Blk_Ws6

iTrader: (4)

Just wondering if I get mac mid tubes with high flow cats how much will I pick up car supporting modes will be - 224 cam,undpulley,ls6 intake,ls6heads
Wanted to know because I hear mac midtubes don't rub so any Ideas fellas?

RyderTA

iTrader: (3)

I used to have mac mids, they make nearly identical power as most longtubes but LT's make more torque throughout the rpm's. They do have better ground clearance though.

Blk_Ws6

iTrader: (4)

Where they quiet?

Hennytime

iTrader: (33)

similar peak numbers but lessw under the curve, not much more that a 1mph at the track trapping

1989GTA

This is a topic I have been wanting to discuss for awhile. That being long tubes versus the shorter length headers. I have seen quite a few posts saying not to use the shorter length headers as they are not worth the small gain. Maybe this pertains to the LSx style motors with their somewhat better exhaust pipes versus what has come on the small block Chevy in the past.

From what I have seen the shorter length headers do not seem to have the same attention paid to the collector area. The longer tube headers seem in general to have a better collector or merge.

In my opinion if the headers where built of the same quality and construction I think the outcomes might be a little different. Joe Sherman posted on another board about all the header tests that have been done on his dyno over the years. He stated from what he has seen the long tube headers will have the advantage below 3500rpm. By the time the rpm gets to around 5000 it becomes pretty even.

From this statement it would appear the only advantage would be in the lower rpms. By the way I asked Larry Meaux the same question. He did not think the short tube headers would be giving up much if properly built. Just some thoughts to ponder.

MattIROC

iTrader: (19)

I made 375/364 with mac mid's through a 6spd and 4.10's with a 232/234 cam, stock ls1 intake, stock 853 heads. They are good if you dont want to go the LT route, and if you need better clearance.

want297z

iTrader: (7)

My auto car with a 383, 238/240 cam, PRC heads, LS6 intake and the mac midlength headers made 440/430 at the wheels. Could I pick up more with the LT's probably, but won't know until I buy them and who knows when that will be.

MonmouthCtyLS7

iTrader: (6)

Like the others have said alot of guys have been pissed when finding out how little they gained after switching to LT's. Plus they have plenty of ground clearance, mine are fairly quiet...though I have a quiet muffler. Well see once I throw a LM on in a few weeks.

dug

iTrader: (10)

I made the numbers in sig with macs. That was without a ported throttle body, underdrive pulley, and untuned.

I prefer longtubes for the sound of the 3"ypipe

RyderTA

iTrader: (3)

They were fairly noisey, just depends on the rest of the exhaust and the muffler. I had a flowmaster and it was noisey but with my Magnaflow it was more tame and sounded better. One thing that always annoyed me was the rasp and that went away when I got my Pacesetters, LTs have a much better tone.

cainsw

iTrader: (11)

I bought a set of MAC's for my 98 when they first come out. I had to wait 4 months on those things to show up! I put them on my bolt on M6 Z28 with 4.10's, MAC catback, PMAF and cutout. Dyno before 311rwhp and 326rwtq, after 343rwhp and 359rwtq. Put a Comp Cams 222/222 566/566 112 (done no tuning and no other mods) and dynoed 371rwhp and 389rwtq. I've installed MAC's on 4-5 other LS cars and they all picked up 25-30 whp. I still have them on my 99. We swapped a set of MAC's for a set of Hooker LT's and picked up nothing at the track. Can't really say they didn't make more power somewhere as we never dynoed after the swap though.

Blk_Ws6

iTrader: (4)

Mac's it is that's all I needed to hear I'am using a 218 224 550 550 116 cam undrplly ls6 heads what you guys think I ll make from this pkg?

allforspeed

iTrader: (1)

hey man, what did your car dyno with the ls6 heads/cam/pulley as it is? any track times?

what kind of clutch do you run and did you upgrade the fuel injectors too?

would be REALLY interested to know

please do before and after dyno's too, everyone here will be waiting.

anyone able to find any good dyno sheets of before and after or of mid length vs. LT headers? i can't find any on the dyno section.

i've also been thinking about these, since i live in san francisco and long tubes would scrape on all the hills and if i get a vette soon, i will face the same decision

cheers,

cainsw

iTrader: (11)

I don't have any dyno sheets comparing the two but we do have 3 LS bracket cars that are very consistent, raced every weekend and the two that had MAC's and swapped to LT's there is no difference at all in ET or MPH.

1989GTA

"raced every weekend and the two that had MAC's and swapped to LT's there is no difference at all in ET or MPH."

That would make sense from what I have learned. In the rpm operating range you would be working in there probably would not be much difference in the power output. At the track with a stalled converter you would almost instantly be out of the rpm range where the long tubes would have a advantage for those running an auto trans. Wouldn't be there long either with a manual trans.

TORCHD 02 TA

iTrader: (39)

You will gain very little of stock manifolds. Why go thru the same hassel doing mid lentgths when you're already there... Do the LTs and call it a day

allforspeed

iTrader: (1)

the guys here are making the point that gains from mid lenghts are nearly the same above 3000 rpm, which is fine for me. i've always thought about putting ported C5 z06 exhaust manifolds on my car. LT will just not work in the city i live, i know i would break them bottoming out on something, so i'd be happy to give up 10 lb of torque in the low end as long as the top end 3500+ rpm was nearly the same as long tubes. ported C5 z06 exhaust manifolds would be cheap and sleeper too, heck, the z06's make 400hp easy with those and were built by engineers, if LT headers made a ton more power you think they would have built something similar on such a high dollar car

also i could probably swing mid length headers past the smog ***** here, LT would be a problem though

i would really like to see a dyno comparison of mid lenghts compared to LT headers.

does the 500hp C6 z06 have a long tubular header?
does the C6 z06 with 500hp have a long tub

99_Z28

iTrader: (3)

If you can get a good deal on them like I did go for it...I only paid $175 for the modified headers (3 bolt collector vs 2 bolt ball) and ory with a flowmaster merge...there might be only a 5hp difference from long tubes with those mods.

allforspeed

iTrader: (1)

i just searched "mac" on the dyno forum and found all sorts of answers. the higher you go up in power the more the long tubes are worth vs. MAC's. one guy gained nearly 20hp going from MAC's to a really high quality long tube at the 450rwhp level.

gectek

iTrader: (2)

Is it just me or does this not make sense. Dont you want the bracket cars to stay the same et? ON bracket, its not heads up so you arent racing for a top et/mph you are racing against yourself/consistency.

The Macs will give you a gain, what that will be and if you will be happy with it is another story. I really like the mids. Not alot of hassle. Its not like the gain from the LTs to the mids will be astronomical, and if you already thought this you would not have started the post in the first place.

IMHO for the price and gains i would go with mids, esp in your situation. There are just some people on here that wont trust anything but long tubes and you cannot get them to change their mind. Everything has its place and time.