swaped over to mn12 car is slower?!
swaped over to mn12 car is slower?! Okay here's the story my mm6 was starting to going in 3rd so I was going to rebuild it but changed my mind so bought a mm12.After installation took it for a drive obviously felt shorter geared like how 5th feels but meet up with the buddies and that's where it hit me.My car is a 99 w/z51 pckg. and 3.15 RE,LG intake and a c5 z modified exhaust and would pull 2 care on my buds I/E cts v, walk on base c5 and would hang with my cousins lq9 cam. bolt ons z28. So we are hanging out and leave to hooters and you know what happends when gear heads drive some where so I do rolls with the v and c5 and they pull me by 2 cars?? Wtf?? Now I've done like 100 rolls with the v and I know that the mm12 slowed me down can anyone explain why??
The LS6 made power higher in the RPM range than the LS1. In addition, to make up for the shorter gearing, the LS6 pulls 500 RPM more than the LS1. Seems now you should change over to the LS6 heads, intake and get either an LS6 cam or a 224R cam. Set your rev limiter to 6500 and you should have a 99 Z51 w/ an LS6 drivetrain. Personally, I would have stayed with the MN6 with a stock motor. But you're better off at least getting an LS6 cam at this point.
BTW, if you car has 3.15 gearing, you had an auto originally. So your gearing is going to be completely different. The 4L60E ratios worked well with the 3.15s. But at this point, you're going backwards. You'd be best off upgrading to 3.42s.
I think I have it figured out now the mn6 made my 3rd go to like 115 mph now it goes to 95 mph but in the gear ratios the 4th gear is the same gear from c5 and c5 z.So by adding more rpm to the gears will put me at higher mph from 3 to 4..so I guess its off to buy a cam 
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Joined: Jun 2011
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From: Fort Worth/Waco, TX
This sounds right.
The LS6 made power higher in the RPM range than the LS1. In addition, to make up for the shorter gearing, the LS6 pulls 500 RPM more than the LS1. Seems now you should change over to the LS6 heads, intake and get either an LS6 cam or a 224R cam. Set your rev limiter to 6500 and you should have a 99 Z51 w/ an LS6 drivetrain. Personally, I would have stayed with the MN6 with a stock motor. But you're better off at least getting an LS6 cam at this point.
BTW, if you car has 3.15 gearing, you had an auto originally. So your gearing is going to be completely different. The 4L60E ratios worked well with the 3.15s. But at this point, you're going backwards. You'd be best off upgrading to 3.42s.
The LS6 made power higher in the RPM range than the LS1. In addition, to make up for the shorter gearing, the LS6 pulls 500 RPM more than the LS1. Seems now you should change over to the LS6 heads, intake and get either an LS6 cam or a 224R cam. Set your rev limiter to 6500 and you should have a 99 Z51 w/ an LS6 drivetrain. Personally, I would have stayed with the MN6 with a stock motor. But you're better off at least getting an LS6 cam at this point.
BTW, if you car has 3.15 gearing, you had an auto originally. So your gearing is going to be completely different. The 4L60E ratios worked well with the 3.15s. But at this point, you're going backwards. You'd be best off upgrading to 3.42s.
But you are right Speedway White is the best. I love my SW Z06!!
I think Speedway White started in 01. (I could be wrong about that, though)
I'd LOVE to have either an FRC or another Z06 in white.
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Joined: Jun 2011
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From: Fort Worth/Waco, TX
And I second that I am actually on the prowl for another vette and I have my eyes set on a 01 SW Z06.
Thought he had two cars there for a second. Last edited by OneBadZ0Sick; Aug 27, 2011 at 06:10 PM.
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SCM_Crash hit the nail on the head before I could reply, regarding the ls6 powerband. You're blowing right through your powerband when you shift especially the 1st to 2nd and 2nd to 3rd gear changes. The M12 gears were exactly designed for the higher rpm capabilities of the z06 engine. OP, nice ride by the way.
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From: Ankeny, IA
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From: Ankeny, IA
If you are going to do that sort of swap, put in a moderate cam and an affordable stage one head from a vendor. You'll make a lot more power and be a lot happier.
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From: ATX
https://docs.google.com/spreadsheet/...US&pli=1#gid=0
Quick spreadsheet I threw together to compare the two. It should be close but not 100% on the money.
Probably the best setup would be 1-4 (well 4 doesn't matter) from the MN6 + 5/6 from the MN12.
Quick spreadsheet I threw together to compare the two. It should be close but not 100% on the money.
Probably the best setup would be 1-4 (well 4 doesn't matter) from the MN6 + 5/6 from the MN12.
I disagree completely. No way I would go through the hassle of a head/cam swap (and the requisite tune) for the small gains a stock LS6 cam/heads give. You can make more power with just a decent cam and headers on an LS1.
If you are going to do that sort of swap, put in a moderate cam and an affordable stage one head from a vendor. You'll make a lot more power and be a lot happier.
If you are going to do that sort of swap, put in a moderate cam and an affordable stage one head from a vendor. You'll make a lot more power and be a lot happier.
Also, keep in mind that with any cam-only setup, you're still going to have to pull the valve covers and replace the springs anyway. So add in the cost of springs. If you go with a LOT of lift, you'll have to fly-cut... So exactly how much power do you want to make without changing the heads?
What's easier and cheaper? LS6 kit. What's going to make more power? A big cam and headers. What's going to achieve his goals? Both. So why is this an argument?
3-4 gear change is a big drop on the mn12. It is the opposite of what you want for roll racing unless your race ends at the top of 3rd.
Spacing of the mn12's 1-2 and 2-3 are similar to the mn6, but since 4th gear is 1:1 on both trannys, the mn12 has the big 3-4 spacing to make up for the numerically larger 1st ,2nd and 3rd gears.
Spacing of the mn12's 1-2 and 2-3 are similar to the mn6, but since 4th gear is 1:1 on both trannys, the mn12 has the big 3-4 spacing to make up for the numerically larger 1st ,2nd and 3rd gears.
If you have a cam that pulls good up top (5000-6500 rpm) I'd say the M12 would be better for a street car. The 2nd to 3rd shift on the M12 is much better than the m6, and on the street this is where most races take place (2nd and 3rd). I don't think I'd run much past 100 anyway. Too much traffic where I live and I'm too old to get crazy on public roads.
The 2nd to 3rd shift on the M12 is much better than the m6, and on the street this is where most races take place (2nd and 3rd).
Sorry to interject some reality here but both the M6 and the M12 ratios are built around 4th gear which as has been pointed out it 1:1. On the M12 the ratios are closer together by having 1st gear taller and 6th gear lower. The ratios on the M12 tranny are closer together than the M6. If you are slower with the M12 - chalk it up to the time spent shifting more often or having a taller 1st gear.
The ratios on the M12 tranny are closer together than the M6. If you are slower with the M12 - chalk it up to the time spent shifting more often or having a taller 1st gear.
