Fragged another one - how long should they last?

[Mr URL]

Re: Re: Re: Re: Re: Fragged another one - how long should they last?

>I was at +12% on WOT fueling with the T+/E, LS-1 MAF.

Really? Seems kinda high setting. I run about the same times as you in my GN and I have it set at zero with injectors in the 80's% range with 45 psi static pressure and 24 psi boost. My T-Type is running in the 100% range with Translator set to 2% rich but has P&P heads, cam, TE-63E turbo, V4R IC, etc. My GN runs ~380 gps air flow 24 psi while T-Type is ~460 gps at 22 psi.

>Generally the duty cycle is in the mid 90's. I've got a couple of >frames with a DC of 100%, usually at the top of each gear.

>I am going to be disappointed if I am out of injector with the >50's and an 11.90 car. Heck I took the Blues to the low 12's. >These 50's have to have more head room than 11.90 with a >3,625 Lb. GN. Don't folks scare the 10's with these injectors?

I doubt you are out of injector but I don't know what effect the high altitude as on the equation though. You would know better than me. I know guys running 10's before going static. With proper fuel flow they shouldn't really be maxed until like 10.60's.

>The pump on the other hand is a 4 year old XP with Volt >Booster. Fuel pressure was 45 line off, pressure moves with >boost. 45 line off and 25 PSI puts the 50's at the magic 70.

Your pump may be getting weak? With 45 psi static and the way our fuel regulators work the injectors are still only seeing 45 psi. I don't think that is your problem. Maybe a double pumper will help you out. My GN with a single 340 the O2's start dropping off in 3rd and 4th gear (830 to 760). In my T-Type with a double pumper and more hp is flat as a board from start to finish (800 - 800)


>I think I remember a while back talk that the 50's kind of wig >out at the magic 70 - maybe there is something there?

I don't think so. I know guys running 30 psi boost with MSD-50's having 47 psi static pressure without problems cause they are still actually seeing 47 psi fuel pressure.

 

[John Larkin]

If # 2 & #3 mains were the problem, then the typical
headgasket-popping center cylinders probably went lean and detonated. I would suspect this anyhow. Ever considered a Power Plate to even out the distribution? Not stealing Chuck's thunder but like he said, those caps are going to need to still be real tight in the registers as well as checking the rest of the bottom end tolerances from soup to nuts. If two weeks from now ain't enough time to spec it out right, it isn't meant to be.

 

[Chris Taylor]

Hi Lance,

Bummer! I think of altitude along with tuning when reading this post.? I would not reuse the bottom end hardware. Your block needs to be checked and if everything is OK; then linehoned with a girdle. I would use new ARP main studs and new rod bolts. As mentioned I would look at a new fuel pump or do a flow test on the pump you are running.

Parts will break when racing. The only question is, when will they break? Some let go before others. I hope you get everything fixed in time for the big show down. Good luck.

 

[Joe 1320]

You have probably looked into this, but have the oil feed holes been opened up to uniform size? Remember Buick did have different sized oil feed holes. The factory used ¼" on the #2 and #3 mains (hint ,hint), 7/16 on the the front , 5/16 on the rear. Opening up the #2 and #3 will help longevity.



My vote would also be steel caps and a girdle.

 

[Chuck Leeper]

Fuelin around??

Chad wrote:
Your pump may be getting weak? With 45 psi static and the way our fuel regulators work the injectors are still only seeing 45 psi. I don't think that is your problem. Maybe a double pumper will help you out. My GN with a single 340 the O2's start dropping off in 3rd and 4th gear (830 to 760). In my T-Type with a double pumper and more hp is flat as a board from start to finish (800 - 800)


>I think I remember a while back talk that the 50's kind of wig >out at the magic 70 - maybe there is something there?

I don't think so. I know guys running 30 psi boost with MSD-50's having 47 psi static pressure without problems cause they are still actually seeing 47 psi fuel pressure.

I think that the 47psi we're talking of here is "delta P", and as such, the psi at the inj has to be base plus boost, in order to attain the delta[net] value of 47. The injector still has 70psi at the rail inlet.. Therefore the system is operating at 70psi, not 47...
I see alot of the "RP, MSD, Delphi,[all the same mfgr] injs that shut off on the bench at high pressures..usually above 70..
FWIW, I can flow any inj at static or pulsed and check the difference, if any...The bench has a timer that will allow for the same total on time when doing this.. I see no difference in the total flow when doing this..

If you have the time, send me the inj's and I'll check them at various pressures and see what you have going..

As for the altitude.... Less O2 at 6000' certainly makes for a fun day to tune an engine!!
Anyone see the thread on the TTA and his woes?? 16# at Kansas City..10# at 6500' and lots of knok!!

back under my inj bench!!

 

[bruce]

Re: Re: Re: Re: Re: Fragged another one - how long should they last?

Originally posted by Mile Hi GN


Generally the duty cycle is in the mid 90's. I've got a couple of frames with a DC of 100%, usually at the top of each gear.

I am going to be disappointed if I am out of injector with the 50's and an 11.90 car. Heck I took the Blues to the low 12's. These 50's have to have more head room than 11.90 with a 3,625 Lb. GN. Don't folks scare the 10's with these injectors?

I think I remember a while back talk that the 50's kind of wig out at the magic 70 - maybe there is something there?

If you hit 100% your out of injector.
As you start to go static, the injector just chatters, and is erratic.
As long as you run in that mode, might start buying more crank kits.

Be sure to get the big end of the rods resized, I'll beat ya they aren't round any more.

You got a DS of that run you can forward?.

 

[ijames]

Re: Fuelin around??

I think that the 47psi we're talking of here is "delta P", and as such, the psi at the inj has to be base plus boost, in order to attain the delta[net] value of 47. The injector still has 70psi at the rail inlet.. Therefore the system is operating at 70psi, not 47...
I see alot of the "RP, MSD, Delphi,[all the same mfgr] injs that shut off on the bench at high pressures..usually above 70..

The pressure matters because the pintle acts like a piston, with fuel pressure pushing on one side and intake manifold pressure pushing on the other side. At low pressures these extra forces are low compared to the spring pressure and the force generated by the coil, but when they get too far out of whack the injector can't handle it. The delta P is what matters, not the absolute rail pressure. If you could pressurize the reciever half of your flow bench you could see this.

 

[Chuck Leeper]

??

Carl wrote:

The delta P is what matters, not the absolute rail pressure. If you could pressurize the reciever half of your flow bench you could see this.

YEP!!

 

[U1ARUNIT]

the Hemco vs Power Plate..

John Larkin wrote:

If # 2 & #3 mains were the problem, then the typical
headgasket-popping center cylinders probably went lean and detonated. I would suspect this anyhow. Ever considered a Power Plate to even out the distribution?

Lance you do still have that Hemco on there right..? That could be why the center is running hotter on ya as John mentioned. There have been guys blow the center holes out with the addition of the Hemco.

I removed mine and I am now experimenting with a plate and a smoothed factory upper as we speak. Just thinking out loud..