LT1guy

iTrader: (1)

If so, post pics!

While the long runner design on the stock 2.8 intake makes pretty good torque, on a modified 3.4 the runners seem a little small. I'm thinking about building a replacement for the runners and plenum that will be slightly larger (probably build the prototype in steel), with fewer radical turns than the stock piece and a larger plenum area. I plan to keep the runner length about the same so as not to give up any torque. I could port the existing pieces out further, but it seems the transitions in this intake could be causing turbulance and may be as much an issue as the size of the runners themselves. Any ideas guys?

Project: 85 2.8 bird

I belive Agood2.8 was working on a new plenum. Other than that.............................

FbodTrek

After I finish swapping in my new 3.4, I plan on Modifying my intake. I'm thinking of lengthening my runners a bit by spacing the upper and middle intake pieces. Another post gave me the idea...I think it would be entertaining to do. I let you know how it turns out.

KED85

I saw the one AGood2.8 made.
It's based on the Holley Ram EFI set up.
Good idea he made & cleanly executed.

TechSmurf

The one AGood2.8 fabricated, however pretty and probably quite functional on his 2.8, was only a replacement for the upper plenum which bolted to the middle plenum, and did not address the middle plenum's runner diameter, nor did it fully address the sharp turn in the middle plenum.. I think custom fabrication would be a good idea. I've been tossing around the idea of a tubular plenum for some time, but I'm far too occupied with other parts of the car to do anything currently, nor would my plan work well on a naturally aspirated car.

Love to see what you come up with, LT1guy

Gumby

A whole new plenum from the heads up would be neat.

6 aluminum tubes that run straight up into an oval fart can with the TB mounted at one end.

But much more than stock would kill the use of them fancy cowl 3 point strut braces. Wouldn't be able to go over top of the engine anymore.

V6sucker

how much can you fab metal? like weld, ect?

I was looking at making a 5" round tube, LS1 style and having the runners come out of the sides 1X1.75(stock port size of lower manifold) and both ends capped rear 1/4" plate front 1/2" then drill for TB (like mustang 75MM-under 200) and the 1/2 plate leaves plenty for tapping and strong bolt to area.

You will need to make your own fuel rails however.
You would shorten the runners to around 7-8" overall including the lower manifold, and heads.

Dale

iTrader: (12)

blue89rs and myself have been tossing up ideas at eachother. He even ordered a book that gives different number ratios, etc. An intake CAN be designed to have become nutral, rather then suction all the time, w/o a power adder.

Its more then just smooth, no bends. It involves where you want your power range, engine size, injector location, diameter of the runners, shape of the runners, lenght of the runners. No where near as easy as one things, plenium size.

To say the least, any production intake is not properly designed.

RBob

iTrader: (1)

Does any company make a single plane 4bbl carb manifold for the 60° V6? Can always use one of those add the injector bungs and a TB.

RBob.

Project: 85 2.8 bird

Nope, don't know of any single plane intakes for the 60* engines offhand.

however...........



Very interesting project Jerriko did

85f-bird

that's crazy project, neat idea, still crazy...guess we can all say that eh, "I LIKE IT" don't know the perfroamnce gain, but in a clean bay, polished up, that'd look bad...real bad.

br()bert

what about an upper and lower that would let you change the valve cover gaskets more easier....!!!!

Project: 85 2.8 bird

my current setup does that

br()bert

yeah well im not up to do a 3800 swap

6SPEED84Z28

iTrader: (1)

the problem is not with the middle or lower runners. it is with the upper plenum and the sharp runner turn from the upper plenum to the middle runners. one of the head engineers from gm on the 60 degree program told me this. i have also talked to the guys that built these engines for off road racing and they said the that the bottom half is a real good design and not worth changing. this is why dean (a good 2.8) built his that way after we talked about it for a while.

Dale

iTrader: (12)

Holly Hell Batman!!! I like that

Anyone got ideas what that came off of? TPI iroc, or is that LT1??

85f-bird

pretty damn sure it's just a TPI setup...but i could be wrong...think the LT1 setup is a little flatter, looks a tad different, maybe narrower too.

RBob

iTrader: (1)

Wow, nothing like a little more plenum and TB.

Did a search for a 4bbl single plane, no luck (yet). Holley and Edelbrock don't have any 60° V6 manifolds listed. A GM site listed a 4bbl manifold but no pic and no description. I'd bet it is a dual plane.

RBob.

TechSmurf

Hmm.. yanno, that whole TPI mod looks.. interesting.. but I would never have reused parts of the upper plenum.

Gumby

"I am modifying another 2.8L upper plenum to fit a TB off of a 350 TPI."


That was creative.
Should let the engine breathas much as it wants.

Gumby

"January 22, 2003
To run the 3.4L right, I needed more air. I chose a throttle body off of a 1987 Firebird GTA with a 350 TPI setup. I used the upper half of the TPI setup and had it welded to the upper plenum of a 2.8L intake. I was able to remove a ton of material that was restrictive. I had the part welded by Sean Power at Power's Toys here in Rockford. He did a great job! I installed the new intake setup this morning. It idles great and the top end power is outstanding. I have drawn a lot of attention with this project and I think its really going to pay off this spring at the track."

http://67.104.247.214/jmb/firebird/home.htm

LT1guy

iTrader: (1)

Glad to know that some people "in the know" agree with me. I'm happy with the torque production (over 200ft/lbs at the wheels, with an auto and a loose convertor) , and I want to retain the same hood (Suncoast Ram Air 1, which doesn't really offer any additional clearance over stock),so I don't really want to alter runner length . I mainly want to eliminate, or smooth out at least, all the transitions and open things up slightly while in the process, to compensate for the increased airflow requirements of a modded 3.4. I don't want to go to a short runner design like an LT1, and kill the torque. If anything, I'd lengthen the runners slightly but enlarge them a bit, not drastically though since I don't want to kill velocity. The base, once cleaned up a little, is really good, a straight shot to the intake valve.

Gumby

This was a nifty idea to add some more fuel at WOT and once you have more air volume.

"September 17, 2003
While I was playing with the fuel system, I had this idea with the 7th injector. The 7th injector, cold start, injector is used to help start the car when its cold. It is not computer controlled but controlled by a temp sensor. When the sensor reads below a certain temperature, it grounds the injector opening it and allowing extra fuel to flow through it. Since the injector does not have to pulse, I installed a switch on the ground side of the circuit so I could activate it whenever I wanted to. During normal driving, it would not make much of a difference since the o2 sensor would just shorten the injector pulse but at WOT, it would just be that much more fuel. And yes, it does make a difference. "

FbodTrek

That looks interesting. It'd be nice if had two comparative dyno graphs.

Blue1989RS

I have an edelbrock intake for 60V6 sitting at home. Single plane, 2 or 4 barrel. I also have the matching Performer cam for a carborated V6.


The only problem that I can see with using the "Cold Start Valve" is that it shoots from Hole 6 and then over to 1 through a hole that goes through all of the intake runners. Hole 6 will run WAY rich. This richness will cause the computer to back off for emissions, causing the furthest hole, #1, to go way lean. I'd look into it before I continued using your hard wired cold start valve.

Blue1989RS

http://www.edelbrock.com/automotive/...chev.html#2.8L

3785
3787
3789

Project: 85 2.8 bird

are you sure that is a single plane base? ( not that it really says anything about it in the text )

Blue1989RS

Yes. How that system works is like this.....the base has all of the runners join up to the middle, just like the lower manifold on a MPFI. Then, there is an upper stack that the carborator bolts on to that is either 2 or 4 barrel. That explains why there are 3 part numbers instead of 2. There is one base and two tops. Sneaky. Took me a while to figure it out.

85 2.8.... Are you running a MAP system or MAF? I assume that you are running a MAP, which would explain why you are running lean. To correct your leaness, you may want to try to increase your fuel rail pressure. That should take care of it and get rid of your cold start trick. Either that or try to run bigger injectors. I could see that causing a problem though.

My dads Turbo2.3 T-bird had problems when he went with a bigger vain airflow meter. It was still the same proportion, but way too much air was flowing. When he tried to correct WOT conditions, it ran too rich at idle. Just right at idle, and it would run too lean at WOT.

So whats the setup??

Dale

iTrader: (12)

T, your getting it wrong

project85 isnt doing that, hes just showing that from another board he attends. Hes doing 3.8 swap

Blue1989RS

Aaahhh.....gotcha. My bad

But I assume that is what's wrong with the setup. Thats why dual TB's and a split plenum would be cool. I'd be the same to the computer.

I'm sure on the Edelbrock setup though, I've got it sitting in the garage with the cam waiting to be put on my bro's s10

KED85

IF ya examine both factory & the Edel 2-piece intakes side by side, you'll notice two differences.
The Edel item, when all pieces put together, only have a real true difference in height.
Other big diff is versitility, as one can swap top pieces (2-bbl using factory carb or a 390 cfm 4 bbl carb).
Besides those details, the Edel & factory intakes are "almost" virtually identical.
On the factory piece, if you increase/add a spacer between factory 2 bbl carb & intake, one can accomplish almost exactly same power increase.
That's why I await smog testing on my Blazer so I can make a spacer outta aluminum block. I plan on adding 1/2" - 1" in space between carb & intake.
I also plan on headers in a short bit on my Blazer, too. That should make the Blazer powertrain upgrade package just right. Any faster in this old 1985 Blazer & I'll just buy a new Buick Rainer with factory installed V8 & what, a 100,000 mile warranty & great new suspension package already done!

In all honesty, since 1984 or so, I've always "wanted" that Edel intake set up (cheap at swap meets!). Upon finally seeing it, in detail, those above mentioned details are only true advantage I saw. For the money, I passed on it.
The 3.4 mill has the Crane 2030 cam already installed, too. 3.4's are an aggressive street package mill, especially in our lighter weight 3 rd gen F bodies (compared to 4th Gens) packaged with efficent exhaust, efficent ignition & efficent outside fresh cold air intake set up.
Upon test driving my Blazer with the 3.4, I felt that bunp in lower back from the new found torque on tap.

FbodTrek

Is your Firebird running with the 3.4? Or are you in the process?

KED85

The Firebird has been converted & running for over 15,000 miles of 3.4 power & TWO CA smog tests.
My Blazer has 3.4 drivetrain & tranny installed etc. I've test driven Blazer & need to make final adjustments & smog it before hitting the road with that 3.4 conversion project. The Blazer is so close!
Just almost finished my Corvette steering column turn signal problem, so I can be back to 2 cars again.
Next is time for my Blazer to wrap up!
I can't wait to drive that 2.8->3.4 Long Block Swap Boogie project!
I really will need my Blazer for my next house rebuilding project.
What pics ya wanna see?
3.4 1985 MPFI Firebird or 3.4 1985 Federal Version Blazer 2SES Carb'd set up?
I got pics of both!

Project: 85 2.8 bird

There is no problems with the way my setup runs. I hard-wired the cold start valve for more fuel at WOT only! The cold start valve gets me more fuel and I know this cause I have an air/fuel ratio gauge. The computer will not try to lean out the mixture at WOT plus I am reprogramming the chip using TunerCat software to take care of many 'concerns'. Since the computer using 1 O2 sensor, I am confused as to how it would determine that one cylinder is rich will the other is not? The routing for the cold start runners goes straight down the middle of the intake feeding 5 and 6 first, then 3 and 4 and then 1 and 2. The size of the runners for the cold start valve regulates the amount of flow in each runner so an approxiately equal amount of fuel is delivered to each cylinder.
I am not sure why anyone thinks that the motor was running lean. That's why I used the larger intake setup. Before it was burning way too rich. But when I installed the 350 TB, I also installed the injectors off of the same motor. Everything is fine now except that the MAF is sending too high of a signal since the bored/camed 3.4 sucks more air than the stock 2.8. That will be corrected in the programming.

So qouth Jerriko

Gumby

That 7th injector use was a good idea. I bet someone could use that for NO2 or on a turbo car for the extra juice at WOT.

Blue1989RS

Well then right on man! I was thinking there was more to the story. Do you still think that the extra fuel is getting down to 1-2 runners? The cold start was intended to work during "crank" mode with low intake velocities. At WOT its moving much faster. If you draw 300cfm at 5000RPM, with intake runners at 3sq.in., then the port velocity is 2380ft/min = 27mph..... My concern was that if the engine runs lean before and now it runs rich, that half the engine is way rich and the other is lean. This would cause an average of "rich" to the 02 sensor while half of your engine is burning due to being lean. At least you were running rich before you did the CSI (cold start injector) thing.

Gumby

Well he keeps saying a WOT it works. So I assume at WOT the computer kind of shuts off and will not make any negative adjustments. It will run as rich as you want at WOT.

And I also assume when not at WOT the computer will adjust to compensate for more fuel.

Project: 85 2.8 bird

Look into the size of the csi runners. You will find that the 5 and 6 runners at the smallest while the 1 and 2 runners are the largest. This was done to help control the amount of fuel being delivered to each cylinder.
Also, I think that I should point out that I removed a LOT of material from mating surfaces of the upper and lower plenums, especially in the area of the inside curve (the most restrictive part of the intake). The port has been moved over 1/4" from its original position and some material had to be added to the inner sides of the casting. The areas were then polished. Once I get my fiberglass cowl induction hood I will be installing ceramic spacers between the upper and lower plenums to help with the airflow problem. I will have to experiment with thicknesses. We do have a dyno at school so as soon as I can I will get the car on it since I am the most curious person as to what the car can really do.

Blue1989RS

Damn man! How much time did you spend on this intake? Did you take any pictures of the inside? That things gotta look sweet :hail: You have to keep us updated when you get that on the dyno and play with runner length! Have you read any of the books by David Vizard? He has some great articles on intake design.

Project: 85 2.8 bird

Read more on the 'Adventures of JERRIKO"

br()bert

VERY nice work:hail: :hail: :hail:

LT1guy

iTrader: (1)

Anyone seen any dyno #s from a setup like Jerriko's? I just wonder how much difference it would make , considering the most restrictive part of the intake is left alone.

Gumby

Even a flow bench test would be nice. Just see how muc the stock system can flow with the double sized TB. Or even open with no TB.

Can't you flow bench with a shop vac and a vacuum gauge???

Gumby

Man this really sucks as I found a page I had lost for a while but then also found out the gentlemen has passed on.

His exhaust and inter cooler flow test should be able to flow bench an intake?

Anyone even thinking about doing a turbo in their life better bookmark this page. Anyone who read his work will learn something. Man was he good.

TurboGus is the guy with th 12 sec 4 cyl with 5-6 fuel injectors. He did awesome work and was a genius at creating more power. Man I feel like crap.

http://home.earthlink.net/~tmahon281/image.html

http://home.earthlink.net/~turbogus2/intercoolers.html

http://home.earthlink.net/~tmahon281/tech.html

http://home.earthlink.net/~turbogus/index-old.html

http://home.earthlink.net/~turbogus/index.html

TurboGus should get a sticky on TGO

br()bert

that sucks! The guy was very smart. I remeber seeing vids of that mini van smoking a corvette

TechSmurf

Uhm... 4th gen LT1.. I can post a link if requested.

EDIT: Nevermind.. this is yet another guy with a turbo caravan on steroids..

Gumby

From another source I hear the mini van was in the 10s last time around.