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#1
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What about using a 4.5 Djet intake manifold to megasquirt a 5.0 Kjet ?
Hi all,
Once I finish rebuilding the timing on my 5.0 M117 I will look into megasquiting it. This 5.0 engine will then be fitted in a W111 Coupe currently equipped with a 3.5 Djetronic engine. The other day I got hold of a complete M117 4.5 Djetronic intake manifold. I did not take the Kjetronic intake manifold out of the 5.0 yet, but at first sight the bolt pattern is the same. My idea is to use this 4.5 Djet manifold and use all the Djet set up already in place in the car: injectors, rails, pressure valve, temp and air sensors, fuel pump etc. That will save me quite some time and money. I looked at the specificities of the various components and apart from the ATS all seems to be within range of the Megasquirt system for the 265 to 275 hp I expect to get out of that engine with both fuel and ignition convertion. I like that Djet manifold because it was designed as an EFI manifold in the first place. Apart from the different routing, the ports seem to have the same shape and length. Their internal diameter is 39.5 mm or so. I will compare this with the one of the 5.0, but if someone has a 5.0 Kjet manifold on the shelf, could he please measure the id of the ports and tell me? The other concern I have is the id of the throttle body: 67mm at the flap, which according to the megasquirt webpage is good for 260 hp only. Could someone tell me what is the id on the 5.0 Kjet? More globally, what’s the opinion of the experts on this board about using a 4.5 Djet manifold and most other Djet components? Thanks!! Last edited by GGR; 08-24-2009 at 05:02 PM. |
#2
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K-jet manifold opening is 2.600" (you do the conversion!) which could probably be opened to 2.800" or a bit larger with no problem. The actual throttle body, at its narrowest point (right at the butterfly) is 2.520" widening to just a hair under the 2.600" width to match the manifold.
The D-jet has been converted to MS by, I believe, Barry up in Washington State. He's got a link around here somewhere to his page detailing the procedure. I'm going to go with the Ford 19 lb. injectors in my '85 500SEL. It means I need a fuel rail made but the availability of the injectors ($20 for a set of 8 from the pick n pull) makes the decision for me. I've got a place which will do all the drilling and tapping of the rail for $120. You still need to adapt a TPS to the throttle body since the existing TPS's are SWITCHES and not sensors. |
#3
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Thanks! That's 64mm at the narrowest. So the 4.5 throttle body must be good for the 5.0 then. The Djet throttle body seems also easier to match with a TPS as there's already a Djet sensor attached there. The Kjet Throttle body requires more work due to its shorter shaft.
I visited Barry's website already. That's what encouraged me to go the same way. He told me he uses the blue injectors on the 4.5 and that their flowrate is too big for proper idle tuning. I will be using the yellow ones that I have on the 3.5, as they have a lower flowrate: The Bosh reference for the 4.5 blue injectors is 0 280 150 036 and their flowrate is 485 cc/min at 3 atm. The reference of the 3.5 yellow injectors is 0 280 150 034 and their flowrate is 338 cc/min at 3 atm. According to this web page : http://www.megamanual.com/v22manual/minj.htm#size I need injectors with a flowrate of 212 cc/min at 3 atm. On that same web page there is a calculator to get the flowrate at different pressures. With 2 atm, the blue injector still has a flowrate of 403 cc/min while the yellow one has a flowrate of 280 cc/min. It's a bit more than what I need, but I think it will be workable. The Mustang injectors have the advantage of being high impedence and do not require the flyback board needed for the low impedence injectors. But they require some machining to fit the Djet rails and I'm not sure I can keep them in place on the head with the same system. All in all, fitting a flyback board seems to be less work. I wonder if Barry fitted one though. As per the 4.5 manifold, I'm left to determine if the inner section of the ports is the same as the one on the 5.0 engine. |
#4
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Gael, call me soon, MS V3 almost finished.
__________________
Regards Warren Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL ENTER > = (HP RPN) Not part of the in-crowd since 1952. |
#5
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I will!
For now I need to read more about megasquirt. |
#6
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The K-jet throttle body is smaller because of the use of the idle air tubes. Most of the air flow at idle is provided through the IAC valve. I'm going to stay with the existing manifold and adapt an IAC to the manifold as opposed to the individual injector ports. The 4.5 throttle body sounds promising and if the IAC adaption doesn't give the results I'm hoping for will certainly be an option to consider. Thanks for the idea!
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#7
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The Djet manifold also uses idle air tubes. In fact, both manifolds have the same design, apart from the throttle body which is in the middle and sticks out making the adaptation of a TPS easier (+ the longer flap shaft). You then have to use the 4.5 air filter box which is already equipped with an ATS... Djet plenum is also already equipped with a MAP sensor duct.
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#8
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HERE is a guy who went through converting on a 450 motor, using the mustang injectors and making fuel rails to allow them.
I haven't finished my install, due to my SEC ending up as the daily driver when the SD decided to play games this winter, but I had a set of fuel rails built off of his alignment specs for ~$170 complete and to my door. (Don't quote me on that price though, it's been a year or so now...) As I was looking at forced induction as an option, the modern injector designs give a lot more flexibility as well, since there are high flow versions available, unlike the older Djet injectors. The modern ones can also be had for less, FAR less if you keep your eyes open for deals! For instance, I got a set of the newer Bosch 'design 3' injectors that have no huge bump in the middle for $20, $28 after shipping. They are 19lb/hr, so about 200cc/min, and good for roughly 250hp from the estimation on the megamanual site. I also ended up with another set of 19lb/hr injectors for free, just because they're the 'old' injectors that many mustangs came with. (Huh, fancy that.. we call 'em mustang injectors... ) These came out of a Crown Vic, but whatever... As a final note, have you found the MSruns.com site? Under the Daimler section they have all the success stories for installs of megasquirt on various MB's including a few 116/117 motors.
__________________
-Josh Testing the cheap Mercedes axiom, one bolt at a time... |
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