[Stuart]

Is there room to mount the ECM above the glove box, under the dash? My daily driver is an old BMW, and that's where they always put their computers. It's out of the way, easy enough to reach for maintenance (just pull the glove box out) and it's not affected by heat. Then, you wouldn't have to make any mods to the kick panel.

[fbrown]

This is where I put mine. There is clearance for the AC duct work, I had the duct work in place when fitting the ECM.

[b-man]

Originally Posted by Stuart

Is there room to mount the ECM above the glove box, under the dash? My daily driver is an old BMW, and that's where they always put their computers. It's out of the way, easy enough to reach for maintenance (just pull the glove box out) and it's not affected by heat. Then, you wouldn't have to make any mods to the kick panel.

Taking your suggestion I pulled the ECM up into that region and gave it a long hard look and some thought.

There's just too little room above the glovebox. Some of the space I need is occupied by a flexible A/C ducting hose that needs to travel over the top of the unit to feed the passenger side cooling vent.

The A/C kit comes with it's own plastic glovebox that's about half as deep as the original, you can't get it in unless the dash cluster is removed. The stock glovebox comes out the from the bottom of the dash quite easily, different story with the A/C unit in the way. I really don't want the ECM packed in where I can't get at it easily, I don't mind it being a little exposed to facilitate having easy access to it.

Right now I'm in the middle of making up a pretty nice bracket that will bolt to the firewall and situate the ECM horizontally instead of vertically like I first envisioned. It will hang down by a lot less, stay tuned.

[b-man]

.....that I might need in my next lifetime.

Lucky for me I found an old bracket in my stash of junk that was already pretty close to what I need to mount the ECM.



All I need to do now is to remove what doesn't look like an ECM mounting bracket.



After trimming 1" off the right side and 1" off the bottom (losing the welded side braces in the process) and drilling & tapping the 4 holes 1/4-28 that mount the ECM the bracket is done. The firewall angles back a bit so I had to increase the 90 degree bend angle of the bracket by about 10 degrees to get the ECM to sit level and tuck up as far as possible.



The ECM doesn't sit any lower than the bottom of the A/C unit so it will not be in the way of my passenger's feet. I still need to mount the TCM to the front edge of the bracket.

The kick panel didn't need any mods, it still fits just like the factory intended. I can crack open the vent on this side to provide a bit of fresh air flow for both the ECM and A/C unit.



It's nice to have easy access to these units even if they aren't all that pretty to look at where they're mounted. Making things easier to service whenever possible is constantly on my mind during this build.

Well, that killed most of my day. Just figuring out what to do and finding whatever materials you need to proceed takes a lot of time, in a fully-equipped shop things definitely go a lot faster.

[b-man]

.....in the garage finishing up mounting the control units today. Once you get some major items in place it makes finding places for the other little things a bit easier.

The TCM found a home next to the ECM. The ECM mounts on four .300" tall standoffs made of 3/8" O.D. brake line tubing. Both units can be bolted to the mounting plate first, then the plate mounts on two 1/4-20 X 3/4" studs on the firewall.

The two studs are actually button head screws threaded into the firewall from the engine side after tapping the sheetmetal 1/4-20. They were snugged down enough so that they won't turn but not so tight that they strip that one thread out of the sheetmetal. A little strip caulk body sealer under the bolt head and flat washer keeps them water tight and helps lock them in place.



The fuel pump relay found a home on one of the ECM mounting bolts. I'll probably come up with a simple sheetmetal cover painted gloss black to hide the ECM/TCM/fuel pump relay unit later on.



This low-angle shot shows the wiring bundled up and pulled to the driver's side and zip tied to keep it in order. The white zip ties are temporary and will be replaced with black ones. I'll get another piece of black harness sleeving to cover up the colored wires and tidy things up when everything is finalized on the wiring.



You can barely see any of the wiring here, it really isn't visible unless you get down pretty low. I'm glad I didn't try to stuff it all up inside the dash.



Little by little.



Thanks for looking.

[Old Goat 67]

Thanks for sharing.
Looks good.

[TheMonkey]

you are doing excellent work. one of my favorite threads on the board.

[fbrown]

Have you hooked up the transmission end yet? How was the length of the trans wiring. I hooked mine up tonight and found it to be a little shorter than I would have liked. The o2 sensor wire however is much longer than needed. BTW I had to remove the header to install the crank sensor wire. Not enough room to get my big hand in there otherwise.

[b-man]

The trans wiring was just barely long enough. I ran the wires down to the pan rail and back up to the large connectors and they fit okay, there's no room between the trans tunnel and the trans in this area to run the wiring. The main harness had to be tucked back a bit into the recess at the top of the trans tunnel just below the passenger side cylinder head to gather enough length to reach the trans connector.

The trans wiring goes right under this cover on the side and then loops back up to the connector:





You can see where there is room for the harness in this older pre-swap pic, the trans tunnel has more room on the passenger side to free up space for the auto trans dipstick tube I suppose:



Thanks for the tip on the crank sensor wiring, I'll be sure to plug it in before I install the headers for the last time.

On the subject of wiring, did you find a 4-terminal brake switch to shut off the cruise control and if so which one did you use? Would a '99-'02 F-body brake light switch work?

Did you change the angle on your knock sensors on the side of the block for a more favorable hookup to the harness? It looks like they both should angle toward the rear instead of the front.

Thanks, Bart

[fbrown]

Brake switches are quite common at least for the 68 up and I would guess that the 68 part would work in your car. Although I ordered mine from Classis Industries (full size Chevy Catlaog) part DR497 - 5.95, I only ordered since I was ordering other parts for my Cadillac. Rock Auto even lists a Delco part. The part I ordered claimed to fit anything from 67-85. I think the only thing that has changed over time is the type of connector that fits the switch. Even the switch on my 94 Fleetwood would have worked. This should be a part you would be able to get from most any auto part store, although they may need one day to get the part. If you are ordering the switch, Rockauto lists several different brands of switchs for 68 GTO's - cruise (4 wire)

From the picture of a 99-02 F-body switch, I don't think it would work, the adjustable shaft portion is too short.

One listing of a non-cruise switch list years from 58-86 so I think a switch for a 68 would fit your car.

I have not repositioned my knock sensors yet, just haven't got to it. Just loosen the bolt and rotate as desired, I have already moved the passenger side to gain clearance for my transmission cooler lines. Looks like it needs to be moved again.

Frederic

[b-man]

Frederic,

Thanks for your response, I was under the impression that a brake switch from a later car that uses cruise control would be required.

Today I was looking for a good place to mount my transmission cooler. The air conditioning condensor takes up the space in front of the radiator where I was first thinking of putting it. There is not enough room up front anywhere behind the bumper.

I am considering mounting it to the passenger side frame rail and to the two floor pan braces just above it. It will go directly behind the body mount brace just underneath the passenger seat.



There is plenty of clearance between the exhaust system and the cooler, the X-crossover is directly across from it so the hot exhaust pipes will be as far away from it as would be possible. I can run the 3/8" steel cooler lines going across to the trans just above the trans crossmember to keep the heat transfer from the hot exhaust minimized as much as possible.



Does anyone see a problem with this approach? With the car moving down the road at normal traffic speeds I would think there should be plenty of airflow.

Would stones or road debris kicked up by the right front tire tend to damage it? The B&M Supercooler I'll be using is a plate-type design that is more resistant to impacts than the tube & fin-type coolers. It's not like there are a bunch of stone chips on the bottom of the floorpans already.

I know that cast aluminum framerail mounted coolers are available, but they don't look like they would cool nearly as well as the plate type cooler I have.

Any helpful input would be appreciated.

[Wick]

I think it might get beat up pretty bad under there and the air flow through would be horrible. Those coolers need good airflow for a trans.

[6 Grrrs]

Many High end builds put coolers under the vehicle. Like you said, it's not like the floor is all beat up there. Mine has a fully painted/cleared floor & there are no stone chips in 2300 miles.

I think you will be safe. There should be plenty of air to cool it. These older chassis don't have any type of air direction (air dam), so most air goes underneath the vehicle. I would think maybe the only issue is that the xmember may block some of the air flow.

[b-man]

.....for mounting the trans cooler, with a little help from my friends.

I will mount it up front instead of taking the easy way out and mounting it under the car on the frame where it really won't do a good job and could end up damaged. I had to be reminded that there is a lot of hot air expelled underneath the car from the radiator, engine block and exhaust system.

The one I have is just too a little too big to fit behind the front bumper in front of the radiator and condensor, so I'll just downsize the cooler and get one about half the size so I can put it up front where it really needs to go. The 4L70E overdrive trans with the lockup converter shouldn't put out quite as much heat as one with a non-lockup converter that will by design slip at least a little 100% of the time.

You can see the top of the cooler here, it is 1-1/2" thick and there is only a 2-1/2" space for it. On the left it's just touching the condenser at the bottom corner, it has to follow the angle of the front bumper and grilles in order to fit.



This cooler is 10" wide (as mounted here) including the mounting flanges and has an 8" core width. I will replace it with one of the same design that is 5-3/4" wide with a 3-3/4" core, it will also be 1-1/2" thick like the larger one:http://www.summitracing.com/parts/BMM-70273/



Should get some pretty decent airflow here and not block too much airflow to the condensor and radiator.



It will mount the same as the trans cooler I have on my GTO shown here, but of course it will only be about half as wide. Plumbing will be done using 3/8" steel hard lines with inverted flare fittings (no rubber hose) like the GTO as well.







Thanks for all the help and suggestions guys, much appreciated.

[fbrown]

If you have a 9.5"-10" TC you will make a ton of heat if running hard, like auto-crossing or trans-am type road course where you will never be in lockup nor should you be. I ran a 4l60E setup for 600HP in my former car, a 94 Fleetwood with 480HP 383. The Fleetwood had both a radiator transmission cooler and a separate transmission cooler mounted in front of the radiator and AC condenser. If I had raced my Fleetwood, the factory transmission cooler would not have been big enough. But since most of the driving was highway with only a limited amount of slow speed wide open throttle, I got away with using the factory setup. My transmission supplier agreed that in my case, I didn't need to upgrade the front transmission cooler, but said he would insist on it if I were to Auto-cross.

Make sure you run a big enough transmission cooler for the type of driving you will be doing. Since you are in AZ you may be able to skip the radiator transmission cooler, but in cold weather the transmission will take a long time to warm up.

You are correct that once you are in lock-up there is little heat generated, but depending on the program on the transmission controller, you may not be in lock-up until you reach 55 mph. I don't know what Speartech set the controller for.

Since I planning to run my 68 Lemans quite a bit harder than my Fleetwood, I'm planning to run a second transmission cooler in front of the AC condenser. For the short term I will just use the transmission cooler in the radiator. I hope to have my car on the road in a month or two, run it for a few hundred miles before starting the frame-off restoration phase of the project. I can't really mount the transmission cooler until I deal with the AC, which for me will be during the restoration phase.


BTW - plan on buying one of the programs that will let you edit the parameters in the computers. Otherwise you will always want something slightly different than the way Speartech setup the program. In addition to having my Fleetwood dyno tuned, I spent many hours tweaking the idle speed, shift points, shift speed, down shift points, TC lockup. The "mail order" tune we got from Speartech will be just a starting point and will probably need slight changes.

Frederic

[Skip Fix]

You do some pretty nice looking fab work! Esp that tranny crossmemeber.

[b-man]

Frederic,

I was surprised to see the GVW ratings on the various B&M race coolers.

The larger one I have (P/N 70266) is rated at 28,000 lbs. GVW, while the smaller one I plan to buy (P/N 70273) is rated at 25,000 lbs. GVW. Pretty surprising that a cooler half the size is rated just under its bigger brother in cooling capacity.

Originally Posted by Skip Fix

You do some pretty nice looking fab work! Esp that tranny crossmemeber.

Thanks Skip, coming from you I consider that to be a huge compliment.

Now, a fan relay question for you guys who know your automotive electrical systems.

I'm running some 4th-gen F-body fans, they're an OEM replacement made by Dorman (P/N 620634).



Would these require the use of two 30 amp relays or two 40 amp ones? I have two Bosch 30 amp relays (0 332 019 150) here that I might be able to use.

My custom Speartech wiring harness already has provisions for computer control of the fan relays, the loop of pink-dark green-dark blue relay control wires are shown at the bottom of this pic:



Where would you recommend that I source the relay plugs and harnesses from, or some new relays if I need to buy some?

Would also be nice to find the OEM connectors that plug into the fan motors.

Any help you can offer on this would be very much appreciated.

Bart

[fbrown]

While the Bosch relay is good enough to control the fans, it is not a complete solution. You need to add a circuit breaker or fuse for each fan, also I recommend that you use a weather-proof connection since the relays will be mounted under the hood. While expensive, a couple of these kits will provide everthing you need. This kit also includes a circuit breaker.

http://www.painlessperformance.com/w...rchField=30130

You should run at least 12 guage wire for the power, 10 guage would be better but is harder to work with. You should be able to buy a few feet of stranded wire at Home Depot/Lowes. If you need to splice/crimp the wire use heat shrink over the splice to make it water-tight.

For your fans, you should be able to get a repair pigtail (usually available from GM dealer) or match the connectors with a little searching. Be aware that it you buy loose terminals and the connector parts, you will probably need a specal and expensive crimp tool. If you buy the terminals be sure to order a few extra terminals. Its bad to get a bad crimp and then be a terminal short. For what it worth it took me a couple of hours of internet searching to find the weather-proof connector and terminals for the fans that came with my radiator.

Frederic

[ponjohn]

Bart- what CPU are you using to manage the EFI?

Some of the aftermarket units have a fan output.

I do not know if that output is PWM or a 12v control signal.

[fbrown]

More thoughts for the fan wiring and other things.

Actually most cars of the 80's up have a underhood power distribution center, that contains fuses, circuit-breakers, relays for all of the high amp devices that are present on moden cars. Depending on how many other items you plan to run, it might make sense to install one. Otherwise underhood wiring might get messy... If the fan relays and circuit breakers are all you plan to install it probably doesn't make sense to add a power distribution center. I'm thinking about it for my car beause I will probably need 40 amp service for the stereo and I could have the fuel pump, fans, ECM and stereo fused and wired from one under-hood location.

Frederic