jmilz28

iTrader: (13)

Ok guys, lots of talking and curiosity on this one:
https://ls1tech.com/forums/showthrea...=889284&page=3

I actually did what everyone was saying was a bad idea, read that thread if you want to know. Everyone said I would lose torque/low end going to the big boys --- WRONG. I lost nothing and bought the last headers I will ever need.

The mods are identical EXCEPT when I dyno'd the car with the ARH headers, I had added heavy *** 17x11 ZR1 OE concepts with 315 rears, which cost power and torque. Both were tuned by Steven at LMR for the setups.

DYNO1 - Mods in sig + MACS + ORY + 17x9.5 rears - 342rwhp/355rwtq
DYNO2 - Mods in sig + ARH 1 7/8 + CATTED Y + 17x11 rears - 344rwhp/355rwtq

To sum up - with the big headers, I lost no torque and picked up 2 ponies even though I added cats AND heavy wheels. That tells me the actual gain was more but offset by the wheels. And this was over MACs with an ORY, a proven power and torque maker on mild setups.

Maybe the 1 3/4 would have been even a little better but I STILL gained everywhere AND have room to grow to big cubes.

DYNOS below:

RyderTA

iTrader: (3)

Very interesting, I currently have macs and i've been thinking it's time to upgrade. Thanks for a interesting thread!

themack56

iTrader: (70)

i was the one that started that thread, and i still havent decide if i was to go with 3/4 or 7/8, this will help me out though thnx

jmilz28

iTrader: (13)

Glad to help fellas!

MikeG

iTrader: (33)

Hmm, the numbers would be alot more meaningful if they were from the same dyno before/after the install within a day or two. Results are still good nevertheless though.

ChocoTaco369

That's really not impressive at all IMO. You went from Mac mids to longtubes and gained virtually nothing at all. Basically, your LONGTUBES did no better than a MID-LENGTH. I think you would have gained a lot more going with a longtube.

I bet if you went with 1 3/4 QTP's, you would have gained an easy 10rwhp all over the entire curve. I've seen 1 3/4 QTP's make 10rwhp over Pacesetters, and Pacesetters will outperform Macs.

The numbers you have are very disappointing IMO, and since it wasn't even a dyno on the same day, they're virtually meaningless. I wouldn't be happy if I spent $1500 on no gain. You could have spent a lot less money and gotten a much bigger gain.

Sorry for being a buzzkill, but this is where internet legends are born and these are the threads that will cause people to make bad decisions. You went from a midlength header with a y-pipe with a terrible merge to a longtube with high velocity merge collectors and a good merge in the y-pipe and gained nothing. This thread is proof that 1 7/8 headers are a bad decision on a 346 because even with better collectors and a much better y-pipe, they can't outperform mids. Again, not trying to hurt your feelings, but I don't want to see a bunch of people buying the wrong product for their car. I feel you made the wrong decision here, at least for the short term. Unless you want to go FI on a stroker, I can't justify the cost of 1 7/8 headers, not when they can't outperform an outdated midlength header with a junk y-pipe. I think this thread is proof of what Tony Mamo had to say in the last thread.

JS

iTrader: (4)

I agree w/Taco,HF cats are worth 5RW max over ORY's so what did u really gain
A few HP for 1500,u got hosed.....

I had Macs,I cleaned them up alittle bit with a wizzer,added a FM merge to the Ory.They made 15RW MORE than Stepped Dynatechs,U can imagine I was pissed.I sold the Dyna's
to a guy with a 427 and had already sold my Macs.I ended up w/Hooker 1 3/4 LT's and they worked well and the car trapped 121 over the Macs 118...


Sorry bud but u got the shaft...
U shoudlve went 1 3/4 LT's

Hardtop

iTrader: (3)

Only problem is he would have to drive with the windows open because of the collector leaks.

RyderTA

iTrader: (3)

Just one thing fellas, it's still a basically stock motor so gains may increase greatly with mods. Just throwing that out there.

ChocoTaco369

No leaks here. Collectors are welded perfectly. If you didn't check the welds over before you install them, that's on you. In 3 or 4 years of QTP's history, there have been what, 3 threads about leaking collectors out of thousands sold?
But still not as much as 1 3/4's. The 1 7/8 headers push the torque curve up too high. You're not going to be able to rev high enough to make use of the extra airflow. We don't have S2000's here, we have cars that redline at 6,000 rpms. The point of the V8 motor is torque throughout the powerband. Why you'd want to kill your torque curve with headers far too big for the application is beyond me.

MikeG

iTrader: (33)

342 hp w/ MACs on Fastlane dyno...

331 hp w/ MACs on HPE dyno...

344 hp w/ ARs on HPE dyno...

wonder what the AR power would be on the Fastlane dyno? The way I see it the TS gained 13 hp going to the ARs.

01MMMZ28

I had some macs w/ a mac catted y pipe and a SLP LM1 catback. I switched to Pacesetter LT's and TSP true duels and picked up some. I picked up 15 rwhp and 14 rwtq.

98Z28CobraKiller

iTrader: (17)

I could be wrong but that isnt how I read those dyno sheets. I thought that the one dyno sheet is the mac's, before and after tuning and then the other is the ARH's before and after tuning.

Please clearify Jimilz28.

As far as whether or not he wasted money, there's to ways to look at that. If he has no intentions of making significantly more power (500 rwhp+), then these headers were a waste of money. If he does intend on getting to these numbers, then he will indeed grow into them.

jmilz28

iTrader: (13)

Cobrakiller, you are correct:
dyno1 is the MACs + ORY + 17x9.5 rears - untuned, then tuned
dyno2 is the ARH 1 7/8 + catted Y + 17x11 rears - untuned, then tuned
All other mods are the same. Yes they are different dynos but they tend to run consistent. Additionally, that variable could make the numbers go either way, so it's just as likely that I picked up MORE than what it shows.

If one understands that the cats and heavy *** rears cost a few ponies, it becomes clear that, at the flywheel I picked up a few HP and torque. Whether the delta is 2, 5, or 15 - it's a gain.

My only goal was not to lose anything and prepare for big power. (Win) If you look at my mods, everything I have done is preparing the car to handle power and have good control over the car. So this mod does that too (Win #2). Finally, I actually picked up a few and didn't lose any HP or torque anywhere. (Win #3) If you look carefully at the graphs and map the points vs RPM, you will see the torque curve did not change.

Yes, it was a good bit of coin but it's what I was after. I wanted:
1. A platform to grow
2. Not to lose any HP or torque
3. Quieter
4. Deeper
5. Less smelly
6. And MAYBE pick up some ponies
7. A quality, reliable system

7 goals achieved, I call that a win. Some people are too thick to get that.

So this is not 100% conclusive, nor was it intended to be. It IS INDICATIVE that, done properly and tuned, these LS engines like to breathe and going big on headers does not hurt at all. It may not be optimal (as some say 1 3/4 are) but my scenario didn't address that, nor was that my intention from the start. Cost was not much of a concern here as I wish I had done it right the first time.

I hope this helps some people consider another option in an educated fashion.

Bad thing is, now I'm kind of stuck. From here, all I can do is add power - so it's time to decide - go into the engine or just spray it and save for an engine!

CHRISPY

The MAC midlength with ORY is a good header, doesn't leak and the ground clearance is great.

Guys have dynoed 500RWHP plus through them...(I dynoed 475 with them)

I think they're a great choice especially for lowered cars...too bad they aren't stainless...

The AR's are a great header too but $$$$ They should last forever though!

radz282003

iTrader: (1)

I had a set of MACs, and with a crappy custom canned tune, put down 334 RWHP. On the same dyno, with standard QTPs and a custom dyno' tune, put down 354. With their HVMCs, custom dyno' tune, and put down 366 on the same dyno'. I'm not spouting about QTP or anything like that, but I think going to the LTs are definately a benefit, and I think it was a great idea for you to have gone as big as you did with the forthought to be able to have a set you wouldn't have to change again as your mods' grew.

Nice job

Firehawk441

iTrader: (41)

Nice gains.

SOMbitch

iTrader: (8)

Blah blah blah blay blah blah blah blah You are so predictable Everybody on here is tired of your on QTP.I had a pair and the QC (welds) sucked so I got rid rid of them before I put them on. You take that risk with Chinese ****. Why dont you and go to LS1.com and hangout with the rest of the teenagers

JCCamaro

+2, your write up is very one sided Choco, you talk as if hes never going to mod his car again

Redlinez

iTrader: (5)

His always have been. I see that you did make gains. You should have dyno'd with your old wheels though, shoulda, woulda, coulda is commonplace around the net. You bought just about the best out there, I think 1 7/8'ths has proven not as good as the 1 3/4 on 346 cubes. Now you just need a cam and gears to have some real fun!