I know this has been talked about before, but I'm still not sold on the reliability of the enlarged injectors, going from 850 to 1200 and beyond. I think I am going to go the route of getting 2 new secondaries and having all 4 be 850's which will be plenty of fuel for my 360 rwhp goal in the future.

Does anyone else have doubts about the enlarged secondaries? I've had mine flow tested and spray pattern was OKAY, and the both flowed 1330cc of fuel, but I just don't test them for some reason, or have peace of mind using them.

Tim

 

Tim,

ErnieT suggested to me to use the 850x4 set up. I too have heard the bored injectors aren't reliable. I don't know what to believe. A bunch of guys use the 1200 and up set up. Have you actually heard of a bored injector failing? I'd be interested in how much, if any, difference it makes performance wise. If it doesn't make any difference, I say use the 850x4 set up.

Don't you have to do something special to install the 850's as primaries? I want to run 15 psi after dyno tuning on my set up. I know I need to upgrade the injectors and it's the last thing I have left to do. Kinda funny this coming up just after you helped me pick a map.

Andrew

Thanks,
Andrew

 

I kinda made an assumption that with the stock injectors that you wouldn't be running 1 of the boost settings at 15 psi since to sustain that boost, your injectors will be wide open, which wears them out faster and also drops the reliability of them. On my 2 boost settings, I have one tuned for 12 psi and the other for a tad over 13 psi until I install the 1300's I have now or decide on the 850 in all 4. I won't tune or try to tune for anything higher just for piece of mind that I don't screw something up. I'd wait if I were you, even with the suggested maps, since going to 15 psi (in the boost control section which has nothing to do with the maps picked other than the extra fuel tuned into the higher pressure cells), since your stock injectors won't be up to that kind of demand. The map should be fine for the 13 psi and lower with the stock injectors, pressure cell 17 and below.

Tim

 

As far as bored injectors failing, I know a few people that have had their engines dyno tuned, on the safe side as well, 11.4 and richer, low knock readings. I don't know if it was the injectors, but all the cars had bored out secondaries.

Tim

 

Tim,

I know of a person who had an enlarged injector fail. But I don't know a bunch of people with that problem so I can't draw any conclusions about it.

If your car is wideband tuned, you might even find that at 14 or 15psi, your duty cycles aren't as high as you think anyway.


Tim, I think you are overly worried about your duty cycles. I've never read a good argument for why a stock injector would be more likely to fail if it is running at a higher duty cycle. I have run high boost for years on stock injectors, and I'm not concerned about high duty cycles at all.

On the other hand, I know if an injector would fail it would be obvious the first time I got on the gas, so that might be why I don't worry about it.

That said, I would go with 850cc primaries if I were you and had concerns about the reliability of larger injectors. It would be a non issue with the 850cc primaries. You will have to make some minor mods to your rail or the o-rings to make them work correctly, though.

Wade

 

Since any old injector can fail, that why I went with all new injectors. 550s for primaries, and new 850s bored to 1200 for secondaries. At 14psi boost, my duty cycle is between 76% at low revs to 80% at 7500rpm. That gives me room for safe growth.

Mine have not given me any problems. Same for Rick's
bored out old 1200, and he runs a 50 shot of nitrous with 12psi boost in summer.

Kyle and I went out tuning my car last weekend in the 90+F Houston heat. Ran 14psi safely with low knock levels. Could feel the difference between 12 and 14 psi boost when making 4th gear runs.

I am only partially back/active to the forum. After 1 month of being in the hosptal for chemo, I am back home for a couple of weeks before having to go back for the second phase, bone marrow transplant.
Chemo is like going for 350 hp, BMT is like going for 500hp.

Thanks for all the prayers and still pray for me so that I can survive the next round.

Love and Speed!

 

Damn Chuck, I didn't know the health issue was that serious. It seems lately, atleast in my area of the country, beating cancer (I guess) has been happening more and more regularly. Look at Lance Armstrong, lung, brain, etc and he just won the Tour deFrance 4 straight times.

As far as what Wade said, I'm going the 4x850 route for my own piece of mind, deaing mainly with flow pattern (atomization) and also general reliablility issues. I bought new 850s, had them bored out, then flow tested to the 1330cc I posted above, but its just a nagging issue with them and I'd rather now go with new 850s all around.

Thanks for the input....
Tim