When to go from 17” rear drag pack to 15”?

Joshinator99 · 09-19-2022, 07:28 PM

Hey fellas, so I’m having issues getting my car to hook even on 305/45/17 ET Street R tires, good burnouts, and launching in second gear. Stock converter, no less. I have a perfect alignment and a crap ton of BMR upgrades too. Plenty of weight over the rear tires… roll bar, full tank of fuel, and big ass ice tank out back. Running skinnies up front as well.

Don’t get me wrong, my 60’ times aren’t terrible (best of 1.47, average of 1.5/1.6), but they’re holding me back from getting into the low 9’s. And, my local track doesn’t exactly kill it on the track prep too. It’s a pretty low dollar operation. The people are nice, but if the track prep is anything like the bathroom maintenance….

So, I suppose this could be a track issue as much as an issue with my setup. Car trapped 148 last run out, so the power is there in my humble opinion.

So, am I at the point where I *need* to do a 15” conversion? Is that how you get down to 1.2 60’ times? Or is the suspension more important (coilovers)? I’m not sure how many 8 or low-9 second guys are on this board, but appreciate any advice or thoughts from the Forced Induction squad.

laynlo15 · 09-20-2022, 06:01 AM

When I had my Red Camaro I was having the same issues before I sold it. I had always wanted the 15" but just never wrote the check. Most of the real fast guys are running the 325-50-15 Street Rs. Maybe look at pulling a couple degrees of timing on the launch to help with the instant boost the PD blower creates. We did that at the Fest to try and calm the new Camaro down but never got a chance to try since it kept raining. I'll find out if it helped next month when we go back to the track. Give it a try.

laynlo15 · 09-20-2022, 06:07 AM

If your running E just pull it out of the Flex Fuel table to about 3000 rpm.

Joshinator99 · 09-20-2022, 07:39 AM

Quote:

Originally Posted by laynlo15

When I had my Red Camaro I was having the same issues before I sold it. I had always wanted the 15" but just never wrote the check. Most of the real fast guys are running the 325-50-15 Street Rs. Maybe look at pulling a couple degrees of timing on the launch to help with the instant boost the PD blower creates. We did that at the Fest to try and calm the new Camaro down but never got a chance to try since it kept raining. I'll find out if it helped next month when we go back to the track. Give it a try.

Quote:

Originally Posted by laynlo15

If your running E just pull it out of the Flex Fuel table to about 3000 rpm.

Good stuff Greg. Thank you!

I wonder what the top 10 guys are doing for suspension?

KingLT1 · 09-20-2022, 08:19 AM

I don't think the issue is 60ft alone. A 1.47 60ft with a 148 trap speed should be a 9.4-9.5 pass. Your missing 3 tenths somewhere after the launch and before the finish line. Are the tires breaking loose once you get out past the 60ft?

laynlo15 · 09-20-2022, 10:57 AM

Quote:

Originally Posted by KingLT1

I don't think the issue is 60ft alone. A 1.47 60ft with a 148 trap speed should be a 9.4-9.5 pass. Your missing 3 tenths somewhere after the launch and before the finish line. Are the tires breaking loose once you get out past the 60ft?

I think 146 is pretty good for a 9.65 so probably a combination as you said so its making some hay down track thru the traps. I think my highest mph was 148 on a 9.40 something pass where I spun the tires just a bit and sometimes when you do that your mph is higher. The guy I sold my car to went 9.33@149 on a really good DA evening in the low 60s, he was about 60 lbs lighter than me which accounts for some of the et and mph plus the good air.

laynlo15 · 09-20-2022, 11:02 AM

Quote:

Originally Posted by Joshinator99

Good stuff Greg. Thank you!

I wonder what the top 10 guys are doing for suspension?

Your welcome and I think most are running BMR since they have the best products.

Joshinator99 · 09-20-2022, 11:17 AM

Quote:

Originally Posted by laynlo15

Your welcome and I think most are running BMR since they have the best products.

I have BMR stuff out back already but was wondering more about springs/shocks?

Joshinator99 · 09-20-2022, 11:20 AM

Quote:

Originally Posted by KingLT1

I don't think the issue is 60ft alone. A 1.47 60ft with a 148 trap speed should be a 9.4-9.5 pass. Your missing 3 tenths somewhere after the launch and before the finish line. Are the tires breaking loose once you get out past the 60ft?

I think I’m going to have to dig into the datalogs a little deeper and have you take a look. Could be TM coming into play. My TCM tune is conservative for sure.

2018ZL1 · 09-20-2022, 01:00 PM

I am right around where you are on power and times. I just put a 3000 converter in mine and it roasts the tires launching in 2nd gear! The 15 inch conversion is on my list of things to do this winter. I also installed Menscer struts up front and rears but I havent had the time to TNT to get them dialed in! My tuner is in the 8's with his 6th gen and he has the Menscer rears and stock fronts, 1.27 60 ft times. Way more options for tires when you go to 15 inch as well!

Joshinator99 · 09-20-2022, 01:33 PM

Quote:

Originally Posted by 2018ZL1

I am right around where you are on power and times. I just put a 3000 converter in mine and it roasts the tires launching in 2nd gear! The 15 inch conversion is on my list of things to do this winter. I also installed Menscer struts up front and rears but I havent had the time to TNT to get them dialed in! My tuner is in the 8's with his 6th gen and he has the Menscer rears and stock fronts, 1.27 60 ft times. Way more options for tires when you go to 15 inch as well!

Great info! Probably time to break out the plastic once again.

ZL1Atlanta · 09-20-2022, 05:50 PM

I was doing pretty consistent low-1.3’s on 17’s at ~920 RWHP. I ended up doing 15’s more because it was already in the shop gettin more power than needing it at the time. After putting them on I didn’t see much improvement at 990 RWHP. That came after switching to launching in 2nd gear. The car has been a 1.20 60’ since then on stock mag ride and springs.

Joshinator99 · 09-20-2022, 06:09 PM

Quote:

Originally Posted by ZL1Atlanta

I was doing pretty consistent low-1.3’s on 17’s at ~920 RWHP. I ended up doing 15’s more because it was already in the shop gettin more power than needing it at the time. After putting them on I didn’t see much improvement at 990 RWHP. That came after switching to launching in 2nd gear. The car has been a 1.20 60’ since then on stock mag ride and springs.

So, what do you think my issue is? Can I ask what tire pressure you ran in your 17’s to get those 1.3’s?

2018ZL1 · 09-20-2022, 06:46 PM

Quote:

Originally Posted by ZL1Atlanta

I was doing pretty consistent low-1.3’s on 17’s at ~920 RWHP. I ended up doing 15’s more because it was already in the shop gettin more power than needing it at the time. After putting them on I didn’t see much improvement at 990 RWHP. That came after switching to launching in 2nd gear. The car has been a 1.20 60’ since then on stock mag ride and springs.

what kind of tires are you running on the rear with the 17 inch rim? If ya dont mind me asking!

09-19-2022, 07:28 PM	#1
Joshinator99 Drives: 2017 Camaro 2SS A8 Join Date: Aug 2018 Location: Petersham MA Posts: 4,740	When to go from 17” rear drag pack to 15”? Hey fellas, so I’m having issues getting my car to hook even on 305/45/17 ET Street R tires, good burnouts, and launching in second gear. Stock converter, no less. I have a perfect alignment and a crap ton of BMR upgrades too. Plenty of weight over the rear tires… roll bar, full tank of fuel, and big ass ice tank out back. Running skinnies up front as well. Don’t get me wrong, my 60’ times aren’t terrible (best of 1.47, average of 1.5/1.6), but they’re holding me back from getting into the low 9’s. And, my local track doesn’t exactly kill it on the track prep too. It’s a pretty low dollar operation. The people are nice, but if the track prep is anything like the bathroom maintenance…. So, I suppose this could be a track issue as much as an issue with my setup. Car trapped 148 last run out, so the power is there in my humble opinion. So, am I at the point where I need to do a 15” conversion? Is that how you get down to 1.2 60’ times? Or is the suspension more important (coilovers)? I’m not sure how many 8 or low-9 second guys are on this board, but appreciate any advice or thoughts from the Forced Induction squad. __________________ 2017 Chevy Camaro 2SS A8 Whipple 3.0, Mast Black Label heads, Fore triple in-tank pumps, 112mm TB, LPE +52% injectors, LPE BB HPFP, 15” conversion *1059 WHP/944 WTQ, 9.48@150*

09-20-2022, 06:01 AM	#2
laynlo15 Drives: 2022 Lt1 A10 Join Date: Nov 2015 Location: clark, mo Posts: 8,860	When I had my Red Camaro I was having the same issues before I sold it. I had always wanted the 15" but just never wrote the check. Most of the real fast guys are running the 325-50-15 Street Rs. Maybe look at pulling a couple degrees of timing on the launch to help with the instant boost the PD blower creates. We did that at the Fest to try and calm the new Camaro down but never got a chance to try since it kept raining. I'll find out if it helped next month when we go back to the track. Give it a try. __________________ 2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff

09-20-2022, 06:07 AM	#3
laynlo15 Drives: 2022 Lt1 A10 Join Date: Nov 2015 Location: clark, mo Posts: 8,860	If your running E just pull it out of the Flex Fuel table to about 3000 rpm. __________________ 2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff

09-20-2022, 08:19 AM	#5
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,793	I don't think the issue is 60ft alone. A 1.47 60ft with a 148 trap speed should be a 9.4-9.5 pass. Your missing 3 tenths somewhere after the launch and before the finish line. Are the tires breaking loose once you get out past the 60ft? __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

09-20-2022, 01:00 PM	#10
2018ZL1 Drives: 2018 ZL1 A10 NFG Join Date: Feb 2018 Location: Woodbine Md Posts: 652 View My Garage	I am right around where you are on power and times. I just put a 3000 converter in mine and it roasts the tires launching in 2nd gear! The 15 inch conversion is on my list of things to do this winter. I also installed Menscer struts up front and rears but I havent had the time to TNT to get them dialed in! My tuner is in the 8's with his 6th gen and he has the Menscer rears and stock fronts, 1.27 60 ft times. Way more options for tires when you go to 15 inch as well! __________________ 2018 ZL1-NFG-A10 New Iron L8T 9.32 147MPH

09-20-2022, 05:50 PM	#12
ZL1Atlanta Drives: 2017 Chevrolet Camaro ZL1 Join Date: Jul 2018 Location: Canton, GA Posts: 405	I was doing pretty consistent low-1.3’s on 17’s at ~920 RWHP. I ended up doing 15’s more because it was already in the shop gettin more power than needing it at the time. After putting them on I didn’t see much improvement at 990 RWHP. That came after switching to launching in 2nd gear. The car has been a 1.20 60’ since then on stock mag ride and springs. __________________ 2017 ZL1 - PB 8.05 @ 172 MPH @ 3730 lbs @ 70 DA (work in progress) Built by Vengeance Racing, tuned by Elite Tuned

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