I am looking into fuel injection conversions for 12a and 13b 4 port engines. I am not looking for anything stock. I have a Wolf 3D, I just need sources for the different aftermarket intake manifolds. Any suggestions on which one is best would be appreciated.

 

Aftermarket EFI manifolds - none

Most people I've seen just make their own, or adapt carb manifolds.

TWM makes throttle bodies with injector bungs, that bolt on to Weber manifolds. They also sell the sweet dual DCOE intake manifold, you could use that with a pair of throttle bodies (for four throttle plates in all) or you could use a single DCOE manifold and one throttle body, but then you'd only use two injectors and they'd have to be HUGE.

 

I thought you could put four injectors in the 55mm TWM throttle body and two in the 48 and 50 and choose which side they were on.

Would 55mm be too big for a 12a. What about one with street ports?

thataway we could run four injectors and have small primary's for driveability.

 

oh yeah that is just for the 3000 series which replaces the weber 48 IDA.

 

Twm have a web site??? Just curious, they sound pretty good.
LATERZ,
Andrew

 

i wanted to ask a question, and i found this thread to be in the same vein as what i ultimately want to know, so i brought it back from the dead ...

anyway, has anyone here actually gutted a carb (Weber, Mikuni or Dell'Orto) to make throttle bodies (or a single throttle body) for a fuel injection system?

what exactly has to be removed from the carburetor to do this?

 

you could do that with the stock carb, the baseplate with the throttles in it unbolts

mike

 

yeah ... i'm sure you could, but i have no clue what is needed for an "ex-carb" to function as a throttle body in a fuel injection application ...

i mean, i'm sure the floats and jet will hit the bricks, but what else has to be removed?

 

I've seen people make throttle bodies out of Holley baseplates.

 

This is what I'll be using when I go bridge-port and EFI. It bolts on to the IDA Weber manifold and comes in sizes of up to 55mm. Good price too. Go to www.efihardware.com to check them out.

 

this brings me to another question ...

as far being applied to a rotary, i know the downdraft style intakes should give a stronger low end, but does anyone have a general idea as to how much more torque it typically has over a sidedraft setup.

i'm a bit a more partial to the sidedrafts, and that's what i would go for if i had the dough to fund my FI dreams, but i'm curious now that i saw the picture that revhed just posted.

 

With a downdraft set up, you're looking to make more gains at high rpm (HP). And, with a sidedraft set, you're going to get better torque.

 

That's a very broad statement. A lot of it depends on how the carbs are set up, not just throttle plate and venturi sizing but also how well it's tuned.

Supposedly the dual 40DCOE setup is the best of everything. They're a straight shot in to the ports, with no kinks like the single-sidedraft "Lake Cities" straight-shot manifold. And they apparently have super driveability (thanks to the decent venturi/throttle plate ratio) along with greater flow ability than a 48IDA. Unfortunately the setup costs roughly as much as a 1st-gen is worth, so they're very uncommon.

 

How do I know how big of injectors to get is I was to order somthing like that? And how many? Also...What is the reccomended hardware to buy to control it? Haltech, Wolf, Mega-Squirt (the homemade one), etc...I was thinking Haltech F-9, with MSD ignition .

~T.J.

 

Figure how much power you figure your engine can make at its peak - let's say 200hp.

Multiply that by 8 which gives you 1600.

Now divide that by the number of injectors, and you'll get your injector size in cc/min.

This will give you more injector than you need, for a safety margin. for example figuring for two injectors this calls for 800cc/min. Stock GSL-SE injectors at 720cc/min maxed out will supply enough fuel for 200hp, but that's maxed out (100% duty cycle).

It's easy enough to remember - HP times eight, divided by number of injectors.

 

So, say I spend over 2 grand for a fuel injection setup. How well do rotories work compared to piston engines. I know rotories have anti backfire (afterburn) systems and what not. Would a rotory with this system be udriveable on the road and with a stock exhaust?

 

Huh? Why would it be undriveable? A good EFI throttle body (like the one I posted for example) combined with a decent ECU will **** on any carb setup in both performance and driveability.

 

Yeah, but will I get back fires gallore?

 

Shouldn't.

 

Tuning, its all in the tuning...

 

damn you guys make me feel soo stoopid haha

 

I'm bringing this one back from the dead once again.

REVHED, you haven't started work on this efi project yet have you? Efi Hardware's throttle bodies look very nice, but I'm curious as to how they would fair against two smaller sidedrafts using the twm dual dcoe manifold. It looks to me like their could be clearance issues with the twm manifold, especially if ramtubes/airfilters are used.

 

bump

 

Nah not yet. The bridgey's getting done very soon and I'll start looking at EFI next year some time. Might be a while though as the IDA will run the bridge-port nicely enough with a slight rejetting.

 

Schweet! Keep us updated.