Mustang and Ford Performance Forums banner
1 - 20 of 25 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter · #1 ·
I'm looking to get another 10-15 rwhp, and similar for torque, and wonder if it can be done with bolt-ons, or do I need to get into the engine? Would a good chip and/or headers (shorty or LT) put me up the the 310-315 rwhp range? Any suggestions? Thanks.

Moonlt ‘01 True Blue Coupe
#813 of 3867 (5/7/01)

278.6 rwhp SAE, 286.3 rwtq (prior setup: with silencer removed,
and Flowmasters)
298.2 rwhp SAE, 291.4 rwtq (with mods below)

Power Mods to date:
Magnaflow X-pipe w/cats and Magnaflow catback, March UDPs, C&L 80 MAF with K&N filter

Already have gears (3.73s) and several Steeda/MM suspension parts.
 

·
Registered
Joined
·
226 Posts
Since you already have the X-pipe I would suggest a set of JBA shorty headers unless you want to buy a new midpipe then longtubes are the way to go. The addition of headers alone will add about 10 rwhp with no tuning. Add in a custom tuned chip done on a dyno (no mail order chips) and you will be solidly in the 310 range.
 

·
Registered
Joined
·
226 Posts
Oh yeah and if you plan on racing the car with any seriousness dump the 3.73's and go with 4.30 or 4.56. I just got back from the modular shootout and I averaged 22.6mpg with my 56's doing 70-80mph the whole way (about 3000-3200 rpm) so they are not as bad as you may think.
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #5 ·
Thanks for the info. I don't drag race, I'm more into the handling thing. But just curious, what times do you think my Cobra would turn with the 3.73s and a good driver?
(Also, your gas mileage is good -- I recently got 23.6 mpg on a trip up the coast (California Pacific Coast Highway) -- with a lot of twisties and rarely got to 5th gear. These engines are very fuel efficient below 3,000 rpm.)
 

·
Registered
Joined
·
105 Posts
JBA shorties with a dr.gas X, or LT's with whatever midpipe you want. Buy a UPR intake tube or make your own like I did. Don't bother with cold air. It's a waste of money. You'll easily be in the 310 range or higher.
 

·
Registered
Joined
·
885 Posts
See sig for my #'s, which were achieved with:

JBA 1 5/8" shorties
Magnaflow catted x-pipe
Steeda u/d pullies
C&L 80mm MAF kit
FordChip custom dyno-tuned chip (I made 308 rwhp before the tune & chip)

Engine is otherwise bone-stock with ~ 7000 miles on it, so it's not even fully broken-in yet... ;)
 

·
Registered
Joined
·
660 Posts
I'm surprised nobody mentioned a larger, oval throttle body? I'm sure people are seeing gains with that...
 

·
Registered
Joined
·
595 Posts
IMHO, a throttle body is a waste of time on a "bolt-on" motor. The restriction is in the intake itself.
 

·
Registered
Joined
·
885 Posts
HWKRCNG said:
I'm surprised nobody mentioned a larger, oval throttle body? I'm sure people are seeing gains with that...
Bob Cosby said:
IMHO, a throttle body is a waste of time on a "bolt-on" motor. The restriction is in the intake itself.
Good words of advice.
Time & time again I see n/a Cobra owners looking for that extra bit of rwhp, and against others advice they go blow a good bit of cash on an aftermarket throttle body. Although the t/b can provide crisper throttle response, they usually offer ZERO rwhp gain. Might be a worthy investment for power-adder Cobra's, but not a good mod for the naturally-aspirated crowd.
 

·
Registered
Joined
·
660 Posts
Bob Cosby said:
IMHO, a throttle body is a waste of time on a "bolt-on" motor. The restriction is in the intake itself.
?Upper or lower intake manifold? Is it the size of the butterflies or what?
 

·
Registered
Joined
·
9 Posts
Bolt on Cat-Back.

See http://www.mustangexhaust.com they did some testing w/ H/X pipes and found that they made little difference as far as power gains. However, cat-back did add 10-12HP.

Myself for now am going with a cat-back in a 99Cobra. Then headers and a new pipe later.
 

·
Registered
Joined
·
885 Posts
Rebis3 said:
Bolt on Cat-Back.

See http://www.mustangexhaust.com they did some testing w/ H/X pipes and found that they made little difference as far as power gains. However, cat-back did add 10-12HP.

Myself for now am going with a cat-back in a 99Cobra. Then headers and a new pipe later.
Actually, you have it backwards - the x or h-pipes make the additional power (it's a toss-up which makes more), and the cat-back adds zip.

You might gain 10-12 rwhp on a '99, but if so, the '01's definately had a better cat-back design. I gained ZERO rwhp from my Magnaflow cat-back - all it did was change the sound and give me nicer/bigger tips.
This is pretty typical of a well-designed cat-back on a n/a car, and others (owners & magazine testing) have had the same results.

I knew this before I bought it though, so I wasn't expecting a rwhp increase.
 

·
Registered
Joined
·
9 Posts
Actually, you have it backwards - the x or h-pipes make the additional power (it's a toss-up which makes more), and the cat-back adds zip

Interesting that your 2001 Cobra appears to perform different with different equpment then theirs.

I hope I don't get too much in trouble for copying some of http://www.mustangexhaust.com info but it's to help Mustang owners so I hope it helps.

VRS X-Pipe v Mac H-Pipe v Stock
unmodified 2001 Cobra
' As unbelievable as it may seem both off-road mid-pipes produced the same overall gains on this 2001 Cobra, which was not much over the stock H-pipe.'

They saw some gains above 6K but below that figure the X-Pipe and H-Pipe were equal to the stock H-Pipe and in some cases below, not much a couple hp, stock H-Pipe.

Cat-Back on http://www.mustangexhaust.com. Did make a difference.
'The stock muffler flowed an average of 174.96 cfm while the Magnaflow flowed a much higher 284.32 cfm! '
'definite increase in power, with peak gains of 6 rwhp and an incredible gain of 15 rwhp at 6800 rpm.'

Thus, they seemed to say different then your experience. Stock headers and Stock H-Pipe were used on their car.

You don't happen to have graphs for the different parts in-line do you? Stock headers - aftermarket X or H pipe - stock cat-back versus Stock headers - stock h-pipe - aftermarket cat-back?

Also they noted and I've a seen a few places noting that there's a decrease on the stock cat-back from 2.5" tubing pinched down to just under 2". That would definitely restrict flow. Seems counter that you weren't able to get any more HP/torque by replacing that restriction.
 

·
Registered
Joined
·
9 Posts
You might gain 10-12 rwhp on a '99, but if so, the '01's definately had a better cat-back design. I gained ZERO rwhp from my Magnaflow cat-back - all it did was change the sound and give me nicer/bigger tips

---

Interesting they tested Magnaflow on a 01 Cobra, same as your car found more hp and torque w/ the Magnaflow.
 

·
Registered
Joined
·
226 Posts
I disagree with the data showing that the catback adds more power. I gained absolutly nothing with my catback however I did gain 9rwhp with the addition of just an h-pipe when I had the stock cat-back. The restriction on my car was definately in the cats.
 

·
Registered
Joined
·
156 Posts
Dave, you are correct. The bigger restriction on the '99 Cobras is the midpipe. One of the ways of acheiving the "fix" on the '99s was freer-flowing mufflers. As a result, changing the catback pretty much just changes the sound.

On the other hand, the '01 Cobras, having been redesigned after the nightmare of the '99s, has the primary restriction in the mufflers. I gained 12 RWHP from a stock catback with welded-in mufflers on my 2001 (but only about 4 RWTQ). I don't know what gain, if any, I got from my X pipe, but I doubt it was much.
 

·
Registered
Joined
·
885 Posts
Rebis3 said:
They saw some gains above 6K but below that figure the X-Pipe and H-Pipe were equal to the stock H-Pipe and in some cases below, not much a couple hp, stock H-Pipe.

Cat-Back on http://www.mustangexhaust.com. Did make a difference.
'The stock muffler flowed an average of 174.96 cfm while the Magnaflow flowed a much higher 284.32 cfm! '
'definite increase in power, with peak gains of 6 rwhp and an incredible gain of 15 rwhp at 6800 rpm.'

Thus, they seemed to say different then your experience. Stock headers and Stock H-Pipe were used on their car.

You don't happen to have graphs for the different parts in-line do you? Stock headers - aftermarket X or H pipe - stock cat-back versus Stock headers - stock h-pipe - aftermarket cat-back?

Also they noted and I've a seen a few places noting that there's a decrease on the stock cat-back from 2.5" tubing pinched down to just under 2". That would definitely restrict flow. Seems counter that you weren't able to get any more HP/torque by replacing that restriction.
I don't know about others reporting an aftermarket Cat-back on an '01 gives good gains - it sure didn't in my case.
The Magnaflow X-pipe on the other hand, gained quite a bit of power - especially in the upper RPM's.
This is the before & after dyno with the X-pipe & stock cat-back:



Next dyno I did after the cat-back showed little/no change anywhere on the graph.
There might have been a 1-2 rwhp/rwtq difference, but this is common on different pulls on different days.

Here's the breakdown by RPM. Best run stock vs. best run with X-pipe:

RPM.........Stock rwhp/rwtq..........X-pipe rwhp/rwtq
2700.........125.5/244.2...............121.4/236.2
2800.........130.0/243.8...............125.9/236.1
2900.........135.0/244.5...............131.0/237.2
3000.........137.9/241.4...............135.3/236.9
3100.........142.1/240.7...............139.9/237.0
3200.........147.9/242.5...............146.9/241.2
3300.........156.6/249.3...............157.7/251.1
3400.........168.4/260.1...............168.6/260.5
3500.........175.8/263.8...............175.6/263.4
3600.........180.6/263.5...............181.1/264.2
3700.........188.1/267.0...............187.7/266.4
3800.........194.6/269.0...............194.8/269.2
3900.........204.6/275.6...............206.2/277.7
4000.........215.6/283.1...............218.8/287.4
4100.........225.6/289.0...............227.0/290.8
4200.........232.3/290.5...............232.3/290.5
4300.........237.3/289.8...............238.8/291.6
4400.........241.7/288.4...............243.9/291.2
4500.........245.8/286.8...............249.4/291.0
4600.........251.5/287.2...............255.1/291.3
4700.........257.4/287.6...............262.8/293.7
4800.........264.4/289.3...............269.9/295.3
4900.........267.8/287.0...............274.8/294.5
5000.........268.6/282.2...............278.3/292.3
5100.........266.0/274.0...............277.6/285.8
5200.........267.0/269.7...............279.9/282.7
5300.........268.2/265.8...............280.9/278.4
5400.........271.2/263.7...............283.8/276.0
5500.........272.2/263.7...............283.6/270.8
5600.........273.5/256.5...............285.5/267.8
5700.........277.5/255.7...............287.2/264.6
5800.........277.5/251.3...............289.5/262.1
5900.........279.6/248.9...............290.1/258.2
6000.........279.8/244.9...............291.0/254.8
6100.........276.7/238.2...............29.06/250.2
6200.........268.6/227.5...............287.8/243.8
6300.........258.2/215.3...............283.1/236.0
6400.........255.1/209.3...............274.0/224.9
6500.........248.9/201.1...............267.3/216.0
6600.........244.7/194.7...............264.2/210.2
6700.........236.9/185.7...............255.0/199.9
6800.........230.0/177.7...............251.8/164.5
6900.........224.2/170.7...............247.5/188.4

This comparison clearly indicates strong gains (on my car) in both rwhp & rwtq from the X-pipe. A little of it comes from the u/d pullies I installed, but maybe 3-5 rwhp/rwtq at best.
I gained as low as 9.7 rwhp/10.1 rwtq @ 5000 rpm, and as high as 23.3 rwhp/17.7 rwtq @ 6900 rpm.
 
1 - 20 of 25 Posts
Top