Intake Manifolds

[XanderWiFi]

http://wot-tech.com/shop/la1-3400-performance-intake-manifolds/cat_56.html

I was carousing through these on WOT-TECH and wondered what difference they made as far as effects on the engine and whatnot. They are all for the 3400 but seem to have differences as far as flow and power. I'm uncertain of how that works: I thought a 3.4 is a 3.4 is a 3.4 ya know?

[JLw7123]

it is the ported intake manifold.nate has the intake manifold ported on his car and he says he notices a difference.

[XanderWiFi]

To take the manifolds off is to have to replace all the gaskets etc right? Big engine job if I remember correctly?

[JLw7123]

why are the gaskets leaking and yes it takes a while. Ask nate

[XanderWiFi]

No my gaskets and engine are fine. I believe I may be getting hooked on upgrading and I'm starting to browse for future projects...

[Nate's Alero]

well, no, the biggest difference you're gonna get is if you do a complete 3.5 LX9 top end swap, you can get heads 200/pair, and manifolds 100/pair, plus gaskets 130/set and you'll feel a HUGE difference

[JLw7123]

get the MLS gaskets from WOT

[JLw7123]

well, no, the biggest difference you're gonna get is if you do a complete 3.5 LX9 top end swap, you can get heads 200/pair, and manifolds 100/pair, plus gaskets 130/set and you'll feel a HUGE difference
yes nate you are going to help me with the 3500 top swap.

[kwhauck]

it's not really that hard, just take your time and if you need to write down what bolts go where and take pictures..

and i can get a complete 3500 engine for $180...

[JLw7123]

oh those are great ideas thank you.

[XanderWiFi]

I believe there is a how-to thread somewhere for it as well...

[JLw7123]

ya there is.

[XanderWiFi]

So prolly better to simply upgrade to a 3500 rather than try a different 3400 manifold? Why am I even thinking this...like I have the know how and tools or something...

[BlackJack]

Personally, I recommend the 3500 heads/intakes, preferably as a set.

The flow characteristics of the 3500 LIM/UIM in stock form are nearly equivalent to a fully ported 3400 set. Add the heads, and port/polish the whole set, and you've got some serious flow.

UIM/LIM isn't that hard to change.

[XanderWiFi]

3500 headers are easier to come by then 3400 I take it?

[BlackJack]

headERS or heads?

The exhaust flanges are the same bolt pattern for either head style.

[XanderWiFi]

I meant heads. So what makes a head ported? May seem redundant but I'm lost with some of the terminology. Also, what other parts will need to be swapped/upgraded as a result. Any negative repercussions from this?

Kwhauk, I definitely can't do an engine swap though it would be cheaper lol.

[kwhauck]

no engine swap, just the top end, but it is cheaper to go to a junk yard and buy a complete 3500 and dissasemble for the parts you need rather than buy them separately.....

[BlackJack]

Here's a lesson in definitions (in my own words):

Ported means material is removed from the air flow path, and in some cases reshaped to enhance flow characteristics (shaping). This removal of material increases the diameter of the channel the air flows through and therefore increases the volume of air your engine can take in. This applies to anything in the intake flow path, from the Throttle Body, to the Upper and Lower Intake Manifolds, and also includes the Heads.

Match-porting means that two different items (such as Upper and Lower intake manifolds for example) are both ported where they mate so it also further reduces flow restriction and turbulence in the flow path.

Polished means the channels are made shiney-smooth which also reduces the resistance the air flow encounters as it passes through.

Gasket Matching means the gasket is also shaped to the exact dimensions of the corresponding ports to additionally reduce the turbulence and enhance flow.

The combination of all of the above will give the optimum flow characteristics when done properly.

[XanderWiFi]

That helps quite a bit blackjack. But could you have a 3500 upper manifold with a 3400 lower manifold. If I am understanding correctly they come that way...but seems like it would not help anything if the lower was a 3400 and upper a 3500 because there is still a bottleneck point. Kind of like how my exhaust performance won't be fully realized until I have headers to open that bottleneck. Oh wot-tech please hurry...lol

[BlackJack]

you "can" have a 3500 upper and 3400 lower, but if you're going ported on that 3500 and stock on the 3400, well..... it seems like there would not only be a bottle-neck so to speak, but seems there would also be a "shelf" as it were for the air flow to get around since the 3400 ports are already smaller than the 3500.

[XanderWiFi]

So unless you do a full conversion there really isn't any point is there?

[WhiteV6]

A 3500 upper ported for a 3400 lower on a stock 3400 lower is still going to improve flow over a stock 3500 on a stock 3400 lower. The advantage to the 3500 upper is the plenum volume, and the broader powerband it will give you. It is best to port everything to match the parts, but you can certainly run a ported upper on a stock lower just as you can run a ported lower on stock heads.

[XanderWiFi]

That poses another question: what is plenum volume? I thought ported just improved airflow compared to a stock. So why would a ported be better than a stock 3500 when you still have the stock 3400 lower bottleneck regardless of ported or stock 3500s?

[WhiteV6]

The area inside the upper intake between the TB and the runners for each cylinder.

The first bottle neck is the air filter. Then the intake tubing. then the maf. then tb. then upper. then lower. then heads. Why do you put a larger TB on a motor and gain power if all those other bottle necks are still in place?

[Redog]

^^ He knows all with this topic. Years of reseach.

I have Stage 2 upper and lower (both 3400) from his site and I feel a difference.

To do an upper, you'll need about $8 in gaskets, no RTV, and 6 bolts (10mm) on the mani, 2 on the TB (13mm), and 2 holding on the coil bracket (10mm or 13mm I forget)

[mbeals]

That poses another question: what is plenum volume?

Plenum volume is voodoo magic. Think about an engine with one intake runner per cylinder fed off of its own bore in the carb/throttle body. If the cylinder starts outflowing the throttle body, the manifold bottlenecks and you lose top end power. Instead, if you introduce a larger, shared volume of air, as the heads
start out flowing the carb/tb, it has a reservoir to pull against, drawing a vaccum. The bigger the plenum, the easier it is to draw a vaccum, but that also means you lose response.

It was a big deal back in the day because carbs were a limiting factor....it was hard to just make a bigger carb. So you either kept adding carbs, or you added plenum volume.

Now this is the part I don't get. With modern MPI engines, plenums should not be necessary. You could use a tunnel ram intake with zero plenum volume and completely isolated runners....no need to worry about mixture or atomization at all in the intake manifold. Yet intake manifolds are still the same as they used to be and (some) engines still show improvements by adding plenum volume. I've even asked old time engine builders who have designed intake manifolds and manifold turtles, and they just say they know it works because it does.

[WhiteV6]

Hard to run a MAP sensor without a shared area between all the cylinders. Its also hell on a MAF to deal with all those intake pulses. When the intake valve closes, it sends a shockwave back up the intake runner. The added area is a buffer between the intake pulses and the MAF. Most independent throttle setups use alpha N fueling, which is RPM vs TPS. Great for the track, not so simple for the street.

Plenum volume and throttle body size are just like carb sizing and plenum area, only we don't have to deal with vacuum at the throttle body to draw fuel in and disperse it to each cylinder.

[XanderWiFi]

Plenum volume is voodoo magic. Think about an engine with one intake runner per cylinder fed off of its own bore in the carb/throttle body. If the cylinder starts outflowing the throttle body, the manifold bottlenecks and you lose top end power. Instead, if you introduce a larger, shared volume of air, as the heads
start out flowing the carb/tb, it has a reservoir to pull against, drawing a vaccum. The bigger the plenum, the easier it is to draw a vaccum, but that also means you lose response.

Just to reiterate so I make sure I understand. The bigger the intake (ported 3500 etc.), the more air it will draw in so the cylinders have a continous flow correct? More continuous flow or an "air reservoir" so to speak-equals more power? But why would a loss in response time be the result? Seems like I would take a loss if I did the conversion or did not do a conversion-just depends on what area I want to take the hit in.

White-are you saying if I did this I would need to extend my tubing from the throttle body to the intake to diminish the shut off backflow that interrupts the MAF? What if I just opted to upgrade to ported/polished 3400s-what would be the complications with that?

[WhiteV6]

No such thing as continuous flow. When the valve shuts, the pulse keeps moving towards the valve, which has also created a wave back up the runner.

You are trying to make this much more complicated and involved than you need to be. The ported 3500 upper isn't going to kill throttle response and will offer the best powerband.

[XanderWiFi]

I got ya. Just back me up a bit. Is there a simple metaphor that can be used? I'm just not a mechanic...I feel I could do this, but I want the ducks in line and such. Sorry if my ignorance is bugging you guys...

[WhiteV6]

You don't need to worry about the MAF, any tubes, or plenum volume. I am not a mechanic either. I deal strictly with performance. Unless you are building a custom intake, none of the details for making a custom intake really mean anything. The MAF/pulse thing doesn't apply in the least with a 3500 upper. If you want to learn how all that stuff works, there are books dedicated to the topic. It gets quite specific and detailed the more you read up on it.

If I try to explain anything in general terms, it just snowballs.

[XanderWiFi]

I see. Thanks for trying.

[XanderWiFi]

Ben, what is the best setup you would recommend on wot-tech? I see the packages and such but I wonder if there is a setup you find to be the best?

[Redog]

^^ depends on your budget. Take a look at his site, he's got lists of stuff from Budget to all out

[XanderWiFi]

no budget. Which set is the all out?

[xXManwhoreXx]

no budget. Which set is the all out?

DIY than... get a dremel and go to work...

[XanderWiFi]

That's...not an intelligent suggestion...

[xXManwhoreXx]

That's...not an intelligent suggestion...

There are tons of DIY porting tutorials on the internet... I have done 2 of my cars

[XanderWiFi]

I am not even sure I will be able to get the produced ones in my car without destroying my engine let along produce them myself. I'm a play-around mechanic and nothing more. And we all know how internet tutorials can turn out...I say tomata, you say tomato and such. I'll take the product straight from the professional, with the professionals advice and have it no other way.

[WhiteV6]

Depends on if you want to deal with a 3500 upper intake or keep a 3400 upper. Heads? I don't know what you want to do to start this discussion again.

[XanderWiFi]

It seems that adding the 3500 heads has the greatest benefit and is not that difficult to convert so I would be willing to go that route.

I actually found an article referring to a 3500 swap but it is old and I think you have made greater strides since then. ported/polished 3400 upper and lower or a ported/polished 3500 upper and p/p 3400 lower? And any accessory parts to boot.

I will be buying a hptuner professional when funds allow and will probably need some help with that too.