couple of turbo'ed 318's but mostly in older dak's....I'm building a kit for my 98 Durango, and figured its the same motor right? So maybe someone could give some helpful info. I'm going to do an underhood setup, I have a buddy who's gonna help me weld and fab all the piping and hack and flip the stock manifolds and everything, so thats not a big problem, but my questions are: Realistically, how much boost will the stock 318 hold? and how much power can i expect?. I'm going to run an FMU, decent intercooler, and possibly run E-85, but thats still up in the air...i have access to free HX40's through my job so That'll be the turbo choice :banana2:...I figure I could get it up and running for about $1000..are there any main problems to be faced with this kind of build, or is it pretty painless? I am just looking to do something a little different but not too extreme...any POSITIVE info would be appreciated
 

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ROFLcopter
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16,692 Posts
You won't need an I\C for the boost you can run, 9psi I would go max. You could add meth injection, it will act as an I/C, but an I/C will rob about 2 psi just to flow the air. You will want sct tuning, a 2 bar map sensor, a wide band, ability to log tps, a/f, rpm and iat/mph. As far as fmu, that will limit you to a 1 bar, which you will need a boost/spark retard knob. I'd go sct, data log, simplicity.

Btw, this isn't different, it's just different to you:)
 

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I want a special title
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102 Posts
Discussion Starter #3
Thanks for the info, i guess i will save the I/C money...so the SCT tuning data logs? or no? is it a handheld tuner, or a program for the stock PCM? I have an AEM wideband that I can pull off of my hayabusa, and a boost gauge and oil press i can get from work, and I guess I'll pick up a MAP sensor...what about injectors/pump?
 

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I Heart Boost...and M/T's
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5,951 Posts
Your not going to lose any boost through an intercooler. If you have the boost controller set to 9psi, it will make 9psi wethere there is an intercooler there or not, and you will make more power, at the same boost levels.
 

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Thanks for the info, i guess i will save the I/C money...so the SCT tuning data logs? or no? is it a handheld tuner, or a program for the stock PCM? I have an AEM wideband that I can pull off of my hayabusa, and a boost gauge and oil press i can get from work, and I guess I'll pick up a MAP sensor...what about injectors/pump?
Why wouldn't you get an IC? If you got the money and the skills, do it!

SCT will work with forced induction but it is a a bandaid fix. If you want perferct drivability, get a standalone. If you want cheap and simple, get FMU and a spark retard box.

I would look up DUNER. He has a quick turbo truck and uses simple parts.
 

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I want a special title
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102 Posts
Discussion Starter #6
Yea, the I/C would really only help the situation, and id prefer it over meth injection, so I'll prob still run one...and the SCT seems expensive...standalone is pricey too..i like simple, but I just get worried because its my daily so I don't want to cut corners that shoouldn't be cut. What about injectors? can stock injectors support 7PSI or so with an FMU? or do i need to do some fuel upgrades? My goal is to just get it setup and running reliably, then worry about upgrades and making more power later on...
 

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"SCT will work with forced induction but it is a a bandaid fix"

Could you elaborate?

I have SCT with a Powerdyne and my AF is PERFECT at all rpms.
 

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"SCT will work with forced induction but it is a a bandaid fix"

Could you elaborate?

I have SCT with a Powerdyne and my AF is PERFECT at all rpms.
There is more to a tune than perfect AFR. Do you have PERFECT drivability under all conditions?

When I had SCT, I was able to get a decent tune, and I never ran an FMU setup, so I can't compare the two. But when I switched to a ECU that recognized a 2-bar (accel DFI), I had perfect and consistent stock-like drivability. No intermittent limp mode, no key-on CELS, better mpg, and no idle issues. All after a few days of street tuning.

Don't get me wrong, SCT works, but how satisfied you are with it will depend on your standards. And tuning it for a 2-bar is difficult due to low resolution.
 

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Turbo Dakota Junkie
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I've had no issues with my FMUs. It goes from perfectly docile to all hell broke loose with no problems at all.
 

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We should be taking our tuning cues from the Viper crowd who also have JTEC computers. A lot of those guys are running boosted apps with SCT and a 1-bar (which works GREAT), and retaining their piggyback boost stuff.
 

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Turbo Dakota Junkie
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1,912 Posts
I've turbo'd roughly 75 vehicles so far, and about half of them have been EFI. I put an aux pump and FMU on every one of them and have had one fuel system failure... which was traced back to contaminated fuel. I still don't understand why FMU's get such a bad rap.
 

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I've turbo'd roughly 75 vehicles so far, and about half of them have been EFI. I put an aux pump and FMU on every one of them and have had one fuel system failure... which was traced back to contaminated fuel. I still don't understand why FMU's get such a bad rap.
Because FMU setups don't cost a lot and can't be tuned via e-mail.
 

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Turbo Dakota Junkie
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1,912 Posts
Can somebody give me a rundown on what an FMU is exactly and how it works?
An FMU is a boost pressure referenced fuel pressure regulator. On these trucks you add an aux. fuel pump into the system that's plumbed thru the FMU. When you are not in boost, the FMU is "open" and allows the additional fuel pumped by the additional pump to "return" or just pump in a loop. When it sees boost, it restricts the "return" line which increases the fuel pressure to the fuel rail.
 

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An FMU is a boost pressure referenced fuel pressure regulator. On these trucks you add an aux. fuel pump into the system that's plumbed thru the FMU. When you are not in boost, the FMU is "open" and allows the additional fuel pumped by the additional pump to "return" or just pump in a loop. When it sees boost, it restricts the "return" line which increases the fuel pressure to the fuel rail.
Duner would you happen to have some kind of diagram of how you have the aux stuff such as pump and FMU plumbed into the system?

thanks
 

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Resleeves rnaz's borings
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9,536 Posts
Yea, the I/C would really only help the situation, and id prefer it over meth injection, so I'll prob still run one...and the SCT seems expensive...standalone is pricey too..i like simple, but I just get worried because its my daily so I don't want to cut corners that shoouldn't be cut. What about injectors? can stock injectors support 7PSI or so with an FMU? or do i need to do some fuel upgrades? My goal is to just get it setup and running reliably, then worry about upgrades and making more power later on...
SCT PRP was selling for $250 shipped last month. I dont think the regular price is much more...
 

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Blown and Squirted
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3,407 Posts
"SCT will work with forced induction but it is a a bandaid fix"

Could you elaborate?

I have SCT with a Powerdyne and my AF is PERFECT at all rpms.
The resolution leaves a lot to be desired. For example, there are five bins for MAP on the spark table. It's great for NA apps, but for boosted stuff, it's cutting it really thin. A lot centrifugal guys have good experience with with it because their airflow is dictated by rpm, and easy to predict (or because they don't know better) A turbo, not so much.
 

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I Heart Boost...and M/T's
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5,951 Posts
I have a diagram I made for the FMU setup on a returnless fuel system. Im with Duner, there is nothing wrong with a FMU, I also made some good power with a FMU and even had a factory fuel pump in the tank!

 

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registered abuser
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I just removed my fmu & aux pump tonight for sct. up for sale now if anyone is interested wink wink
 
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