Ok everybody,

I am going to a carb setup on my 2.8. I have searched around and found alot of info but not all is specific info. If someone could step up and give me part #'s for intake manifold, riser, distributor, a good carb, with or without egr, and whether or not I should get a fuel pressure regulator or an inline pump. I would like a start to finish this is what you need. Oreif, I see you stand out in the carb threads. your help would be appreciated. Also would like to know if a 4 bbl would be overloading this engine. It has approx 6,000 miles on a rebuild so clean you could eat off of it Bored .060 Heads shaved .012 A very strong running engine until it of course runs out of breath.

Thanks for the info.

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Bill McConkey
85 GT
86 GT Parts Car

Edelbrock Performer Plus intake manifold (it says Torker II on the upper piece)
Holley 4160, 390 cfm carb. Jets, #49 or #47, #31 shooter, orange accellerator pump cam @#1 hole, lightest yellow spring for vacuum secondary. Call Holley at their 888 number and tell Jeremy that Arn referred you.
Vacuum advance distributor from a 1984 S10, Jimmy, etc.
You run it without the ECM.
Try a 180* thermostat. Carbs don't like heat.
As you have likely read, don't even consider it until you have ported your exhaust manifold and Y pipe. If you don't it's like stuffing a whole orange down your throat.....it just chokes.
You are well advised to consider a scoop.

If you need help PM me. I've got mine up and running after my share of errors and equipment choice errors. We carb'd guys are happy to help. Also try www.hotrodders.com

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here are some part numbers for Arn's stuff:

Carb Kit, 390cfm 4bbl p/n: 510-0-8007k $303.99 Jegs
Carburetor Base p/n: EDL-3785 $153.95 Summit Racing
Riser Intake p/n: EDL-3789 $89.95 Summit Racing
Distributor (1982-85 Chevy S10 w/Vacuum Advance) $166.99 Autozone

The stock carb comes with #51 jets I think, so you'll need smaller ones like Arn said. You'll also need an adustable fuel pressure regulator so you can dial down the fuel pressure. Your V6 puts out over 40psi and you only need about 6-8psi for the carb. Best bet is to put in a 4cyl fuel pump since they put out much less than the V6 pump.

As far as making it work, that's where I'm not sure. I don't think you can use the ECM after you do the swap, so an aftermarket ignition system would be the next investment. Anyone want to help me here?

Heck, with the new intake designed by FrancisT, I really don't think it would be worth it to go carb anymore....unless you prefer it over EFI. The new intake would be cheaper unless you buy some of the parts for the carb swap used.

good luck
Dave

Thanks Dave,

Don't go to the bother and expense of a new fuel pump though. If you buy a Duke fuel pump, you also have to buy a fuel regulator anyway.

Go to www.malloryracing.com and look for the 4309 bypass fuel regulator. It handles 60 psi down to 4 psi and does not creep. It works great.

You will want a fuel pressure guage (more like NEED), and you should stay away from the fluid fills. Our engine bays get hot and the fluid fills read lower the higher the temperature. (I'll give you a fluid fill if you want the headache)

When you get your carb, ask for the 3/8" fuel line. Run 3/8" right from the start and you'll be better off.

Thanks for all the input. I will start getting some pricing together and see where it takes me. Ditch are you speaking of the trueleo intake on the forums? If you are is the improvements over stock comparable to going with a carb setup? My only worry with carbs is the stuck float or leaky connection turning my baby into a bbq. I will investigate both. Thanks again

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Bill McConkey
85 GT
86 GT Parts Car

Bill, here is some inspiration below. The way to avoid a stuck float is to make sure your carb is either fresh out of the box or stripped and dipped. The way to avoid a gas leak is to run your fuel pump and check everything before you start it. Good luck.

Arn

Note this is with the 2300 flat track racing carb. I now have the 4160

[This message has been edited by Arns85GT (edited 09-30-2005).]

quote Originally posted by billmcc: Thanks for all the input. I will start getting some pricing together and see where it takes me. Ditch are you speaking of the trueleo intake on the forums? If you are is the improvements over stock comparable to going with a carb setup? My only worry with carbs is the stuck float or leakyconnection turning my baby into a bbq. I will investigate both. Thanks again

Yep, the Trueleo. From what I've seen, it flows just as good as a carbuerator. The only reason people went to carb was because it was about the only alternative to the fiero intake. Now that the Trueleo is out, people can get great flow without going carb. As far as I'm concerned, it is the way to go if you're looking for the cheaper route....MUCH less work as well.

as far as leaky connections in the fuel system, if you do it right you won't have any problems. I have a carbed 3.4 with over 3000 miles on it so far, no problems. Get steel braided 3/8 fuel line from summit, along with swivel style AN hose ends. When you see how these things work, you'll see that they're nearly bulletproof.

I'm not trying to steer you away from the carb, just want to give you other options if all you're after is flow. IMO, a trueleo is only $600....it's a simple bolt on. It does the same as a carb will do.

As far as carbs go, Arn is a great source of info as he has installed one on his car. Two other people who are good with carbs are Oreif and Stratohacker (SP?). These are the three guys you want to talk to if you choose to do the swap. I bought a carbed 3.4 off a PFF member (Oreif), so I don't have the full experience of an install. The work was already done for me. I just bolted it to my tranny and went.

On my comment above about whether you can use the ECM. I thought about it and it makes sense that you simply can't. An aftermarket ignition system is the way to go. Figure another ~$200 for that.

Dave

[This message has been edited by ditch (edited 09-30-2005).]

The Truleo Intake is only the upper intake. Wouldnt you need to port the middle and lower to be able to match the carbs performance??

quote Originally posted by BrewCheese: The Truleo Intake is only the upper intake. Wouldnt you need to port the middle and lower to be able to match the carbs performance??

the main restriction on the 2.8 fiero intake is the upper part "plenum". Just look at one...they bottleneck right after the throttle body. The trueleo replaces both the plenum and the middle intake from my understanding. I think that the difference will be negligible for a bolt-on carb vs. trueleo intake...without porting

There is quite alot of differences between the Truelco and a carb. And let me say both have their fans.

First off, the Truelco does not change your ECM settings, injectors, or sensors and there are limitations with all of those items. You will need to address all of those things and do some electronic analysis in the process.

True, it will open up the top end, but you are still stuck with the emissions oriented ECM and all the sensors etc.

The carb takes you outside all of that. You can get a speed shop to re-curve your vacuum advance distributor to suit the engine's demands. This is cheap and very flexible. I had mine recurved for $70cdn, outside the car.

You can set your vacuum to open plenum (un-gated) vacuum and run full vacuum right from idle. This increases gas mileage around town bigtime. I currently have quite a bit more than 1/2 tank in the car and I am at 130kms since the fillup. This is better than the car could do before.

Your Edelbrock intake is a proven and reliable intake and race-tested. Not to criticize the Truelco, but it is the new kid on the block. The Edelbrock intake flows at 410 cfm and is more than the 2.8 engine will likely need. If you change to a 3.4, it will go with you.

You do not need the expense of an electronic ignition. You just wire your ignition wire to the coil and distributor + line and it works. Here is the pic.

What you have is simple electricals, mechanical fuel delivery, and simple 1950's analysis if you have a problem. This is not the case with electronic modules such as the ECM and MSD units. You need an electronic analyser and possibly a laptop.

The MPFI fans don't mind this and you can buy an analyser from an auto supply, and you can play with chip programing, and it is interesting and can be fun.

Carb guys like simple and mechanical.

Both types have strong points and weak points. The MPFI tends to run better in cold weather. Carbs can ice up.

Carbs are dead easy to adjust, MPFI is not.

Your choice, and good luck with it.

Arn

Well most info has already been given.

Some additional notes:
With a 2.8L You would be better to change the stock 51 jets down to 46 or 47 on the Holley 390 CFM carb.

You don't need an aftermarket ignition, But it does help.

You don't use the Fiero ECM for running the engine. It does control the in-tank fuel pump. (3-second pump up when the ignition is first turned on and the safety feayure of turning the fuel pump off in case of an accident.) You just leave it in the car and remove the light bulb for the "check engine" lamp.

The Trueleo does come with a new PROM and it replaces the upper and middle sections of the Fiero intake.

Cost difference depends on where you get your parts. Occassionally you can get the parts for the carb'd version from Ebay or the S-10 forums. This will save you LOTS of money. I've seen used set-ups with intake and carb being sold for less than $250. New the cost is about the same. (around $600)

If you keep the V-6 fuel pump use a high quality regulator. (like the one Arn is using) The lower quality regulators tend to cause "pressure creep" at low rpm or idle. Pressure creep is where the regulator can't hold back the high pressure properly and forces gas into the carb which forces it out the ports and floods the engine. The V-6 pump pushes 40-42 psi, the 4-cyl pushes 9-12 psi which is easier to regulate.

I recommend using Russel or Aeroquip braided hose for the fuel lines. They don't leak, provide a good connection and they help keep the fuel temp down. If you buy a used carb, I would recommend getting a rebuild kit for it. The cost less tha $20 and you can clean everything up and install the new jets. To avoid stuck floats, Use the stock Fiero fuel filter and add a second small micron fuel filter just before the fuel pressure gauge.

There is no power difference between using the Trueleo or going carb. I built two 3.4L engines and except for the intake/fuel delivery the engines were identical. The horsepower at the crank between the two engines was +/- 2hp. Both engines were tuned on a dyno which either way you choose to go, would be something I highly recommend.

Sorry I didn't answer earlier but Wednesday morning my DSL modem died and I just received the new one today.

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Happiness isn't around the corner...
Happiness IS the corner.
ZZ4 Powered !!

quote Originally posted by Oreif: You don't use the Fiero ECM for running the engine. It does control the in-tank fuel pump. (3-second pump up when the ignition is first turned on and the safety feayure of turning the fuel pump off in case of an accident.) You just leave it in the car and remove the light bulb for the "check engine" lamp.

Oreif has been of great help to me in my build. Many thanks Oreif. The main difference in our wiring was that I don't have the ECM at all. PBJ wired it up with a switched feed to the relay. I don't have that 3 second delay. When the ignition is on, so is the fuel pump. It was, however, pretty easy for the alarm installer to disable my fuel pump BTW, if the relay goes, you just have to bridge 2 terminals and it starts right up and stays on so you can get home.

Arn

Wait a min here... I have an 84... I am going to be swapping in my re-done 3.4 in a few weeks here.. You mean I shouldn't upgrade to the 2.8 fuel pump? and I should just get smaller injectors for the carb? That would actually be awesome if I could do that... Lemme know, thanks guys.

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Custom Fiero Fiberglass

quote Originally posted by Custom2M4: Wait a min here... I have an 84... I am going to be swapping in my re-done 3.4 in a few weeks here.. You mean I shouldn't upgrade to the 2.8 fuel pump? and I should just get smaller injectors for the carb? That would actually be awesome if I could do that... Lemme know, thanks guys.

If you are going with a 4-bbl carb on a 3.4L the stock 51 jets are fine. If you have an 84 keep the stock fuel pump. You only need the 2.8L fuel pump if you are going fuel injected. There are no "injectors" inside a carb. If it looks like a carb and has an injector, it is a TBI set-up.

Bang on again Don't spend the $$ you don't have to. The Duke's fuel pump will do nicely and you can put the Holley blue fuel regulator on it. If, on the other hand you have a 3.4 with TBI, different story. But I thought we were talking about a carb on a 2.8???

TBI would be real nice. It is an expensive bit of equipment to purchase and having it already would be a nice touch.

Arn

[This message has been edited by Arns85GT (edited 10-01-2005).]

Since we are posting pics of an engine thought I might throw mine up there as well. I made quite the mess of my dads shop putting humpty dumpty back together again.

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Bill McConkey
85 GT
86 GT Parts Car

Now of cause I'm a bit bias on this topic, but both will provide a big improvement over the stock intake. I'll admit I have no info with respect to gas mileage with the carbs version, but we have heard back from users that that they get better gas mileage with our intake than with the stock intake. Whereas the stock intake results in a rich from around 4.5k and up, it's understanderable that you could improve your gas milage while also getting more useable RPM and power. Not too many mods out there that can make that claim. I forget who reported that mileage thing first, but you can find his comment on the "Hi flo update" posting that's been running on here for like forever. One other thing and some may dispute this which is fine; carbs work, but I think FI is more/easier to tune and thus probably has more potential. If it wasen't the better setup, the auto makers would not use it so extensively. Good luck with whatever setup you chose.

OK, Here's pics of the 3.4L.
On the engine stand:

In the car: