Found super cheap 55# injector prices
02-17-2004, 04:26 PM
#16
Addict
Rennlist Member
Rennlist Member
Matt, my question is why? It's cheaper, easier, and lighter to put in a pair of ballast resistors than to put in a fan/heat sink. This is one case where it's so cheap and easy it's not worth the risk to me, when a DME costs at least $50.
Sam
Sam
02-17-2004, 04:49 PM
#19
Race Director
Ok, then I have no diea how you would put a heat sink and fan on the stock setup... I cant recall there baing that much room, and how do you power it? More trouble than its worth I would think.
02-17-2004, 04:55 PM
#20
Race Director
NZ951, you can measure impedance on the injectors with a voltmeter. Set it to the low-resistance range and just connect to the two pins on the injectors. Your Link manual gives you the various configurations you can run with the numbers of injectors you can run in parallel per driver. Due to the simple square-wave driver signal, it might be best for you to get high-ohm injectors and run them in parallel pairs. I don't know where it's hidden in the manual, but sequential fuel-injection switches over to batch when the duty-cycle increases above 50% (due to single counter).
Matt, there are hardcore racer guys who aren't regulars on this Rennlist. They've learned to take safety precautions like roll-cages, automatic fire-systems, race seats & harnesses on their cars. In the beginning, you'll see them with simple bolt-in harness bars, manual 10-lb fire-extinguishers and basic harnesses with sternum-straps. But in time, they'll learn their lesson and go to the full-extent of safety. Same thing with their mods, O-ring heads, larger fuel-pumps, ballast-resistors, etc. Some of the new guys, will go straight to the high-end mods to start with, becasue they know they'll eventually have to do it anyway. Why tear things apart twice and after you've had a failure only to end up at the same place?
"then I have no diea how you would put a heat sink and fan on the stock setup... I cant recall there baing that much room, and how do you power it? More trouble than its worth I would think."
There's a thread somewhere where John Anderson burned himself on his DME. He ended cutting hole in the case and putting in a PC CPU cooling fan. On the Link box, the entire case is a think aluminium heatsink, so for the same heat-dissipation, it won't heat up as much.
Matt, there are hardcore racer guys who aren't regulars on this Rennlist. They've learned to take safety precautions like roll-cages, automatic fire-systems, race seats & harnesses on their cars. In the beginning, you'll see them with simple bolt-in harness bars, manual 10-lb fire-extinguishers and basic harnesses with sternum-straps. But in time, they'll learn their lesson and go to the full-extent of safety. Same thing with their mods, O-ring heads, larger fuel-pumps, ballast-resistors, etc. Some of the new guys, will go straight to the high-end mods to start with, becasue they know they'll eventually have to do it anyway. Why tear things apart twice and after you've had a failure only to end up at the same place?
"then I have no diea how you would put a heat sink and fan on the stock setup... I cant recall there baing that much room, and how do you power it? More trouble than its worth I would think."
There's a thread somewhere where John Anderson burned himself on his DME. He ended cutting hole in the case and putting in a PC CPU cooling fan. On the Link box, the entire case is a think aluminium heatsink, so for the same heat-dissipation, it won't heat up as much.
02-17-2004, 05:07 PM
#21
Race Director
Danno, I bought some 850cc low impedence injectors of Luke. They should be here in a day or so! I will talk to Link and get some resistors made up or advise on how to run them for my setup.
02-17-2004, 05:21 PM
#23
Danno - I read you I am just not sure I understand you. I certainly respect your opinion on this subject. What I am asking is, if it is that big a problem with the DME overheating, why not cure the problem. Seems like the resistors are kind of a band-aid. It *seems* like the likehood of overheating the DME is minute at best and if it is a racecar then there should be room to add fans to the DME (or stand alone unit).
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
02-17-2004, 05:29 PM
#25
Resistors change the circuit beyond just adding resistance.
Both are band-aids really, the right answer is injectors with the proper impedance!
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Both are band-aids really, the right answer is injectors with the proper impedance!
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
02-17-2004, 05:49 PM
#27
I am crapping them as we speak :>)
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
02-19-2004, 02:28 AM
#28
Drifting
Join Date: Jul 2003
Location: Golden, CO
Posts: 2,163
Likes: 0
Received 0 Likes
on
0 Posts
Well if you use high enough wattage resistors, they won't even get warm much less hot. So since there are two lines that need resistors, you would add 1.5 ohm resistors to each line. Making each signal wire in the pair be a 2.5 ohm load on the dme. 12/2.75=4.3 amps. 4.3*12=51 watts @100% duty cycle. Most likely you won't be running the injectors at 100% duty cycle all the time (at least I hope not) and since they are peak and hold, you won't be using nearly as much amperage as the above figure. Therefore, you should be able to use about 25 watt resistors and be fine with a small heatsink (as I did). If you wanted to be absolutely sure they wouldn't get hot, get a larger wattage resistor. Most likely the latter option will use much less space than a heatsink/fan combo. But I can easily make a heatsink w/fan combo if I find they get too hot (as I have access to hundreds of types of heatsinks and nearly millions of different types of resistors.)
