275/50/15 killing 1/4 mph

[Onalky87]

M/t et streets....I have heard many people on here saying although they could get 1.60 60' with them they couldn't get more then 112-114mph outa them. Maybe Because there no taller then stock? Or does this make no sense? Bc I'm buying these tires probably and am hoping to trap 116-117 Mods on sig running 23#

[bison]

Originally Posted by Onalky87

M/t et streets....I have heard many people on here saying although they could get 1.60 60' with them they couldn't get more then 112-114mph outa them. Maybe Because there no taller then stock? Or does this make no sense? Bc I'm buying these tires probably and am hoping to trap 116-117 Mods on sig running 23#

With the vig locked you will easily trap 117mph

[Onalky87]

Even with those tires? And how do u go about locking the converter? And when do u do it? Half way threw 3rd I'm guessing.

FYI I plan on leaving on 7-9# on the trans brake Maybe 10# bc at 10 my vig stalls at 3000rpms exactly

[Onalky87]

Anyone?

[DailyDrifter]

If Bison said you'll trap 117................you'll trap 117 . Gnttype.org has directions for locking the converter.

[pacecarta]

i went 128 on my 255/50-16s and they are even shorter than those 275/50-15s, used OD with a AC 9" non lock converter, and 60s were 1.50s

on my 87 with a ta 49 went 116.99 with the same little tire not using OD , motor was stock unopened at the time , locked 10.5" converter

[Onalky87]

I can't find it on gnttype. Can someone post a link. Bc there's no button or anything for it as far as I no.

Bison, do u think with a 10# launch on the trans brake and lockin the converter on third 11.2@118-119 is out of the question? Or cud it happen

[pacecarta]

Switches

basically connect a switch to the F(top left) and A (top right) terminals of the ALDL connector under the radio pod

[Onalky87]

Thank u very much

[DailyDrifter]

Originally Posted by pacecarta

Switches

basically connect a switch to the F(top left) and A (top right) terminals of the ALDL connector under the radio pod

Oh you got to be kidding me I just spent 10 minutes looking for the damn link Switches. I got treed bad.

[UNGN]

If you are running 114 with 26" tall tires, you will go faster with 28" tires.

I went 118.3 in D with a stock, unopened long block, a TA49 and 275/60's and I'm not that good. Oh it was also done at a 1000 ft altitude, slippery track not one below sea level or prepped so good high 12 second cars pull the front wheels.

[WSLN 6]

Yep, back in the day when I was trapping 115mph, I switched to 275/60's and it went 118mph.

[Onalky87]

Originally Posted by WSLN 6

Yep, back in the day when I was trapping 115mph, I switched to 275/60's and it went 118mph.

But did your et drop also? Bc if the car will b faster I'll get 60s sense they will be on different wheels and only be on at the track

[UNGN]

My Et Dropped because I could leave with more boost than the 50's so my 60 fts were quicker, too.

On a perfectly prepped track, a 50 series tires should 60 ft quicker than a 60 series tire... but in the real world of the typical track prep on a street tire night, the 60's were much more resistant to blowing off than the 50's.

My best ET of running 50's for years was 11.92 @ 114. I switched to 60's and went 11.66@116 with really no other changes, eventually running 11.53@118.3 by swapping on skinny front tires.

[vacuum 6]

Best MPH with 275.50.15 was 119.96 with trap RPM ~5700. See sig below.

[Onalky87]

So you guys definatly think that an 11.2 at 118 is possible for my setup?

[UNGN]

Originally Posted by Onalky87

So you guys definatly think that an 11.2 at 118 is possible for my setup?

I ran 118.3 with a TA49 with a garrett housing, a Stock intercooler, stock D5 converter, 36lb injectors and a $20 Thrasher Chip on 23 psi of boost.

With 28" DR's, your set up should run over 120 mph.

[northerngn]

see sig
best mph with 275 50 15 was 106
now i run 275 60 15
seem to hook better too...8lb trans brake launch non lockjing converter(i think the extra sidewall height helps with the wrinkle action)
ill see if i can find the pic i took side by side the 275 60 is quite a bit taller 2 inches is huge
check back later ill see if i can find the pic
-dan

[Onalky87]

Thanx for all the info guys!!! And ya if u do find them pictures post them. I'd really like to see them

[JR'S1QUICK86]

What psi did u run in the 275 60-15

[UNGN]

Originally Posted by JR'S1QUICK86

What psi did u run in the 275 60-15

16 to 18 psi works fine at the track.

24 on the street.

[Amelio]

I have been deciding between the two sizes also....I just went to the track a few weeks ago for the time trying to work on my tune. I am running a 275/50/15 BFG DR and I was trapping 115 @18 psi I want to start going more boost but at the top of third I was hitting my rev limiter right at 5600rpm.

I think from what everyone is saying I need to go to the 275/60/15 and gain 2" taller to get the revs down.

[blacksix]

11.50@118 with 275/50 Mickeys, 1.65 short time. All I have is the OEM tach with a few missing lights, so I have no idea what she was revving. TC was locked, though.

[bison]

Originally Posted by Onalky87

Even with those tires? And how do u go about locking the converter? And when do u do it? Half way threw 3rd I'm guessing.

FYI I plan on leaving on 7-9# on the trans brake Maybe 10# bc at 10 my vig stalls at 3000rpms exactly

Id try to keep the engine rpm between 4500 and 5100. Use the online calculators to calculate your zero slip rpm in 3rd and just try to get it to drop to 4500 when its locked. You will probably be best locking at 103-105mph with those tires. Trapping higher than 117mph will be easy if the tune is good and the boost is up. Plan on high 20's for 119-120mph. Cam and heads would net a lot at this point. Your vig seems tight down low if its only 3000 at 10psi. Not the usual from what ive seen.

[bison]

Originally Posted by UNGN

On a perfectly prepped track, a 50 series tires should 60 ft quicker than a 60 series tire

Not if the car has the power to pull through the taller tire. Its a hell of a lot harder to get a better and consistent 60' on a 26" vs a 28". When building a car that has any appreciable power you would pick the tallest widest tire you can ge tin there and then gear the car for the quarter mile.

[Amelio]

Originally Posted by blacksix

11.50@118 with 275/50 Mickeys, 1.65 short time. All I have is the OEM tach with a few missing lights, so I have no idea what she was revving. TC was locked, though.

Well that is somewhat of an issue for me because I do not have a lock up converter. I was not able to watch the tach (on scan master) to well going down the track but every formula I plug gives me 5600rpm @115mph with a 26" tall tire. The only thing that makes sense to me is go to a 28" tire basicall the 275/60/15

[northerngn]

Originally Posted by JR'S1QUICK86

What psi did u run in the 275 60-15

i ran 18psi at the track
30 on the street
-dan

[Onalky87]

Originally Posted by bison

Your vig seems tight down low if its only 3000 at 10psi. Not the usual from what ive seen.

Is that a bad thing bison? I was told it's a 3200 stall

[bison]

Originally Posted by Onalky87

Is that a bad thing bison? I was told it's a 3200 stall

Its not a typical stator/ pump configuration found on TR's. A vig at 10 psi is usually over 4000. The converter isnt very efficient anyway so you will need to lock it to get any good mph.

[Onalky87]

So should I change it? Or run it a few times the way it is first? Also, what could be the negitives about that happening