Guys,...

Has anyone removed the stuff mounted on the firewall on the passengers side of the engine bay? It would be the AC stuff that is mounted over there on the firewall. There appears to be a round portion of it and also a square looking thing that comes out parallel to the side of the motor and makes getting the header bolts and #6 & #8 spark plugs a bear to get at. (this might be the heater core...and I do not want to remove that if that is what it is, but if its AC related then I would like to remove it.)

Second is will the removal of any of this stuff leave gaping holes in the firewall? Or will this stuff simply unbolt and pull off.

I am trying to free up some room under the hood for the DFI Gen 7 system I am getting and would like to possibly mount it and the MSD in these locations to the firewall.

I called Hooked-up cause he did this and it really cleaned up the engine compartment but I can't remember exactly what it looked like behind the items removed.

Thanks for any help you might be able to give....

PS: you can see the square thing I am talking about in the lower left hand corner of my sig picture....there is a round thing further down that is out of sight....both of these items I was thinking about removing...

 

Jesse,

I took mine off it leaves behind two large holes in the firewall. One round one behind the blower motor and one rectangular one behind the evaperator. The heater core is inside the car under the dash.

 

It leaves a big gaping hole in the fire wall...Particularly if you do the "Jeb" method of removal and use a Sawzall...

Seriously, anyway you remove the A/C/Heater box and core you're going to have a hole there. I'm simply using a piece of .063" aluminum to cover it...Afterall mine's a racecar now and racecars don't need no stinkin' A/C...
-Jeb

 

ski, the problem with removing the big black box and covering the hole is that you'll also loose the heat ducting on the car. I tried this a year ago. If you had an old housing you could cut the part off where the A/C stuff is and make a cover to still allow the fan to blow heat into the car ( if you need heat? ) . I probably made that more confusing than it needs to be.

 

so from what i'm understanding here, as long as we use an old box to fab that cover (whack off ac crap, reinstall) i'll still have heat? fabbing a cover should be no sweat for either of us. i was looking at the same mod as i will need the extra clearance for the conversion...

 

any clues how much this stuff weights? If you tell me its 50+ pounds it might be worth the hassle, but if its like most other things...20 lbs is not worth the hassle and I will have to find another place to mount the DFI stuff..

By the way while in dicussion...does anyone know if the hoods are different on the 90-91s for the ECM to fit out under the hood above the battery/power brakes? That is where I was going to make up a plate for and mount the DFI if this did not work....

 

Jesse..man too bad we don't live by each other. I spent 2-3 hrs taking that crap off to first find out it doesn't weigh much more than 10-13 lbs.

As for mounting the DFI, here's my suggestion. I moved my battery to the back compartment behind the pass seat, this fit right in and i reused the original mount with a lillte trimming, then this opened up a very large place with the frame right there for making good mounting brackets. I had a 1 gal fuel cell there at one time, but have since just used the one system. This would give planty of room, move the battery weight to the back of the car, and has some air vents right by for air circulation for the DFI.


Yes, if you cut up the original housing and made a ducting system you could still retain the heat, it's actually the blower is all your creating ducting for.


Mike

 

This is on a '90 model

www.huntforpro.com/Chris/firewall001.jpg

www.huntforpro.com/Chris/firewall002.jpg

 

Thanks a ton for the pictures! That solidifies that this will not be happening on my car. Those holes are a little too big for my liking.

The wife just called and said that my DFI system just showed up at the house. Unfortunately she did not sound as excited as I do, nor did she take me up on my offer to let her install it ( in bikini with me directing activities from lawn chair equipped with beer holder). She said not to push my luck. :o

Also I have to finish up Jerkyboys gear change tonight - so the DFI will have to wait till tomorrow night or perhaps I will take a day off work tomorrow to play......

Anyways thanks a TON for the information guys....I like Mikes idea of moving the battery to the rear compartment, I already have a kill switch for the battery - and I bought an optima battery that is sealed already so perhaps I will layout the routing of the wires....

I laid it out and all I think I need to do is the following....

Correct me if I am wrong here....rules state the kill switch must me on the + side of the battery...

If I move the battery to the rear compartment.

1. Run the alternator to the + side of the kill switch and the battery to the same + side.

2. Then run another line from the - load side of the kill switch to the location behind the battery to supply all the main power components....

3. Run the line that used to come off the + side of the battery to the starter from the junction point behind where the battery used to be.

4. Then run a new ground from the battery to chassis.

When the switch is killed - then the power should be killed to the car. Correct me if I am wrong....

 

I don't know about all that. I hooked mine up just like the general did (with longer cables). I've never been asked where it's at by anyone, 1.5 yrs later.

 

You have better luck than I do. 1/2 the time they ask me where its at and its in the stock location.

They always reply with is that stock?

My reply at that point is, yeah its all stock.

 

It's not worth it... 12 lbs 4 oz to be exact; that's for the heater core and it's plumbing/ducting and for the A/C/blower box. I thought it would be more but standing there looking like an idiot with a 14"x18" hole in my firewall proved to me it wasn't. It's true that ounces make pounds and anytime you can increase the hp/lb ratio you'll go faster; but I should've cut up my wife's 150k mile crap-box '85 and left my pristine (albeit highly modded) 80k mile '90 ALONE!!!!

There's no difference in hoods, but the later cars ('90-96) that have the computer under the hood have different braces that allow the computer in there. I usually mount my DFI units inside the car; the latest one is Ransome's car and it's under the passenger seat with the harness going under the carpet and through a grommet in the firewall.. Real clean (and DRY) installation and you don't have to worry about running your serial cable for your laptop BACK into the car to tune it on the fly.
-Jeb

 

Basically, YES! My car doesn't have the junction block behind the battery like yours, so I'm not positive about #3. I would run the (2 gauge) cable from the load side of the shut off to where ever the pos bat cable presently goes, either the junction block or the starter (starter, I would think), and then connect the two together as they are, now.

To gain a little room around the right side of the engine, some people doing big block swaps have substituted in the air box from a ZR1 car. Apparently the LT5 engine requires extra room, where we would all like it.

RACE ON!!!

 

Jeb...yeah that is what I figured i would wind up with a huge hole and no savings ......like my wallet with this car!

On your installs...I laid out the harness and I wish they did not give you so much leader on the harness ususally they don't give you enough with this stuff and this sucker is LONG!

Anyways I was thinking about up in under the headlight, where the harness came back around almost perfect, but a few of the HUGE azz relays along the main harness, then interfere with the hood latch closing.

So I am now back to the battery area. The more I think about moving the battery the less I like it. I have a TON of stuff running in that area of the car and it would all need redone.

I am not thinking about mounting it up where the 90s cars have theirs along that angled pillar - and then put the extra leader of the harness down in under the battery where there is tons of empty space.

This would conceal a great portion of the harness that I do not need and leave just enough for the rest of the harness.

Most of the stuff is pretty straight forward. But a few things I was not completely sure of, and perhaps you can help me out....

1. The hookup for the distributer is not real clear. I brought up the help menu and found the connector I guess they request you use. But how do I hook up to the distributer with the use of the MSD? They mention nothing about this..............

2. THere is a loose wire for the fuel pump voltage...I assume I can just connect to the alternator for this since my fuel pump is a walbro hot wired kit and the pump gets its power from the alternator.

3. The fuel pump and other stuff should come on by itself since the previous wiring is left untouched.....right?

4. How important is the MTS (manifold temp sensor)...the one that measures the surface temp of the manifold...seems like a PITA to try to mount and it mentions without it the temp is assumed to be 100*F.

5. The knock sensor wires are WAY too short and I guess if I should choose to run them I can cut the wires and connect up to it.

6.Something that is sorta bothering me about this is I feel that the ESC should be tired into my stock ESC....but perhaps its all built into the ECM already.....can someone clarify this....???

Well I am beat and am heading off to bed.....thanks for any help on these that you might be able to shed some light on.....Most of these are just things that popped into my head while snaking the harness around in the car and looking at the connectors....

CFI- thanks for the confirmation of the kill switch layout...I will utilize that layout if the need arises to clear up some more room for this install.

The harness is not all that big, but just getting it into the right position for everything to reach should prove interesting.

Well I am nearly falling asleep while typing so I am off........

 

i just looked up the ZR1 box on corvette central and it's almost 300 bucks...no thanks, either i'll hack or eliminate it when the time comes. it's a summer car anyways...who needs heat/ac when the top comes off?

good luck with the DFI ski, and hopefully i see you down at the drags this summer!!

 

I'm telling you, you REALLY need to put the ECU INSIDE the car for not only ease of installation but ease of tuning. Your serial cable isn't long enough to install the ECU up under the headlamps and that's something you don't want to have to run out from under the hood and through the window in order to tune or datalog. Put it inside the car! Plus, that will eliminate your troubles with the "long" harness leads.

I can send you some pics of the piggyback system I just installed on Ransome's '92 if you want.
-Jeb

 

Jeb I decided against the up front headlight location - due to exactly what you mentioned....

What I am really struggling with is the ignition setup...

The adapter they supplied I don't think its compatible at first glance....

Also how the hell do I hook up the MSD6al to all this..... Can I call you or can you explain how you did this.,,

Thanks.,,,anyone else feel free to chime in...

 

Did they send you a harness for the F-body separated coil HEI?? If so you can splice that in. As for your MSD, it piggybacks in just the same as it did before. All the ignition box does is amplify your spark and offer rev limiting (which the DFI does too); the ECU still controls ignition and will operate the same as it did on your factory ECU.

You do know that none of your guages are going to work with this system don't you? Unless of course you obtained a piggyback harness to direct fit into your OEM harness. www.fasttrackperformance.com

Any help you need just let me know...Or Tom Wong...
-Jeb