MACs vs Grotyohann headers... dyno results
11-25-2001, 10:45 PM
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MACs vs Grotyohann headers... dyno results I have seen a few posts recently wondering the power difference between MAC mid-lengths and the Grotyohann longtubes. I did this exact swap earlier this summer in anticipation of my future mods. At the time, I had the Lunati/B1 cam, 4:10s, and all the bolt ons. Only thing changed between the two dyno runs were the headers:
- Blue graph: Grotyohanns w/ 3" y-pipe and a Flowmaster 3.5" collector
- Red graph: MAC headers w/ 2.5" y-pipe and a 3" Flowmaster collector (primaries ported).
Was the swap worth the money? For me, it was. I knew I had much bigger things ahead. <img src="images/icons/grin.gif" border="0"> On a bolt on car w/ stock internals, there will be little to no gain going to long tubes. The MACs are well worth the money. However, if you do plan on heads/cam, longtubes would be money well spent.
Jason
[ November 25, 2001: Message edited by: Jason99T/A ]</p>
- Blue graph: Grotyohanns w/ 3" y-pipe and a Flowmaster 3.5" collector
- Red graph: MAC headers w/ 2.5" y-pipe and a 3" Flowmaster collector (primaries ported).
Was the swap worth the money? For me, it was. I knew I had much bigger things ahead. <img src="images/icons/grin.gif" border="0"> On a bolt on car w/ stock internals, there will be little to no gain going to long tubes. The MACs are well worth the money. However, if you do plan on heads/cam, longtubes would be money well spent.
Jason
[ November 25, 2001: Message edited by: Jason99T/A ]</p>
11-25-2001, 11:25 PM
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Re: MACs vs Grotyohann headers... dyno results Wow, even more great information! Thanks a bunch Jason! Keep up the good work. <img src="images/icons/smile.gif" border="0">
11-25-2001, 11:33 PM
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Re: MACs vs Grotyohann headers... dyno results Jason,
Looking at those two dyno runs, I don't know if there is a significant enough difference between the two of them to say with any certainty that the Grotts are better than the MACs. Two dyno runs on the same setup can vary around 5 RWHP easy.
I'm actually kind of surprised to see that the runs were that similar. Maybe the Grotts show a difference on the bigger cubed motors?? <img src="images/icons/confused.gif" border="0">
Looking at those two dyno runs, I don't know if there is a significant enough difference between the two of them to say with any certainty that the Grotts are better than the MACs. Two dyno runs on the same setup can vary around 5 RWHP easy.
I'm actually kind of surprised to see that the runs were that similar. Maybe the Grotts show a difference on the bigger cubed motors?? <img src="images/icons/confused.gif" border="0">
11-25-2001, 11:44 PM
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Re: MACs vs Grotyohann headers... dyno results Weather Guy: I totally agree with you. The MAC dyno run was made in MUCH cooler/dryer air than the Grot. dyno run. As much as the dynojet can correct, it still isn't going to be that accurate given the huge difference in conditions. For the Grot. to make more power given those conditions, I was pretty happy. I don't think they would have shown any gain at the track though with that setup.
Tony has a graph comparing the FLPs to the MACs on the same day when he still had heads/cam. He gained pretty much everywhere in the rpm band. This would be a more accurate comparison.
Jason
[ November 25, 2001: Message edited by: Jason99T/A ]</p>
Tony has a graph comparing the FLPs to the MACs on the same day when he still had heads/cam. He gained pretty much everywhere in the rpm band. This would be a more accurate comparison.
Jason
[ November 25, 2001: Message edited by: Jason99T/A ]</p>
11-26-2001, 04:04 AM
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Re: MACs vs Grotyohann headers... dyno results Jason99T/A,
What are the differences between the Grotyohanns & MAC headers with regards to the following:
1. Primary pipe bore diameters?
2. Primary branch lengths?
3. Ceramic coatings etc ?
We can't get these headers in Australia but am interested in finding out how the key dimensions affect the LS1 performance.
Many thanks
What are the differences between the Grotyohanns & MAC headers with regards to the following:
1. Primary pipe bore diameters?
2. Primary branch lengths?
3. Ceramic coatings etc ?
We can't get these headers in Australia but am interested in finding out how the key dimensions affect the LS1 performance.
Many thanks
11-26-2001, 09:11 AM
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Re: MACs vs Grotyohann headers... dyno results Another great post Jason! This is great info, and it will save a few guys the added expense of LT's if they're just going to stay with bolt-ons.
FWIW, I had the Macs on my 383 in my T/A, and I swapped out to the FLP's right after they came out. The gains were HUGE all across the board! I had swapped out to a very loose Vigilante 4000 converter that was costing me 38 RWHP locked vs. unlocked, but I still saw the huge gains. I showed an additional 10 RWHP at 7,000 RPM, but I had as much as 25+ RWHP and RWTQ in the mid-range. I gained over 40 RWTQ at various RPMs.
FWIW, I had the Macs on my 383 in my T/A, and I swapped out to the FLP's right after they came out. The gains were HUGE all across the board! I had swapped out to a very loose Vigilante 4000 converter that was costing me 38 RWHP locked vs. unlocked, but I still saw the huge gains. I showed an additional 10 RWHP at 7,000 RPM, but I had as much as 25+ RWHP and RWTQ in the mid-range. I gained over 40 RWTQ at various RPMs.
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11-26-2001, 09:17 AM
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Re: MACs vs Grotyohann headers... dyno results Question for you guys that did MAC vs Longtube dynos, did the MACs have those POS MAC cats or were both dyno runs off road pipes only?
I’m planning on MACs in the spring when I do a small Comp cam (212/218). With this tiny cam and stock heads/intake, do you really think I’d see much gain with LTs over MACs? I’m not going to use those God awful MAC cats though, I’ll get RT bullet cats welded in...
I’m planning on MACs in the spring when I do a small Comp cam (212/218). With this tiny cam and stock heads/intake, do you really think I’d see much gain with LTs over MACs? I’m not going to use those God awful MAC cats though, I’ll get RT bullet cats welded in...
11-26-2001, 10:05 AM
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Re: MACs vs Grotyohann headers... dyno results Just a small info bit for those who would like to buy Macs but think they don't perform on a heads & cam car.
I have Macs headers that I ported the snot welds. I also heard how bad the Mac cats are so I ordered the off road pipe and had 2 (2.5" C&L) cats welded in and I loped off the Mac collector and had a flow master collector welded in.
I any running a very mild cam (COMP 216/220) and I am still able to turn over 405 rwhp!
http://www.mindspring.com/~trehr/Dyno/cutoutopen.jpg
My macs cost $450 + $140 C&L cats + $39 FM collector + $50 install/welding = $679
Nice saving vs. the $1,300 FLP retail.
I'm sure I could pick up more HP & TQ with long tubes in various parts of the RPM range but for a $500 savings ... I'm still a happy 400+rwhp LS1 owner <img src="images/icons/grin.gif" border="0"> !
I would swap my Macs fo a set of coated long tubes anyday ... as long as I don't have to invest the extra $$
One last MAC + I have never had any rubbing/knocking or banging caused by my MAC headers or Y-pipe. I have 4 friends with the Macs and they have had no banging either. They also install from the top which I think is a BIG perk!
End...Mac sales pitch!
Todd Rehr XLRATE
405.8 rwhp / 384.6 rwtq
'99 30th Anniversary TA WS6 (#1118)- M6: MTI lid, K&N, FRA, Fernco Coupler, TB bypass, Ported and polished TB, LS6 Intake, Cooling Fan Switch, Mac Headers and custom Y pipe (C&L high flow cats and FM collector), McCord 2nd Gen Power Cutout, SLP underive Pulley, MORE stage 2 CNC heads (2.08/1.60) & Comp Cam (216/220 - 525/532) & top end kit, Ed Wright programming, MAFT, KnockOut Box, Line-Loc, Harlan Shift Light, Pro5.0, Star Stage 2 clutch, 4:10s, Boxed LCAs, Nitto DRs(on 17" 30th rims).
I have Macs headers that I ported the snot welds. I also heard how bad the Mac cats are so I ordered the off road pipe and had 2 (2.5" C&L) cats welded in and I loped off the Mac collector and had a flow master collector welded in.
I any running a very mild cam (COMP 216/220) and I am still able to turn over 405 rwhp!
http://www.mindspring.com/~trehr/Dyno/cutoutopen.jpg
My macs cost $450 + $140 C&L cats + $39 FM collector + $50 install/welding = $679
Nice saving vs. the $1,300 FLP retail.
I'm sure I could pick up more HP & TQ with long tubes in various parts of the RPM range but for a $500 savings ... I'm still a happy 400+rwhp LS1 owner <img src="images/icons/grin.gif" border="0"> !
I would swap my Macs fo a set of coated long tubes anyday ... as long as I don't have to invest the extra $$
One last MAC + I have never had any rubbing/knocking or banging caused by my MAC headers or Y-pipe. I have 4 friends with the Macs and they have had no banging either. They also install from the top which I think is a BIG perk!
End...Mac sales pitch!
Todd Rehr XLRATE
405.8 rwhp / 384.6 rwtq
'99 30th Anniversary TA WS6 (#1118)- M6: MTI lid, K&N, FRA, Fernco Coupler, TB bypass, Ported and polished TB, LS6 Intake, Cooling Fan Switch, Mac Headers and custom Y pipe (C&L high flow cats and FM collector), McCord 2nd Gen Power Cutout, SLP underive Pulley, MORE stage 2 CNC heads (2.08/1.60) & Comp Cam (216/220 - 525/532) & top end kit, Ed Wright programming, MAFT, KnockOut Box, Line-Loc, Harlan Shift Light, Pro5.0, Star Stage 2 clutch, 4:10s, Boxed LCAs, Nitto DRs(on 17" 30th rims).
11-26-2001, 10:10 AM
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Re: MACs vs Grotyohann headers... dyno results MACs are great with a little work. I ran 11.4@124mph through the full exhaust with the MAC's on the car and never had a problem with them. I dont think the 4-6RWHP difference you typically see is worth the price difference in my opinion. This winter I am going to pull the headers and change the collectors to three inchs and modify the Ypipe a bit as well. Might pick up a few horses in the 4500-6500 range. Right where I need the extra power <img src="images/icons/grin.gif" border="0">
Cheers,
Chris
Cheers,
Chris
11-26-2001, 10:11 AM
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Re: MACs vs Grotyohann headers... dyno results I had a set of Mac's and the MAC ORP. We ported the welds and I had the headers ceramic-coated. They are an excellent bang for the buck.
But a big motor was in my future so I bought a set of used TTS longtubes.
But a big motor was in my future so I bought a set of used TTS longtubes.
