30th t/a

iTrader: (51)

i got a comp xe-r 230/230 110 cam. will i need to install 30lb injectors? mods are in the sig.

the guy doing the dyno says i will need to upgrade

the person i bought the heads from used the EXACT comp xe-r cam and he used the stock injectors with NO problems

what do i do??

BBADWS6

iTrader: (8)

No, you should not have to upgrade. I ran a cam with more duration that that with a full bolt on car and wasnt leaning out. You can check it with auto tap or ls1 edit if you are really worried, but ive heard of 450hp cars using the stock fuel system.

gomer

iTrader: (13)

I'm running stock injectors on my car.. but my 2002 injectors are a little larger than your 99's. I really think you'll be ok, if you are really afraid of running out of injector, I've seen stock 2002 injectors for sale really cheap. I think TSP has some new ones.

9T9BlueTA

iTrader: (2)

My 99 is fine with a slightly bigger cam and heads on the stock injectors. I have #30's in reserve just in case though. I advise you to make your decesion before hand so you dont have to get tuning a second time for the injectors.

30th TA 0219

TSP has them for $100, or the LS6 manifold with injectors for $400!

CHRISPY

TSP has SVO 30# injectors for 100?

30th t/a

iTrader: (51)

i just bought the 28.8lb injectors for $68 shipped. they should be able to do the job.

Colonel

The stockers are fine for that kind of power. Even the smaller 26.4 lb injectors will do just fine at 450 RWHP. The larger 28.6 injectors have been known to run at 500 RWHP+ with no problems, but that's pushing them to the limit.

StevieZ

iTrader: (3)

My car (98) ran out of injector at 420rwhp. The injector duty cycle was 120% pretty much across the entire rpm range and they went static at anything past 6000 rpm. I went to the SVO 30lb'ers which are 36 lbs at GM psi.

94form2000z

iTrader: (10)

They were not sufficient in my setup. Had to upgrade to a set of 28.8's Couldn't keep the Ltrims @ 0! I'd suggest at least picking up someones 28.8 stockers.

Colonel

Couldn't keep the Ltrims at 0? What the heck would that have to do with your stock injectors? Nothing. No offense, but you're misunderstanding something. There's another problem there. Vacume leak, exhaust leak, bad O2 sensor, bad programming...but it's NOT because your injectors were too small for a heads/cam engine. Even if they were too small for the engine, that in itself wouldn't effect your Ltrims.

There are people everyday who think they've maxed their injectors out when they look at injector pulse widths/duty cycles at 450 RWHP or less. I've seen it a 1000 times. But never ONCE have I seen anyone actually run lean at that powerlevel due to the injectors being undersized. Ain't happenin'.

Please don't get me started on the whole "my injectors are maxed at 380 RWHP" thing. I've heard that nonsense so many times....anyway. Seriously, if they are TRULYmaxed out (meaning, you started to run lean) anywhere south of 450 RWHP, you have problems. Maybe faulty or clogged injectors or more likely, a lack of fuel pressure to the injectors (can't blame the injectors if the FP is not there.)

94form2000z

iTrader: (10)

LOL don't get all riled up. What I am saying is that Tech IIing the car while we were doing my LS1Edit session. We could not get rid if the +LTrims. No matter how much fuel he threw at them in edit (which was more than he had ever done on another) according to him "OBSSSD" Anyways changed the injectors (which only had 50k miles) to a set of '01's and reedited to have the problem resolved. They simply could not supply enough fuel for my setup.

Not saying more pressure wouldn't have made sufficient fuel either. Why bandaid? 28.8's stock fuel pump = plenty of fuel for me.

Colonel

LOL! I'm not riled up. Just drinking too much coffee for this time of the day. But I would like to help you get a clear understanding of this and possible of what happened to cause you Ltrim situation.

How + were the Ltrims and are you talking about at idle?

Ok, would you agree that the injectors will supply enough fuel for 400 RWHP? Ok, are you making 400 RWHP at idle? See my point?

I had the stock injectors in my 422 to begin with when it was capable of about 500 RWHP. It maxed out those injectors at 480 RWHP....but the Ltrims were fine.

You had another problem or your guy didn't know what he was doing with Edit. Your injectors have 10 times the capacity needed to choke that engine down with fuel at idle.

94form2000z

iTrader: (10)

Get back to you tomorrow on it. Gotta leave work to get my kids,
By the way Chris Robinson (OBSSSD) tuned it and is very good at it. Probably the best in DFW as far as Drivability and Performance combined goes.

Real quick the LTRims would go up to +20 and everywhere in between. He tunes while driving under alot of different throttle positions using the TechII.

I am @ 400RWHP. Well I was in my a4 before the PT4000. I had a SS3800 went to the PT. Changed my numbers a bit. 381/415 now. Hopefully he will read this and jump in. Either way I'll be back tomorrow.

Colonel

"Get back to you tomorrow on it. Gotta leave work to get my kids,"

Ok, I should be around then. I'll leave you with this food for thought...

"By the way Chris Robinson (OBSSSD) tuned it and is very good at it. Probably the best in DFW as far as Drivability and Performance combined goes."

Then he knows that stock sized injectors work fine for Ltrim readings regardless of the power level.

You said it was fixed with NO other changes than the injectors? If so then there was likely a bad injector. The Ltrims should have been + on one side of the engine only if this were the case. If it was both then sides and no other obvious things were changed to correct the problem (correction of an exhaust leak or replacement of a bum O2 sensor) then it was likely a vacume leak issue that was somehow resolved. Or there could have been bad injectors on both sides of the engine (bad fuel perhaps?). As I mentioned before, an exhaust leak will also cause madly positive Ltrims but you didn't mention any exhaust work.

Later.

CHRISPY

If you have a pump volume issue or a regulator problem it could appear the injectors aren't keeping up.

That is why it is important to have a fuel pressure gauge on the car when dynoing. If you FP drops like a rock your pump is weak and you should look at another or at least:
1) increase the voltage to the pump
2) swap out the pump or add an inline

Finally, the drivetrain will also play a factor. A 9 inch equipped car with TH400 making 450RWHP is likely to be VERY close to 500RWHP in a T56 car with stock rear.

Something to think about

TaTommyWS6

I think may people who got bigger injectors with relatively low rwhp are did so because they don't want to even be close to the limit. They want a bigger "safety zone"...

Tommy

PS Did I mention I upgraded my 26#ers for 28#ers on my little setup

30th TA 0219

no, sorry for the confusion, 28.8s

94form2000z

iTrader: (10)

"By the way Chris Robinson (OBSSSD) tuned it and is very good at it. Probably the best in DFW as far as Drivability and Performance combined goes."

Then he knows that stock sized injectors work fine for Ltrim readings regardless of the power level.

You said it was fixed with NO other changes than the injectors? If so then there was likely a bad injector. The Ltrims should have been + on one side of the engine only if this were the case. If it was both then sides and no other obvious things were changed to correct the problem (correction of an exhaust leak or replacement of a bum O2 sensor) then it was likely a vacume leak issue that was somehow resolved. Or there could have been bad injectors on both sides of the engine (bad fuel perhaps?). As I mentioned before, an exhaust leak will also cause madly positive Ltrims but you didn't mention any exhaust work.

Later. [/QUOTE]

Well I'm not sure about him knowing about the 26.6's being enough to work fine for the LTRims.

There were literally no other changes. Not sure on the vacuum leak as I had no surging or any other evidence of a vacuum leak. Maybe the injectors were bad.. don't know. The first time he tuned it I was using 87 Octane (yeah I knwo I deserve a nice kick in the ***) so i was getting KR and bad readings on the LTrims. Made me go get good gas for a week and come back. KR was gone but still unabel to get enough fuel to keep BOTH sides 0'd out.

Simply changed injectors and did another tune. Adjusted fuel tables and eveerything was great. There have been a few others I've read here and there that changed these out as well. I just look at it as insurance either way. I'm not running a dry nos setup anyways. So they will be sufficient for me.

samz28

running the injectors static causes a momentary point in time when they CAN remain half open/closed. It's a tuners nightmare as well. Dunno why folks like to run their shiz at static DC% then wonder why they lose a piston someday. Its just a matter of time. Probably that time your losing and rocking a 150mph run down the freeway

wanna do it right? or not. Thats what it boils down to.