Largest High Impedance injectors
Not sure how either would perform on an LS, although Bob at Schimmel did say they have sold a few sets to vette guys with good success.
I was going to go down that road.....but decided upon a different path
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I dont like them. So dont know if its just them, or all big high-z injectors. I am going to dump them in the near future though.
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You would be surprised as to how well they work given their size.
Sometimes things do get better over time...
There are a good number of people out there who have purchased them. It will only be a short amount of time until we start to hear feedback about them on the forum. There will be a learning curve but the end result should be quite positive.

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Big injectors only really become a concern, at low rpm's/loads when small amounts of fuel are required.
But low-z injectors fire differently, and offer better control, which is why they are favoured.
Big injectors only really become a concern, at low rpm's/loads when small amounts of fuel are required.
But low-z injectors fire differently, and offer better control, which is why they are favoured.
Bosch Motorsports makes a high impedance injector that is rated at 658 grams/minute at 3 bar (894 cc/min, 10.97 grams/second or 87 lbs/hr at 43 psi (300 kPa/3 bar)). I think the maximum rated operating pressure for these injectors is 8 bar (800 kPa or 116 psi). At 8 bar these injectors would flow around 1074 grams/minute.
Bosch Motorsports offers a gasoline and a methanol version of this injector.
According to the Bosch Motorsports injector sheet I have, the gasoline version is Bosch Motorsports part number B 280 434 499/2 and the methanol version is B 280 434 499/1. I think the last time we purchased the gasoline ones, they sent us the methanol versions (even though we specified gasoline). I am assuming the methanol version just has different materials in it to cope with the different fluid.
We have purchased a couple of sets of these for different project vehicles but be warned, Bosch Motorsports parts are very expensive. I think we paid around $400 or $500 per injector.
BTW - I haver two sets of used ones next to my desk.
The 70 lbs-hr injectors we sell on our web site and on eBay are the Siemens Deka injectors. Mototron used to sell them/badge them but they were made by Siemens. These are the same injectors Racetronix, Edge, MSD and others sell as well.
The 70 lbs/hr or 8.8 grams/second rating is at 400 kPa (58 psi), the standard LS1/LS6/LS2 etc. fuel system operating pressure.
At 300 kPa (43 psi), the pressure more often used to compare injector sizes, these injectors flow 61 lbs/hr or 7.6 grams/second.
I think the original Mototron design rating was 10.7 grams/second at 6 bar and that works out pretty close using P/V calculations.
I hope the clears up any confusion on the flow ratings. It can get confusing because unless you know what pressure someone is testing at, you can't compare the flow ratings. Different OE manufacturers and different vehicles use very different system operating pressures (and some vehicles now use variable fuel pressure too). The injector manufacturers design the injectors for the specific OE manufacturers needs so they are designed to flow the fuel flow needed at the pressure the OE manufacturer intends to run. The designed flow for a Ford injector might be at a 270 kPa fuel pressure (and then we go and use it at 400 kPa and, voila, we have a "bigger" injector). A true standard for flow ratings doesn't exist (at least it didn't 5 or 6 years ago when I was part of a SAE aftermarket committee looking into creating a standard). It gets even harder to compare when you start talking about the spray angles. For example, what percentage of the fuel has to fall into the 10 or 15 or 20 degree cone? Not every manufacturer does it the same and not every OE specifies it the same.
Sorry for going on - what was the original question? 8-)





