Trying to get my 96 Cobra back into shape...

[NotA5oh]

I'm sad to say I have had my Cobra on the back burner for about a year now

Up until about a week ago I hadn't done anything but drive it a few times, but then I had a "run in" with a newer bmw M3 and my beloved American V8 didn't pull away from him like it should have. Needless to say that lit a fire under my ass and I need to get this thing back into shape.

So I have a few questions about things I have been researching and was hoping to get some knowledgeable feedback from you SVT guys.

1. I can't seem to find a oil/air separator for the vac line running from the passenger side valve cover to the air intake tube. Can I just fab one up or is there a reasonably priced one available?

2. I'm thinking about going with either 4.30's or 4.56's. Has anyone put these in a N/A Cobra with a T56 swap? I was wondering about how the driveability was for street use.

3. Will going with a 4.30 or 4.56 compensate for the low end loss of the IMRC delete or will it cause more harm then good for my car assuming it will be staying N/A for awhile?

4. Is there a line lock kit for the 96-98 Cobra? I can only seem to find universal ones or 99 and up ones...

 

[Gallows]

1. I have one of these Moroso catch can for the oil problem but need to figure out where I am going to put it.

2. I am s/c, imrc's deleted and a short runner and have 4:10's and am seriously looking at 4:30's when I do the T56 swap so either the 4:30's or 4:56's will be fine.

3. ^

4. No specific kit but still doable Launch Control

 

[NotA5oh]

I saw the one like in your picture but I dont quite understand how it would work... It looks like it would let the air out and not back into the intake. Would that cause problems with idle or vac loss?

Nice looking black Cobra by the way

 

[Gallows]

Thanks for the complement There are fittings, one on each side that the line connects to. I was also told to pick up a breather for the driver side t go in place of the oil fill cap. My tuner told me that my tune would need to be adjusted for the unmetered air. The reason I am going with the catch can is oil is getting into my intercooler & S/C.

 

[NotA5oh]

Ahh I couldn't really tell if there were two ports on that thing, it's kinda cool looking though.

Yeah I saw the intercooler pic on the 03 KB Mammoth install that was in MM&FF and it looked like there was oil on it That can't be good. I have oil all over my intake pipe/TB ect and im willing to bet thats why my IMRC is sticking. But im on can 2 of the seafoam trick and it seems to be working I just want to prevent any more oil going in there.

 

[Gallows]

I have a cheapie oil separator on the car and there is still a lot of oil getting by so the catch can is the best setup to prevent it. I am having a problem on deciding on where to mount it though. The S/C & intercooler take up what little space there was in the engine bay and in front of the rad. It was suggested to try behind the nose but I haven't had time to see if I can get it to fit.

 

[SVT32VDOHC]

I wouldn't go 4.30's or 4.56's with a T56. Last Cobra I saw with that setup was shifting like a mad man at the track. 2nd gear was a joke. He was in 5th at the finish line ready to go into 6th.

 

[Gallows]

New gears aren't set in stone but I figured with the lazy first gear of the T56 they might be a better option. More homework is required I guess.

 

[NotA5oh]

Well last summer with the t56 and stock rear gears I was shifting from 3rd to 4th right at the 1/4 mile mark. Would 4.30's really be to low for a mostly stock 96 cobra?

 

[slayr281]

http://customers.lastcallracing.com/download/file.php?id=8

I've put an Excel spreadsheet together that calculates all your speed at 500rpm increments across all popular gear sizes from 2.73 to 4.88, just need your tire size and gear ratio (1 for 4th, .67 for T45 5th, .63 for T56 6th, etc)

Stock rear gears (3.27) on a T56? I haven't driven my Cobra in a while, but I recall taking 3rd to 6500 or so which had me at just under 120. With 4.30s, you'd be at 90mph at 6500 in 3rd (1.30.)

I'm assuming that when you said you're shifting right at the mark, you're pulling a 115ish trap, and by my calculations, that's 6500rpm in 4th. If you get any more power, you'd be shifting into 5th, or pushing your car past 7k.

So, with that said, you might think about 4.10s which give you a little more mph per gear. 4.30s now might be perfect, but if you mod the car any more and pull higher speeds, you'd likely be crossing in 5th. The 4.10s give you 5-6mph per rpm over the 4.30s.

As for the line lock, there's no real such kit for our cars, but that doesn't mean you can't do it yourself. It's just a little custom work, but it's definitely possible.

 

[NotA5oh]

Thanks slayr, and I was taking it to 7k last year because I didn't know I was wasting my time and hurting my motor

 

[slayr281]

It's not so much hurting your motor, for instance, my built block is just fine revving to 8k, but it's wasting your time with that you've already hit your peak hp, and are now losing power the longer you go. More or less, on a stock Cobra, our power peaks at around 5500rpm, however, depending on your mods, that curve may have moved a little farther back like 5700 or 5800, but also a little higher up.

 

[NotA5oh]

I thought I read in my Sean Hyland 4.6 ford engines book that the 96-98 Cobras peak hp was at 6200 rpm but I could be mistaken. Either way I dont need to take it to 7k

On a different note, I am getting quotes today for the 4.10's and I was noticing that Americanmuscle.com had the set on sale for 159.99 shipped! Seems like a deal to me. Do I need to worry about replacing/rebuilding the trac-loc unit or anything else while I'm having someone tear into the rear end? And should I have any specific rear gear oil put in? Thanks!

 

[slayr281]

Actually, you're right, it's right around 6200 on a Cobra, those rpms I was quoting were for GT's.

As for the gear swap, we used 75w140 per Ford specs on a 4.10 install this weekend. 2 quarts of that, and a bottle of friction modifier will do the trick. If you're doing the install yourself, watch out as that stuff has a tremendous stink. Wear clothes you'll have no problem throwing away should you spill or accidentally smear it on yourself.

 

[NotA5oh]

Thanks for the heads up on the gear oil, I had a run in with that stuff in highschool and it sure is a nasty smell! Haha
As for doing it myself, I wasn't going to but the two quotes I got today are insane! One was 700 and the other 1040$ ! I might be rethinking this one. How hard is it and what will I need besides what comes with the gears when I order them?

 

[slayr281]

Depends on what and who you're ordering through.

When getting aftermarket gears, unless you're getting a package from somebody, they are just the ring and pinion. When we do them, we usually get a master bearing kit so we have all the little things because we have no idea what the condition of the customer's set is when they come in, and it'd suck to have it in the air and disassembled only to be short a couple of items. Chances are, you'll only need to use a couple of those shims or bearings, but it's definitely better to be safe than sorry.

How hard is it? Depends on your experience level and how many times you've done it. Our tech guy usually does them in around 2 hours on and off the lift, but he has done thousands of gear installs in his 30+ years. If I had a book/guide, I could probably do it with the proper tools, but it is pretty precise in how you install them and to what tolerances. That's where the experience pays off. It may take you a couple of times to get those gears in exactly as they should, and if the gears are off, you'll be wishing you sent it off to somebody else

 

[NotA5oh]

I don't think I want to risk installing them myself, thanks for the advice I called randys ring and pinion over in Everett and I'm going to take the Cobra over there as soon as the damn hood canal bridge opens up!

 

[NotA5oh]

Well the bridge is
Open now so I can get over to the Seattle side now, so I will be headed to randys ring and pinion next week as long as they still have a opening. I think I have made up my mind on the 4.10's because I plan on going supercharged eventually.

Now that I have my livewire from SCT working I got to drive it with the new tune and it's driving alot smoother with the canned tune for premium gas. I didn't tweek any of the timing or wot fuel settings yet but I'm just wondering if it would be safe to play with those a little or should I just leave them alone till' I get a wideband o2 hooked up?

 

[jeremy canter]

I've had cars and trucks with gears and to tell you the truth > 3:73's is all you need > my lightning had 4:10's in it and it was just to much gear > the truck was pushing over 300hp at the wheels and was a total MONSTER to drive anywhere > to work or the track > the only thing was it got 14 mpg on the highway and that was being easy on it >mu convertgot just over 20 mpg and it had 3:55's in it > I plan on putting 3:73 's in my 98 cobra later this summer .

 

[COBRA90GT]

...I've had cars and trucks with gears and to tell you the truth > 3:73's is all you need > my lightning had 4:10's in it and it was just to much gear...

...I plan on putting 3:73 's in my 98 cobra later this summer ...

While 3.73 may work best for you in a LIGHTNING, the majority of COBRA owners opt for a higher gear ratio instead. For reference, here's why (as taken from Alternative Auto's site):

4.6L Mustang Tech Q & A

4V Cobra: The Cobra has an entirely different engine than most people are used to. It performs best at high rpms, upwards of 7000. It's power band is relatively high due to the deep breathing nature of the two intake valves. When gearing a Cobra, 3.73's just aren't enough. They don't allow the engine to reach its powerband quickly enough. 4.10 gears are an excellent choice and 4.30's are even better. This may sound very steep if you're used to the average 5.0 which needs to be shifted by 5600 rpm. But since this engine will easily rev to 7000 it needs the extra gear and it likes it. 4.30's are our #1 choice, naturally aspirated or supercharged. At 80 mph in fifth with 4.10's the engine only turns about 2700 rpm, completely tolerable.