some newbie performance questions

[ignorant prodigy]

I don't even own an LS yet.. just have some questions



From what I've read the engine is a high compression motor so 93 octane is required.
Coming from a SC grand prix that's no big deal. But my main concern with this is the ability to modify the engine for more performance.. and running the risk of popping a piston. I understand it has a single knock sensor? how effective is it in retarding the timing?

What are the main restrictions in the set up? for instance, the grand prix's manifolds and down pipe were a big exhaust restriction. Does the LS have good size manifolds/headers? If I were to add more air, how manys lb's are the injectors rated for? and how's the fuel pump hold up over time?

How much play is there is the heads of an LS.. would bigger valves and a port job be beneficial?

How's the transmission hold up to extra abuse?

Just from reading this forum I've notice that there isn't a whole lot to be done. Considering the grand prix's aftermarket has grown it'll be nice to have a challenge with the LS

I did read the 12 page thread about adding the t-bird m90. It's a very clean setup from what i can tell. I'd love to see some 1/4 times when it's all said and done.

 

[Clown2theleft]

I could have sworn the minimum octane rating is 91, not 93, but I've only gassed it up twice, and ran 93 once and 94 the second.

As far as everything else... Sorry. I'm not familiar enough with the car to answer, but I bet someone around here is...


Best,

--The Clown to the Left

 

[Dartastic]

I could have sworn the minimum octane rating is 91, not 93, but I've only gassed it up twice, and ran 93 once and 94 the second.

As far as everything else... Sorry. I'm not familiar enough with the car to answer, but I bet someone around here is...


Best,

--The Clown to the Left

Im in California and all I ever see is 91 and thats what I use. The LS runs fine on it. I only gas up at Chevrons.

 

[Quik LS]

From what I've read the engine is a high compression motor so 93 octane is required.

LS has a 91+ octane recommendation

It runs 10.55:1 compression - so modifications are limited.

I understand it has a single knock sensor? how effective is it in retarding the timing?

Usually you can get better performance by running closer to MBT (minimum for best torque) spark or LBT (lean best torque) fuelling. The LS already runs LBT fuel (approximately 12:1 air/fuel ratio, compared to the normal stoichiometric 14.6:1) at wide open throttle.

Spark is normally the minimum of MBT and at the spark level at which knock begins (borderline). Running closer to MBT when the engine is borderline limited would mean running higher octane fuel - since the LS already runs on premium, so we are always teetering on knocking....

What are the main restrictions in the set up?

The PCM. You must implement every change through a 're-flash' of the PCM code. We have come along way in the last year on the ability to do this - using the SCT XCalibrator and a tuner that understands the LS. You can purchase the software directly - but is frankly is more complicated than I can handle.

I Does the LS have good size manifolds/headers?

Tough to get to - but there is probably a small hp gain for someone willing to try

I were to add more air, how manys lb's are the injectors rated for? and how's the fuel pump hold up over time?

They are a Delphi FJ10533 injector. The LS uses an 'air assisted' injector - which means that there is a air line coming from the intake into an 'air rail' half-way up the injector to mix air into the fuel delievery. This adds better atomization to the fuel spray.

Changing the injectors is a challenge - since you will not likely use the 'air assisted' type when upgrade - you'll have to go through a dramatic re-tuning - running very very rich initially. (this is the point where I am at in the SC installation on my LS)....

How much play is there is the heads of an LS.. would bigger valves and a port job be beneficial?

A port job should add some good hp

How's the transmission hold up to extra abuse?

the pre-03 LS used a 5n55r - I believe rated for about 340hp
the 03+ use a 5n55s.

the trannie will be the weak link.

Just from reading this forum I've notice that there isn't a whole lot to be done.

almost zero afermarket - there just isn't alot of people will to tackle performance upgrades on the 'luxury' vechile. As the cars are changing hands to 2nd and 3rd owners - typically younger - most stuff is starting to show up.

I did read the 12 page thread about adding the t-bird m90. It's a very clean setup from what i can tell. I'd love to see some 1/4 times when it's all said and done.

me too

 

[mespock]

almost zero afermarket - there just isn't alot of people will to tackle performance upgrades on the 'luxury' vechile. As the cars are changing hands to 2nd and 3rd owners - typically younger - most stuff is starting to show

That is one of the biggest downfalls for the LS from waht I hear..... basically no afermarket mods. You can do a little air intake, exhaust, Hmmm.. very little room for a Super Charger but with work it can be done.

Too bad they didn't base it off the Mustang! Then you'd have all the mods you'd ever need.

It's still a fun car to own...

Oh that's right there are those exhaust spinner things LOL.....

 

[00ls-sport]

i run 93 as there seems to be no 91 octane in MA. when i travel, i keep it 93 even when there is 91....i figure the car is used to that, so might as well keep it that way.

 

[Silver02Sport]

91 is the minimum though I have never in my life seen anything but 87/89/93 hell I didn't even know there was such a thing as 91 octane before I got my LS but apparently it depends on your region.

As far as your other question there really isn't much you can do to the LS for most people the only options are a CAI, SCT Xcal 2, and if you got a 02 or below you can also get an exhaust. all that should get you to around 300-320 HP depending on your year and how aggressive you set the computer.

Quick's SC project is being followed pretty closely here simply because its one of the few possible ways to get some real power out of the car there are a few Turbo LS's around but they all put the turbo in the back and I think they only got about 60HP from it.

I have never heard of any real problems with the trany other then the fact that there is no dip stick and the pan is sealed shut. Some people have found the programming in the computer for the trany to be a bit flake but I believe that can be fixed with the Xcal 2. But since there is no LS out there making just gobs of power I don't think anyone really knows how much it can take. But since a variant of the 5R55N the 5R55S is being used in the new Mustangs I don't think it will be to long before we know for sure.

I don't know about the rest of the info you asked for though but maybe this file will help.

I assume you know the difference between the sport and non-sport packages as well as the 99-02 and 03-06 differences I only bring it up since you do not have one yet and there are plenty of times I see someone saying dam I wish I knew that before I bought my LS don't want there being another.

 

[Silver02Sport]

Dam Quick beat me to it agine guess that what I get for takeing the time to spell check . How do you do it Quick (personly I think your a ford spy)

 

[Dartastic]

Dam Quick beat me to it agine guess that what I get for takeing the time to spell check . How do you do it Quick (personly I think your a ford spy)

You spellcheck?? LOL!!!

 

[ignorant prodigy]

reply

Spark is normally the minimum of MBT and at the spark level at which knock begins (borderline). Running closer to MBT when the engine is borderline limited would mean running higher octane fuel - since the LS already runs on premium, so we are always teetering on knocking....

Hows the 02 sensor in the car... is it accurate? The GM Delco ones would get less and less accurate the hotter they got.. they are narrowband sensors and it sometimes made tuning a bitch. Honestly I'd prefer running a richer condition just for a sliver of peace of mind...

The PCM. You must implement every change through a 're-flash' of the PCM code. We have come along way in the last year on the ability to do this - using the SCT XCalibrator and a tuner that understands the LS. You can purchase the software directly - but is frankly is more complicated than I can handle.

The grand prix's pcm is the same. do the computer require a "CASE learn" after every write? If so does the Xcalibrator have that as an option? I'm not sure as the GP only had one cam.

They are a Delphi FJ10533 injector. The LS uses an 'air assisted' injector - which means that there is a air line coming from the intake into an 'air rail' half-way up the injector to mix air into the fuel delievery. This adds better atomization to the fuel spray.

oh thats delightful.

Changing the injectors is a challenge - since you will not likely use the 'air assisted' type when upgrade - you'll have to go through a dramatic re-tuning - running very very rich initially. (this is the point where I am at in the SC installation on my LS)....

personally I think thats better than the opposite ..only you may foul plugs pretty quickly going through your first runs

A port job should add some good hp

sign me up then. I'd love bigger valves but I'd probably have to check out the stock ones first. Not sure if you're familiar but with so much compression I wonder if Ford used hardened vavles seats or not. I'd assume so to be on the safe side.

the pre-03 LS used a 5n55r - I believe rated for about 340hp
the 03+ use a 5n55s.

the trannie will be the weak link.

bummer.




Thanks guys for the detailed responses!

 

[SoonerLS]

91 is the minimum though I have never in my life seen anything but 87/89/93 hell I didn't even know there was such a thing as 91 octane before I got my LS but apparently it depends on your region.

91 is the top grade around here. But we do have a local station that has 87/88/89/90/91. Yep, that's five grades.

I assume you know the difference between the sport and non-sport packages as well as the 99-02 and 03-06 differences

I know the difference between the '99 LS and the '00-'06 LS. The '00-'06 LSes actually exist...

 

[rocket5979]

+1 for most of what was already said.


One more thing i would like to add is that a turbo would probably be the best way to go on these. I don't know if and how long it will be before Quik may or may not offer that roots supercharger as a kit for the LS's. Remote mounted single or twins gated to low boost will produce allot more hp than a supercharger will and also be more gas friendly when driving around town depending on your driving habits.

The problem with any kind of custom centrifugal charger is the mounting position needed on these cars. If you notice, there is a sort of lip that overhangs the front accessory belts and pullies. The only access is at the top which is where the alt is if I remember correctly. A roots nosedrive fits perfectly in that spot, but a whole centri head unit would not. That will severely hinder the ease of custom fabbing a centri mount and adding boost that way.

The best three ways to add significant power to this car are run a roots like Quik, turbo it, or nitrous.

I plan to go the turbo route, but still have not decided on whether I want to run twins or a single. The turbo LS project is months off from even beginning as I have a much bigger car project on my plate right now.

 

[Silver02Sport]

I know the difference between the '99 LS and the '00-'06 LS. The '00-'06 LSes actually exist...

I know I keep doing that. I guess its because the first time I ever drove a LS was 1999 when I was buying my first car.