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View Full Version : High-flow injectors & 3" downpipe installed



ThreeQuarter
03-24-2008, 12:49
I have recently installed new "performance" injectors from USDieselParts.com (a.k.a. Gomer's Diesel). I am told they are rebuilt injectors with new nozzles, high-flow, and not high-pop. Replaced my factory (as far as I know) injectors with these perf. injectors at 195K miles. I have been reading people's educated guesses and personal experiences about the high-flow injectors, and some posts here had me a little worried that I would see a big drop in fuel economy. So, I just want to share my initial findings since installing hi-flows.

Also, while my turbo was off, I installed the 3" mandrel-bent downpipe that Gomer's sells. Since I did both improvements at the same time, I can't really say for sure if the injectors or the downpipe can take the credit/blame, so take it for what it's worth.

First thing I noticed is that I blew chunks of soot out of my exhaust the first time I fired it up. Sometimes I've seen diesels blow wispy black flakes that float around the garage for awhile, but these were heavier chunks that all landed a few feet from the tailpipe. My guess is the free-er flowing exhaust from the larger downpipe loosened it from the soot trap (which is now the most restrictive point in my exhaust).

Here's the real results on fuel mileage that I found over the weekend: went 490 miles and got 16.3 mpg. Over Christmas (last highway trip I made similar to this one) I used four tanks of fuel and got between 14.5 and 15.6 mpg each time.

It's possible that my old injectors were out of shape, so ANY injector would've been an improvement (and maybe stock injectors would've gotten even better mpg), but I don't know. Whudda y'all think about these numbers?

More Power
03-24-2008, 14:01
Best test would be to compare new or new reman OE factory injectors to new "performance" injectors. A good test would include a dyno and long-term fuel economy evaluation (5 or more tanks with each set).

A few weeks ago I learned that USDP now leak tests their reman 6.5 injectors after being torqued into an actual cylinder head. I was told that one now and then would pass their injector test procedure (pop, nozzle leak & spray pattern tests on the bench) but a rare customer would report a leak in the injector body after they installed them in their engine. Apparently, installing them in a head puts different stresses on the injector body when compared to their bench test fixture. Leak testing each reman injector in a cyl head solves that problem.

Jim

ThreeQuarter
03-24-2008, 18:35
Yep, just sharing my experiences...specifically that the MPG didn't tank (pun intended). I will post more when I burn a few more tanks.

Good to know that about USDP, thanks.

Ben