(I debated asking this question in the alternative FI area but since this question had to do with a modified TBI system... so I felt that it probably belonged here more so then the other area.)

Question:

Is there any benefit to be had by running a "naked" TB with a MPFI common rail fuel injector set up on any 2 or 4 barrel intake manifold? Basically similar to the Edelbrock TBI MPFI Conversion except getting a better manifold and custom mounting the FI rails to it?







Here's why...I already have the Edelbrock 3704 (It can be any 4 barrel manifold for that matter) and thought it would work better as a MPFI conversion when using a blower...that way the injectors on top wouldn't get in the way of a power adder's air flow coming to the engine and then have the fuel spraying directly into each cylinder.

Is it worth even doing this to a 2 barrel manifold? I am thinking probably not and that a 4 barrel manifold would be a better choice....but in general...is my thought process sound on this?

Thanks,

JB

 

if you use a throttle body without the fuel parts, it's basically equivalent to a TPI throttle body(roughly).

If you are using a BBC one with bigger blades, then it's even better. But you should have no issues with doing what you are proposing, other than closing up the hole left where the injector pod was (as far as air leaking in, not filtered by the air cleaner). This is more critical in boost applications, naturally.

you might have a slight restriction due to the throttle bore diameters, but in most cases, HP is limited on TBI's due to fuel capacity, not airflow.

in the case of supercharging, it will benefit you to run MPI injectors, as fuel capacity is easily determined by 8 injectors, rather than 2, and are also vacuum/boost referenced as well. TBI injectors are barely big enough for naturally aspirated engines, with boost demanding even more fuel.

Oh yeah, as to the question of 2 or 4 barrel manifold, it's probably not a huge difference, but I would think the 4 barrel, given more plenum volume, would work better.

Additionally, with boost, you are also minimizing air flow restriction through the throttles, as power is as easy as turning up the boost to overcome the restriction.

 

Sounds like you're looking at something similar to what I was going to do, and it is fine. I was coming from carb to SFI, and I could've just put a throttle position sensor on the carb and plug various holes to use that as my throttle body.

 

Just run a single plane carb intake with TBI on top of it. You'll be fine.

 

OK Thanks Guys. I would've responded sooner but Third Gen never sent the notice to my email letting me know that the thread had responses...

Yup this is what I am thinking of doing. I figure I could use the 2 barrel for now...although I would be investing money into getting it customized for MPFI...I at least won't HAVE to buy another manifold. Besides...I just want to use it temporarily anyway. I figure if I can use what I have I can spend most of the money on the shortblock and upgrade the top end later on after more money becomes available in the future. I mean even if the thing was only puttin gout 360-400 at the Fly Wheel...that would still be more then fine in my book. I just want to hear the whine! LOL...and as long as I am not trying to push a tone of boost...it should be do-able. Honestly...I think the EBL and a quality Short Block are the short term up front important pieces to this puzzle.

 

Just so you guys know I am still thinking about this thread...I found this and it looks interesting...I don't know if I have ever seen this before and not that I am considering getting it but I was looking at it mostly because if its design....

http://www.re-racing.com/store/produ...ducts_id=11015

If you have any thoughts about using MPFI with a lone TBI on top...feel free to offer up any ideas or input you may have.

Thanks.

JB

P.S. I found this too...its an EGR Adaptor kit...

http://www.re-racing.com/store/produ...ducts_id=11281

 

I think all of your questions have been answered.....

use a single plane, either modified for injectors, or cast that way, an adapter for a spreadbore/squarebore carb to TBI, remove the injector pod, and cover up the hole.

should work mighty nice. From there, if you think the TBI is holding you back, you can bolt on a 4 barrel that has a carb flange.

 

Oh yeah your right I know...all my initial questions have been answers but I am pondering different variations...Its been nice finding stuff to look at and compare... that's all.

There's some interesting things I have been finding....this one does exactly what you talked about jwscab...I wish I could see an up close shot....

http://www.howellefi.com/shop/custom...13&cat=0&page=

 

yep, that's pretty cool, just pricey, which is going to happen when they sell you the whole package.

you could also buy an elbow and run a Ford throttle body, an LS1 throttle body, or similar style monoblade TB's, which may be cheaper than a 4 barrel, and lends itself well to supercharging.

check out anesthes' threads in the alternate efi forum for his vette, supercharged with a single plane intake, and intake elbow, with a single large monoblade.

 

YUP! Totally...I looked at that as well...I got that idea a long time ago from a guy over on FSC forums...he put an Elbow-type single blade TB and a Batch Fire Ignition with a Procharger...it was sick...he had about 600 hp out of that set up..he said he did it on a budget and it worked out VERY nicely...that's what got me hooked on all this stuff...that guy changed my whole thought process when he sent me pictures of his engine...

I am going to check out that thread in the Alternate EFI forum now...