vernw

iTrader: (2)

I data logged a WOT run this morning using Datamaster in my $8D 383 Super Ram this morning. Naturally, I have some questions...

FWIW, I'm testing out a SAUJP conversion to the AXYC manual bin I've been running. Just made the changes in AXYC to match SAUJP where I could.

At 4800RPM I hit a 80% duty cycle on my LS1 28# injectors, and by 5500RPM it hit 90%. I'm currently running an AFPR set to 43 at idle with the vac line disconnected.

I also noticed the engine falterring a bit (or at least flattening out power wise) at about 5200 RPM.

Recommendations - should I swap to larger injectors, or try raising the fuel pressure. If the latter, what would recommend for starters?

If anyone is interested in looking at the DM log, let me know and I'll e-mail it t you (no place to host it, sorry).

Thanks in advance for any and all replies and thoughts.

Grumpy

Crank the pressure up, and the volume goes down. Might get by for a while or forever, but the pump just ain't going to last as long. Slowly running an engine leaner, and leaner, is being really cruel to it.

I wound up swapping out injectors 4x on my car. I could have saved alot of time, and money by doing it once.

42.5s (009s) seem to be problematic for alot of people.

I had real good luck with the 40 red stripes, and the Motoronic 60 PPH injectors.

junkcltr

iTrader: (1)

Grumpy,
That is interesting what you said about the injectors. I am in the middle of doing a turbo install on my car and was looking to get some Ford 42#/hr M-9593-F302 injectors for it and start learning the $58 code next month. I am still in the middle of making pipe, brackets, etc.
Where you referring to these as problematic? Never heard of the red stripe 40s. I will have to look into that.

Oh yeah, I would install larger injectors instead of upping the pressure. I does pay off in the long run.
J

RBob

iTrader: (1)

Stock GM TPI fuel pressure for the later years is 43.5 - 47 psi. I wouldn't hesitate to go to the 47 psi and if the vehicle has a good pump (GM LS1, Walbro,. . .) you could go higher to 50 psi.

RBob.

EdgesZ28

Are they from a LS1 engine? It is my understanding that stock LS1 injectors are set at 4 bar (58 psi). If that is true, having your pressure set at 43.5 psi is like a 24# injector.

I would crank the pressure up to 58 psi and see what difference it makes. It costs nothing and may solve your problem. Ed

vernw

iTrader: (2)

Thanks for the replies, folks!

I've got a new TPI fuel pump in the tank, not an LS1 unfortunately, but I think I'll still try raising the pressure to 48-50 and see what happens.

There seems to be a lot of confusion on the rating of the LS1 injectors - at least to me. I've seen everything from saying they're only 24's at 43 PSI to they're all (SVO, LS1, TPI, etc.) rated at the same pressure, and are just run at a different pressre. So I guess I'll try raising it first and see what happens.

Again, Thanks for the input!

junkcltr

iTrader: (1)

One other thing you forgot to mention. What is the air/fuel ratio where in general and especially at the 90% point. Is it being over fueled at this point already so that the 90% is artificial?

vernw

iTrader: (2)

I'm still trying to extract the WB AFR from my Datamaster logs. I thought I knew what to do to get that, but it's not working at the moment. NB voltages were in the .93 range though.

Z69

IIRC, I stuck the AFR in the FP volts spot for the aldl.
DM will divide that value by 10 I think.
I changed the patch to use Learned IAC specifically for DM use if you want to fix you bin. DM displays that value in its' raw interger form. So 14.7 would be 147 etc.
I'll send you the updated ecu vern.

Grumpy

So that'd make it ~12:1 or maybe down to what?, 8:1?.

vernw

iTrader: (2)

I got the patch from Scott working this afternoon, shows the AFR in the Min IAC position in Datamaster (THANKS AGAIN, SCOTT!!!)

So I'll get some logs tonight and early tomorrow morning and verify the fuel pressure, and see if I need to raise it (with y'all's asistance and input, of course!)

Thanks for the replies and ideas!

vernw

iTrader: (2)

I've raised the fuel pressure to 49PSI, and data logged a WOT run. I'm still getting over 80% duty cycle at 5200 RPM, but the WB is showing an AFR of about 12.1 at that time, so it doesn't look like I'm running out of fuel yet. Motor sure seems to drop off though.

One thing I just realized though, shouldn't I be changing my injector constant since the raised fuel pressure is in essence resulting in larger injectors than their 28# rating?

Think I need bigger injectors?

I've also swapped around my WB vs. my NB (side to side) and my passenger side is definitely running richer than my drivers side. No WOT runs after the swap, but there's about a 1.0-1.5 AFR difference between the two banks of the motor on the WB (chows that much rich with WB on right side, that much lean with WB on left side). But I guess that's a topic for another post.

MrDude_1

you have the injector constant wrong already.

at 58 PSI, it is 28.71 according to GM.
i trust GM more then everyone else's opinion of what they flow.

your lines and pump can handle 58 PSI no problem.. they're the same lines and pump 100s of us LS1 swap guys use.


here's the stock GM injector size vs manifold pressure chart, taken straight off of my LS1s PCM... all of the 28# ones are identical.


since your pressure is manifold referenced and not referenced from the atmosphere, you're only worried about the first number.

vernw

iTrader: (2)

Thanks for the reply. I had just about convinced myself they wer really 28# at 43PSI after all the reading I've done on it. Now I'm confused again (which isn't too hard to do!)

How in the H3LL is a guy supposed to know for sure? Send what he thinks is a perfectly good set of injectors off to get them cleaned and flowed?

.
.
.
.
.
I've sent Rich over at CruizinPerformance an e-mail asking about the LS1 injector ratings. Maybe he can tell us for sure....

vernw

iTrader: (2)

Unfortunately, I haven't gotten a reply yet....

MrDude_1

im 100% positive they flow a avg of 28.71 @ 58psi..


since they're LS1 injectors, you can do a search at www.ls1tech.com its a all tech LS1 board... like the thirdgen.org of the LS1 world.

vernw

iTrader: (2)

I'm so confused.... first ya say 58, now ya say 53 PSI, and I still haven't heard back from Rich. May just have to call him....

MrDude_1

WHOOPS. 58PSI... the stock GM fuel pressure. idonno why i typed 53...but its 58.

vernw

iTrader: (2)

Well, they do kinda look a lot alike.....

Z69

Try goggling the p/n.
Racetronix or 5.0 will sometimes list stock injector p/n's
and their ratings.
I have a set of 2? lb ers off a dodge I got for free that I found the rating for this way.

vernw

iTrader: (2)

Here it is straight from Rich @ Cruizin Performance:

LS1 injectors are rated by GM as 28#/hr at 58PSI. That's what he tests them at, and they're usually pretty close. Running them at 43PSI usually nets around 25-25.5PSI on these injectors. However, the flow pattern on them is still very, very good. No noticeable degradation in spray pattern on these at the lower pressure.

SVO (Bosch) injectors are actually his first choice for his own personal use. And they are rated at 39.5PSI, meaning of you ruin them at 43PSI they'll actually flow a little more than their rated level.

Now I know why my duty cycles are so blasted high. And I also went the wrong cotton-pickin' direction with my injector constat, didn't i?

Back to the tuning board mode before going any farther with the spark tables..... at least until I find the $$ for SVO's. Sure wish I hadn't sold that old set of SVO 30's I had!

x 1000

vernw

iTrader: (2)

Want some more confusion on this? Racetronix says the Bosch part number 0 280 155 931 (GM# 12561462) flows 28#/hr at 43PSI and 32#/hr at 58PSI from their flow testing. Said there are actually two different EV6 GM injectors.

So now I'm really confused once again. Sure wish it wasn't so easy to do....

MrDude_1

if it was me:

id set the fuel pressure at 58psi.

set the injector constant at 28.7


you then have a known correct injector setup.... run the car, datalog, and rough it in from there.... the duty cycle should be reasonable... later on if you make more power and start going past 80% again, then get diffrent injectors....

vernw

iTrader: (2)

Would you still do that if you were using a fairly new TPI (not LS1) fuel pump?

MrDude_1

yea, i would.

vernw

iTrader: (2)

Guess tomorrow night I'll try that out. Spent today moving 1300# of topsoil and reseeding part of the yard under a big old oak tree.

That and swapping the dizzy, disconnecting and plugging the EGR, re-attaching the A.I.R. after removing it for test, and I'm still running richer on the pass bank. Gotta fix that before doing much more tuning so I can tell what's really going on I think....

JP86SS

iTrader: (1)

Hey Vern,
Now I feel bad that you need them.
If mine wasn't so close to being put together I'd send them back to you for what I've got into them. I'm really hoping your LS's work out for ya.
If you are really stuck and want to try them I can send them by the end of this week, they're all ready cleaned and good to run and I'll be going back overseas for a week to 10 days so the slight delay is inevitable on my rebuild.
I'm giving up on the cam for this year (too much reading to do and $ ran out) so I'll be digging into putting all my parts in when I get back. (so You'll have to give them back )
Let me know if it's worth the time to you with the SR to swap them in/out a few times and I'll do it.
Jp

vernw

iTrader: (2)

I really appreciate the offer, but if I tear that b!tch down again I won't be doing it a second time to swap them back out if I can help it! I appreciate the offer, but I think I'll just try to find some on eBay or somewhere. I'm running the fuel pressure at 49 PSI right now with a 30# injector constant and a quick test this morning only hit 66% duty cycle at 5100 RPM, but it wasn't quite WOT either. So will check it a time or two more before changing anything at all. Thanks for the offer, I really appreciate it!!!!

JP86SS

iTrader: (1)

I wasn't sure you really wanted to take the chance on creating another problem by tearing it all down again but thought I'd offer anyway. Looks like it's beginning to come around. 66% is better than before so there is still hope.
Could always put a big pump in the back seat and run at 100 PSI

MrDude_1

lol.

to be honest, i would never go over 65 or so... even thats pushing it.

only reason im saying 53, is because thats what the stock LS1 injectors are known to run at.

vernw

iTrader: (2)

Uh, you mean 58PSI, not 53, right? Blasted typos.... :duh:

I won a set of new 30# SVOs last night on eBay for $152, have had less than a hakf a tank of gas run thru them. So I guess once they get here I'll be putting them in and dropping the pressure back to 43 or so. Except these are really rated at 39PSI, right? So won't I have to calculate the new injector constant?

Anybody need a set of LS1 injectors with about 4K miles on them? Or my brand new spare set?

JP86SS

iTrader: (1)

BTW, 100 was not meant to be serious
Even going 58 on the L98 stuff worries me if using any type of compression (screw type) clamps and line. Below 50 you can get away with it.

Oh boy, here we go again

I'm interested in that result as well cuz I'll be lowering my FP as well.

vernw

iTrader: (2)

According to the equations, an SVO 30# that was rated at 39PSI would use a 31.5 #/hr injector constant at 43PSI....

MrDude_1

dammit! i KNOW its 4 bar.... 58PSI (ok 58.8 techniclly is 4bar, but work with me...)



i have no idea why i keep typing that.... and then when i re-read it, i dont even catch it.

vernw

iTrader: (2)

Thanks!

I figure I've got to find out why the passenger's side is running 1.2 to 1.5 AFR richer than the drivers side before any more tuning changes are done. Otherwise I'll never know which way to go with the tune....

Hopefully I can resolve it before the new injectors get here.

Going to be pulling plugs and wires tonight looking for something "different".....

vernw

iTrader: (2)

Well, I pulled the plugs over the weekend, and low and behold 7 of them all look like the attached pic. Cyl #1 was slightly leaner looking (about normal), but that's probably due to the flow characteristics of the SR and having to flow around the corner to the #1 hole in another corner. A buddy with a SR siad his #1 always looks slightly leaner as well.

Anyway, they all look rich. So I guess I'm looking for ideas on how/why the NB sensor thinks there's too much oxygen in that bank of the motor....

Anyone willing to look at all the plugs and make sure I'm seeing them right, just send me an e-mail address to send them to, or look here:

http://www.cardomain.com/ride/552958/4

Z69

looks like it gets rich going towards the back.
1-4 looks a little too lean
5-8 looks a little too rich
IDK if this is normal for a SR.
How does the base of the plug tip look?
You might try a projected tip also.
Some people bad mouth them due to potential detonation
inducing tip hanging out in the chamber.
I think this is mostly a tuning issue. Or chamber design. Not an extended tip issue.
A R42xx or 43.

vernw

iTrader: (2)

"How does the base of the plug tip look?"

You lost me there, Scott. Whcih part are you calling the base?

"You might try a projected tip also."

I can do that with an NGK UR4 I believe. Or a UR5. Don't have a cross reference to any other plugs that way.

"I think this is mostly a tuning issue. Or chamber design. Not an extended tip issue."

I won't rule out a tuning issue, but the NB BLM's are looking fairly close under cruise conditions. But why or how would that cause the leaner left bank/richer right bank discrepancy?

"A R42xx or 43"
Wish I could, believe me. The R43TS plugs are too long to fit under the SLP Tri-Yheaders on at least 3 cylinders and pretty darn close on at least 3 others.

If I assume you're right about the tuning issue, where would you suggest I start? Does anything show up as obvious to you? (Thinking spark vs. VE, etc.)

Sure appreciate the reply, Thanks!!!

Z69

The base of the center electrode where it meets the steel shell. Hard to see. Depending on which way your eyes went, you may need a magnifying glass to see it. If the tip is black and the base is white. Then you don't have enough time on them or you might need to swap to an extended tip.

Your plugs don't show a side to side diff in afr.
There is no dramatic diff in color side to side.
Which a 1.5 diff would show up as.
The front 4 are on the white side and the back 4 are on the black side.
So you have a leak somewhere I'd guess causing the NB split. Or maybe a gnd issue.
For the front to back color diff. Ask the other SR users.
Or look for a real small vac leak.
I had a small one on my carb setup that the cam masked.
Showed up as a real lean cruise. Plugs were white with only a hint of tan.

If your cranking compression is 180psi or more I'd go with the #5 plug. Also depends on Tstat temp and CAI use.

Your not the only person I've seen on here with a side to side issue. No clear cut solution that I've seen.
If it's a mechanical design issue, you'll be stuck.

What's your IAC steps at idle and cruise?

Tri y's...hmmmm

vernw

iTrader: (2)

Please forgive the length of this response, I'll try to answer each question individually and hopefully we can get this figured out... appreciate your trying to help me regardless!

Plugs with a closer examination:
#1 Strap is clean light (metal) colored all the way to the base. Porcelain is light tan, slightly darker (brown) on one side of it.

#2 Strap is pretty dark all the way to the base, if anything its blacker from the elbow on the strap to the base. Porcelain is pretty black, too.

#3 Clean light (metal) colored strap all the way to the base. Porcelain is light tan, slightly brown on one side.

#4 Strap is slightly darker but same color all the way to the base. Porcelain varies from lite tan to brown.

#5 Slight darkening of the strap, same color entire length. Porcelain is darkened (dark brown) as well.

#6 Identical to #2, both strap and porcelain

#7 Strap is pretty black all the way to the base. Porcelain almost all black too

#8 Strap is pretty black all the way to the base. Porcelain is black on one side, light brown on the other.

Yeah, I see that too. Regardless of what the NB (drivers side) and WB (passenger side) are reporting.

I'll check and clean the 2 grounds on the back of the heads tonight.

[QUOTE]Originally posted by Z69
For the front to back color diff. Ask the other SR users. /QUOTE]
Will ask around on this idea.

OK, where would you expect it to be? In the front or rear area? Would it be up front if that area seems to be running leaner?Should I re-seal the plenum and runners. Or go all the way to the intake manifold to motor gasket? (Hope not!)

My cranking pressure is typicall in the 210-220 range, so I'll try some new UR5's. Currently running a 180 thermostat, and the CAI is the factory 91 Firebird with the filter behind the right side headlight. I've also relocated my IAT sensor to directly above the filter in the plastic air tube.

Hopefully not a design issue. I would think that would have shown up somewhere before this....

Idle IAC is in the high teens to low 20's. Cruise runs more like 35-45 driving around in town (1500-2000 RPM), don't have any recent highway logs (2400RPM, 70MPH) to report IAC on. Can get some though if it would help.

And why do you say that?

I REALLY appreciate your help on this!!!!!

Z69

I chased my tail for a while looking for a runner leak.
Had pcv issues too which fooled me.
Turned out to be a TB leak. This was a carb remember.
A vac leak will always have an effect on a carb app.
IAC is a vac leak remember.
While I can think of an instance that might cause what your seeing. I don't have a feeling for how probable it would be.
Or how to find it. Just do the std vac leak TS proceedure.
With a SR, I wouldn't jump into resealing it. Unless you suspect you made a mistake when assembling it the last time.

I need to look at your plug pics again. I was at work last time so I rushed it.

IAT, you've already tuned around it being relocated to some extent. If your running a stock TPI MAT sensor. Have a look at how it is constructed. I can send you a pic if needed.
Them review Rbobs' post on how the 8D code works with the MAT.
And draw your own conclusion on the merits of moving it.
All I'll say is Mat is a more appropriate name for it imop.

TriY- I've never ran them. I wonder what they might do to the distribution at low rpm where they are designed to work.
Have to look at the tube length and firing order.
I also think they are only for low rpm cruise situations and are redundant on a 383. If they were so great, the oem's would be running them.

If I had your little cam and had to pull my SR. I'd put a bigger cam in while I was half way there. But that's just me.

vernw

iTrader: (2)

ECM grounds on the back of the heads are fine/done. Drivers side was a real bear. <sigh>

I'll try checking for a vac leak again. Last time through I used O2 safe RTV on all the gaskets hoping to eliminate leaks, plus I was re-using them. Maybe thats the problem....

I've got a set of SVO 30's I set off to Cruizin today, so will be disaassembling the SR to put them in probably next weekend. Then I'll have a known GOOD set of injectors, will use the standard fuel pressure, and of course have to re-tune again. Got new SR gaskets on the way as well.

I'll try to dig up RBobs post as well. I moved it due to the heat sync problem that obviously is going to occur. Not as issue with current location. I'm also using Glenn's relocated inverse MAT values.

Z69

As long as you're using Glenns table you should be ok I'd think. I don't remember if he posted the whole years worth of table though.
You might swap to an open sensor for faster response though. The ZR1 sensor/bin uses the same table values as stock aujp. And it's threaded. I've read of others using the Fiero sensor. Found this out after I did all that research of course.

- I think the Rbob thread is up in the stickies. Accounting for heat soak is one of the reasons it is the way it is.

I'd be careful with 220 psi. Your borderline for just about anything to cause detonation on PG. Course you probably have the 93 stuff......

vernw

iTrader: (2)

Actually 92 Octane is what I'm using, that's the highest normally available locally in Dallas.

As for the IAT sensor, I think I've got one of the finer wire-type sensors I think you're referring to, just haven't installed it yet. Guess I'll do that this weekend, too. What I've actually got is the TPIS #300-164 MAT Relocation Kit, which is "using a 1992 and later MAT" that is plastic and has more of a wire type sensor end instead of the large brass sensor is a brass housing.

I'll try to find Glenn's latest info and see if he has the full year round temp data done.

I'll also check for RBob's post.

I also plan to pull the headers and check for leaks on the top and bottom flanges (at least the driver's side for sure) this weekend. I've already got the copper gaskets to replace the 6-layer aluminum Percy's gaskets. Got a new set of SLP collector gaskets I've held back as spares, too. Sounds like the driver's side has just started leaking again at the head flange around the #3 or #5 cylinders, so this will kill two birds with one stone (eliminating the leak as well as checking for extra air getting into the exhaust for the NB to read and react to). If I find any openings in the headers on either flange's gasket side, I'll get them welded up before it goes back on.

I also just received a piston stop from FedEx, so I'll be verifying my timing pointer this weekend. If it's off, that would explain a lot about why I'm seeing knocks while using such low WOT timing values. Of course, the exhaust leak could be getting read as knocks too, I suppose. Will also verify the headers aren't hitting anything and that being interpreted as knocks.

Hmmmm... I wonder if that BMR strut tower brace could be hitting on the top edge of the SR, there's less than a 1/4" clearance on one corner. That could also be a "false knock" producer, couldn't it? Have to try pulling that to see if that's the case before doing anything else so that I know the actual cause....

Any other suggestions or ideas?

Lo-tec

If you have a spare set of heads lying around, I would bolt a header on there with no gasket (torque it), and check how straight (or warped) the flange is. I had two sets of SLP's that were warped (one barely used, and the warranty replacement). I could slide a .020" feeler gauge in there easily, and it leaked from the start. The only solution after getting a warranty set that was just as warped was to take them to my local machine shop and have them sanded flat. 5 years later and still no leaks with a regular fel-pro header gasket.

vernw

iTrader: (2)

Thanks for the reply, Lo-Tec. I was planning to pull at least the driver's side this weekend (if not both) and go to the copper gaskets, so I'll try straight edging them to check for warpage. Don't have any spare heads laying around, wouldn't this be just as good a check? (a metal straight edge, like a carpenter's square)

Lo-tec

Hard to say, but it might work. My problem was with the the flanges being cocked, probably tweaked when they welded it up. The center two would seal at the top, and barely touch the gasket on the bottom and leak horribly. Same on one end one. When I put them on the head and cranked down the bolts, I didn't need a feeler gauge to see the problem.

FWIW, I just pulled them after only being on for 2-3 weeks with new gaskets, and the impression in the gaskets (which still look new) was perfect all the way around the port. You might want to examine your old gaskets also (if they're not cooked).

vernw

iTrader: (2)

My current gaskets should be able to show the indentation, so I'll check for that, too. Good, Idea, Thanks!!!

vernw

iTrader: (2)

Well, I got the driver's header pulled off this weekend. DOn't know if it happened during the removal or was alreadt there, but the back (#7) A.I.R. tube was cracked all the way around and could have been a potential fresh air source for the NB. Got it welded back up, installed the solid copper headers gasket, put the original one wire NB sensor back in so it's using the factory harness w/o splices and/or hacks, fixed an oil leak (half the pan bolts were barely finger tight) while I was under it, and did a test drive to work this morning after resetting the ECM.

It's definitely helped the wb/NB discrepancy a little bit. At a 2300 RPM cruise I'm around 14 AFR now +/- .3 or so fluctuation with BLMs 126 +/- a couple.

So I'm getting closer. Will pick up a new propane torch on the way home tonight to spray unlit around the SuperRam lid and both ends of the runners to see if I can spot a vac leak. Once my SVO 30's make it back from Rich @ Cruizin I'll be tearing it down to install them anyway. Got my new Summit SR gaskets, so will assemble it w/o RTV this time (dry) so hopefully no leaks.....

Will pull the right side header at that time to check it and trash the other 6 layer exhaust gasket as well.

Any other suggestions?