sagebrush rebel

I am very interested in this build. I have a Crower BBC mechanical injector that I want to convert to EFI to run a Greenwood Corvette.

This what Hilborn has to say on IAC on their manifolds

So how does an engine with one of your IR manifolds idle without an IAC valve?

When used with a 4 barrel type common plenum manifold, an IAC valve is an integral part of controlling warm idle and decel rpm. This is due to the turbulence created in a common plenum manifold. A Hilborn IR manifold on the other hand, does not have this disruptive turbulence and provides a very stable idle and decel stability even with large camshafts. Our manifolds reduce the roughness at idle dramatically, allowing idle speeds down in the 650-700 rpm range without affecting the exhaust "hit" we all want.

Looking forward to watching this build.

Luce

ITB (individual throttle bodies) eliminate the reversion spitting fuel from cylinder to cylinder and should improve the idle quality over a big plenum 4 bbl or even single plenum port injected setup. But without the IAC valve, you have to resort to a solenoid to up the idle, or maybe a first gen 1988 or so dodge type motor driven linear actuator to "give it a little gas" I'm thinking I'll get the best of both worlds with my mini plenum set up. I'll definitely let you guys know.

Megasquirt extra firmware has a new(ish) hybrid speed density/Alpha N tuning algorithm I'm excited to try. Under light loads, it operates as a speed density map where this works well, then after 80% or so load, it switches to alpha N when the MAP is too low to give meaningful readings.

If you want an interesting read, start on page 54 for the ITB stuff.
http://www.msextra.com/doc/pdf/Megas...ing_Up-3.4.pdf

Luce

Here's a little more wasted bandwidth...

Added the O2 bung and completed the additional transistors to the ECU for the coil packs, IAC, fan control and shift light.

BLUE1972

NICE BUILD

Luce

I used up some scrap square tube. I realized there was no carb boss to bolt the usual lifting hook to. AND my accessory stuff makes it impossible to get a clean chain to the heads. So I whipped up a lifting apparatus that uses my crappy HF tilt.

I also made some legs so I can mount the new SPI flywheel and dial in the bell housing. I don't know if blueprint line bored the crank, and if they did, the tranny will be screaming for mercy in 100 miles.

I also want to run the engine over with no plugs with the starter and be sure I have the timing offset in the ball park, and the firing order right. With all of the wires, connectors and coil packs all wired up by me, getting the firing order is not so trivial as chasing the plugwires from the cap to plugs. I also have a rat nest of wires on the bottom of the ECU wiring the 4 BIP373 coil igniters bolted to the aluminum angle to the connector.

bmans vette

Question for you sir....

I need to add 2 bungs to my headers also.
In your pic it looks like you welded with tig welding....correct?
Did you do anything special to keep the heat from discoloring the headers?
I have side pipes I will be installing and want to add a bung to each side.
Any suggestions would be appreciated.

I am subscribed to your thread....excellent work.

Thanks

Bman

Luce

Here's a little secret. Putting 2 bungs in a V8 is a waste unless you have the ability to trim each cylinder individually. Even then, I question weather the O2 sensor is quick enough to say, that was cyl 1, that was cyl 3, etc.

The inner 2 left banks should be grouped with the outer 2 right banks. That's how a 2 plane intake is set up, so each side of the carb gets 4 equally spaced sucks from the cylinders it feeds. I rely on all cylinders being equal in air flow and fuel delivery and only sample one side.

As for welding, I just tigged it. I should have solar fluxed or back gassed, because it did sugar a little in a few spots on the back side. The front got the pretty gold and blue colors that I just wiped off with a little stainless wire brush. It is a little tricky with the bung being .120" and the header being .063, and having a .05" gap.

Are your side pipes stainless? I used 309. It has become my go to filler because it flows so nice. I'll try to find some pics of the cobra side pipes. I did them out of a mild steel weld it yourself header kit. I didn't know how much noise I could tolerate so I didn't want to spend too much in materials on them. I had less than $200 before ceramic coating them. I migged and grinded them.

Luce

I got sidetracked. What I wanted to point out was how I made a pocket for the O2 so it didn't have to stick up in the air like a morning wood pup tent. It may react a little slower, but works fine for a tuning aid. You want the O2, so it sees all 4 cylinders, so it needs to be after the collector, But like a Cobra, that's outside of the fender.

bmans vette

Great info.
My thinking was that a bung on one side only gives you half the picture.
So my plan was to put O2 sensors in each side with a switch on the dash to switch from one bank to the other.
If you and no one else sees any value to this, I'll go back to the single bung setup.
Thanks for all the additional info.
My side pipes are Doug's and they have the ceramic finish.

Much appreciate your sharing of info along with such detailed pics.

Thanks
Bman (Dennis)

Luce

If they're ceramic, they're likely mild steel, and that makes them much easier to weld. You can easily mig it, but you'll have to grind off the ceramic coating where you weld. Read up about O2 placement. You need to put it high enough to not risk condensation getting on the sensor. But with a side pipe, it looks like a bird sitting on the pipe.
Mine is at about 3 o clock.

The last pic was just for farting around while I was waiting for the Jones glass pac.

bmans vette

Thanks again. Obviously the sensor needs to be in the collector which creates a challenge with sidepipes. I do like how you built up the connection on your Cobra. With sidepipe covers it will not be so noticeable.
Thanks for all the great info.

BLUE1972

There is a company that makes a "screw" in sensor mount. It has a "thin" flange on the inside and a sleeve with a nut on the outside. The nut pushes the outer sleeve against the header and tightened the small inner sleeve / flange against the inside of the header . It looked real nice.


I saw it at a car show last summer - I had asked the owner about no weld on the bung.. he said he did not weld and liked the look better.

I don't know who made or how easy it is to find.

bmans vette

Thanks for the info.
Would be nice to check it out.
Off the top of my head, I would wonder about rust being introduced around it and if it loosens over time.
I'll search for it to see if they address that.

Txs again......

sagebrush rebel

I hope you can answer a couple of questions. You said you have had experience with Megasquirt. Why did you pick MS2 over MS3? I read the part you outlined on the ITB's and it seem pretty reasonable, but won't MS3 do the same thing after setup. My concern is that I live at 4500 feet elev., but if I take a short trip to Lake Tahoe I climb to over 8000 ft. Also, do you have the diameter of the MAP and Ford IAC lines. Do you like the Ford IAC better than the GM stepper motors? It sure looks like it is easier to install. Keep the pictures coming, love your build and workmanship. Thanks Don

Luce

Quick answers. The biggest advantage MS3 would be is built in data logging to a SD card. Otherwise, MS2 handles all I'm asking it to do. MS3 would be better if I was messing with full sequential. But that would also require 6 more added injector drivers and a cam signal. Also, the MS2 case is 1/2" shorter. Hate to do it, but it's going in the cubby opposite the battery. I think you can hook a second MAP pressure to read altitude, and I think it would be a good idea with itb's and changing altitudes. AS it sits, MS2 default is to check MAP before cranking and use the reading for altitude compensaton, but there is an option in tunerstudio to read a second MAP for varying altitude.

The map sensor is on the megasquirt board, so along with the wiring harness, I'm running a polypropelene tube from the manifold sensing plenum to the ecu. As for the IAC, megasquirt can run the GM type stepper or the ford type PWM. The ford valve uses one less output, but the main reason I went with the ford was the layout. The 2000 or so 5.4 valve has a 5/8" hose boss that plumbs to the air tract somewhere, and a flat mounting surface that very easily lended itself to my uses. The GM only comes with a pintle you would have to machine a pocket for. I simply glued a crankcase breather to the IAC and bolted it down to a hole in the manifold plenum. Clean and easy. Different years chance the location of the connector and hose barb, but this listing has the best pics. http://www.ebay.com/itm/Fuel-Injecti...VWm4ar&vxp=mtr

With Speed Density, actual airflow through the valve doesn't factor into the fueling equation, and in Alpha N, it'll be insignificant, so it doesn't have to be plumbed back in before a MAF sensor (I won't have one)

Luce

Altitude is a significant factor. Here's a funny story. I live at 70' above see level, and have a friend with a Cobra and MS3. He lives at 1800' or so above sea level. He came down to a dyno day with me and a bunch of megaquirt guys, and his car fell flat, pig rich and didn't do so well. After scratching our heads we finally figured it out. The top row in the fuel map had never been tuned because at 1800', you wont ever see 30" mercury on the barometer. His car ran great where he lives and when we've met up in the hill country, but along the coast... not so much at WOT.

Luce

Wiring harness is mostly done. Still need to get a good ground lug for the back of the block, do the fuse block and O2 sensor controller.

The loose pink wire will connect to the old coil power and energize a relay that will power up everything. The loose purple will go to a oil pressure idiot light that ties into the ECU. I'll repurpose the fasten seat belt light on the center console to act as a shift light 500 RPM before rev limiter), and low oil or high temp warning light. with a really bright LED.

Maybe tomorrow I can finish it up and apply power and verify all of the sensors are giving sane readings and test the injectors and coils. I hope I have them all in the proper order. If not, It would be easier to change it in the ECU than the harness.

Luce

More pics closer to done

Luce

Let the games begin!

I guess they didn't electroplate any bolts back in 72. I broke a few off. I guess I'll be cutting a couple of thick washers to emulate the double bolted backer nut for the lower control arm and use high end grade 8 fine thread bolts and deformed thread nuts. Need to start a mcmaster carr list.

The bushings interior rubber seem in fine shape, despite the age of the outer exposed parts, but I couldn't tell that until destroying them pressing them out. I bought all new tie rods, idler arm, bushings and ball joints. All top shelf Moog stuff.

Luce

Little bit of mission creep.

You can see the empty engine bay through the hole in the firewall.

I have then new Borgeson box stabbed, but I'm not using the cheeze grade 5 bolts that came with it. The tie rods are really chowdered up, and I can't justify what the Corvette venders want for a pair, so I ordered some 10" x 5/8" radius rods and lock nuts, It'll be so much cleaner too.

I guess they didn't line bore the engine. The bellhouse had less than .003 of run out, so no need for offset dowels. After the new clutch gets here I can stab the tranny. There's a few more things I want to clean up and mount before ti goes in, and a few more little things I want to do to the engine first, but it's almost ready to go back in.

Looking for a leak(s) in the firewall, I can't believe that every C3 doesn't fill with water with every little shower. While I do have a few little rust holes in the bottom triangle of the bird cage, that's not where the water gets in. One of the screws that's supposed to hold the kick panel was missing, and water runs in there, but I think the bulk of it may be where the rubber strip is missing right under the A pillar at the door. The body mount under it is rusted, but not to the point I'll do anything more than coat in Phosphoric acid rust converter. All of the grommets on thr firewall are gone, and it's possible water was getting in behind the old heater cover. I'll address all of these before the engine goes back.

I'm sand blasting and powder coating all of the A arms now.