Era #708

[cbmax]

With any luck my ERA 427 chasis # 708 is about 3 to 4 months away.

Going with 15 inch pin drive wheels (Trigos) and TKO 600.

Here are the loose ends.

1) Should I consider upgrading front brakes to 4 Piston 12 inch rotors? ($1200)

2) Should I consider optional upgraded suspension (outboard brakes)

3) Tire selection. Would you consider BFG drag radials, Rear size 325/50/15. Would drag radials be a poor choice period for someone new to a car of this magnitude? Better choice in 15 inch?

I forsee car being used predominantly on the street for some spirited back road cruises. However, can't rule out the possibility of doing some closed course stuff some day. Is up front investment worhwhile?

I often times have the tendency to overbuy.

[Adrian472]

Hi Cbmax

I would choose the custom rear end $800 option for several reasons , makes changing rear pads alot easier and its good for resale plus you will not have the worry of the sometime broken weld on the lower arm.
The brakes on the front from what i have heard seem to be ok for normal street use unless you wanna go racing, but i think that could be something you could do your self at a later date with some aftermarket calipers and rotors. But i personnal would go for the big brakes cause it add to resale and bragging rights.
Best of luck
Adrian

[John Martin]

No
No
No
So what color ?

[cbmax]

Thanks Adrian.

From what I'm told though, if you are going with larger brakes in the rear, you need to put larger brakes on front at same time. Not exactly sure why.

John thanks forthe input but do you mind explaining your responses.

Color will be gloss back with red stripes.

[John Martin]

Just from your intended use , Mine is set up stock . As for the ocasional closed track , I beleve you can change your pads .
I think you will be very happy !

[Adrian472]

Originally posted by cbmax


Thanks Adrian.

From what I'm told though, if you are going with larger brakes in the rear, you need to put larger brakes on front at same time. Not exactly sure why.

That would be due to keeping a good front to rear brake balance, which could be adjusted hyd. with a bias adjuster.

Adrian

[Excaliber]

If your not doing 5 or LESS laps on a road course the inboard rears and stock fronts will be fine. After four or five laps, depending on the track, you will have NO BRAKES due to over heating if you go racing. For many people 5 or 6 laps is a LOT, you may be tired out and want to come in anyway (tires over heated, etc.).

Even the big fronts and outboard rears may not cure the HEAT problem. You'll need high temp fluid and high temp pads and brake cooling ducts. Those high temp pads only work when hot, so their dangerous on the street. Being able to change pads easily (or at all) DEMANDS the out board brakes on a Jag IRS suspension.

The reason to go with multiple piston calipers is for better "pedal feel" or "modulation". You can control "impending lockup" and be more sensitive to threshold braking with a mulitple piston disc brake combination. After all, even a single piston caliper can "lock up the brakes". THATS something you DON'T want to do coming into a corner hot! So go with multiple piston calipers if you go racing! If mostly street is the goal, save some money and go stock (and drive within your limits)!

The drag radials offer the SINGLE most important thing a replica needs, TRACTION! But the drag radials aren't gonna cut it in the corners, and THATS where you really need the traction! These cars "spin out" (tail happy) very easily, and good traction is the number one thing that may save your butt when you screw up and hit the throttle to early. Tires, don't try to save ANY money here, step up to the plate and spend as much as you need to get it right. I'm running the old Goodyear "Bill Board" bias ply tires (15") about $170 or so per tire. NOT DOT APPROVED, I don't care, they are about the BEST traction out there (and they look really cool and are period correct). Another choice might be Yokohama "Auto X" tires, these offer good traction even when cold (which is typically when and how you would run an Auto X event). There are a number of good tires out there, some are difficult to find in 15", but that IS the size I would go with. Goodrich T/A's are quite popular and quite "dangerous" in my opinion. They just don't have the traction these cars need!

One more thing about "spin outs". Don't go with a rear gear ratio to low. You WILL have plenty power. A taller gear (3:31 for a Jag would work) will help you control wheel spin easier. Wheel spin is the number one cause of "tail happy" spin outs!

To low a rear gear will actually SLOW DOWN your 1/4 mile ET time due to launching and tire spin problems. Many find that launching in 2nd is quicker! I run a 3:31 with a TALL first gear close ratio top loader. 1st gear is good for about 65 mph, now THATS a TALL GEAR! However, I run the 1/4 in 11.90 seconds, and by ANY standards that is QUICK!

[The Dreamer]

Sprited Driving = Big Brakes, Its cheaper to do it now than later.

Upgraded rear doesn't seem to have wheel hop problems like some of the Jag rears have.

I went with Yokohomas as most say they are better tires (stickier) than the rest of the 295/50/15 tires out there.

[Excaliber]

Good point about wheel hop Dreamer, that can be a serious problem on many IRS cars, and ERA is no exception. ERA does offer a wheel hop damper, not sure it is now standard or an option. Even if I didn't get the out board brakes I would certainly inquire about the wheel hop problem.

I have inboard brakes and also have the modification, ZERO wheel hop under even the most severe conditions. My friends FFR solid axle shakes itself to death with serious wheel hop. Stock suspension on his!

[Adrian472]

From i have heard you can convert a Jaguar IRS rear end to outboard brakes using the later XJ40 rear uprights which are in fact outboard already, im not sure whats involved but it would not be much because most Jaguar parts are interchangeable and its the parts that was used on the Aston DB7 which was based on XJS floorpan and running gear.

Adrian

[cbmax]

Okay

Sounds like I should stay away from the BFG Drag Radials if majority of intended use is spirited back road street driving. Correct?

Was considering the Yokohama Avid S/T's mentioned by Dreamer. They do offer correct size in 15 inch.

Now for more on the brakes an suspension. Still not sure if standard package will be sufficient.

Can you just go with the larger front brakes and keep the standard rear suspension package?

This is my first Cobra!

[cbmax]

Anyone have any other thoughts?

It would be an expensive proposition to do this down the road I would think.

ERA rear is $4,500.

Can you do bigger front brakes with standard rears?

How about upgraded rear supsension and standard front brakes?

[DonC]

I went with the larger front brakes combined with the ERA rear suspension to keep things balanced. I'm very pleased with the results. Was thinking about going with the standard front brakes with the upgraded rear but decided against it. There is a reason why the upgraded fronts are recommended. In any situation the front brakes are working harder than the rears.
Went with the upgraded rear for two reasons. I used to own an XKE and even with a lift changing the rear pads was a pain not to mention any work necessary on the calipers themselves.
The second reason was to eliminate the wheel hop that could happen with the standard rear end. While not a problem with everyday driving, even somewhat spirited, it can show up when leaned on. The aftermarked hop prevention linkages appear to take care of the problem but I prefer not to have it in the first place.
I'd recommend bouncing your ideas off Bob P once you have done all your research. He can save you a lot of heartburn down the road.
DonC

[Chaplin]

I have the standard front brakes and standard in board rear brakes. If I were going to do it again, I would probably up grade both. Although the brakes are perfectly adequate for street driving (which is all I do) it would be nice to have a little extra stopping power. Plus, that ERA rear assembly is very pretty.

I should add that with the standard rear, I have had absolutely no problem with wheel hop whatsoever.

[cbmax]

Don

Thanks for the input.

Guess I'll suck it up now and invest the extra $1900 for upgraded front brakes and optional ERA rear.

Checked out your gallery. Which Cobra is yours?

[P Martin]

CB,

Just curious, What motor are you using?


Pat

[TampaFla]

I purchased the 15" wheels but then found out they won't fit my car (have the larger front brakes). Ordered 17" wheels. .

[cbmax]

Pat

My engine builder is trying to get a hold of one of the Genesis 427 iron blocks through Ford Racing.

CB

[DonC]

CB:
Starting on page 3 of the gallery the red with gold stripes.
The other photos are of the Shelby that was such a problem for the guy with cancer.
DonC

[Excaliber]

Whew, $9000 is a BIG price increase all right. Those larger brakes and up-grade rear end won't return near that on "re-sale". Of course everyone says your not supposed to worry about re-sale, but I do!

On my first Cobra, an Excalibur, I was racing it hard on the road track here. My brakes were terrible!! I up-graded the calipers to Wilwood multi piston units, high temp pads, high temp fluid and added some brake cooling ducts. Cost about $500. Night and day difference!! That bad boy would haul you down in a hurry and not overheat! The best part for me was more brake feeling and control. Rotors remained the same. I had a brake bias balance control, HIGHLY recommended. Add the anti wheel hop kit to the stock IRS and bam, your done!

Hey, just my opinion, thats what I would do!