placd1

iTrader: (3)

I've got a carbed old school 13b motor at present and would like to convert to EFI. Aftermarket throttle bodies run in the range of $1000 and then some form of engine management is necessary so that's another $600 - $1000.
I know that there are resourceful rotorheads on the forum, so my question is :
Can EFI conversion be done on a budget of say <$1000 ? Junkyard parts or GSL-SE EFI equipment etc.
Who's been there and done that and has some tips or advice to share? The lines are open, first caller.......

placd1

iTrader: (3)

Anyone?

rotordogg

iTrader: (4)

Cheapest is a gsl se wiring harness, manifolds and ecu. Technically, any generation would work.

placd1

iTrader: (3)

Thanks Rotordogg! So the GSL SE manifold and ECU would be a viable starting point. What would be the limitations with the factory equipment? Maximum injector size and HP potential?

82transam

iTrader: (18)

One issue you will have whichever way you decide to go is that your engine doesn't have any provisions for injectors. On the SE/FC/FD etc engines there are bungs machined into the center iron for the primary injectors.

Whatever manifold you end up choosing will need something machined into it for the injectors, or an adapter plate made of some kind. Once that is resolved it's "just" a matter of bolting the rest of it on and wiring up a factory ecu etc.

If you're going to go this route, I would lean toward FC parts, over the SE stuff. The SE setup is quite a bit more antiquated than the FC parts (not that they are cutting edge high tech, I realize this) but that's just my 2 cents.

Another option is to find something in a junkyard that has a suitable throttle body with injectors on it (think 80's GM and Ford) and adapt that to your engine, then run it with a DIY Megasquirt ECU. I would suggest researching Megasuirt setups, even if you don't end up using that ECU, you'll find all sorts of great suggestions about how to adapt EFI onto a carb'd engine (rotary or not).

Many ways to go about it, good luck!

Jeff20B

iTrader: (13)

I think whatever you're doing is going to be way more effort than it's worth. Take it from me. I've done a limited number of EFI setups and they failed to "wow" me.

Also what 82transman says is correct. You're better off getting an actual GSL-SE shortblock and/or longblock with manifolds and ECU with harness than coming up with an adapter plate for the injector bungs. That's work and they tend to leak from what I've read on this forum.

Here is an idea. If you're into building engines, you could get a GSL-SE intermediate plate (this is for the injector bungs) and an RB lower intake manifold from their weber/dellorto kits. This would let you bolt a GSL-SE upper manifold to your 4 port 13B. Then a "simple" matter of wiring the ECU or tuning if standalone. The stock N304 ECU should work as is because it just listens to the AFM and takes an RPM signal and load ie engine vacuum and calculates fuel, so I'm sure a GSL-SE ECU could work on a 4 port. Of course you'd lose out on the aux ports, if you care about such things.

I am a bit biased towards carbs and swapped a hogged out Nikki and a 74 ported 13B into my GSL-SE. It was awesome with an RB long primary exhaust and got even better when I swapped to an S5 turbo and a full 3" exhaust.

I mention this because I can make a direct comparison to the EFI setups I've built and driven lately vs carbs. In a nut shell, the EFI setups are plain, unexciting, slow, and take a long time to set up even if everything is there, where as a carb would have taken one quarter of the time and probably drive about the same, if not better, and can have more power.

For example I installed a complete S4 NA ECU and engine in an 84-85 chassis for PercentSevenC. It already had the ECU hold down hardware and the big hole in the firewall, so the ECU went right in. It only needed an MSD fuel pump installed and the FC ignitors took a few minutes to figure out where to put them in a 1st gen engine bay. He has power steering making it more difficult. The harness needed some trimming down to get rid of the rat's nest connectors and other unneeded wires, plus added the CAS wires with shielding. Lots of hours, head scratching, drama, effort, and the end result is humdrum at best. In other words, EFI isn't worth it even if everything is there, and certainly not worth it for a project like yours.

Sure it has more power than the stock Nikki on the modded manifold it had before. The tip-in is decent. The cold starts are easier by a slight margin (no choke to pull which equals really just a 1% increase in convenience in my opinion, lol). It also will tend to stall coming to a stop at random occasions and the owner is still playing with the TPS to try to get rid of it. So in all, a pretty successful install, more or less, and he seems to like it, but is also considering a future MegaSquirt swap. Not sure what that means, but I wish him good luck with it.

I've installed a couple of MegaSquirts too. I can do wiring just fine and actually kind of like it, so the soldering and harnesses are no problem. However the ECU tuning throws me for a loop. I don't like computers. To trust one on an expensive engine like an REW or even a 20B is not my cup of tea. And then the owner of the FD setup in his 1st gen can't get it to run right either. He knows more about ECU tuning than I do so I'm of no help to him. He wants to test a carb and DLIDFIS to get to the bottom of why his MS is running so poorly. Testing various things until he isolates the problem (we think it's ignition but who the heck knows at this point).

If I had to do it over again, I'd get a JW manifold and a boost prepped Holley. Or maybe mod the JW manifold for a Nikki. Seems kinda backwards going to a small carb on a seemingly big engine, but really the FD came stock with 74 spec secondaries and small primaries. They can be ported out somewhat, but the Nikki on my 74 ported R5 13B does fine. Infact if an aluminum plate was installed on the JW to allow the smaller Nikki stud pattern and runner hole spacing to fit on the Holley square bore pattern, you'd get a nice little anti-reversion lip. The stock Nikki manifold actually has this on the Y intermediate plates with tall runners and the intake manifold has short height runners. It has a step in the right direction. The JW and FD engines don't have this, so if it could be added some how, that'd improve stuff.

I know you have your heart set on EFI. That's the point of this thread. But I have some good experience with the old school 4 port 13Bs and can offer unique advice. I need to ask what type of carbed intake manifold do you have right now? If it's a hitachi setup, I understand your frustration with these. They are small carbs meant for stock ports and only made an advertised 110HP at 6k and 117 or 120 torque at 3500 to 4000 RPM depending on year. I've recently tried a hogged out Nikki and I saw 8k instantly on my tach for the first time. The engine is a fresh rebuild so I've been taking it easy and only recently gotten the 7k RPM tach buzzer to make its noise, too. Anyway it seemed to like to rev that high where as before, the Hitachis always sounded anemic up past 6k or so. All I had to do is take a Nikki gasket, mark the stud hole spacing on the hitachi manifold, carefully drill and tap for the Nikki stud pattern and cut channels if the manifold didn't have any (the 74 to 76 manifolds don't but the J-spec NO manifolds do). I'd have to say my basic NA setup with the same RB long primary as what went into Percent's car had more power and better, more rewarding driveability than his recent S4 NA swap into a similar chassis; both 84-85 - his is a GSL, mine is a GSL-SE which is obviously heavier with bigger brakes and rims with taller tires etc compared to his stock plus wheels. I won't ever got back to EFI.

If you have a weber or holley intake manifold, I understand the frustration with those too. All I can say about those is I undertstand your wanting to go EFI but the end result still might not be worth it. If everything is installed correctly and tuned, you'll probably only have about as much power as the weber or holley, but the driveability should be better, but by how much? It's true that big V8 carbs and Italian racing carbs leave something to be desired on a rotary due to their strong reversion pulses at low RPM, and being mounted sideways in the case of Holleys and Edelbrocks leads to flooding probs. But would it be worth the hundreds of hours and thousands of dollars to go EFI? You know, we're getting into the driving season. Do you want to spend it installing EFI? Or actually out driving? Been there, done that too. Wasn't worth it. Glad I have a Nikki now. Starts right up and runs awesome, whether warm or cold. Goes around corners fine too. It is a rotary carb, after all.

Sorry for the book. Cliff note: EFI sucks.

Jeff20B

iTrader: (13)

Ok, I just searched for some previous posts of yours. I thought I recalled something to do with carbs and you but I couldn't quite remember.

You should have mentioned you had a bridgeported 13B with an enlarged Nikki already. Could have saved some typing time. Oh well, maybe it'll help somebody.

As for your specific questions, You basically need a really big setup. The stock GSL-SE intake manifolding will be far too small. It's smaller than an S4 manifold, and I've heard those are only like 300cfm. Your bridge is going to need something a lot bigger.

Since you're already doing this the hard way, with a bridge on the street, what I'd do is I'd bite the bullet and get an RB holley intake manifold for the 4 port 13B (around 300 bucks), then I'd get a 4bbl TB (like 700 I think) and a standalone like a MegaSquirt (they vary depending on how much you want to build yourself). This will get you into the ballpark for flow and tuneability on a brigeport.

P and B ports do better with EFI because they have weak low RPM vacuum signal. Ask peejay. Also ask j9fd3s. Mr Peepers does well with a carb, but it took a while to get there.

placd1

iTrader: (3)

Thanks Jeff20B, I've been following your posts regarding carb tuning and your work on Nikki carbs in particular. The beauty of the forum is that I can count on solid advice from guys like you who have already tried all the things that I'm just imagining at this point.
I'll definitely ask Peejay about his setup since he's been running a bridgeport with homemade EFI for years now and has achieved reliability and good mileage (two seemingly impossible things when it comes to bridgeports!)

Jeff20B

iTrader: (13)

Thanks. Yeah I just hogged out two more Nikki venturis today. Got them around 24.7mm again. This seems to be the natural amount of material to remove with the tools I use. It just happened to be perfect for the drill bit I also like to use to drill the stock jets out to 117 - 118. It's an SAE size but I don't recall the number. It is also perfect for the primary slow air bleeds if you take a set of spare nickel plated 60s from the secondaries of another carb and drill them out to 118. This brings the idle circuit back into calibration so the mixture screw works again (not sure if Sterling ever fingered this part out as I recall some of his carbs had serious idle problems but none of mine have).

Just curious. What mods did you do to your Nikki to make it work on a bridge? Maybe there are some tweaks you could do in the mean time while you save up for the big EFI setup. I gotta say my carbs with their 24.7ish primaries and stock secondaries are perfect on a 74 ported 13B. Heck I'm curious what your ports are like too. Do you recall port timing of the ports both intake and exhaust? And for the eyebrow ports, how big are they? And which intake manifold did you use? Any way to identify it? Any good pictures of it? And your ignition was what again? Was it direct fire? If so, what kind? MSD or DLIDFIS?

placd1

iTrader: (3)

I'll slip into my archive tomorrow and post some pics of the ported irons. All work to date has been done by Steve Wallace out in Abbotsford,BC. The Nikki has been hogged just shy of 24 mm, mechanical secondary conversion also. Like I mentioned in previous posts, the low end grunt isn't too bad but she runs out of breath when you hit 6000 rpm. She'll rev to 8k but its an uphill battle. The sweet spot I've discovered is around 5500rpm.
I scrapped the MSD setup since it became apparent that the MSD 6AL box that I was using was faulty, the stock ignition setup with 2 MSD Blaster 2 coils is doing well so far.
One detail I didn't mention before is that the engine was assembled using 12a irons and 13b housings. A bit of a frankenstein with a 12a front cover in order to retain the original radiator. 4 port goodness!
I really want to squeeze the full potential out of this setup (it dynoed at 176 rwhp with the RB streetport long primaries and power pulse muffler and 87 octane pump gas). Call me crazy but I'd love to keep her NA and faithful to the FB heritage.
If it proves uneconomical, then I'll just go ahead with my long term plan and do the TII swap (I already have a fresh rebuilt TII,hybrid turbo,Microtech LT8, TII gearbox and modified drive shaft to fit the FB).

wankel=awesome

Peejay is using a 4bbl holley carb as a throttle body for a multi port injection set up. I am not sure if he is using just the primary injectors or has added secondaries to his manifold though.

For the bridgey I would def use something with an aftermarket intake manifold. The RB holley manifold focuses power band up wayyyy high and is part of why Peejay has had his success with it on an bridgeport.

82transam

iTrader: (18)

Some good info from Jeff in here as usual. I'm quite happy with my S5 T2 setup running the stock S5 ECU. I built an MS3 and attempted to get the car running on that 2 years ago with limited success. Went back to the stock ECU and haven't looked back so far. I do plan to get back into that MS3 one of these days though, if only to learn more about tuning... Metal work and body work/paint is more my thing anyway...

I have done quite a bit of research about how to FI the 12a in my blue FB, really just for the hell of it, but basically concluded it's not worth the effort. Much easier to start with an engine made to be FI and go from there. Or as Jeff says, just stick with a carb

Just my 2 cents though

highnitro12187

iTrader: (21)

i know a guy with a 13b running a gm TPI setup off a 3800 v6, running full stock wiring harness and stock v6 ecu. inline fuel pump. gm ignitors. just make an adapter flange for the throttle body to intake and your good to go. His car runs and drives great.

82transam

iTrader: (18)

He kept the FB distributor I guess in that case?

placd1

iTrader: (3)

That's an interesting setup Highnitro12187. I've heard about people using GM throttle bodies for EFI conversion but never met anyone who had firsthand experience doing it.

placd1

iTrader: (3)

Jeff20B these are the pics of the half bridgeport that I currently run.

Jeff20B

iTrader: (13)

You copied from an FC iron? Did you know you can go wider on an FB iron? This is due to not having a coolant seal in the way. Not sure if you knew that, and I can't really tell from the pics if you widened yours.

Another thing is the length of the eyebrow. You should have made it longer. Ask peejay. He says any time you do a bridge, it will mess with your idle fuel requirements etc. Since they're already needing to be messed with, might as well go for the longest and widest eyebrow you can because the longer and wider it is, the more power you'll make everywhere. FC owners are at a disadvantage here because they can't go as wide as FB owners.

One last thing is the side ports themselves. Looks like you ported them larger too. When I did my half bridge, I left them at stock timing and just cleaned up casting flash. Seemed like a good idea once it was up and running. I also obviously cut the eyebrows as long and wide as I could.

Hope I didn't ruin your day.

placd1

iTrader: (3)

Not at all Jeff. I opted for the half bridge over a full bridge because while fuel economy isnt a real issue to me, I wanted to maintain low rpm driveability and still have good power up top. The half bridge was a great compromise and gives that signature brap brap brap also.
Everyone who has driven my car always comment on how smoothly she functions at low rpm driving (<3000 rpm) and the fact that I manage 290 km per tank (16 gallons)
Steve Wallace is my engine builder and he does fantastic work as a lot of BC forum members can attest. Budget constraints when my engine was being built are the sole reason why I opted to mod a Nikki carb rather than buy a larger Holley or even Weber carb. The Nikki has been great and reliable but the power bug demands that I go bigger really soon.

Jeff20B

iTrader: (13)

Man, all this talk about half bridgeports makes me want to do another one! And with your experience using a Nikki and it not being large enough, makes me think that pulling the secondary venturis and going "naked" is the way to go. I even have a carb already. It's the one I just got done modding today. A 79 so it has the larger primary side in the air horn. I hogged the primary venturis out to 24.7 to use the standard drill bit (117-118) in the jets and all that, so the primary side is done, but I'm aching to pull the secondaries now and do a little venturi effect in the TB itself!

You see, there is a slight step that needs to be smoothed down when you remove the venturis. And the nice part is the secondaries won't be moving any air until the engine's RPM is high enough anyway, so I feel pulling them won't cause too many problems. Heck we already get away with mechanical secondaries on these things with just a little hiccup when they open. I can live with a slightly larger hiccup if it means I get to keep using a Nikki and not have to resort to EFI.

Oh, we also know the Nikki's fuel capability is enough to support a turbo 13B at an S5's turbo's stock 7psi wategate spring setting (my engine still lives without an intercooler), so it ought to be plenty enough for an NA half BP, you know?

And you're right, that brap brap brap would be amazing to have again. Check a short video of it idling with the choke on, then pushed in. Not too shabby.

Jeff20B

iTrader: (13)

One question I need to ask. Does your intake manifold have channels?

peejay

In my experience, they drive the same. Going to full bridge over half bridge just meant more power everywhere (and more time spent porting)

Same here... although I've done quite a bit better than that economy-wise I can usually expect 300mi from 13 gallons but can get more when the weather is right.