superscotty19

Hey everybody!

I have an 86 TA that I want to put an Edelbrock Performer intake manifold on. First of all, I know there's significant power gains, but has anybody noticed any mileage improvements/cutbacks? Also, because my car is an 86, it has the EGR valve and therefore I supposedly need part #3701, as opposed to the oh so common 2101 for most SBCs. I'm wondering, do I "really" need to get the 3701, or can I make the 2101 work, and if so, how?

please reply to scottcarsonREMOVETHIS@sasktel.net (omit the obvious)

Thanks a lot!
-Scott.

Air_Adam

If you have stripped your emitions, dont bother with the EGR manifold. You wont need it. I took the EGR system off my L69 and haven't regretted it at all.

If i were to get one, i'd get the non-EGR manifold.

superscotty19

Thanks!

I know now that EGR is "Emissions Gas Recycling" or something like that.

I do have my emissions left on the car as far as EGR goes (I think .... what does the EGR look like/where is it located?), and there's supposedly some strict regulations up here in Canada coming up pretty soon, so I should probably keep it. Luckily, I just found a 3701 on ebay so I'm gonna try for it.

-Scott.

James Montigny

Exhaust Gas Recirculation Valve. Factory manual says: "The EGR system serves to recirculate a part of the exhaust gases into the intake system for the purpose of lowering the maximum cumbustion temperature in the combustion chambers and thereby reducing nitrogen oxide emmissions."

Malfuntioning EGRs cause Rough idling, stalling, surging.

8Mike9

Welcome to thirdgen.org.

If you have functional or visual emission testing, you need the 3701.

AJ_92RS

Here's a good explanation of what an EGR does, and why you should keep it.

RB83L69

If your car already has the factory aluminum manifold, you won't notice much of a difference from putting one of those on.

I'm going to assume this is a LG4 car....

The first thing it needs is exhaust. All the way from the heads to the street. Get a chassis-specific set of headers and a high-flow cat and a cat-back, BUT NOT for the LG4; any piece that fits with what you now have will preserve the first bottleneck of that motor, namely the tiny Y-pipe and cat inlet & outlet. I'd suggest SLP headers if you really want to bite off, or Edelbrock TES, and then the cat & cat-back, for something like a 88 350 TPI. Do it all at once, every single piece, because every bit of it is different-sized from what's there.

The next thing you need is a cam. The LG4 comes with the tiniest cam Chevrolet ever put in a small block; even tinier and wimpier than the ones in those might 165 HP 350s of the 70s. While you're doing the cam, always replace the valve springs and their hardware, and it's a good idea to get rid of the factory rubber rocker arms, so you don't give away various amounts of lift at each valve, usually anywhere from .030" - .060" leass than the "theoretical" "specification" lift you would see in a book or something.

The next thing you need is gears. You probably have 2.73s now. A set of 3.42s or 3.73s will wake your car up to the point you won't recognize it.

Somewhere along the line you'll need an air cleaner. A dual-snorkel cold-air system such as the L69 is better than an open element.

After that, port & polish your heads.

Then after all that, an intake might make a noticeable difference.

To give you some idea, I'm running a 305 in my car right now with the exact same intake, by part #, on it that you have; the stock intake, the stock L69 air cleaner, stock cooling system except for a Stewart water pump, stock carb, stock dist, stock exhaust except for Edelbrock TES; every single piece of emissions equipment installed and operating, from when I lived in an "enhanced" emissions area of Southern California; and the car does about 210 RWHP on the dyno. That's about 260 at the crank. That's about 100 HP more than your car does..... with the same intake.

Conclusion: you don't need an intake to make more power yet.

The correct way to modify a car is to identify the one single part that's imposing a limit to the car's performance that cannot be overcome, and replace it with one that overcomes the limit. Note I said "car", not "engine". Unbolting things that sit up on top where everybody can see them, and re-bolting big shiny new chrome and aluminum ones in their place, is the sure road to a thin wallet and a car that isn't any faster than it was; maybe even slower.

Air_Adam

Sounds to me like all you modified is the exhaust system and swapped the water pump on your L69. How did you get it up to ~260hp? Did you change the cam too? You didn't mention the cam...

Anywhoo.. Take RB's advise. He is right. Find the part that bogs it down the most and work your way back to the part that has the least negative effect on it. The stock aluminum intake is a good one. I have one on my L69.

Ray87Z

Interesting article on a LG4 buildup. www.inter-scape.com/ray/305buildup.htm

Note that the baseline already has the exhaust taken care of. You won't get the ~20hp/20ft-lbs that they did from the Performer over the LG4 intake if you're still running the stock exhaust choking everything... Also worth noting that the Performer RPM made another 15+ hp on the stock cammed LG4 (not sure if that will fit under the firebird hood)...

RB83L69

I've got heads & cam too, but nothing spectacular obviously. My main message is, the intake isn't where you'll pick up power, because it's not the choke-off point.

superscotty19

Thanks, guys!

Well here's what's happened since my first post: I did get the Edelbrock 3701. So that means I've got a Crane Cam, MSD coil, FlowTech headers, and the 3701. I didn't touch the gears (I have stock 2.7x) because I know that if I do, I'll get crazy speed off the line, but only off the line, and my mileage will suffer.

Now, last year I went on a huge road trip (without coil, cam, and intake upgrades), and got well over 500km/tank (~28MPG). This is on a Q-jet I might add. This year, I went on another trip, but with the additional mods. I only got max 450km/tank, BUT, my EGR was disconnected before the trip due to malfunction. I know I have WAY more juice in that engine than before the last trip, and I'm almost positive that with the EGR fixed, the mileage will pop right back up and I'll have one sweet setup - good enough power, and great mileage , making for one fun car to regularly drive.

johnblacksox

I'm new to this board, but it looks great. I'm also looking to fix up my '86 LG4...

I'm confused by this part:
"The first thing it needs is exhaust. All the way from the heads to the street. Get a chassis-specific set of headers and a high-flow cat and a cat-back, BUT NOT for the LG4; any piece that fits with what you now have will preserve the first bottleneck of that motor, namely the tiny Y-pipe and cat inlet & outlet. "

What do you mean, 'not for the LG4'? I thought that installing better headers (SLP/Edelbrock) and exhaust (Flowmaster) would eliminate the bottleneck out of the engine.

After doing the headers/exhaust, if I get a new intake & cam (Edelbrock 3701), you say:
"While you're doing the cam, always replace the valve springs and their hardware, and it's a good idea to get rid of the factory rubber rocker arms"

I'd be taking it to a mechanic, so what would I need to tell them to replace? Just the valve springs? Is that a big project, and what happens if I don't replace them?

-John

Sitting Bull

Exhaust systems that are specially packaged for LG4s do not have a solid 3 inch exhaust. Usually they give you a y-pipe that is 2 or 2 1/4 inches, etc. So, if you buy one of the specially packaged deals just get one meant for a 350, as it will have all the good parts you want.

The stock valve springs are likely kaput and will doubtless puke on you if made to run on a cam with decent lift. The LG4 cam is pathetic with .350 and .385 lift. A decent cam will have in the .42x to .45x region. The stock rocker arms aren't very consistent in their ratios, so new roller tip ones from Comp or Crane will make a nice difference.

(BR)G-Machine

Whenever I hear someone wants to put an EPS intake on their car I suggest this one because their ARE alternatives out there, and some good ones.

Weiand G Team

Now this one is a single plane so your not gonna want to use it on a 305 with the stock cam, but I agree with what I thought I saw somone else post, that you gotta do the exhaust, cam, and heads before you do the AMERICAN ISSUE lg4 intake. Canadians got a cast iron intake that is worth swapping.

RB83L69

Right about the exhaust; if you buy, say, TES for the LG4, it will come with the drinking-straw Y-pipe, because it has to so that it can hook up to LG4 exhaust. Same for a cat-back; if you buy one that will hook to the LG4, it will have to have the same drinking-straw inlet, so it can hook to the stock Y-pipe. That's why you don't want ANYTHING that will fit LG4; it will preserve the bottleneck. The other parts are the same shape, follow the same routing, bolt to the heads the same, etc. etc.; they're just made out of bigger pipe.

If you change the cam but don't replace the valve springs, 3 things will happen:

1. The seat pressure of crappy stock springs is very low even when new, and it goes away over time; so if you go put some aggressive cam with steep ramps in there under a bunch of worn-out already weenie stock springs, the valves will bounce off the seat when they're supposed to close, which is the most common kind of valve float. This leads to: loss of power in the very RPM you're trying to make power in by changing the cam; broken parts; and excessive wear on the entire valve train.

2. Stock springs are made of few turns of thick wire. Their pressure is not linear with deflection; that is, to push them twice as far, the force on them is not doubled; t goes up faster than that. So even though they have low seat pressure, they will generate very high open pressures when used with good cams. The coils of wire may even stack up and bind, in which case the valve train is then trying to compress solid metal, which doesn't work very well. Again, very rapid wear on the cam, lifters, retainers, and rockers will result. Better springs are made of more turns of thin wire, which has a more linear force-displacement curve, less heating (heat being the biggest enemy of springs), and greater space within the spring, which allows higher valve lift before reaching coil bind.

3. Overstressed springs break. When they break, the valve falls into the cylinder. I don't know if you've ever seen what happens to a motor when a valve falls into a cylinder at speed; let's just say that since valve fragments are not compressible, often there is NOTHING at all that can be salvaged after this failure, not even the head castings. Pistons come to pieces, valve stems go through cylinder walls and head castings, rods bend and break, etc.

Bottom line: Change the springs. Don't even wonder about whether you can get away with not doing it; it's cheap insurance. Also, the cam mfr will usually not warranty the cam if the correct springs are not installed (correctly) at the same time as the cam. It is not a big project at all, assuming that you're not going hog-wild with the cam.