kp

iTrader: (34)

I was just going through some dyno files here and though this might be of interest to some for the old MAC/LT debate..

Both cars have the exact same mods, exact same tuning, I copied all my tables right to the other car (cant get much closer on the a/f between the two). Same cam, same gear when these dynos were made. Only difference between the two cars (both have less then 10,000 miles on them) is mine has MACs with the supposedly crappy MAC cats and a magnaflow exhaust, the other car has Hooker LTs with an ORY and a SLP dual/dual. I would try mine with the ORY but it sounded so bad I didnt even make it out of my subdivision before I turned around and put the cat Y-pipe back on it.

Nothing earth shattering but food for thought, interesting around 6200rpm things start to even out but between 5-6000 there is a good 10-11rwhp difference. I'm going to swap out the MAC cats for some catcos in the future to see how bad those MAC cats really are, I dont think they are too bad though...

VINCE

iTrader: (1)

The cats are killing you.. I took my cats off and gained 20rwhp w/Mac Headers..

kp

iTrader: (34)

So if I took my cats off the Macs would make more power then the Hookers? cool

VTtransam

Thanks for the graph! I have the Mac headers with Mac cats also. I think some of the gap can be made up by taking off the cats. This makes me rethink wanting to get longtubes. Thanks for taking the time to do this.

Matt

FAST LS1

iTrader: (2)

Not to be picky, but they are on different cars and every car dyno's different. Were the cars of the same year? Also they have different cat-backs which I would assume the SLP is just a tiny bit more restrictive than yours, but you do have cats. Logically I just don't see how Mac's are every going to equal LT's, because in the end they are midlengths. Especially on a car that has a cam, I would think there would be a little bit bigger difference. That difference would only get bigger the more mods you do to improve flow. The price difference for Mac's is gone now that those pacesetter LT's have come out. To me that's the new bang for the buck header. I still like my Hooker's though since they have primaries that are a lot closer in length.

kp

iTrader: (34)

I dont think 10-14rwhp between MACs and LTs at 5-6000rpm is anything to sneeze at - the peak power may be close but thats about it. I have two 2002s here with the exact same mods that dyno within 3rwhp of each other, the 2000 has no EGR and an LS6 intake and the programming on all three cars is exactly the same (I know-I did it). They all have less then 10,000 miles on them also. I had the dual/dual on the 2000 and it dynod exactly the same as the magnaflow. You will see some error I'm sure but I run these cars a LOT on the dyno and you would be surprised how close they are - if they werent I would think something was wrong..

I dont cheerlead for anyone's headers (unless of course they want to donate three sets ) but I have always read how crappy the MAC cats are and they dont look too bad to me on a car with a small cam, that was my point. Things may change when all three cars get TEA stage 1.5s 5.3 heads next week, we'll see..

CHRISPY

My car works great with MACs (see sig) also I saw a superstroker dyno over 500RWHP through MACs with the MAC 2.5 inch ORY!

I am keeping mine, might weld on 3 inch collectors...

Cheers,
Chris

2MCHPWR

iTrader: (10)

very good info.
thank you.
i'm surprised you see the SLP dual dual dyno the same as the magnaflow. i thought magnaflow would be better.

and the difference in power between the two headers looks to be what i would expect. ~10 hp and ~10 tq
MAC's aren't too shabby.

NicD

iTrader: (7)

two different cars, each with different headers and cats/no cats. There can be no comparison between the two. Each is different.

Now if you do back to back dynos on the same car with the same exhaust configuration only changing the headers, then you can draw conclusions.

JS

iTrader: (4)

I've had 3 sets of headers.(MACS,DYNAS,HOOKERS)
IMO the best all around header is MAC.

Chris is TOTALLY correct.
I've seen many cars dyno BIG # threw Macs.

I was stupid for taking the Macs off my car.
I now have Hookers and they do make more power than my Macs but IMO the gain wasnt worth the hassle.

If u are on a budget,Get MACS!!!
Otherwise I'd opt for FLP's,They come w/wo cats and are a very nice headers,just a bit $$$..

kp

iTrader: (34)

Yup, then you would come on here and post 'well the car wasnt tuned for those headers so you cant draw any conclusions.' If you cant get three cars with the exact same mods and programming to dyno within 1-2% of each other then something is wrong. Its free info - take it for whats it worth.

mgreen

Hey, Kevin.

What kinda y-pipe was the car w/ the hookers running? The y-pipe that Hooker sells for $170 is kind of a POS when you see how the 2 pipes merge together.

I have the mufflex 3" to 4" w/ the flowmaster collector. Although I'm sure hooker's would flow just as well if it had the nice flowmaster 2 -> 1 collector.

Mike

NicD

iTrader: (7)

not really, once the car has a good tune on it, swapping headers is negligable.

Its called different tolerances and in general differences in motors. None are the same.

I do realize it's free info and I took it for what it's worth. I just put in my two cents.

kp

iTrader: (34)

Hey Mike,

They both have the hooker y-pipe, The collector isnt so hot on them but it doesnt look horrible. I wasnt trying to convince people MACs are better or as good as hookers - just it doesnt seem like the MAC cats are so bad. Only thing I really dont like about the hookers is they bang the k-member and body in quite a few places, other then that I'll probably put them on the 2000 in the future. I got the MACs from John so I thought I would use them on one car.

I'm putting TEA stage 1.5s on all three cars this week and we'll see what happens then

You guys need to take a ride down here one day and play around on the dyno, I'd like to see what your car puts down on our dyno, its only 600 miles

kp

iTrader: (34)

I never claimed it was perfect info or the gospel truth, but how often do you have 3 cars that have the exact same mods (except headers) and tuning in the same shop on the same dyno? Its a little better info then 'my budy just put hookers on his cars and picked 2mph over the macs at the track' IMO. If anyone doesnt see it as such doesnt bother me - i'm not selling anything here. Unfortunately I dont have the time to switch headers and catbacks right now just to see, but anyone can come down and do it if they want I will probably switch to long tubes/no cats after the heads on the 2000, but that wont be for few weeks..

mgreen

Well, I agree w/ ya that they all make pretty much the same HP. . .

My hooker collector on the driver's side used to make contact w/ the undercarriage. . . but I took a ~2 inch piece of heater hose, put a hose clamp through it, and then around the collector.

In addition to that I have a Engine brace on the pass. side which helps stiffen the engine up a little bit. No contact w/ the K-member ever though.

Anyways, yeah it'd be cool to take a ride down and dyno. . .I'm on a strict budget right now though since I'm unemployed.


later

kp

iTrader: (34)

Well unemployed = lots of extra time Wont cost nothing to dyno but the gas driving back and forth may offset that

I am going to have to do something with limiting engine/trans movement anyhow. Mt car with the 12 bolt + a 5500rpm clutch dump on ET streets bangs the MAC y-pipe and there is almost 4" of clearance on the LH side

VINCE

iTrader: (1)

Lets take my car for example.. I had T1 cam, Mac Headers w/OR PIPE, pulley, no cutout, ed tuning, no shortbelt, and lid.. I dyno'd 390rwhp/380rwtq in the summer. I never dyno'd my car in the winter.. I also had 3.42's.. I now have TEA Stage I heads with Futral Motorsports cam, 4.10 gears, dual cutouts coming off custom 3 inch Y-pipe, MAC headers, ported tb, still ed tuning from back then.. I dyno'd 421rwhp/390rwtq.. My best tq was 396, but that was with a smaller cam.. I've been through 5 cams.. Anyway, look at setups similar to mine with longtubes and see what heads they have. My #'s are right up there and sometimes higher. Also, I am still on a old tune.. I need ls1edit.. I do think I would pick up downlow with Longtubes, but peak will not increase w/out better tuning.. Macs are great. No doubt about it.. Raging Motorsports first car dyno'd 435rwhp with MACS and the B1 cam with their heads..

Bowtieman4life

iTrader: (1)

Only one person responded to my post. They got 23 hp from running a long tube header. That means that the mac headers are only good for 13 hp. That's not very much for such a big investment. I was hoping to get 30 + hp and torque from a header swap. Then I heard that 2000 and newer cars have better ezhaust manifolds and that the gains are even less. Has any seen serious gains from running headers.

GrannySShifting

iTrader: (10)

yes the car will run faster with headers period at least .15 more liek .2.3 in alot of cases