660's are too big. I run 550's in my 1G with a bigger turbo and have no problems at all with 18psi on pump gas. I still have a TON of room to move on them.

 

I plan on going with a larger turbo within the next year. I hate to have to upgrade the injectors again.
Turbochad, what is your injector duty cycle at 18 psi on 93 octane?

 

i have seen people run 680's and 720's with a s-afc, 660's aren't a problem.

of course it is entirely possible to get too much timing advance. so if you really don't think you're going to use that kind of fuel, maybe 550's would be better for now.

my 550's are at ~81% now on my small 16g @ 18 psi, a higher flowing turbo would easily put my injectors out of their useful operating range.

marshall

 

I don't believe he has every put down any numbers, his car wasn't at battle but that was the last time I really went to the track for an event. Has he shown at any since?

According to him my car only runs 14.9's. And I have done nothing to is since he told me that. Funny huh?

For Jimmy

 

yeah, now that you mention it, he said that his car will run 10's, not that it does run 10's, there is a big difference. He does have a nice setup though. I was going to have him help me tune until he told me that he tunes off of egt's and o2 voltages only. I think that that used to be the best way to tune a dsm, but times have changed.

 

He also thinks 14,000 degrees is the highest your egt gauge should go.

Thats what he argued with me about and he no longer likes me.

 

I'm glad that he's not tuning my car. 14,000 degrees huh? If I remember high school chemistry, there isnt a single metal that will stay solid at that temp. I'm tuning my car for 1550 degrees tops to be on the safe side.

 

2G doesn't like to give timing. on a 1G, 550s are acceptable. a waste for 2Gs though

 

Okay.. a few things to add..

I don't know that much about 2G's. Sorry, on my 1G, with 550's, a 17C (which is basically a Big 16G under 20psi, just spools quicker), FMIC, my VPC (with 550 chip) is set at 2% Lean with most of my AFC settings set to the lean side too except for the upper end of high map.

Now, as for tuning, I don't know this guy you are talking about, but personally I would never seriously tune a DSM by stock O2 voltages and EGT, and definatly NOT to 1400. At the top of 3rd under 18psi on 93 I hit about 1600 with just a tad of knock (not enough to pull timing back). I might use O2 and EGT to get a base line, but it's my datalogger or nothing.

One more thing, Tuning off the EGT can be a little tricky. Things like where the probe is mounted, what type of probe, and what type of gauge will effect the temperature. Mine is mounted about 1.5" from the collector in runner 1. It's VERY fast and my gauge is cold point referenced, so it's pretty accurate.

 

While I'm thinking about it, fuel system has a good deal to do with the size injectors you should get. I'm running a Walbro LP255 hardwired with a CAS adjustable FPR set to stock fuel pressure. I have to go back through all of it after christmas when my adjustble cam gears get here, my crowers need to be degreed something fierce.