Going for 12s w/bolt ons
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Joined: Aug 2003
Posts: 2,925
From: Detroit
I'm trying for bolt-on 12s too. I'm running 13.2 @101.74 with a 1.77 60 and the only mods I have are PS longtubes, 2.5 true duals/ with bullets dumped, Vig3200, 3.42s, Welds front and back, LCAs, and a Madztune. Its weighs 3680lbs with me in it and still has stock airbox.
I've read about a lot of guys running 12's with my set up, what's holding me back?
Sorry about the hijack. Figured the answer to my questions could help you as well.
I've read about a lot of guys running 12's with my set up, what's holding me back?
Sorry about the hijack. Figured the answer to my questions could help you as well.
12's were tough for a while with minimal mods, I was stuck @ 13.1 for a while... I had stock manifolds, gutted cat, cutout, and stock (2.73) gears. I got the gears and exhaust work done and was in the 12.6 range, then weight reduction, suspension, and tires got me to where I am now...
cool i dont think i made any of their events this summer, but im definitely around mt clemens and berrymores during the summer
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Joined: Aug 2003
Posts: 2,925
From: Detroit
Change the rockers and springs, it's not that much work. I already ran mine to a 107 trap (13.8 ET though... 2.5 60' 
) after that mod.
Or look into gears.... maybe consider 4.11s instead of 4.10s if you can find them! (37 ring gear teeth and 9 pinion gear teeth vs 41 ring gear teeth and 10 pinion gear teeth so they're stronger).
Randy's Ring & Pinion sells lots of different gears, I have Yukon (truck) gears, they're probably pretty effing strong
) after that mod.Or look into gears.... maybe consider 4.11s instead of 4.10s if you can find them! (37 ring gear teeth and 9 pinion gear teeth vs 41 ring gear teeth and 10 pinion gear teeth so they're stronger).
Randy's Ring & Pinion sells lots of different gears, I have Yukon (truck) gears, they're probably pretty effing strong
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Joined: Oct 1998
Posts: 3,144
From: Jackstandican
Jordon Musser's recipie for going 12's bolt-on with a '94 Z28 M6:
All engine bolt-on's
MAC shorty headers and Y-pipe including straight pipe.
Borla cat back
K&N CAI
Back seat cusions taken out
Passenger seat taken out
BFG DR's
Stock 3.42 gears
It's possible the serp. belt was removed for the run as well. Not absolutely positive on that.
I believe ran a best of 12.7 @109 at Texas Motorplex
Shawn97Z28M6
All the above except with SLP CAI and SLP shorties w/ Y-pipe and no cats going through SLP 2OTL. and ran a 12.8 @ 107
Both had stock rev. limiter and shifted at 5700rpm.
Whenever they lined up you could tell it was them from the last stall in the pits. You'd hear the engine rev to 5500rpm or a bit more and a bog when they let the clutch out. I believe they both were in at least the 1.9s 60' territory if not 1.8's.
All engine bolt-on's
MAC shorty headers and Y-pipe including straight pipe.
Borla cat back
K&N CAI
Back seat cusions taken out
Passenger seat taken out
BFG DR's
Stock 3.42 gears
It's possible the serp. belt was removed for the run as well. Not absolutely positive on that.
I believe ran a best of 12.7 @109 at Texas Motorplex
Shawn97Z28M6
All the above except with SLP CAI and SLP shorties w/ Y-pipe and no cats going through SLP 2OTL. and ran a 12.8 @ 107
Both had stock rev. limiter and shifted at 5700rpm.
Whenever they lined up you could tell it was them from the last stall in the pits. You'd hear the engine rev to 5500rpm or a bit more and a bog when they let the clutch out. I believe they both were in at least the 1.9s 60' territory if not 1.8's.
Last edited by SS RRR; Jan 2, 2008 at 03:46 AM.
Thread Starter
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Joined: Aug 2003
Posts: 2,925
From: Detroit
Ive been cutting 2.1s on street tires from only 2250 RPM... thats all the traction i could squeeze out of the street tires.
ahhhh, you said "(truck)' thats what got me.
Last edited by JoeliusZ28; Jan 2, 2008 at 11:53 AM.
Thread Starter
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Joined: Aug 2003
Posts: 2,925
From: Detroit
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Joined: Jul 2006
Posts: 309
From: Bartonville, Ill
Jordon Musser's recipie for going 12's bolt-on with a '94 Z28 M6:
All engine bolt-on's
MAC shorty headers and Y-pipe including straight pipe.
Borla cat back
K&N CAI
Back seat cusions taken out
Passenger seat taken out
BFG DR's
Stock 3.42 gears
It's possible the serp. belt was removed for the run as well. Not absolutely positive on that.
I believe ran a best of 12.7 @109 at Texas Motorplex
Shawn97Z28M6
All the above except with SLP CAI and SLP shorties w/ Y-pipe and no cats going through SLP 2OTL. and ran a 12.8 @ 107
Both had stock rev. limiter and shifted at 5700rpm.
Whenever they lined up you could tell it was them from the last stall in the pits. You'd hear the engine rev to 5500rpm or a bit more and a bog when they let the clutch out. I believe they both were in at least the 1.9s 60' territory if not 1.8's.
All engine bolt-on's
MAC shorty headers and Y-pipe including straight pipe.
Borla cat back
K&N CAI
Back seat cusions taken out
Passenger seat taken out
BFG DR's
Stock 3.42 gears
It's possible the serp. belt was removed for the run as well. Not absolutely positive on that.
I believe ran a best of 12.7 @109 at Texas Motorplex
Shawn97Z28M6
All the above except with SLP CAI and SLP shorties w/ Y-pipe and no cats going through SLP 2OTL. and ran a 12.8 @ 107
Both had stock rev. limiter and shifted at 5700rpm.
Whenever they lined up you could tell it was them from the last stall in the pits. You'd hear the engine rev to 5500rpm or a bit more and a bog when they let the clutch out. I believe they both were in at least the 1.9s 60' territory if not 1.8's.
Them are some good recipes for 12's there. I would also add to the fact that synthetic fluids thru-out would need(be helpful) to be added as I have done. However I don't have headers on yet and I'm about there.
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Joined: Oct 1998
Posts: 3,144
From: Jackstandican
Yeah they both had stock clutches which made it much easier on the drivetrain, but yes, for them in order to cut those kind of 60' time w/ stock gears high rpm launches were necessary.
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Joined: Mar 2004
Posts: 2,705
gears will hurt your mpg's anyone who thinks different is a fool. When i had 3.42's doing 80mph in 6th gear would tack 2k. With 3.73's doing 80mphs tachs 2300rpms. 4'10's would be 2500rpms at 80 mph. But they do help out the car a ton. i gained 2 mph and .2 in the quarter with 3.73's
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Joined: Oct 1998
Posts: 3,144
From: Jackstandican
If it does hurt mileage then it is minimal at best. One of the reasons why steeper gears hurt mpg in a short term way is because once people get them they love to keep their foot into the gas because the car "feels" faster, or they'll stab a cam into their engine which will not run optimally with a given cylinder head. Running higher rpm in an engine is not what hurts fuel economy. RPM vs. load along with VE is what is detrimental to fuel mileage.
Thread Starter
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Joined: Aug 2003
Posts: 2,925
From: Detroit
I guess there is the 2% possibility everything holds and the fronts come off the ground.
Thread Starter
Registered User
Joined: Aug 2003
Posts: 2,925
From: Detroit
gears will hurt your mpg's anyone who thinks different is a fool. When i had 3.42's doing 80mph in 6th gear would tack 2k. With 3.73's doing 80mphs tachs 2300rpms. 4'10's would be 2500rpms at 80 mph. But they do help out the car a ton. i gained 2 mph and .2 in the quarter with 3.73's
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Joined: Nov 2003
Posts: 1,756
From: West Linn, OR
gears will hurt your mpg's anyone who thinks different is a fool. When i had 3.42's doing 80mph in 6th gear would tack 2k. With 3.73's doing 80mphs tachs 2300rpms. 4'10's would be 2500rpms at 80 mph. But they do help out the car a ton. i gained 2 mph and .2 in the quarter with 3.73's
And, only a fool looks at half the picture...