thinking ahead, minimal mods for blower

[John_D.]

I want to do the blower bolt-on, and not take on the exhaust mods. At least not anything cat-forward. I might go cat-back, later. But I figure the boost will be 90% of the gain, with only another 10% or so, playing with the exhaust. I'm all for getting the 90% easy, and letting the 10% slide... The only concern with this approach, being the stories here about blowing dipsticks, seals, etc.

The two approaches I've seen here to deal with that problem have been:
1. Eliminate exhaust restrictions.
2. Improve the PCV side of the equation.

The pcv mod would be my first preference.

So, I have what may be a dumb question, but maybe not... Seems that the pc valve itself will be the weak link in keeping boost from entering the crankcase directly. Have you guys moved the intake end of the pcv upstream of the blower, or have you left it downstream? Upstream it should always see vacuum, where downstream it's going to get hammered when the boost comes on. Plus the pcv will still be able to be active under boost conditions, helping to additionally relieve any pressure that may slip into the crankcase from the cylinders.

p.s. I love this idea of putting a blower on a stock sleeper v6!!! I hope you guys get the brackets and stuff worked out.

[Mcaanda]

Run a search, I answered this SAME question about a month or so ago....

And if you dont go with exhaust route, why even waste your time with a blower?
Your force feeding your engine with more air, but dont want to allow it to breathe better?
IMO, your going to be wasting your time if you dont, and your performance will suffer.

[John_D.]

I searched all over the place on this topic, and only found a few vague references to pcv mods. One post mentioned blocking a port. So I had to ask the direct question.

I didn't find anything specific to relocating the suction end of the pcv hose, and that is the aspect I want to know. If you addressed that, point me in the right direction, and I'll be glad to go read up on it. Much better to learn from others, I don't have the time or the patience to learn it all from scratch myself, that's for sure...

As far as exhaust mods, the only specific numbers I've seen from researching V6's for '98 up (not SOTP, but dyno numbers and e.t.'s) suggest a max of 5-10 hp gains for headers, cat-back's, mufflers, and so on. Makes me think the factory system is pretty close to where it needs to be, for the money.

So if I can get 100hp off the blower, and only another 10hp for the exhaust, I'll be tickled to go blower only and leave the factory stainless system intact.

I am curious though, if there are real numbers available to support larger gains from exhaust mods, and which specific mods provide them. I used to put headers on everything I had, but after dealing with the inevitable leaks (at the block and at the collectors), starter heat shields to keep starters alive more than 6 months, engine compartment heat increases, plug wires, and the list goes on, I'm more reserved about going down that road than I used to be.

I'd rather spring for a better intercooler if I'm going to spend additional dollars on the car.

[Rik]

<blockquote>quote:</font><hr>Originally posted by John_D.:

As far as exhaust mods, the only specific numbers I've seen from researching V6's for '98 up (not SOTP, but dyno numbers and e.t.'s) suggest a max of 5-10 hp gains for headers, cat-back's, mufflers, and so on. Makes me think the factory system is pretty close to where it needs to be, for the money.

So if I can get 100hp off the blower, and only another 10hp for the exhaust, I'll be tickled to go blower only and leave the factory stainless system intact.
<hr></blockquote>

That 5-10 hp gain is on the NORMALLY ASPIRATED engine. Making the air go out faster doesn't help all that much without any extra coming in.

On the other hand, if you put a blower on and leave the exhaust stock, it will become a big BOTTLENECK.
Shirl's car, if I remember the article in GMHTP correctly, ran something like a 15.1 AFTER installing the supercharger, and about 15.4 stock. Not much improvement, right? After adding headers, cat, and catback, it ran 13.99.

So if you DON'T upgrade your exhaust, you will be pretty much wasting your time on the supercharger.

Rik

[John_D.]

<blockquote>quote:</font><hr>Originally posted by Rik:

That 5-10 hp gain is on the NORMALLY ASPIRATED engine. Making the air go out faster doesn't help all that much without any extra coming in.

On the other hand, if you put a blower on and leave the exhaust stock, it will become a big BOTTLENECK.
Rik<hr></blockquote>

Good point, and it makes intuitive sense. I went back and doublechecked a couple of sources based on your feedback, to find some firm data to back it up or disprove it.

First I checked the Vector link at the top of the bulletin board page - they got 100 dyno hp with no exhaust mods, 3.8, 8.65psi, probably a '97 (the article was in '97).

Then I checked Shirl's link (Shirl if you're listening, your link on your profile has an extra HTTP in it, so it didn't display, but I was able to right-click on the "red x" and get the url from doing a properties on it anyway...) and Rik you are right, they did end up doing exhaust mods, with e.t.'s to back them up, on a '96. They didn't say what the boost level is, in the article. If it is non-intercooled, it may be on the light side, which would account for some of the difference. Maybe Shirl or someone who knows can shed some light on this angle.

I also checked the technical database on this site, general information by model year, and there were some slight changes on the exhaust in '98 but nothing that sounded significant. (I was hoping for something to help me out here...)

Finally, I understand that intercooling, besides preserving the engine, will also permit more boost. More boost should compensate for the exhaust, I would think. I am planning on an intercooler on mine.

Anyone else with specifics, please chime in, for this project I am not wanting to run an experiment. I just want to bolt it in and have instant fun. (and still curious about the intake side plumbing for the pcv...)

[Jason]

You really need to do the exhaust right along with the blower. Most of these guys know what they are talking about when it comes to adding a blower. I dont personally have one but i read way too much and know some stuff. I agree with the bottleneck comment. You cant give your car more air without giving it a way to expell the added exhaust that the blower is going to create. SURE headers catback and a highflow cat may NOT give that much gain on a N/A engine like somone else has said, but when you add that nice whining PROCHARGER your gonna need those. This goes along with the dipstick blowing out. STEFAN was having that problem until he opened up his exhaust as much as he could.That solved the problem. If i remember he was running like 9-12psi when the dipstick was blowing out. The more boost you run the MORE LIKELY its gonna be that that dipstick is gonna get shot out. You cannot compensate for Poor flowing exhaust with MORE BOOST from the Blower. That makes no sense to me anyhow. Heres what gets me...your gonna put between 1500-3500 into the blower and NOT do anything to the exhaust. YOur already spending a ton of money for the blower so why not spend a LITTLE BIT more and do the exhaust up right. Itll save you Headache later on. Sorry for the book but its just me 2 cents And BTW i dont beleive there is a such thing as MINIMAL mods for a blower. If you dont go all out and do it right...SOMETHING is gonna break and cost you EVEN MORE money later on.

[ January 26, 2002: Message edited by: Jason ]</p>

[John_D.]

I have to draw the line somewhere. My natural tendency would be to do heads, bottom end, exhaust, over-boring, etc., etc., and the next thing you know, I'm working on the car more than I'm driving it. So I'm taking a hard line and going minimal.

From what I've read on this site, the base 3.8 should tolerate non-intercooled 9psi, so intercooled should be even safer and stronger. Detonation being the thing to watch out for, not boost. It is not in the plan to ever try to go beyond 9psi (or that's my story at the moment anyway).

My original concern, the reason I created this thread, was the issue of blowing out the dipstick (and possibly the seals).

And what I'm really fishing for, (STEFAN can you help me on this??) have some of the V6 SC pioneers been unintentionally pressuring the crankcase through the pcv system as a result of boost pushing through the pc valve? And can this be solved simply (the simpler the better, for me) by keeping the pcv upstream of the blower instead of downstream? I would much prefer to re-plumb the air end of the pcv upstream of the blower, than swap out the exhaust, just to fix a crankcase pressurization problem that may or may not be a backpressure problem.

If the overall power still ain't there, I can always do the exhaust later to finish it up. This way I'll know for sure if it is needed.

But I don't want oil blowing out of the engine... So I need to have a solution for this, going into the adventure.

[Jason]

Not being a jerk or anything but instead of messing around with the PCV stuff why dont you ya just spring for the exhaust and be done with it? qw knoq its a proven solution to the dipstick problem. I relize your goal is SIMPLICITY but i doubt messing with the PCV system is gonna be any MORE SIMPLE than redoing the exhaust.

[John_D.]

We kinda got stuck on the exhaust part of this.
The Vector project got 100hp without it. I believe like a lot of things with cars, choices on mods (performance or style) is just a matter of opinion. For me, I'm cool with holding off on the exhaust.

To me the pcv is an accident waiting to happen. If the boost pressure gets past the valve, there go the seals. So my question is still, what is the experience level with this? Has this already been thought about, and is already covered and I'm just playing catch-up? Does it need to be addressed with the upcoming kit? Am I the only one thinking about this?

Seems like this would just be a little bit of insurance to avoid:
1. oil loss,
2. resulting engine damage or at least cleanup,
3. the pain in the *** of replacing seals.
(I like to bulletproof.)

maybe the thread title should have been "minimal mods, with one concern..."

p.s. to Rik, I found a post from Stefan in the kit thread, where he says Shirl is running 6psi. So I can see where her setup would be more susceptible to exhaust restrictions.

[ January 26, 2002: Message edited by: John_D. ]</p>

[Shirl]

You should definately consider an exhaust for the car if you're going to get a supercharger. The stock cat will end up frying anyway (if you run rich). And believe me, you'll want to run rich. It happened to me and it happened to someone else I know who tried to run the stock exhaust. One thing to remember is that when you do one thing, you have to do another to balance it out.. hence more air coming in should equal more air going out. Besides, imo, the exhaust was THE best mod I had done to the car. I'll never forget the day I brought the car home after getting headers, a high flow cat and a Borla 3" catback installed, then taking off the right pipe and firing it up.. WOW!!! Not only will it sound and look killer, it'll be an absolutely functional outlet for the burned fuel. Whether you do it when you get the blower or down the road.. you WILL eventually need it [img]graemlins/burnout.gif[/img] BTW, thanks for letting me know about the url..

[Shirl]

I take that last part back.. there's nothing wrong with the url [img]tongue.gif[/img]