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og
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Discussion Starter · #1 ·
i'm planning on upgrading my fuel system this weekend but jeff lucius has pointed out the vast electrical difference and this has raised some concern for me. does anyone out there know if there is a company that makes higher flowing injectors than the stock 220cc that have a low resistance? are all the injectors that go into the tt (i.e. upgrades, 450cc etc) low resistance? how much of a concern is this? please excuse my ignorance, i'm trying to understand this one ;) thanks, safe travels.

- mike
 

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here

You can swat the TT to a NA BUT you need some sort of a fuel managment to be able to control/tune the higher flow injectors.

if stock size is 220, the 360cc from the TT will be fine taking in consideration that you will use something like an AFC to reduce the 360cc by 50% in idle and makinf it a 180cc, then a fuel pressure regulator will help u fine tune as well, but there is not real reason to do this unless you are heavy modded, if you higher the Fuel pressure and install an AFC/AFR with the stock injectors you should have enough fuel to push 280bhp or so.

Hope i didin;t confuse you

Mario Deniz
www.dspracing.cc
 

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Discussion Starter · #4 ·
thanks mario but my concern is electrical as opposed to physical installation or fuel management. the fuel management is ready to go, i'm installing the pump and a-f/egt gauges this weekend and have the injectors on hand; the concern is electrical, due to some posts by jeff lucius... lemme see if i can dig 'em up... here they are:

"VR4 injectors are low-resistance and use a seperate resistor (located on fire wall near battery) to lower the voltage. NA injectors are high-resistance. Not a good idea to mix the two. The ECM and fuel injector electrical circuit are designed for either low or high resistance injectors - not both."

here's the other info:

"VR4 injectors are low resistance (2-3 ohms). NA injectors are high resistance (13-16 ohms). Put the correct type injectors in your car. Using the wrong resistance-type injectors will likely not deliver fuel correctly or predictably, and runs the very real chance of damaging the ECM, which is part of the electrical circuit for the injectors."

so you can see where my concern lies. you raise another question for me tho, will i still need a fuel pressure regulator with the afc, turbo pump, egt and a/f gauges? can't i regulate with the afc?

- mike
 

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ok

For FINE tunoing i will include both regulator and AFC, about the ohms of each injector I will need to do the test. But i was of the idea that they were about the same...IF THEY ARE NOT the same just take off your stockers and have RC make them any size you wish to.

Mario Deniz
 

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Discussion Starter · #6 · (Edited)
can anyone tell me what are the dangers of running without having the ohms be the same? what type of risk am i looking at here? i know a couple of guys who have 'em in and have had 'em in for a little while without difficulty; i still look forward to the results of your test mario.

- mike
 

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Discussion Starter · #7 ·
so... has anyone ever had a problem with this?

- mike
 

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I am curious about this as well Mike. Maybe check with a local injector shop and see. It's not like the whole car runs on a different electrical system. At worst I would guess you need some sort of resistor/regulator (excuse the terminology, I don't have access to my shop manual) off of a TT. Just isolate the part and hit up one of the many guys selling parts off their wrecks.
 

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Discussion Starter · #9 ·
well as it turns out absolutely no need to go with higher flowing injectors on a na. i had my car dyno tested and tuned saturday night and at wot it needed to be leaned out, by 7000rpms i was at -10% or so, we squeezed ~5 additional hp out. now when the supercharger goes in it'll be a different story, but until then just get an afc and tune her in, you'll be happy.

- mike

p.s. dyno says 183.7 fwd hp, not too shabby :D

p.p.s. when i do put the supercharger in i am planning on finding a set of 220 injectors and having 'em enlarged, that way no resistance issues. i'm sure i can find someone willing to trade 220s for the 360s i've got right now ;)
 

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I went thru my shop manual and it looks like the injector juice is supplied by 2 MFI relays. The ECU controls the pulse rather than the current so my guess is you can run the 360s if you change the relays. Dodge could not give me a price w/o part numbers so if you did want to check this option out you would have to get the p#s off the actual TT relays. I would guess if will cost you $50 apiece or more to get your 220cc injectors modified so this would give you another option if the relays are cheap.
 

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Discussion Starter · #11 ·
nuck, that's a great idea! hans n i were talking about putting some resistors in line to make the low resistance turbos higher resistance. i talked to rc and it would cost ~$175 APIECE to have the 220's enlarged, i could get NEW 310 or 370 for ~$85 apiece high resistance, so that's another option. i'm going to look into the relays tho, thanks for the idea, i'll keep ya posted!

- mike
 
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