I am pondering getting either a full exhaust or stage 1 kit from ZZP.
The stage one kit is around $350.
The exhaust is probably $500-$600 with parts and installation.
The stage 1 kit gives 30 more hp supposedly.
The exhaust, I would guess to be around a 20 hp gain wise.

The kit is is nice, but... the installation would require the new pulley installed.
Plus it would need the computer to be swapped.
There is a section where the exhaust is crushed down by the factory, a bad stricture to the exhaust from what I heard.
To install it, they would probably charge me $135 or so to install.
I already think my motor had the thermostat is already a 180 degree one.
The K&N filter I would just drop in myself.
Probably would cost me $90 to have the computer installed.
Probably would cost me $180 to have the pulley and belt installed.
So, $755 plus tax and other fees or so to have the stage 1 kit on my Monte.

So... $600 for an exhaust: around 20hp. $30 per hp
Or... $755 for a stage 1 kit: around 30hp. Around $25 per hp

The advantage of the exhaust is having a 2.5" DP, 2.5" cat and catback would allow the motor to run cooler. Am I wrong on that assumption?
This in turn would help prevent pre-detonations as such. I live in a desert, heat is a concern.
The exhaust does not seem like it should have been put on the Monte Carlo SS as the stock configuration does not support the output.
Meaning, at 240hp, it should have been 2.5" for this output. Plus... that stricture... why did they do this?
I talked my Dad as he is an engineer, he said his bit on it... something about fluid mechanics I think and raising pressure which would create higher velocities of the exhaust gases.
Kind of like pinching the water hose, the velocity of the expended water raises due to the stricture.
Maybe the Chevy engineers did this for that reason or? Either way, it sounds like 2.5" is what is supposed to be more inline when supporting 240hp or so. Look at a exhaust diameter calculator for reference. I think I read it right that it should be 2.5". I hear the Monte SC is only 2.25" and the stricture is I can't remember but I think it is like 1.75" or something like that. The power logs/ exhaust manifolds are also anemic from what I read. Am I wrong?

The advantage of the stage 1 kit is that it will gain more power for less... but I live in an area that does not have 93 octane.
So... ZZP would have to mod the computer to reflect this.
Also, I don't want them changing the max RPM. Why? I don't think the rev limiter should be messed with. The limits are set for a reason. If the motor had upgraded head internals, then maybe I would allow it. But not on a stock head.
That mod on the tune to not allow for higher revs would also diminish gains.
How much? I don't know. But if I were to guess, probably 10 hp. Wild guess... but then if I am right. The exhaust would seem more beneficial.

I might get the oil catch can on this motor too.
It keeps the intake from getting the hot oil vapor as direct.
It has to travel thru the aluminum can and snake back to the intake which the distance should cool the intake temp.

I could be wrong. I am no expert.

That is why I am asking for input.

Which route should I go for?
Stage 1 (wimped out with no 93 octane and stock rev limiter)
...or DP all the way back 2.5" exhaust?

Also, does anyone know how much boost I will lose when going with the larger exhaust?

Thank you all for any input!

 

I also have a 2005 Tony Stewart. I put on the zzp 2.5 exhaust system on it. Stock downpipe (cat). I didn't notice and extra power. I put a zzp stage 2 on my other car and noticed a difference. I believe the zzp stage 2 and the zzp exhaust are close to the same price. I could be wrong.
Zzp flashed my computer with the stage 2 and I ran it like that on 91 for about 5000 miles and no problems. After 5k I put more zzp mods. I would not worry about them flashing your computer I didn't have any issues. The pictures are of the zzp and stock exhaust. I'll try to post the before and after video on my coworkers youtube page. The install was quick and easy. No need to pay anyone to install it.

 

Assuming by exhaust you mean catback - itll give you near zero. People have made pretty good power on stock cat backs with 3800s, so it's certainly not a giant restriction on a near stock engine.

If you're serious about modding your engine, you'll need to come to terms with this. The SC pulley is the #1 thing dictating how much air goes through (and thus how much power the engine makes). Certainly you cant just slap on a 2.55" without blowing it up, it needs supporting mods, but all mods on a supercharged engine are done with the goal of eliminating KR so you can drop the pulley further.

The nice thing with the modular pulley that the stage 1 comes with is that it makes future pulley changes super easy - no specialized pullers or anything, just take the belt off, take out 5 bolts, and you're ready for a new pulley.

There are only 2 places of real concern the U bend by the cat (not sure if 6th gen montes have those, but the stage 1 kit addresses that), and then the downpipe. Nothing in the catback is crushed down enough to be of concern at stockish powe levels.

Yes. Engine temperature is controlled by coolant temp which is dictated by the thermostat / heat dissipation of the radiator. Exhaust diameter has nothing to do with it.

How do you figure it doesnt support the power output? Stock dyno numbers are usually around 190-200 at the wheels, which is right about 240 crank, so it seems to support it just fine.

Everything on your car was done for a very specific reason. Nothing was just a random mistake. With that said, the reason can be bean counters overruling engineers as well, but in this case, the difference between 2.25" pipe vs 2.5" pipe is negligible when they're buying tens of thousands of sets.

Dont worry so much about looking at generic exhaust diameter reference charts, focus more about what actually works on this platform. The fact that no one is really gaining any power replacing the catback clearly shows it's well enough designed to not be a problem.

To be fair here, they dont set it at 10k. I want to say they set shift points at like 6k, a couple hundred over stock. If you don't like it, you can certainly specify what you want exactly with a custom pcm.

Not that ZZP has the engineering capability of GM, but it also isnt some random dude making parts in his shed. Theyve probably modded more 3800 cars than any other company, so they know what's ok and what's not.

Thats the problem with working with theory. Your exhaust # is a total guess (a VERY high one IMO) as is your suggested reduction in power by not going a couple hundred RPM higher.

It's not so much about cooling the intake temp. The volume of oil vapor being ingested is very low so theres not a measurable impact to the larger air mass. The primary feature is to catch the oil so it doesnt end up caked all over the intake or in the combustion chamber.

I'm all for catch cans, but they're a PITA to install on the L67 due to the completely contained PCV system. You can't just snip some hoses and stick a can in like you can in 90% of the cars out there.

Stage 1. As noted before, if you really want to make more power, the focus needs to be 100% on that SC pulley. Do the supporting mods you need to keep it knock free on that pulley and you're GTG.

0, not that it matters. Losing boost would imply the engine is more efficiently using the SC's output air. Changing the exhaust and gaining near 0 power would also imply that boost wouldnt change.

The thing is, people dont really measure boost often on L67s because it doesnt really matter. Supercharger RPM (ie pulley size) and KR (knock retard) are what matters.

 

What support mods do I need to prevent KR with the stage 1 kit?

Thanks guys for the input!

 

In theory, the idea behind the package is that you can just drop it in and not have to worry about it. In reality, you'll still probably have some KR. Unfortunately theres no way to know for sure in advance besides putting it on and scanning.

The upside is the pulley is pretty large, so its not a critical concern like chipping pistons with smaller pullies, but if you've got some KR, you could just continue to do supporting mods one at a time to make it go away (with the benefit that you get the added power from that mod + the extra timing from it not pulling that out).

 

What support mods do you suggest to lower KRs?

Thank you for the info thus far.
Stage 1 sounds like the route I will probably go.

I pondered getting some octane booster too. But, I wonder how effective some of them really are.

 

Depends on how much you have and what your long term goals are. The approach would be different if you slapped it on and had 2 degrees vs if you had 16 degrees. Same goes for if you had say 16 degrees and were generally done modding vs if you planned to keep going deeper down the mod rabbit hole.

In general anything that improves air flow, cools the intake charge, or adds octane would help. IE basically any legitimate engine mod. Some are just more drastic than others.

There is legitimate octane booster out there, but Im very against it for a few reasons:
-As you noted, its not all equal. You'd hate to run out of your supply of real stuff only to swap to another brand that doesn't live up to its claim.
-How do you know that its equally / throughly mixed in? Ideally you'd put it in before filling the tank, then drive a bit to mix it. But how would you ever prove its ready?
-It makes filling up more of a pain. You've always got to carry some with you and then calculate how much to put in to match how many gallons you need.
-It gets expensive. I'm not sure how many miles youve got, but its easy to do the math - if the car has say 75k worth of miles left of life to go, its easy to figure how many bottles you'll use at your current mpg before the car's life is over. My guess is thatll easily equate to enough $ to do a few more mods to reduce KR.


Also in general on a setup like this (say a 3.4" L67), its really goofy. Its a lot of extra effort for a car thats really not making much power in the grand scheme - still likely sub 300 crank hp. The hassle might make sense to some on a really heavily modded 500+ hp setup, but not on something still making less than a new sedan off the production floor. Not trying to knock your car / setup - but having to hassle with stuff like that on something thats not making a ton of power will get old quick.

The other thing on a SC setup, if theres enough KR to consider needing more octane, it means the pulley isn't matched properly to the mods / engine. And when we're talking something like a 3.4" L67 with a few bolt ons, there are lots more mods out there (and even larger pulley size options) to eliminate the octane concern.


If more octane is really desired, IMO the 3 best ways to do it on the 3800 are: E85, meth injection, race gas.

 

Just did the quick math on Boostane Pro just going from 91 to 93, assuming you have 75,000 usable miles left on the car.

That works out to $457 in octane booster over the rest of the life of the car. Obviously having it tuned for a higher than 93 octane would consume more and increase the costs further, but it seemed like 91 to 93 would be the minimum anyone would want.

Certainly other options too - you could save a bit by buying and storing it in bulk, but my point is on a 3.4" L67, there are useful mods that can be done in that price range.

 

Just looked into Boostane Pro, of all the things... it says not street legal. Probably has some sort of excess pollutant or???

Would the ZZP stage II kit CAI or K&N Wizair CAI intake help cool the incoming air?
I always look at those short ram kits with boxes as a WAI with a not so protective shield around it.
In other words, hot air is probably going into the intake anyways.
In turn, a supposed Cold air intake is just a Warm air intake with a gadget that does not actually get cold air into the intake.
I could be wrong.
But some look like, how can it possibly draw cold air in and block hot air out with that set-up?
Not saying ZZP's CAI is that way, but I am saying I have seen other set-ups and think that.
I ask because someone here must have one and can chime in as to whether it works or not.

I have watched CAI vs WAI on Youtube, and the one thing I disliked was the dyno was with the hood open if I remember correctly.
So that WAI has that huge fan they use is probably allowing colder air into the WAI.
The CAI with it's bends and longer length made the comparison to me under that comparison of the hood being open, not a open and shut case of a WAI getting more hp.
The CAI when driving around is drawing lower temp air in, albeit probably less velocity.
The WAI when driving around is stuck under the hood point blank to the very hot motor, sucking in very hot air.
Although the WAI has less bends and is shorter which is probably landing it higher velocities of air, the hot air coming in probably negates a lot if not most or all of the benefits of that higher velocity of air coming in with extremely hot air coming in instead.

I could be wrong, I don't have a lab nor was I good in science class.
But it seems feasible.

 

They address that in the FAQ on their site- but you're exactly right:

"The reason why we have to put Street Legal vs ot Street Legal is pertaining to the concentration of certain active ingredients (doesn’t contain lead) that the EPA deems not legal for on road use only, when blended above 103 octane."

Looks like its only not street legal blended over 103 though. To be fair, its likely no one would do that anyways. Its almost 9 oz / gal to get to that level from 91, so you're talking over a gallon of this stuff a fill up which would be horrendously expensive for a street car - thats like +$90 fillup buying in bulk. Which on top of the price for the rest of the gas to fill the tank is probably almost exactly the cost to fill the car with legitimate unleaded race gas.

IATs (measured pre blower) would be nearly the same as stock as the stock air box draws from the same general region and blocks out the engine bay air.

With that said, it has the potential to reduce post blower temps as positive displacement blowers gain efficiency by minimizing how hard it is for them to suck air in.

IMO a CAI is a worthwhile mod (ZZP, CAI, or even an ugly DIY version).

The K&N "CAI" is exactly what you're describing. Its a short ram with mediocre walls around the sides to try to force it to pull from the fender / behind the headlights. In practice, its just like you're thinking - if theres a gap there with pressure on one side (air coming through the radiator ) and vacuum on the other (from the filter) - the hot air is going right through the gap. I had one on my GP GXP and IATs were worse than stock everywhere.

The ZZP and Wiz are both good, true CAI. Rather than trying to figure out how to seal the walls to an irregular hood like the K&N, they just put a lid on it so the only hole is behind the headlight and or up against the fender.

With that said, you can also DIY one as well. Probably won't look as good, but its not hard to replicate the function they get if youre not into spending $300 on an intake. Especially since the power gain from this mod alone isn't going to be huge.

The one upside to any of them is getting to hear that beautiful supercharger whine!

TBH there aren't a lot of bends in the Wiz or ZZP. Certainly more than a filter slapped on the TB, but not that much more, and the bends are fairly straight.