blade7

Some used 55lb injectors with a pair of resistors have been listed on ebay, I read conflicting reports on different forums about the need for resistors, some say the injectors can be modified so resistors aren't required, others say these injectors aren't correctly rated and cause heat build up in the ECU, and resistors are the correct solution for aftermarket injectors ?.

Eric_Oz_S2

Resistor are used where stock is high impedence (like a 968) and you want to run low impedence injectors. The turbo has low impedence injuectors, and you can run high impedence with the stock resistors or remove the resistors. You don't need to add resistors except as noted in the first sentence.

schip43

Yep what he said! I run 55 with out resitors and no issues..with the ijnjectors at any rate.

Scott H

Wrong. The turbo uses a weird injector that is higher than most low-impedance injectors but lower than high impedance. The stockers are around 4.5ohms, aftermarket low-impedence injectors are around 2ohms. The ballast resistors are there to keep from cooking the injector drivers in the DME. For the cost of the ballast resistors vs. the cost of a new DME/DME repair you would be stupid not to run them.

blade7

I think that sums up what Clark's website states, as I said one vendor said their injectors are modified, another said no resistors required

schip43

Yep everybody is correct! My 55's are from Lindey and do not require an injector box. The ones on Ebay most likely do.

Scott H

I would go with what you know to be true and what works. I have never heard of modified injectors for these cars. The car will run with the low impedance injectors, but more heat will be produced (especially if you're at a high duty cycle for prolonged periods of time, ie. on a race track).

You can buy the resistors individually from Newark: http://www.newark.com/ohmite/850f1r0...w-1/dp/65K0059

You'll also need to mount them to a plate to sink the heat away from them. Buy a couple extra ballast resistors and leave them in the car "just in case."

schip43

Well it's not really hard to check is it? I can measure mine with a DVOM correct?

Scott H

Nope, just put the meter across the two pins on the bench. I have some 72# Seimens that come in at 2.5ohm, I believe Delphis are 2.8ohm.

schip43

I'll check and post tomorrow.

blade7

Thanks for all the posts, I'm inclined to believe unless there are 4.5 ohm 55lb etc injectors being produced resistors are still the correct solution. How/where are the resistors wired in ?.

schip43

Still haven't checked mine yet been suoer busy, but as to how to wire... this is where I am when I'm not here. DIY on wiring resistors!


http://board.tercelonline.com/viewthread.php?tid=41009

jimbo1111

I have a set of Siemens 72 lb injectors that make a racket after prolonged use or track days. I'd be interested to here others comments.

KEVIN ANDERSON

The 951 injector drivers can handle 3.5 to 5.5 ohms of resistance. So injectors below 3.5 need resistors