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…. :faint: 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. :usa2:

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.

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

Good stuff Greg. Thank you! :happy0180:

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

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.

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?

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.

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. :smiling1: :bonk:

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.

:happy0180:

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?

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