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Discussion Starter · #1 ·
Well... I Took The Car To The Track Fri. Night And Didnt Do So Well ... 2 Weeks Prior I Ran On A Friends M/t Drag Radials 255/50/16 .. These Were Pretty Bald And I Spun Bad... I Cut A 1.77 60' And Went 11.88 @119 Mph .. So That Week I Added Bmr Lca's And Relocation Brakets And M/t 26-11.50-17 Et Streets .. I Couldn't For The Life Of Me Get The Car To Cut A Better 60' Than 1.89 .. I Lost 4 Tenths And 7 Mph ... All Of This Is Me Lauching At 4800 Rpm And Hooking Up Perfect... 12.10 @ 113!!! Is It My Clutch ???
 

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you went with larger and heavier tires--- track conditions and air temp. different than the earlier runs--- i was always taught to launch at a constant 3000 rpm, at 4800 rpm all i do is smoke tires
 

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What kind of burnout where you doing? How much air pressure in the tires? Since you are running a different set of tires, you now have to adjust your air pressure, burnout, and launch parameters till you find a happy medium again.
 

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Heavier tires can do it, but my concern is the et reduction.

Typically, you lose/gain 2 tenths in ET for every 1 tenth you gain/lose in 60'. The fact that you lost about a tenth in 60' but slowed down 4 tenth leads me to believe something else isn't right.

Even if the tires are a little bit heavier, relying on averages (again) you give up a tenth for every 100 pounds of additional weight. Even if the tires were 10 pounds more heavy per wheel (which would be a lot) that still doesn't explain two tenths.

I'd look at the clutch, maybe, but first I'd look at the suspension changes. It'll be free to look at it, and is more than likely to be the cause.

Check the pinion angle and make sure nothing is binding up.

I'm not completely convinced that aftermarket is always better than stock. (But that could just be me.)

I'm not sure what kind of power adder, if any, you're running but belt slip, inconsistent bottle pressure, etc... can also cause similar issues.

Now I'm just thinking "out loud." :)
 

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The ET Streets are a lighter tire vs. the DR (approx 6 lbs per tire), however they are slightly taller (26.5 vs 26.1). How much pressure were you running? Mine work best between 11-15psi.

I would say the lower MPH is more due to weather or something other than tires.
 

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Breaking ****
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wish i could race in February :( Usually lost mph is a slipping clutch, but if it's slipping bad enough, you'd smell it on the return road.
 

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Frustrating it could be my friend..been there, done that...But dont get anxious, u need to re-look over everything, especially the pinion angle of the control arms...Than recap as to what your air pressure was...since u went with a new tire u have 2 find that sweet spot again..Trial & error..It's also possible your clutch could be slipping as well,losing 4ths right off the bat,makes me believe it may..
Me personally I never liked throwing a ton of mods in the car @ once..I always liked 2 do some than goto the track & see where I am...Cause than ya never know what the gains/loss if any were..
I really hope u find the problem if any..Good luck
 

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Discussion Starter · #8 ·
The Car Has A Paxton 2200 .. Tires Were At 18 Psi. The Control Arms I Bought Arent Adjustable ... So Unless The Relocation Brackets Changed The Pinion Angle It Should Be The Same .. I Didnt Know If Me Dead Hooking Was Causing Ghe Car To Bog A Lil.. If Thats The Case Some 4;10's Might Be In Order .. And I Believe These Tires Weight Less .. I Also Used My Stock Pony Wheels On The Front Instead Of The Heavy 20's That Were On It When I Ran On The Dr's... Im Stumped ...it Was A Nice Cool Night Out And It Was The Day Before The Battle Of The Brands At Orlando Speed World So Track Conditions Were Great .. I Dont Think Traction Is The Issue
 

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The relocation brackets do change your pinion angle. You need an adjustable upper control arm to set the pinion angle correctly since your lower arms are non adjustable. I don't know about your loss in et but it may be you are hooking so well it's causing you to bogg slightly which slows down everything especially building boost on your Paxton.

Earl
 

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Discussion Starter · #10 ·
the Relocation Brackets Do Change Your Pinion Angle. You Need An Adjustable Upper Control Arm To Set The Pinion Angle Correctly Since Your Lower Arms Are Non Adjustable. I Don't Know About Your Loss In Et But It May Be You Are Hooking So Well It's Causing You To Bogg Slightly Which Slows Down Everything Especially Building Boost On Your Paxton.

Earl
Just Got Off The Phone With Dennis At Bmr And He Said The Brackets Do Not Mess With Pinion Angle...
 

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Did you just add several parts at once?

It may just be getting used to the combo again...

Im not saying your not driving the hell out of the car, may just need to drive the hell out of it a tad different w/ the new mods 'till you find the sweet spot.
 

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Discussion Starter · #13 ·
I Added The Relocation Brackets , Lca's And The Et Streets .. I Dunno Man .. I Watched A Video Of The A Pass I Mad E The Weekend Before And I Hopped The Car Out Of The Hole And It Fell On Its Face And Still Trapped At 118 Mph.. Hell I Have Missed 2nd Gear And Trapped 115-116 .. My Freind That Was With Me Has A Kenne Bell On His And He Had The Same Problem .. He Lost Like 7 Mph And 5 Tenths.. I Wonder If They Doin Something To Prepare For The Battle Of The Brands ??
 

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odd that both of you have same problem... I wouldnt do anything until you make another trip to the track; see if it was the track, learning curve, or... b/c if you change too much now... you'll really have a mystery on your hands.
 
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