decisions, decisions, decisions....

[PJG1173]

Ok starting to gather parts for my next EFI project. currently I have a vortec 350 in my toyota bored .030, GMPP vortec heads, 9.8 compression, vortec rpm airgap intake, holley 650dp carb, and a comp cams extream energy 4x4 280hr. the speed shop that built it said it should be capable of pushing 380 - 400 HP. so far I've collected up a 454 TB with 85# injectors, a 16168625, holley BB TBI to squarebore adapter, and a pile of wires. I also have the original vortec intake with factory spider assembly and most of the wiring less pcm.

So my questions are:

which route would be better?
can the 8625 run that spider?
what would the pro's and con's be?
would one make more power than the other?
should I look at a tpi setup with a vortec base?

[gregs78cam]

Well that cam is recommended to 5800rpm, a TPI set up will never get you there while producing 400hp, it just can't flow enough. I don't know enough about the factory spider setup to comment on that. Or go the easy route and put a 4bbl intake and adapter on it. Up to 5800rpm I don't think you will be giving anything up.

[EagleMark]

I do beleive that PCM will run CPI becaue the 427 does.

But don't beleive there is anyway to increase fuel in the spider to match engine, none that I have ever seen?

Ditch the BB adapter and get a real one if your going to run a carb intake.

TPI will run out of air before you run out of cam.

So that leaves finding an intake to match those heads and the RPM range of that cam and going with the BB TBI or MPFI.

IMO...

[93V8S10]

The 8625 will run the spider.

[Six_Shooter]

So is the spider basically an MPFI, or SFI set-up, electrically?

[PJG1173]

I do beleive that PCM will run CPI becaue the 427 does.

But don't beleive there is anyway to increase fuel in the spider to match engine, none that I have ever seen?

Ditch the BB adapter and get a real one if your going to run a carb intake.

TPI will run out of air before you run out of cam.

So that leaves finding an intake to match those heads and the RPM range of that cam and going with the BB TBI or MPFI.

IMO...

http://www.summitracing.com/parts/PFS-52028/ this is the intake I already have on the motor. doing some reading it looks like I'd need somewhere around 80 psi to use the spider, but IDK how I could get it that high. I just don't know if the juice is worth the squeeze going with the factory vortec intake.

[PJG1173]

So is the spider basically an MPFI, or SFI set-up, electrically?

It came off a 97 vortec 350 i would assume its sfi. there are 16 pins on the elecrical connection.

[EagleMark]

So is the spider basically an MPFI, or SFI set-up, electrically?

It came off a 97 vortec 350 i would assume its sfi. there are 16 pins on the elecrical connection.

It's kinda like a big POS master control valve with popet injectors on each cylinder that will not open till they reach 40 PSI. They are prone to clog, prone to failure and prone to no way to upgrade... I take that back I remember a company that installed injectors on the ends with a new POS controller so it is MPFI without poppet valves with no way to tune but a major improvement on a stock engine.... just forget it and do anything else.

The intake you have matches RPM range for your cam if I looked them up properly, so see what an aluminum plate adapter would fit the BB bores in intake to clear the big throttle blades without maching intake and your ready to start a BB TBI conversion.

[PJG1173]

thanks that was the input I was looking for. I was kind of getting the impression that there was a reason I couldn't find anyone using this intake and injector assy on a modded motor.

[gregs78cam]

http://www.summitracing.com/parts/PFS-52028/ this is the intake I already have on the motor.

HHMMM. Looks just like my AirGap only $120 less than I spent 9 years ago. Funny how prices drop after the 'cool' factor goes away. Why not put bungs in that manifold and go PFI. I've thought about doing it with mine.

[1project2many]

Clarifications:
1) 80 psi not acceptable with spider injector
2) Vortec V8 spider injector not like 92-95 Vortec V6 spider injector. 8 individual control valves, not one master valve.
3) Vortec intake does not easily lend itself to standard injectors.
4) Different OEM injector available for Vortec manifold with hoses runing out to 8 tiny MPFI injectors at end. May work with 80 psi. Pacific Performance forum was doing lots of Vortec related stuff a few years ago.

5) Here's a quick thread that will bring you up to speed on some Vortec stuff including a common solution for more power: http://www.hotrodders.com/forum/2-38...ce-208667.html

Marine world is a common place to find manifolds. Also consider having injector bungs welded into current carby manifold. Prices are often very reasonable. You'll need to have rails made up as well but still possibly cheaper than buying new Marine manifold. Another solution, though not cheap, is here:http://www.firstfuelinjection.com/products.htm You might be able to use the base and get creative/lucky doing craigslist and Ebay searches for the rest of the system. There's also this manifold:
350-7138.jpg
Edelbrock #7138. About $450 if you look around. Still requires TB, injectors, and fuel rails.

Here's a decent price on the lower half, injectors, and rails of a really great manifold:
http://www.ebay.com/itm/Mercruiser-3...s_Gear&vxp=mtr
I have used these manifolds and they'll easily support 400 hp. Add a homemade plenum and TB and you're good to go. Everything is stainless, brass, or aluminum so no worries about corrosion. It's this manifold without the upper half or TB:
Mpfi4.jpg

HTH

[EagleMark]

That is one sweet looking marine setup but man pricey.

I have read about using an LT1 intake and maching a hole for regular distributor, but don't know if that is true or possible? If it were there are a lot of LT1 intakes around way cheaper...

[EagleMark]

Just read the link at hotrodders from 1project2many and man the marine intake is sweet compared to truck!

What I did find interesting is the CA mod to vortec trucks by replacing the spider and 8 actual injecters looks way better then poppet valves, but can you change size of those injectors or fuel pressure and tune it?

Real injector conversion over poppet valves...






Stock poppet valves...

[1project2many]

Should be able to increase pressure. I may have found specs once showing max pressure is fairly low, can't remember that at this time. I'd have to use OEM part no to cross over to Delphi or others to retrace steps or search through pacific performance forum as I might have posted answer there.

[PJG1173]

from doing additional research making the stock intake work would cost as much as going with a marine intake, which by the way I already looked at and determined it was out of my price range at this time and possibly for quite some time. I think I'm going to have to work my way up to MPFI and stay on the road to TBI for now. I have though about sending my existing intake out to get modified but I haven't done any research to get price estimates on what it costs. is MPFI really needed? would I see that big of a difference? is the difference worth the additional cost?