"Positive HP & TQ Gains - SVT Cobra?"

[SVT30]

Positive HP & TQ Gains for SVT Cobra

Okay, what would you recommend, to gain HP & TQ out of a SVT Cobra naturally aspirated 4.6 motor?

As we all know, an engine is simply an air pump. So help me with getting air in and then out of an SVT Cobra, naturally aspirated version.

Examples could be:

1) Larger throttle body [$195 or so]?
2) Is SVT factory air-cleaner satisfactory [$95 or so]?
3) Has Cobra factory stainless exhaust, is that good enough?
4) Chip upgrade [about $265 or so]?
5) Or should I get a Tuner [$400 plus]? Allows for easier hook up, I’m told, as well as easier to set straight, if a tech does something to it [government mandates] while doing regular maintenance.

Recommend favored manufacturers and prices if you have them.

I’m not into super or turbo charging, so that’s out. I want my car to “throb,” not “whine.” I like the sound of air being pumped in “naturally” and prefer it being pushed out “naturally.”

Note: Before someone flames me, turbo charging is sometimes okay. Like when trying to squeeze as much juice as one can from a smaller motor. Evo [19 inches, how long before it explodes?] and WRX STi come to mind. Not all carmakers can come up with an S2000 type making naturally aspirated 240 HP from four smallish cylinders.

a) In some cases one can pick up say 11 to 14 HP with bigger throttle body and improved air-cleaner.
b) In some cases a better exhaust system can pick up 14 to 16 HP.
c) Some tell me you can pick up about 15 plus or minus a couple HP with a performance chip or tuner.

My other question is this? Are the above improvements for a SOHC 4.6? Or, as I’m told, the same improvements can be had for a DOHC 4.6?

All told the above comes to about 40 HP more or less, and probably roughly the same TQ. That would make the SVT Cobra 360 HP versus 320 HP, right?

Or are the gains for a SVT Cobra less than for regular SOHC 4.6 which hasn’t been tweaked by the factory?

After all, Ford supercharged the 4.6 to get to 390 HP.

Lastly, I don’t want to go totally nuts here money wise.

Comments welcome . . .

[Hammer]

First question:
What year is your Cobra and what mods do you currently have?

As far as gains per mod go, its just way too hard to take a number and start adding things up.... a dyno is pretty much the only way to get definate before\after stats on any setup.

You have to help me... what gear ratio comes on your Cobra from the factory? Some Cobra guys may want to shed some light on what they think the best ratio is for street\strip duty.

In most cases, gears are one of the best bang for the buck mods there are...

Some other things to look at:

An 80mm C&L mass air kit... (Comes with a K&N filter)

A dyno tuned chip with multiple selections... (One for a base tune and several other more radical configurations when that Camaro comes a calling)
I recommend a JMS tuned Autologic chip...
www.jmschip.com

For exhaust, I'd go with a Bassani X-pipe and just about any cat-back system you like depending on what pleases your ear. (I lean to Dynomax)

Other than that, a small shot of nitrous wouldn't hurt....

[Dark_5.0]

1st let me state the obvious............Gears help the most on SVT cobras.

After that an FR 500 cat back with an O/R X pipe is your best bang for the buck HP wise.

[SVT30]

Okay . . .

First, appreciate the initial replies from Hammer & Dark_5.0.

This will appear a little long, be that as it may, please indulge, thank you.

Actually have two Cobras, one is mine the other my nearest and Dearest. Both are stone stock. Probably will not mess with her 2001 for now.

The one of interest is ’99 Coupe with 17K miles, previous “older” one owner. Has been to Ford SVT Dealer for make over from Ford’s HP snafu. The car is a five speed, 3:27 final drive, as mentioned stone stock right down to the factory shifter. Had car checked [popped valve covers, et cetera], everything is at, or actually better than tolerance. Exceptionally clean inside and out. No door dings, hardly any rock chips.

Runs extremely well, loves to rev, makes it to the upper rev band with easy abandon, even the Ford shifter works quite well, haven’t missed third yet.

Bought it because price was right and wanted “stock” Cobra that hadn’t been abused. Car has absolutely no after market stuff on it, period. Big reason I bought it. Also it is Electric Green, with two-tone Parchment interior, really different look, one I really like. Must help the interior also, that Ford ignored. To date, Ford always seems to skip over interiors. Hope new Mustang holds the interior shown to date.

The above will change however, based on my initial post.

Hammer, understand your issue with dyno versus cumulative. However, in the past when modifying a car, each added perf mod did accumulate onto to the other. Suffice it to say, we didn’t take one mod off then check dyno for each as we went [cost].

Only times we would “take off” a mod is when the dyno went the other way. Rarely happens, to be sure, but . . .

This time I won’t have easy/cheap access to a dyno to check add of each mod.

Hammer talks about chip versus tuner. Though, his recommendation is more of a programmable chip.

He also mentions a cat back exhaust.

As for nitrous, not for me, thanks.

Dark mentions gears. Experience others guys have with gearing would help. 3:73? 4:10? Such radical gearing makes one wish for a 6-speed, does it not?

Dark also talks about cat back exhaust. What HP increase would one get going from Ford stainless stock Cobra exhaust to a good after market cat back? Anyone have dyno experience here? Classically, what has been claimed for such a mod? Yes, I can read manufacturers’ claims, but would appreciate other’s thoughts.

This may sound a bit strange. My primary interest at this point is bumping HP & TQ, without super or turbo charging as in previous post. Therefore, I’ll probably wait on gearing, at least for now.
- - - - -

Really appreciate the feedback, it will help me, as well others who may be contemplating modifying their Cobra rides.

Another sub-subject. What would you begin with? Exhaust? Chip? Other?

Thanks guys . . .

And please anyone else who wishes to shed light on the subject, do feel free.

p.s., There’s a guy I know with a 2001 SS Camaro who lives down the road apiece. Eventually I want a piece of him. But, not right now. So help me become competitive [I assume right now, he’d kick my a**], yet be able to live with my car in regular duty. And yes, if I must go for gearing to make it happen [the SS Camaro], I will. Some say I have a chance, others say not. What say you?

[Hammer]

Thanks for the info SVT, it really helps when advising others to know what you're working with.

As Dark said, the best bang for your buck is going to be gears. I'd like to have some Cobra owners jump in, but off the cuff I would advise going with 4:10s...

As far as the exhaust is concerned, most of your power increase would come from a mid-pipe replacement such as a Bassani X-pipe, the catback system is more for sound than anything else, as the stock setup isn't very restrictive. (In my experience, nothing much is shown from a dyno with a cat-back only swap... although I have seen much more dyno numbers on GTs than Cobras...)

[Dark_5.0]

The FR 500 cat back will add a legit 8-10 RWHP and sounds awesome. I personally seen it dyno proven. But like all good things it is expensive $600.00.

[Dark_5.0]

If you are not gonna swap to a solid axle. Polyurethane bushings and an 03 cobra pinion brace are a must for the rear and both of these things together cost under 200 bux.

Those two mods were the best thing I ever did.

[Hammer]

The FR 500 cat back will add a legit 8-10 RWHP and sounds awesome. I personally seen it dyno proven.

Thanks for the info Dark, the Cobras are definately different animals when it comes to bolt ons....

The best improvement I've seen from a cat-back only install so far is around 6rwhp, and that was (of course) on a GT...

[SVT30]

Well let’s see . . .

Bassini, BBK, Borla, Dynomax, Flowmaster . . .

Then there’s “X” versus “H.”

Some review sites complain about raspy sounds from some cat backs, as well as excessive noise. I don’t want the local constabulary either hunting or finding me because of overly load pipes.

So . . . which cat backs provide improved HP & TQ while improving exhaust note, but aren’t too noisy doing so?

Also, do you guys agree with the scavenging effects and so forth brought on by X pipes?

[Hammer]

My old yellowjacket had the Bassani X with cats...

Gave me a noticeable top end gain, and the sound was quite cool. Kind of like a NASCAR sound but not loud until you romped on it...

As far as nice sound without a high annoyance level... the Dynomax setup and the MAC setups seem to have a nice sound without waking up the neighbors\law enforcement...

Flowmasters are the king of "Pull Me Over" loud... I'd stay away from those...

My opinions on X versus H pipes come from some dyno sessions I was privy to witness last year...

Same car with same setup except for 4 types of mid-pipes being changed...

Two were X pipes, two were H pipes...

Bassani and Magnaflow (X)
MAC ang Dynomax (H)

There was always a good improvement over stock and while the Xs did a little better with rwhp, the Hs did a bit better in rwtq. I believe there was a much expanded test in one issue of MM&FF which came to similar conclusions.

[Dark_5.0]

The FR 500 cat back is on my wish list. It is slightly louder than stock at an idle. But when you get on it a flapper valve opens in the muffler and it sounds freakin mean.

[SVT30]

Dark,

In the Ford Blue Oval forum [Cobras], someone has a set of FR’s for sale, might want to check it out, may save you some money.

http://warnerrobert.com/

Hammer,

Appreciate heads up on pipes. I’ve noticed more than one complaint about X pipes and certain manufacturers of pipes which are too noisy. Thus my caution in this regard.

This will be a W-I-P for sure. So far pipes are up in the air, Densecharger has been recommended several times, not many have gotten into the chip/tuner arena, some have said to not mess with throttle bodies, no gain there.

Posts have been helpful, appreciate same.

[Nazman]

I run a Dr. Gas and Flowmasters and the sound is just wild! The Dr. Gas will give you good HP as well!

Naz

[96_4.6]

What about the mac pro-chamber H-pipe, its supposed to rule all

[96gts4.6L]

Originally posted by 96_4.6
What about the mac pro-chamber H-pipe, its supposed to rule all

That's what I hear a lot too. When i finally decide to get some LT's, I'm going with a Mac Pro-chamber. But for a 4.6 32v, I'd go with an X, b/c X-pipes give better gains on high rpm cars.

[SVT30]

Nazman, 96_4.6, appreciate the feedback re: topic, yours and other posts do help, thanks.

96gts, nice ride, always liked the "rounded" look of this Mustang series. Too bad can't have umpteen rides, right?

[Nazman]

Just for a quick comparo, here are some dyno charts when I was running a MAC H-Pipe and with my Dr. Gas X-Pipe.

Keep in mind that the Dr. Gas HAVE CATS and the H-Pipe was an O/R.

Same mods, just a diferent tune (same tunner).

MAC O/R H-Pipe:


Dr. Gas X-Pipe w/Cats:


More TQ and one HP with the Dr. Gas X, also notice that the car makes over 300RWHP alot longer with the Dr. Gas.

Just my .02

Naz

[SVT30]

Everyone in this thread thanks a lot, really good stuff. Of the three forums I've joined since getting the little M-Cobra, this one highlights.

Anyway, does anyone know what the average/general loss for a naturally aspirated Cobra is? Loss, in this instance is let's say 320 HP & TQ at the motor, what percentage loss is there from there to the wheels [friction from the tranny, gearing, et cetera]? Assumes 5-speed, w' diff less than 4.10s since they cause "more loss" than say 3.73 or stock 3.27.

Seems to be consensus re: H vs. X especially with a 32v 4.6, that X w'cats is best. I'm guessing scavenging effects of X because of higher rev of 32v.

There is divergence re: manufacturer, however. Assuming HP & TQ are similar gets down to sound.

Some guys seem to feel that X pipes are too noisy and raspy sounding at 3,000 and up. Any experience, thoughts here would be great?

Makes me a little twitchy that I see a certain number of guys selling their X systems.

[93GTDIN]

I dont believe 4.10's cause a greater powerloss than a numericaly lower gear. Most of the drivetrain loss is in the transmission, or in your case, the IRS, which is significantly less effective at transmitting power than the SN95's live-axle.

As for gear, go no less than 4.10's. They are a great city/highway/track gear b/c the revs are tolerable, first gear is usable, and the pull is sick. The only problem with 4.10's is at the track, you'll need to shift to 4th right before the traps. Many cobra owners i've spoken to recomend 4.30's. These apparently put you well into 4th gear before the traps, so you can "pull" through the finish line. TO me, 4.30's seem like they would be a bit much for the street.

As far as bolt ons, they're worth practicaly nothing, and the HP/dollar ratio is pitiful. A near surefire way to gain 20+rwhp would be longtube headers (BBK, Kooks, Bassani anything but MAC) and matching X-pipe. Catback, as stated, is all about sound, not rwhp. The FR500 is definitely cool, what with the pressure activated muffler valve, but if you're interested in keeping the police at bay, my Pro-Flow mufflers are quiet and behaved in normal driving with a significant growl at WOT. Too quiet for me, but you may like it.

Dino