Advice on EFI upgrades

[randy88k5]

OK, now that Ive driven the Blazer for a little bit, the bigger tires and running gear has me thinking a power upgrade might be in the future. I have a new crate motor for the 1988 model, has about 15,000 mi on it right now. I kinda wanted to keep it since its fairly new. I like the SBC and really dont want to go BBC right yet.

Currently Im running stock TBI. I was going to do a chip mod, but my friend and I have been bouncing ideas off eachother about diffrerent set-ups.

Ive searched on here for a bit, but now seem to have more questions than answers.

1st Idea: TPI swap. I concidered swaping over to TPI, but I found that that system isnt too much better than what I have now.

2nd Idea: Edelbrock system. The ones I see on the website look as if they are designed for going to FI from a carbed setup. Also stuck with chip. Can do minor adjusting, but need a new chip when hardware is changed.

3rd Idea: Accel DFI. This looks to be the best out of the bunch. Bit pricey though.

4th Idea: Stick with what I have and put CFM-Tech stuff on it.


What I am looking for:
I would like more power, but only when I want it, not all the time. I need to be sniffer smog compliant. Also it will be driven on the street and highway, so fuel mileage is a concern. An ajustable fuel curve is a must. I need to be able to turn it down when needed. It needs to be reliable. It needs to be compatible with my 700r4, cable driven speedo. I would like it to be tunable with a laptop.

I would like to keep most of what I have, but when I look at the different systems, it looks like my factory heads would be pretty restrictive. Then I would need [new] headers (havent bought the ones for the factory heads yet. I guess I wont now). Then a cam swap would probably be in order. Then a few other things like ignition and double roller timing chain and such. Then there is the LS1 swap. I need to stop somewhere.


What do you all think would be better. I like the Accel system, but it looks like other mods would be neeed. Would they be worth it? It uses a higer pressure inline pump, what happens to the stock intank TBI pump? What other mods should be done?

I know a tunable FI system for all-around use is gonna be expensive. I know that. I will save and budget accordingly. I just want to be able to justify that expense.

Plea$e give me $ome advice...

 

[k20]

Edelbrock makes a kit to convert from tbi-mpfi. Its what I have on mine, and uses the stock wiring over. Pretty sure they make on for the sbc. They will provide a chip for it.

 

[1979jimmy350]

with TPI you can make a lot of power with upgraded parts also there is a lot of tuning info out there for the TPI and it would be compatible with every thing else you are running

 

[randy88k5]

Are you running different heads or cam? How do you like the power? Can you use a laptop or just the Edelbrock control thing?

 

[beastofablaze]

Where do I start?

Ok, first off tbi can make plenty off power... up in the neighborhood of 400. I'm running a holley 670 cfm tbi (stock tbi is 440 cfm), larger fuel pump, adjustable fuel pressure regulator, holley 2" efi manifold, headers, single 3 inch exhaust, 10:1 compression, cam, and I'm using a prominator to tune it.

Your good up to around 375-400 hp with this setup and probably 435 ft lbs of tq, and with the prominator you have full control over your fuel maps. The Pro version which i bought lets you tune it while your driving. It can also save 6 different fuel maps right into the prominator which you can access using the switch that bill sells with it. That means you can burn a map for fuel mileage, one for smog, one for power, etc and all you have to do is flip the switch to change them. All the hardware is included with the prominator and to your door, the switch, prominator, and all the hardware you need is only $300.

Here is the link to the prominator... http://www.speedtronics.net/aboutprominator.asp

The inline pump for the edelbrock system can be bolted right in... I was told you could run the wires from the stock pump straight to the inline pump and just leave the stock intank pump in. I took my intank pump out but you can leave it in without any problems.

The stock heads will need to go if you want to make good power. Currently I'm running some ported stockers and with my setup it should make 330hp and 400 ft lbs. Darts will be comin very soon and should bump power to 400 hp which will definetly leave some hp on the table because of the tbi's restrictions. Take a look at the dart heads on ebay... platinum iron eagles can be had for $759 to your door brand new and complete. Those heads are a 50-70 hp bolt on depending on your setup.

 

[TrcksR4ME]

Go over to thirdgen.org and do some reading. There is lots you can do to your TBI for more power.

 

[k20]

lol, as you can see my 496 is a wee bit beyond stock, so I had to do a few chip mods to get it dialed in, my cam is way beyond stock, so kinda blew any chips edelbrock had, out of the water. And you modify it like you do the TBI, by burning chips.

As for other options, I need a little more airflow for my motor to breathe at upper rpm, I have a chance on an 8-71, depending on what parts a friend of mine decides to put in his 502. If I dont go blown, Im thinking about swapping to this FI. http://www.mass-floefi.com/ Its an aftermarket mass-air style system. Mass air kills any speed density setup IMO, only problem is, it can be a little more fragile, because you have to worry about water, dirt, whatever getting into the mass air sensor, but if you got mud & water in it, its going in the engine anyway.

 

[Thunder]

I would like more power, but only when I want it

5th: Idea

whipplesurerchargers.com
All you need to make it work on pre 89 models is a serpentine belt system.

If not supercharge. Then i would go with Accel DFI and Heads, roller cam, intake, Yull be spending about the same either way.

 

[randy88k5]

lol, as you can see my 496 is a wee bit beyond stock

Sorry, I didnt read your sig line lill just now. lol. Looks liek a neat system. I kinda wanted something programmable, but Ill keep that in mind.


beastofablaze: Thanks for all the info. I was considering the prominator too. I definately like the adjustability of a chip. I want to be able to kep the fuel economy for daily or semi-daily driving, but can crank it up when needed. What kind of gains and fuel milage have you ben seeing out of it?

TrksR4ME: Yeah, I know, I was doing reading on thirdgen, but most of what those guys are saying is about perminant power upgrades. I want something more selectable.

1979jimmy350: I was considering the TPI upgrade. From what Ive seen mostly is people jumping from carb to TPI, not from TBI to TPI. From what I gathered, the performance upgrades and cost really dont add up to be beneficial.


I know what Im looking for is a bit ofa pipe-dream, but im hoping there is something close enough. I bought a Jet 6-pack chip a while back, with the same PROM settings as I have now. I havent used it yet, that might be what Im looking for already. Just with all of the stuff Ive been bouncing around, I didnt want to open it and install it yet incase I wanted to resell it.

 

[beastofablaze]

I'm still waiting on my computer to get here...I'm having them solder it into the ecm for free. Should be here in a week or so.

I really don't know much about tpi but tbi has been good to me... its simple makes good power and is hard to beat for simplicity, off idle torque, ease to work on, price of parts, and if you go with a bigger tbi money for power. One thing you can do is take a stock 454 tbi and bolt it onto your 350. Used holley 670 cfm tbis can be had off ebay for less than 150 bucks.

Do your homework on this one tho. I thought mpfi would be too expensive but with my tbi setup I ended only saving 200 bucks then if I went with the edelbrock mpfi but I also have the prominator and don't have to run back to edelbrock with my wallet open every time I modify something. I bought the manifold, tbi, and fuel pump new which costed me about 700. with the prominator its $1k. Thats really not that good as far as hp limit vs money but 400 hp is plenty and I here some people were having problems getting the edelbrock mpfi to pass smog.