[Mfirebird]

hello all,

I am very sorry about creating another post about a camshaft question, but after looking through the other posts, I am still left with questions, that I hope you guys can help me out with. I figured it was time to ask some experts. -- sorry for the length.

I have a 1995 firebird, LT1, automatic. 140k on her, finally have to replace timing chain. While I am doing this job I am going to replace the water pump and everything else in the way. I do all the work to the car with friends of mine, we love working on the car. I know the job is going to be a pain, but I am not worried about the job itself.

I am posting because while we are replacing everything, I want to throw a sweet camshaft in the engine to make it even better. I LOVE the sound of a camshaft so I really want to do this, but please let me know if you advise against it.

please note: I have an exhaust cutout and a borla muffler if this helps...

This car is never going to be my racecar, realistically. But I do want the cam for sound and for moderate gains. I am NOT interested in having to get a tune and NOT interested in getting roller rockers (don't want to have to get the lt4 knock module).

Considering a comp cams cam. part # 07-501-8. 212/218 duration, .488/.495 lift and 112 LS. I am not a cam expert by any means but I thought the 112 LS would give some choppy idle and the rest seems modest so I think it would be a good fit? I do not know though. also considering the lt4 hotcam too but wanted to suggest something different. let me know if anything fits my wants? thank you.

I know I am going to have to get springs. I have NO idea how to match springs to a cam. No idea what springs I would need. any help here would be great.

Since I am buying so many parts I want to avoid lifters, retainers, pushrods, etc... but please let me know if you suggest anything. I am not going for huge horsepower numbers so I thought I would be okay with just the springs?

I hope this makes sense to someone why I want to do this. I know its a bit weird to do this mostly for sound, but while I am pretty much there, I want to do it.

Thank you very much in advance! any insight would be greatly appreciated!

I am not in a rush to do this job... but I do want to plan ahead and get everything I need.

 

[sea dog]

I suggest talking to Lloyd Elliot of Elliot port works. He is a premiere lt1 head porter. He can suggest either a off the shelf cam or a custom grind cam to meet your needs. He will also suggest the needed valve springs and other supporting parts you will need.

While changing the water pump be sure to modify it to keep opti dry if it ever leaks from weep hole. The mod is done by driving a plastic fitting into weep hole. Sealing around fitting with silicon or epoxy. Then attaching tubing and routing it so opti doesn't get a bath if pump seal fails in future.

 

[Mfirebird]

Thank you very much for the response and for the contact! I appreciate it

Also I have heard of that water pump mod and will do it thanks again

 

[wav6644]

212/218 duration will be an awesome cam, especially since you opened the exhaust up a bit. You should be a little more raspy, and the check engine MAY come on here an there on idle. You would also benefit greatly by upgrading the torque converter to 2400 to 2800.

You should opt for 105lb to 130lb springs. If your not doing Forced Induction in the future, you can probably should go with 105.

I know you want to avoid doing lifters, retainers, and push rods, but I would strongly urge you to look into uprgrading them as well. You are putting a more aggressive cam in, you need the rest of the moving parts up to the challenge. Honestly the only thing I would reuse would be the rocker arms... and I would even replace the rocker arm bolts.

Depending on how far you want to take this upgrade, you should pull off the heads, install cometic head gaskets, and if you don't want are looking for boost on a buck grab a dremel and grind and polish kit. Don't go crazy with the grind, just smooth things out.

Your other option is to have someone Stage 2 or 3 your heads. You'll get an amazing upgrade, but it usually starts around $1,500, and you send them the heads.

 

[Mfirebird]

Sorry for my delay in response, I wasn't expecting anymore help with this, so thank you very much! I do not plan on upgrading too much, just wanted to throw a cam in while I was doing everything. I really appreciate the insight! Thanks again. I will mostly just do the 105 pound springs, since I will not be doing forced induction. I will look into the lifters, retainers, etc... thanks for being honest.

 

[wav6644]

Honestly if your just looking for bang on a budget, and doing it yourself:

Pull the Heads and Intake Manifolds Off, and do a simple polish (just smooth out the exits and inlets, and carefully smooth out the chambers around the valves). Thats about $20 worth of sanding/grinding/polishing bits.

Headers if you don't already have them. Thats about $350, but a foundation mod and a must if you already got the heads off.

Grand Prix 2004-2008 GTP (Supercharged) fuel injectors. About $40 to $60 at a salvage yard.

Your cam, about $320.

Upgrade the Torque Converter ($500 to $800),

Trans Cooler for around $50

and Finally a Custom Tune around $150... it is a must for the upgraded Fuel Injectors and Torque Converter and you optimize the full effects of the cam and intake/exhaust upgrade.

Upgrading a cam without the Torque Converter will wear down your trans... and upgrading your torque converter without the trans cooler will burn up your trans........ its all connected, some power mods without other supporting mods can lead to repairs.

Since your not planning on forced induction, you can probably get away with stock valves, retainers, and seals, but I would sill upgrade the Pushrods and Valve Springs... These upgrades will ensure you get a nice upgrade with lasting power.. Don't forget new resuable rocker arm bolts... at $20 its not worth taking the chance on an old bolt breaking.

Also remember, since your cam is coming out, your really going to want to upgrade the Timing Chain... they don't usually snap like a belt, but don't last forever if you got it off to do the cam replace it.

Sorry to pile it on, but its better to do it once and do it right.

Shortcuts with bolts ons is one thing, but engine/trans internals is nothing to skimp on.

 

[Mfirebird]

Thanks again for the help, sorry about the delay in response. As I mentioned, my only reason for considering the camshaft swap was because I have to go in and change the timing chain anyway. So while I was doing that, I wanted to swap the cam out. I would have never thought of how a different cam would require new torque converter and so on. So for that reason, I will probably stay away form the cam swap until a little later on in the car's life.

Thanks for the suggestions, I honestly do not have headers, so I should probably do them and polish the heads like you said. I know there are a lot of threads on header install but just a few quick questions if someone doesn't mind helping me...

I know the install is a pain, but I will not be doing it alone and I will (hopefully) figure it out eventually.

If I keep the EGR/AIR...

I just need to buy better gaskets, extend the O2 sensors, attach a y-pipe after the headers, attach the single cat (I have a '95) after the y-pipe, and then attach the exhaust after the cat?

Will I need a tune if I keep EGR/AIR?

Will I pass emissions?

thank you again for the help, sorry to drag this thread on.

 

[wav6644]

What exactly is your end game???

You have an LT1 that is probably putting out around 250 HP at the wheels, assuming that you have done nothing major in the ways of modificaitons. Do you want to put another 40 at the wheels and get into LS territory, or do you want to go even farther?

If you haven't even tackled the Headers yet, then you should probably hold off on any engine internals for a while. Upgrades to the Cam, Heads, and Intake suffer greatly when the exhaust is restrictive. CAI and Headers and exhaust uprades won't get you much at the wheels, but they sure will earn their keep when you start upgrading engine internals and Fuel System.

As for your EGR/AIR question,

Leave it be. You will see almost no gains from removing them, and you will probalby not pass an emission test.

Pacesetter makes a set of headers that will bolt up the EGR tube right to your new header.

Don't mess with relocationg the O2's, they are in the locaitons where they are at for a reason. Your new headers will have bungs for new O2/s... never reuse O2's, especially all PreCat sensors. You run the risk of going rich or lean and damaging your engine all because unevenly burned O2's.

You will only need a Tune if you delete the PostCat O2 sensor, otherwise you will get a Check Engine light, and will not pass emissions test.Tuning after upgrading exhaust can get you a little gain, but in my opinion is not worth the cost of tuning.

My advice:

Tackle Exhaust all together.

Headers,Cat Back Exhuast, High Flow Catalytic Converter

Your probably looking around $700 in parts, maybe less if you buy used.

You will have a noticeable increase.

Then you can decide how much more your want to get out of your car.

 

[Injuneer]

95 (OBD-1) doesn't have after-cat O2 sensors. No codes, no SES for removing the single cat. I personally would not delete the cat. Little to be gained, and your exhaust will smell. I run dual cats on the street on my 800 HP LT1. They are flanged so I can drop them out when I run leaded fuel at the track.

If he uses long tube headers, he will need O2 sensor harness extensions. Virtually any headers made for the 93-95 LT1 will relocate the O2 sensors, particularly the driver side that is mounted in the bottom flange of the exhaust manifold. Since the 95 O2 sensors are 4-wire heated type, closeness to the engine is not as big an issue.

You will benefit from a PCM tune on a totally stock LT1. You can gain 10-15HP simply by leaning out the overly rich "power enrichment" (PE) mode target A/F ratio.

 

[wav6644]

Good to know about the O2's in the LTs.

 

[Injuneer]

In any state that rigidly enforces the FEDERAL emissions standards (like CA) it is illegal to relocate the cat(s) or change the number of cats. Hence, long tubes are not legal on an LT1 at all in states like CA. Since he lives in PA, it depends whether he is in an urban or rural area. Rural areas have very limited emissions checks.

 

[Mfirebird]

Thanks again for all the good help! Like I said in my original post, I do not have anything great planned for the car. I just love having it around and working on it. I originally only wanted to upgrade the cam since I already have to replace the timing chain.

That being said, I am planning on getting some long tube headers with EGR/AIR along with those O2 sensor extensions. I plan on keeping my cat and Il definitely look for a place around me to get a good tune.

Thanks again for the help I really appreciate anyone who helped me with this!

 

[wav6644]

I would suggest checking with a local shop about what is legal and not first. Since your not planning on going all out on a build, I'd suggest upgrading to a mild cam with the timing chain repair, you may be able to leave it at just a cam swap if you don't go too aggressive. You will see a noticeable gain, but nothing substantial, and probably won't have to do a Torque Converter upgrade either if you keep it mild. Just be prepared for valve seal leaks down the road.

Also you will get the most out of a cam upgrade when the engine breathes better. CAI if you haven't already, and a headers and cat back... you could probably put on a Magnaflow high flow catalytic converter, without any legal snags, I've read on their packaging that they are street legal in every state.

 

[Injuneer]

Just curious....what is the flow rating of the Grand Prix 2004-2008 GTP (Supercharged) fuel injectors? The stock LT1 injectors (94-97) are rated at 24.9 #/HR (programming value) an will support up to 360 HP at the flywheel (assuming 0.476 #/HR/HP BSFC and 85% max duty cycke). GM did upgrade the injectors in the LT4 version of the engine to 28 #/HR.

Also curious about "resuable rocker arm bolts". The LT1 3/8" screw-in rocker arm studs are seldom replaced with a simple cam swap when using a fairly mild cam (as discussed above). 7/16" studs are available, but not necessary at this level.

CAI and a 3" mandrel-bent catback (combined) will typically add 25 HP at the flywheel on the LT1. I verified that back in 1995 when I started modifying my LT1 (Callaway Honker + Borla Catback). Simply bypassing the throttle body coolant will net 6 HP at the rear wheels, dyno proven. 1.6X full roller rockers are a 10HP gain. Avoid underdrive pulleys and the throttle body air-foil.

Some good info on LT1 basic mods - from more than 15 years ago, but still valid:

http://www.ws6.com/mycar.htm

Seems like we may be mixing LT1 and 3.8L tech.

 

[wav6644]

The L32 (2004 Plus) Supercharged Grand Prix were around 32#. The L67 Grand Prix were 36# from my sources on the Grand Prix Forums.

 

[Injuneer]

Thanks.

Guess I can't use them to replace my 78#/HR (at 58 psi) Bosch low impedance units.