Todd2001SS

I have a 01 SS and bought the 4psi ATI system and in short after dynoing at 400rwhp I want a bit more.

I am happy with there being no boost until the upper rpms which means no pressure on the engine for normal driving.

I thought with upgrading to the 7psi kit it needed new injectors, pcm reprograming, and a possibility of needing another new fuel pump (upgrading the one that came with the 4psi kit).

It may of been my misunderstanding only, but I want to pass this info along to folks who start with the 4psi system then move up to the 7psi.

I called ATI and they said the only thing needed was a new pulley and belt. $110.00 2nd day air.

Just some simple info that I wanted to pass along.

I talked to some of places selling the ATI kit and they told me I needed injectors, programming, ect, to move up to the 7psi pulley.

NOT TRUE

Todd

<small>[ April 01, 2002, 01:08 PM: Message edited by: Todd2001SS ]</small>

Blackbird

Good luck to ya.

I can guarantee your already maxing out your injectors on 4psi and now you want to move to 7psi? Those things are gonna run static under that much boost which will...

1. eventually fry the injectors because there running at 100% so often

and

2. if your fmu hiccups at all your engine is toast.

Timing - you may get away with a stock curve if you have 93-94 octane - Maybe

Personally I think your $110 pulley is gonna eventually cost you your engine but hey it's your engine and your $$$ so do what you want, but I would NOT recommend others to do this.

My $.02

<small>[ April 01, 2002, 01:30 PM: Message edited by: Blackbird ]</small>

Todd2001SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Blackbird:
<strong>Good luck to ya.

I can guarantee your already maxing out your injectors on 4psi and now you want to move to 7psi? Those things are gonna run static under that much boost which will...

1. eventually fry the injectors because there running at 100% so often

and

2. if your fmu hiccups at all your engine is toast.

Timing - you may get away with a stock curve if you have 93-94 octane - Maybe

Personally I think your $110 pulley is gonna eventually cost you your engine but hey it's your engine and your $$$ so do what you want, but I would NOT recommend others to do this.

My $.02</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Not looking for a fight, just looking for facts.

Why would ATI give me this information if it was not true?

I told the person who I was talking to, at ATI, other folks recommended the above upgrades that you mentioned and he assured me it was not necessary.

Here is what I am seeing with the 4psi system...

*2-3 lbs of boost at around 5k rpm. Maybe with the 7psi pulley it may be 4-5 lbs, will that make a huge difference? Will the LS1 with a true 4-5 psi be that bad off?

*My driving habits are not in the 4500-5500 rpm range. I'll be honest, I want paper bragging rights. I may go to the track once a year, maybe.

Does your opinion still stand? I would like to here more comments on this topic from you and others.

Thanks, for your advice <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

XLR8NSS

iTrader: (4)

I'm going to have to agree with Blackbird.

I had the same kit as you and I would say it's possible to run 7psi on the base kit(FMU, inline pump, stock injectors+tuning) BUT, I would not recommend it.

The stock injectors can barely keep up with 4psi let alone 7. The FMU adds fuel since the injectors can't. The reliability of the FMU is not something I would bet my engine on. Plus it's not good to run your injectors 100% and it may cause one to fail. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

So, yes it is possible but, Highly NOT recommended.

Johnnie

XLR8NSS

iTrader: (4)

Oops, almost forgot.

If you plan on running 7psi here is what I would recommend.

- 42# injectors(at LS1 pressure), maybe bigger if you think you might do other things in the future.
- a nice intank pump. (ARE is having a GP on a new intank setup in the sponsors section)
- programming to take care of the injectors and whatever else you might want done.

That should do nicely for 7psi. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Johnnie

Blackbird

seeing 4psi vs 7psi is very different.

All my comments were based on 7psi, if your only seeing 2-3 now, and only plan on hitting 4-5 in the future, then your probably fine for the most part. Betting the saftey on your FMU though is still occuring. While a FMU does do the trick of making your fuel system appear bigger than it is, if that FMU fails you under full boost your in for trouble. But then again one could argue if my fuel pump dies, my fuel filter gets clogged, an injector dies, basically if any piece of the fuel system fails and prevents proper fueling then I am in big trouble then too. Agreed.

So basically the FMU is just another component you have to hope doesn't fail. Hundreds, heck probably thousands of blower cars use the FMU's without issue. It pretty much comes down to how paranoid are you. If you understand what your doing by going with an FMU and feel comfortable with it go for it. If not, build a proper fuel system to support your blower.

FWIW I used the FMU on my kit while running 4.5psi and it worked fine. Now though, since I am moving up to 6psi plus some other goodies the margin of how much fuel is needed and how much fuel would be supplied if the FMU failed is much too great to risk IMO and thus my moving to 42# injectors, custom tuning, an external regulator to prevent fuel pressure drop, etc...

So as far as what ATI told you, yes it will technically work but as far as being a safe way to do it, now that's another story.

Hopefully that isn't just a bunch of jabbering and makes some sense <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

<small>[ April 01, 2002, 04:59 PM: Message edited by: Blackbird ]</small>

Black LS1 T/A

Truly running at 7 PSI and having what is "called" the 7PSI pulley is two different things.

If the "7 PSI pulley" gets you to 5 PSI where you were running on 2 or three PSI with the "5 PSI Pulley", then yes... you may be OK.

But if you truly run 7 PSI of boost without getting the fuel in to support that, either we'll never hear from you again, or you'll come back singing the blues.

In your first post, you made it sound like ATI was saying you can run with 7 PSI, and that's hard to buy. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

But, of course, even the guys selling the upgraded kits like GWP say you may need a smaller pulley to maintain a certain amount of boost depending on your car's mods and the elevation above sea level.

Be carefull, though. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Todd2001SS

Hey guys,

I really value you information, thank you for you input.

I can not see there being an actual 7psi of boost with the 7lb pulley. Just relating the performance of the 4psi pulley.

Next question, who has run the 7psi pulley and what were the actual boost levels? What mods are you running?

Thanks again,

Todd

Rock

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Black LS1 T/A:
<strong>Truly running at 7 PSI and having what is "called" the 7PSI pulley is two different things.

If the "7 PSI pulley" gets you to 5 PSI where you were running on 2 or three PSI with the "5 PSI Pulley", then yes... you may be OK.

But if you truly run 7 PSI of boost without getting the fuel in to support that, either we'll never hear from you again, or you'll come back singing the blues.

In your first post, you made it sound like ATI was saying you can run with 7 PSI, and that's hard to buy. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

But, of course, even the guys selling the upgraded kits like GWP say you may need a smaller pulley to maintain a certain amount of boost depending on your car's mods and the elevation above sea level.

Be carefull, though. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">WIth the P1SC and 3.4" pulley I don't think I've ever seen 7psi, even on an otherwise totally stock motor. Now I see a touch over 5 with headers, cut out, no cats. I cranked down my belt a little more yestarday though and haven't been out to test.

I'm just outside Philly, according to a site I just found I can be anywhere from 0-441 ASL.

highgmc

awe now you DID IT! got me started!

before I get into detail, am I wrong by thinking "since the free flowing exhaust is making less boost YET more HP you will still need larger injectors?"

as many of you may have seen me posting, (yes no track time or dyno #'s yet)
I only "see" 2-3lbs boost but am running slp longtubes no cats and wide open borla. I get it about less boost because of the free flowing exhaust and yet more HP.
I too want more boost!

I have no access to a tap etc... BUT my fmu is cranked all the way rich. the other night my buddy was tailgating me in his 01 Z28, it was dark and when I floored it and looked back in the rearview mirrow I saw a black puff of smoke come out of my exhaust and he said he saw the same. (saw it because of his headlights) So I think I am plenty rich with my fm cranked all the way up.

from what I get ati now has programming with EVEN their #4 kit now (this scares me not having programming and going to #7)

I don't think that with the #7 pulley I'd see more than #5. DOES THAT MEAN AT #5 with the #7 pulley I'd be safe on the fmu ALTHOUGH I am making more hp with the free flowing exhaust?

to put this in a nutshell, I know very little about a charger and don't want to blow my motor, but after spending $5k on the ati am disappointed in the small gain and little boost. I take the info here serious and have gathered that it may be best to save $ and goto the GWP stage 2 complete kit.

sorry for the long story

<small>[ April 01, 2002, 06:34 PM: Message edited by: terry99ta ]</small>

highgmc

like todd said, if we do the #7 pulley we'd probably still only see #5 if we are lucky. would it be safe?

I am so close to calling ati to order the pulley and belt............. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Black LS1 T/A

Terry, that's why I told him to be careful. If he has mods to flow the power, he may still be taxing the fuel system if he goes to the smaller pulley.

I know it's tempting. But you may not be riding long after that. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

highgmc

black ls1 ta,
how about with me knowing that when I floor it I shoot black smoke out the exhaust? wouldn't that mean I am rich (with fmu all the way rich) and be a BIT safer?

so so tempting....

highgmc

http://www.mlbuie.com/cgi-bin/ultima...c&f=1&t=000012

or another... below

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As I posted before my ati #5 kit is putting out #3 with my slp longtubes/off road y/ open borla.
can I safely go up on the pulley with just running off of the FMU? If so which pulley? I just talked to the guy who did my charger and he said ati will be giving a superchips programmer out now with their base #5 kit.

also was told I can safely goto #7 WITH JUST MY FMU and adding injectors and programming? Is this true withOUT running a different fuel pump?

thanks again guys!

--------------------

99 TA
ati #5
slp longtubes w/o cats
borla cat back wide open
moser 12 bolt 3.73's
33 spline, eton, ta cover
vigilante #7 pump
hal front and rear shock kit

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Posts: 5 | From: pa | Registered: Mar 2002 | IP: Logged

Jason
Moderator
Member # 3
Member Rated:

posted March 13, 2002 12:13 PM
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quote:
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Originally posted by terry99ta:
As I posted before my ati #5 kit is putting out #3 with my slp longtubes/off road y/ open borla.
can I safely go up on the pulley with just running off of the FMU? If so which pulley? I just talked to the guy who did my charger and he said ati will be giving a superchips programmer out now with their base #5 kit.

also was told I can safely goto #7 WITH JUST MY FMU and adding injectors and programming? Is this true withOUT running a different fuel pump?

thanks again guys!

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Your doing just fine. The boost being low is, in a way, a good thing. It means were moving alot of air with your motor. AKA good HP. Now as far as uping the boost. Keep in mind you only have a 26# inj. At 60 #'s of fuel psi, that works out to be 30# inj. At 80#'s of fuel psi it works out to be a 35# inj.

Now the next figures I'll give you are conservative but safe, and that's what matters.

a 26 # inj @ 80#'s psi will support 448 Flywheel HP. 380 rwhp @ 15% loss. I know people have made more but we want safe.

Now our stage 2 kit comes with 42 # inj. for basically stock motors. We quote 500-525 rwhp with exhaust and ~9 #'s boost.

The 42's at 60 #'s psi will support a safe 614 Flywheel HP (521 rwhp ~15%loss).

I would not try to run a custom program on top of a FMU. It will take you forever to get the map dialed in.

I really don't think there is a better way to make power than with the SC, the right inj. for the power, enough fuel pump, and the correct fuel and timing tables. Thats what GM did from the factory (minus the SC) isn't it?

I probably didn't answer your question as easily as I could of but this is all information which is important for you to learn and understand.

Jason

--------------------

http://www.goldenwestperformance.com (303) 346-5232

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Posts: 23 | From: Littleton, Colorado | Registered: Jan 2002 | IP: Logged



All times are Eastern Time

<small>[ April 01, 2002, 08:35 PM: Message edited by: terry99ta ]</small>

Black LS1 T/A

Yes, Black smoke is usually an indication of being too rich (assuming you have no actual mechanical problems).

Hey, go for it. Just be careful that you keep enough octane in there and check your A/F with a dyno pull and ATAP if you have it.

Have fun... for a LOoonnnggg time! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Todd2001SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by terry99ta:
<strong>black ls1 ta,
how about with me knowing that when I floor it I shoot black smoke out the exhaust? wouldn't that mean I am rich (with fmu all the way rich) and be a BIT safer?

so so tempting....</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">10-15 more rwhp for me with the A/F dialed in and I still left it a little rich.

The amount of adjustment left in the FMU is huge to richen things up for a little more boost after dialing it in for the #4 pulley. I do understand though running the injectors to their max is bad all of the time.

It was so rich, all the way through the complete rpm band it was off the chart. Now it's correct.

The person at the dyno place said since there was so much adjustment left tha going up in boost seemed pretty safe. It was not like FMU was just making it with the proper fuel mixture, it was drowning the car.

more thoughts for everyone. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

highgmc

so how can a dyno tell if your rich or lean? does it somehow hook to your port under the dash? details please? I have no way of autotapping it but there is a local shop that charges like $125 for a dyno.
If I get the pulley couldn't they tune it with just adjusting the FMU?

Black LS1 T/A

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by terry99ta:
<strong>so how can a dyno tell if your rich or lean? does it somehow hook to your port under the dash? details please? I have no way of autotapping it but there is a local shop that charges like $125 for a dyno.
If I get the pulley couldn't they tune it with just adjusting the FMU?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">They stick a probe up your tailpipe and determine the A/F ratio per RPM increment.

Yes, any on-car adjustments that can be made then and there should be done, and another run done. Boy! $125 is STEEP!

highgmc

I just ordered the #7 pulley, it'll be here thursday! yipee ati said I am safe since only seeing such low boost now.

they said to get the a/f ratio at 11.8 on top (what do they mean by that?)

I DIDN'T pay only $110, even after telling them that you did! I paid 135 + shipping!!!!!!!! GRRRRR!!
45 for the belt and 90 for the pulley.
I will post results!

Mark C

A few words of caution:

Ignore all the boost pressure numbers. Once you start changing the exhaust, headers, and heads, it's just a number. Whats important from a fuel quantity point of view is the horsepower level. If you're making 500 flywheel hp, who cares if its 2 psi or 8 psi...you're making 500 hp, and you need the fuel to support that.

I wouldn't even think about increasing boost without knowing exactly where I was fuel-wise. Dyno the car now with a wideband, and a fuel pressure gauge. Get an autotap for the run. You can tell from the injector pulse widths, MAF, and the A/F ratio just how close you are running. You can even figure out when (powerwise) the injectors will max out.

A big question mark is the fuel pump. I think that with the 99 and up cars, the fuel pump would give out before the injectors (again, powerwise), and if so, a large intank would be incredibly desireable if not outright mandatory. The injectors may be good enough, but only because of the FMU. 80 psi, if thats true, that helps a lot, but even then its 26 * 1.33 (because your base pressure is 60) = 35 lb/hr.

Just as an example, with my stock tuning (12.5 A/F), larger intank pump, 28 lb injectors, and a rising rate regulator, I will run out of injector first, at about 480 rwhp. And I have a turbo system. With the additional power to run a supercharger, that would probably be 440. With your pressure, and injectors, youd probably run out about 510 or so, but like I said, that pump is very suspect.

But, as was said before, the FMU is a shakey way to do it. I've seen A/F dyno runs with these, and they have a spike before the FMU kicks in. Not saying its terrible, its just quick and dirty.

Anyway, forgive me for rambling.